STUDIES ON VARIOUS TREATMENT CONDITIONS AFFECTING UREA-AMMONIATED RICE STRAW IN GHANA BY BERNICE SEFAKOR QUASHIE A thesis submitted in p a rtia l fu lfilm en t o f the requirements fo r the Degree o f Master o f Philosophy Department o f Animal Science University o f Ghana Legon; Ghana, June 1992 University of Ghana http://ugspace.ug.edu.gh uTABIiE OF CONTENTS ‘ PAGE TITLE PAGE •«• ••• • .» • • • ••■ i • TABLE OF CONTENTS . . . i i - DEDICATION . . . . . . . . . . . . . . . V • DECLARATION . . . v ii ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . VH* ABSTRACT . . . . . . . . . . . . . . . IX. LIST OF TABLES . . . . . . . . . . . . . . . X I. LIST OF FIGURES . . . . . . . . . . . . . . . .Xlii * CHAPTER 1: INTRODUCTION ........................................... 1 CHAPTER 2: LITERATURE REVIEW 4 2.1 Introduction . . . . . . . . . . . . 4 2.2 Nature and Quality o f Ava ilab le Feed Resources 4 2.2.1 Crop Residues and Agro Industria l By-Products 4 2.2.2 Constraints to the optimum u t i l iz a t io n o f crop residues in Ghana . . . . . . 6 2.3 Poten tia l Feed Value o f Crop Residues 6 2.3.1 Intake o f Crop Residues . . . . . . 6 2.3.2 Factors a ffe c t in g intake and u t i l iz a t io n o f straw and other low qua lity roughages by ruminants . . . . . . . . . . . . 8 2.3.3 Chemical composition o f r ice straw . . . 9 2.3.4 M icrobial Degradation o f fib re in the Rumen 15 2.4 Improvement o f Nu tritive Value o f Crop Residues 16 2.4.1 Introduction . . . . . . . . . . . . 16 2.4.2 Physical Treatment . . . . . . . . . 17 2.4.3 Chemical Treatment . . . . . . . . . 18 2.4.4 Use o f Sodium Hydroxide . . . . . . 19 2.4.5 Use o f caustic ash o f some crop residues 19 2.4.6 Use o f Ammonia . . . . . . . . . 20 2.5 Urea Treatment . . . . . . . . . 20 2.5.1 Factors influencing the e f fe c t o f urea treatment . . . . . . . . . . . . 21 I j 2.5.2 E ffec t o f urea ammoniation on feeding value o f straw and on animal performance . . . 24 2.5.3 Supplementation . . . . . . . . . 26 University of Ghana http://ugspace.ug.edu.gh IH 3.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.3 ' 3.4 3.5 4 4.0 4.1 4.2 4.3 4.4 CHAPTER 5: 5.0 5.1 5.2 5.3 5.4 CHAPTER 6 : 6.0 CHAPTER 3: EXPERIMENT 1 ............................................ 3.0 T it le : Determination o f optimum urea concentration, moisture le v e l and treatment time fo r urea ammoniation of r ic e straw in Ghana Introduction Materials and Methods Location o f experiments Experimental Design Ensiling Process Chemical Analysis In V itro D ig e s t ib il ity Results Discussion Conclusion EXPERIMENT 2 T it le : E ffe c t o f type o f s i lo on the nu tritive value o f urea ammoniated r ic e straw Introduction Materials and Methods Results Discussion . . . EXPERIMENT 3 T it le : E ffe c t o f urea ammoniation on the degradation o f r ice straw incubated in nylon bags Introduction Materials and Methods Results Discussion EXPERIMENT 4 T it le : The po ten tia l o f urea-ammoniated r ice straw fo r dry season feeding o f sheep in Ghana 1 6.1 Introduction . . . . . . . . . . . . 6.2 Materials and Methods . . . . . . 29 29 29 29 29 30 30 30 31 32 40 42 43 43 43 43 44 45 46 46 46 46 48 49 51 51 51 52 University of Ghana http://ugspace.ug.edu.gh IV 6.2.1 Animals and Management . . . . . . 52 6.2.2 D iets . . . . . . • . . . 52 6.2.3 Experimental Design and Feeding . . . 53 6.2.4 Chemical Analysis . . . . . . . . . 53 6.2.5 S ta t is t ic a l Analysis . . . . . . . . . 54 6.3 Results . . . . . . . . . . . . 54 6.4 Discussion . . . . . . . . . . . . 57 CHAPTER 7: GENERAL DISCUSSION ................................ 58 8 CONCLUSIONS ............................................. 60 REFERENCES . . . . . . . . . . . . . . . . . . 61 APPENDICES ................. I . . . 69 University of Ghana http://ugspace.ug.edu.gh VD E D I C A T I O N This work is dedicated to my husband, Peter and my son Sesi. University of Ghana http://ugspace.ug.edu.gh VI D E C L A R A T I O N This d isserta tion is the resu lt o f my own research work and i t contains no material which has been accepted as part o f the requirements fo r any degree in any University or any material previously published or w ritten . References c ited have, ho'wever, been fu l ly acknowledged. Bernice Sefakor Quarshie (STUDENT) Assoku Animal Science Department Legon Dr. F. Fianu (CO-SUPERVISOR) Dr. K. Amaning-Kwarteng (SUPERVISOR) University of Ghana http://ugspace.ug.edu.gh V I I ACKNOWLEDGEMENTS I am sincere ly g ra te fu l to Rev. Dr. K o fi Amaning-Kwarteng, Dr. J.E. F leischer and Dr. F. Fianu, my supervisor and co-supervisors respec tive ly fo r th e ir never fa i l in g support, unlimited guidance and encouragement, constructive cr it ic ism s and immense assistance in the course o f th is study. My deep appreciation and sincere thanks are extended to the fo llow ing fo r the immense help and spec ia l in te res t they showed during th is p ro jec t. Dr. E.A. Canocoo, Dr. B. Awumbila, Miss G. Aboagye, Professor R.K.G. Assoku, Dr. G.E.S. W illiams and Mr. & Mrs. K. O ffe i. I wish to acknowledge my indebtedness to : Mr. Kwartey Quartey and Mr. David Mensah fo r th e ir s k ille d , resourceftil and patient management o f experimental animalsj Mr. Abubakari Yakubu fo r valuable and excellen t technical assistance; Mr. Kwarteng and Mr. T. Amedzekey fo r valuable assistance in s ta t is t ic a l analysis, Mr'. 0. Debrah, Mr. S.K. Ottoo, Mr. Enoch Laryea, Mr. Kwei Mensah and Mr. Josef Grinner fo r th e ir h e lp fu l assistance at the Agricu ltu ra l Research Station , Legon. I am also g ra te fu l to Mr. Maxwell Odonkor, Mr. E.T. Obodai and Mrs. Lynda Anyomi. Without th e ir assistance th is wark would have been more d i f f ic u l t . j I am grea tly indebted to Mrs. Faustina Korsah fo r assis tin g in typing and prin ting out the thes is . My sincere thanks and appreciation !are extended to my colleagues Messrs G. Banini, E. Otu, Tackie, Seth Akah, A. Tei-Munu and Boateng fo r th e ir useful and valuable discussions, company at a l l times. University of Ghana http://ugspace.ug.edu.gh I would l ik e to express my deep appreciation , sincere gratitude and unlimited indebtedness to my husband Peter lamakloe, my s is te rs Sika, Cherie and Aimee, my brother Andy and my parents fo r th e ir understanding, encouragement, patience aivl peaycsr gupperb ilurliia tlu? uoueso uf th is auuily. F in a lly , I ascribe to the Lord Jesus the g lo ry , honour, and praise due His Name. Without His enablement, i t would have been impossible to begin and complete th is study. University of Ghana http://ugspace.ug.edu.gh IX, A B S T R A C T Four experiments were undertaken to evaluate the e f fe c t o f various treatment conditions on the nu tr itive value o f urea-ammoniated r ic e straw. Experiment 1 was carried out to determine the optimum condtions necessary fo r ammoniating r ic e straw with urea. The factors investigated included urea concentration (3 .5 , 4.0, 6.5 and 8.0% W/w), treatment period (7 , 14 and 21 days) and moisture le v e l (40, 50 and 60%), in a 4 x 3 x 3 fa c to r ia l experiment. Samples were analysed fo r t o ta l N itrogen content, neutral detergent f ib r e (NDF), acid detergent f ib r e (ADF) and in v it r o organic matter d ig e s t ib i l i t y (IVOMD). Results showed that the optimum urea concentration, treatment period and moisture le v e l ware 6.5%, 21 days and 40% resp ec tive ly . In Experiment 2, the optimum conditions obtained in Experiment 1 were used to trea t r ic e straw which was then stored in d if fe ren t types o f s i lo (earthern p it , cane basket and cement cu lvert) to determine the best s ilo to use. The earthern p it was found to be the best among the s ilo s with i t s contents having a N content o f 1.75% and IVOMD 52.65. Straw from the basket and cu lvert had 1.55% and 1.10% N and 50.03 and t 48.21 IVOMD respective ly . The in s itu rate o f ruminal dry matter (DM) I , disappearance (DMD) (3-72h) and extent o f DM disappearance (72h) investigated in Experiment 3 indicated that urea University of Ghana http://ugspace.ug.edu.gh Xammoniated straw was more fermentable In the rumen o f sheep compared with untreated r ic e straw. The rate and extent o f DMD was found to be 0.48%/hr and 44.64% fo r untreated r ic e straw and 0.74%/hr and 58.97% fo r ammoniated r ice straw. Urea treatment s ig n if ic a n t ly increased straw intake but did not prevent sheep freight loss in Experiment 4. Straw ensiled with urea fo r 21d and fed to sheep with l i t t l e supplementation can supply maintenance needs o f ruminants during the dry season. University of Ghana http://ugspace.ug.edu.gh Table 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 3.1 3.2 3.3 3.4 * 4.1 5.1 5.2 *1 LIST OF TABLES Page Some nu tr itiona lly important crop residues and agro-industria l by-products produced in Ghana 5 Proximate composition o f major crop residues 13 Detergent f ib re content and in s itu degradab ility o f major crop residues .................... . . . ••• 14 Currently ava ilab le treatments fo r improving the nu tr it ive value o f crop residues . . . . . . 18 The e f fe c t o f s ilo type on mould attack, d ig e s t ib i­ l i t y and intake o f urea ensiled r ic e straw . . . 25 Protein content, intake, (OMI) and d ig e s t ib i l i t y (OMD) o f urea-treated r ic e straw . . . . . . 24 Voluntary intake and d ig e s t ib i l i t y o f selected crop residues . . . . . . . . . . . . . . . 27 Possib le sources o f nu tritiona l supplements to crop residues in Ghana .................... . . . . . . 28 Some factors a ffe c t in g urea-ammoniation o f r ic e straw and the le v e ls studied in Experiment 1 30 Chemical composition o f untreated r ic e straw 32 Percent Nitrogen content o f straw a ired fo r 30 minutes as influenced by le v e l o f urea, length o f treatment and moisture le v e l . . . . . . . . . 33 Percent N itrogen content o f straw a ired fo r 24h as influenced by le v e l o f urea, treatment period and moisture content .................... . . . . . . 33 Chemical composition and IVOMD o f straw samples taken from the various s i lo s . . . . . . . . . 44 Rate and extent o f Dry matter disappearance (DMD) o f urea-ammoniated (TS) and untreated (OS) r ic e straw . . . . . . . . . . . . . . . . . . . . . 48 Nitrogen and NDF contents o f untreated (US) and urea- ammoniated (TS) r ic e straw a fte r incubation in rumen o f sh eep ............................................................. 49 University of Ghana http://ugspace.ug.edu.gh XI ! Page 6 . i f Chemical composition o f Untreated r ic e straw and experimental d ie ts A (sprayed with only mineral so lu tion ), B (trea ted with NaOH and sprayed with mineral so lu tion and C (en s iled with Urea and then . sprayed with Urea-N fr e e mineral so lu tion ) (Values are means o f three analyses per sample) 55 6.2 Dry Matter (DM) intake, organic matter (OM) d ig e s t ib i l i t y and metabolizable energy intake (MEI) r e la t iv e to maintenance energy requirements (Mm) by sheep fed d ie ts A, B and C* (Values are means o f f iv e sheep per d ie t ) . . . 56 University of Ghana http://ugspace.ug.edu.gh Figure 2.1 Figure 3.1 Figure 3.2 f. Figure 3.3 Figure 3.4 Figure 3.5 LIST OF FIGURES Page : Structural formulae o f c e l lu lo s e , ‘ hemi- ce llu lo se , pectin and lig n in . . . . . . 10 : The N content o f urea treated r ic e straw as a ffec ted by various urea concentration and moisture le v e ls . . . . . . 34 : The N content o f urea treated r ic e straw as a ffec ted by various treatment periods and urea concentrations . . . . . . 35 : The N content o f urea-treated r ic e straw various treatment periods and moisture le v e ls ............... . . . . . . 36 : In v it r o organic matter d ig e s t ib i l i t y o f urea ammoniated r ic e straw as a ffe c ted by various urea concentrations and moisture le v e ls ................ . . . . . . 37 : In v it r o organic matter d ig e s t ib i l i t y o f urea ammoniated r ic e straw as a ffec ted by various treatment periods and urea concentrations . . . . . . . . . 38 X I II Figure 3.6: In v it ro organic matter d ig e s t ib i l i t y o f urea- ammoniated r ic e straw as a ffec ted by various treatment periods and moisture le v e ls 39 University of Ghana http://ugspace.ug.edu.gh The main feed resource fo r ruminants in Ghana is the natural grassland. Rose-Innes and Mabey (1964) and Fianu, Atta-Krah and Koram (1972) have indicated that crude protein contents o f Ghanaian grasses, in general, ranged from 5 to 13% in the rainy season, but f e l l to about 3% In the dry season. Consequently, ruminant animals gain veight during the wet r season but lose weight in the dry season. In the face o f th is feed resource inadequacy, increasing but e f fe c t iv e use o f crop residues in feeding ruminant liv e s to ck is a good a lte rn a tive since about 6 m illion metric tonnes o f residues are produced yearly (F le isch er, unpublished). Crop residues are, however, known to have low nitrogen content and low d ig e s t ib i l i t y . Consequently, they have a low animal production po ten tia l. Rice straw, fo r instance, contains about 80% p o ten tia lly d ig e s t ib le substances and Is therefore a source o f energy. Hovrever, i t s actual d ig e s t ib i l i t y by ruminants is only 45-50%. Furthermore, the amount the animal can eat is lim ited to less than 2% o f body weight because o f the slow rate at which i t is fermented in the rumen (Jackson, 1978). Most o f the work done on low qua lity roughages reveals that physical and/or chemical treatments with or without supplementation (w ith energy, protein and m ineral) improve the u t i l iz a t io n o f these feedstu ffs o f ruminants.j University of Ghana http://ugspace.ug.edu.gh The upgrading o f low qua lity roughages by means o f ammonia treatment has been reviewed by Sundstol, Coxworth and Mowat (1978). An in d irec t method o f ammoniation o f crop residues has also been reported by Jayasuriya & Perera (1982) and Naur (1986). This treatment depends on the enzymatic release o f ammonia from urea (o r other non-protein sources o f ammonia e .g . biuret added to the roughage) in an aqueous medium. Research resu lts have proved ammoniation by urea to be e f fe c t iv e in improving the in v it r o organic matter ft d ig e s t ib i l i t y (IVOMD), voluntary intake and in vivo d ig e s t ib i l i t y o f wheat straw (K r itz in ge r and Franck 1981; C loete, De V i l l ie r s and K ritz in ge r, 1983). This method o f ammoniation appears to be r e la t iv e ly sa fe , uncomplicated and inexpensive when compared to sodium hydroxide treatment and anhydrous ammonia treatment. Success with urea ammoniation however, depends strongly on the e ffectiven ess o f u reo lysis which in turn is re la ted to urease a c t iv it y in the m ateria l, moisture le v e l o f the material, environmental temperature, urea le v e l and length o f treatment. (Guessous, e t a l , 1989). L i t t l e work has been done in Ghana to elucidate the treatment conditions that a f fe c t the urea ammoniation o f straw. The ob jective o f th is study is therefore to evaluate the factors that influence the e f fe c t iv e ammoniation o f straw under Ghanaian conditions using urea as the source o f ammonia. The factors are: treatment period, urea concentration and moisture content o f straw. University of Ghana http://ugspace.ug.edu.gh The e f fe c t o f type o f s i lo (earthern p it , cane basket or cement cu lve rt) on the nu trit ive value o f treated straw w i l l a lso be determined and a prelim inary study on the po ten tia l o f the ammoniated straw as a dry-season feeding material embarked upon. University of Ghana http://ugspace.ug.edu.gh CHAPTER 2 LITERATURE REVIEW 2.1 INTRODUCTION The major crops grown, in Ghana and which provide residues o f po ten tia l value fo r ruminants are shown in Table 2.1. The residues produced at harvest or during the farm processing o f the crops, (s tovers , straws, haulms, vines, leaves, peels ) are not being maximally u t il iz e d because o f a number o f constraints. One o f the major constraints is the generally low nu trit ive value o f these crop residues. They have low nitrogen, high f ib r e contents and are poorly digested such that they barely meet the maintenance requirements o f liv e s to ck (Sundstol, t Cox worth and Mowat, 1978). They reed to be upgraded by treatment or appropriate supplementation in order to exp lo it fu l ly the ro le they could play in ruminant nu trition . The fa ctors that in fluence the intake and u t i l iz a t io n o f r crop residues and the various treatments adopted to improve th e ir nu trit ive value are reviewed. 2.2, NATURE AND QUALITY OF AVAILABLE FEED RESOURCES 2.2;1 Cro£ Residues and Agro Indust r i a l By-Products Crop residues are defined by Smith (1987) as the material i l e f t a fte r harvesting the crops (maize stover, cassava tops, maize cobs, cassava peels , r ic e straw ). These materials are usually high in f ib r e , low in nitrogen and are w idely d istributed : in I the farming communities o f Ghana. Crop residues usua l l y tli® a va ilab le feeding material during the dry season. University of Ghana http://ugspace.ug.edu.gh Table 2.1: Some nu tr it ion a lly important crop residues and agro-industria l by-products produced in Ghana Cro£ Maize Rice Sorghum Wheat (imported) Groundnut Cowpea Cocoa Cotton Coconut O il Palm Plantain and Banana Sugarcane Cassava Sveet Potatoes f Pineapples and citrus fru its Residue Stover Cob Stubble Straw Stover Haulms Husks Vines & Pods Pods Husk Leaves Psudostems Peels & re je c ts Tops Peels & re jec ts Tops (lea ves ) Vines and Peels Tops By-Product Bran Husk Bran Husks Rice m ill feed ' Bran’ Bran Groundnut cake Shells Cotton seed cake Copra cake Palm pressed f ib r e Palm kernal cake Molasses Cane ju ice Bagasse Starch Pulp University of Ghana http://ugspace.ug.edu.gh Agro-industrial-by-products, on the other hand, are produced mainly a fte r processing the crops and could be physically and nu tr it ion a lly d if fe ren t from the sta rtin g crop. They could be r ich in nitrogen and low in f ib r e (eg . o i l seed calces, some brewery and flo u r m illin g by-products) or low in nitrogen and high in f ib r e (eg . sugarcane bagasse, palm press f ib r e ) . A few l ik e palm kernal cake are high in both n itrogen and f ib r e . Since they are produced at fa c to ry s ite s , they are less widespread in loca tion . These agro-industrial-by-products are genera lly used as supplements to low qua lity forages fo r ruminants and therefore not used as basal feeds. 2.2.2 Constraints to the optimum u ti l iz a t io n o f crop residues in Ghana When fed unprocessed to liv e s to ck , crop residues are poorly consumed and u ltim ately resu lt in slow growth rate . Crop residues are bulky and are unfortunately ava ilab le mainly in areas with low animal population density. The cost o f transportation from production s ite s to liv e s to ck areas may be so high, that farmers are forced to just burn these residues as a means o f disposal on the farms. There is a need to educate * farmers on the means o f improving the feeding value o f crop residues and the usefulness in feeding them to animals. 2.3 POTENTIAL FEED VALUE OF CROP RESIDUES 1 2.3.1 Intake o f Crop Residues ; In studies in which crop residues were ifed as the sole or major m ateria l, intake and d ig e s t ib i l i t ie s o f the d ie t were University of Ghana http://ugspace.ug.edu.gh founfi to be very low. Cheva-Isarakul and Cheva-Isarakul (1985) fed adult wethers, weighing about 30kg, f i v e d if fe ren t v a r ie t ie s o f r ic e straw ad lib itum to estimate voluntary intake and d ig e s t ib i l i t y . On the average the sheep consumed about 2.2 percent o f th e ir body weight or 52 g/kg metabolic weight o f the straw. Dry matter d ig e s t ib i l i t y was 49.8%. Suriyajantratong and Senetas (1985) reported higher dry matter intakes (2.9% o f body weight) fo r sheep fed groundnut haulms compared with findings o f Cheva Isarakul and Cheva Isarakul (1985). The d ig e s t ib i l i t y o f groundnut haulms in the la t t e r study was 52%. Alhassan, e t a l (1984) fed goats with a number o f low qua lity forages namely sorghum stover, maize stover, sorghum leaves and cowpea vines. Dry matter d ig e s t ib i l i t y o f these materials were 52, 53, 57 and 47 resp ec tive ly . Even though the d ig e s t ib i l i t ie s observed in th is study were comparable to that o f Suriyajantratong and Senetas (1985), intakes observed by Alhassan et a l (1984) ware lower (1 .1 , 0.7, 2.0 and 0.8% o f body: freight resp ec tive ly ) than those observed frith sheep by the e a r l ie r workers. D ifferences in intake could be associated with' animal species d iffe ren ces (Rees and L i t t l e , 1980). According to Doyle (1982) and Pearce (1984), materials with such low dry matter d ig e s t ib i l i t ie s coupled with low intakes may not s a t is fy maintenance needs o f the animals, hence the need to upgrade the residues to improve th e ir nu tr it ive value. University of Ghana http://ugspace.ug.edu.gh 2.3.2 Factors a ffe c t in g intake and u t i l iz a t io n o f straw and other low qua lity roughages by ruminants Composition and u t i l iz a t io n : I t is possib le that the components o f Dry Matter (DM) rather than DM d ig e s t ib i l i t y may determine intake o f low qua lity roughages. B laxter and Wilson (1963) .suggested 8.5% as the le v e l o f Crude P rote in (CP) at which the a c t iv ity o f c e l lu lo ly t ic microbes in the rumen might be lim ited by the a v a ila b il it y o f N itrogen (N ). Intake o f low qua lity roughages has a lso been found to be in verse ly rela ted to the C ell Wall (CW) content o f the material (Goering and Van Soest, 1970). Nutrient Imbalances; There is widespread evidence that imbalance o f nutrients such as N and other minerals and vitamins depresses feed intake and animal performance. L iveve igh t losses resu lting from feeding o f a l l low qua lity roughage d ie ts p a ra lle l those on low prote in dry season grazing (Rose-Innes, 1960; Larsen and Amaning-Kwarteng, 1976). Anderson (1978) id en t ified CP and Phosphorus (P ) as the major d e fic ien c ies in straws; Calcium (Ca) le v e ls are marginal and (Zn) de fic ien cy could a rise *Aien straw is fed fo r extended periods. To achieve maximum intake o f straw, a CP content o f 66-85 g/kg DM has been found necessary (B lax ter and Wilson, 1963)'. Straw: Concentrate r a t io : The o v e ra ll e f fe c t o f supplementing straw d ie ts with moderate le v e ls o f concentrate is to increase not only straw intake, where Rumen Degradable Nitrogen (RDN) is lim itin g , but a lso to ta l DM and Organic Matter (OM) intakes. Church and Santos (1981) observed that with small amounts o f University of Ghana http://ugspace.ug.edu.gh 10 OH C H jOH i - ' LtJl l l ' c 2 . l a . T h O CO 1 1 u l o s o u n i t : *'■ — 1 , •) Cj 1 U C O J i V ! . i i O H - o o F i g u r e 2 . | ^ t h e i i c i b l c v IU j I o su un i t f ' - l , -I x y i u p y ; -u.. CHOOH CHOOH . O F i g u r e 2 . | c The p e c t i n u n i t c j c i l a c Cop yra nur on ic . i c i o CH = CHCH2OH F i g u r e l . 1 d i hc ' jcisic l i g n i n u n i t , d e r i v e d ' f rom p r o pane , H may be li o r -OC!i , University of Ghana http://ugspace.ug.edu.gh protein concentrate such as soya bean meal, intake o f both straw DM and e ie rgy s ig n if ic a n t ly increased« by almost 43%. Consumption o f straw DM improves wLth increased intake o f concentrate t i l l the concentrate le v e l is over 20% o f the to ta l DM intake (Crabtree and W illiams, 1971). 2 . 3 . Chemical composition o f r ic e straw The major fra c t ion o f roughage (up to about 85% o f cerea l straws) is structural c e l l w all (CW) which is l ig n o -c e llu lo s ic in nature and consists mainly o f the polysaccharides ce llu lo se , hem i-cellu lose, pectin and th e ir d er iva tives and the non-polysaccharide component, lign in . These ex is t in close physical and chemical association . They can vary widely in properties depending on the r e la t iv e proportions o f the components and th e ir chemical bonding and d is tr ibu tion In CW. The manner in which the components are complexed with each other and with minerals is a lso a source o f va r ia tion (McManus, 1981). C ellu lose : This is usually the most abundant structural polysaccharide molecule. I t is la rg e ly c r y s ta l l i t e and organised as m ic ro fib r ils held together in matrix o f la rg e ly amorphous non-cellu lose polysacharides, l ig n in and some glycoprotein . Cellu lose (Figure 2.1a) is a lin ea r polymer o f high molecular weight bu ilt up o f up to 10,000 beta-1 , 4-linked glucose units. The conformation obtained with th is type o f linkage strongly favours the formation o f hydrogen bonding between sugar units in the chain and between adjacent chains. Cellu lose is characterised by high mechanical strength and resistance towards chemicals. The a c c c e s s ib ility o f c e llu lo s ic University of Ghana http://ugspace.ug.edu.gh 11. : materials to enzymatic hydrolysis may vary considerably and can be increased by treatments which increase the surface area, make the ce llu lo se less c ry s ta llin e , more svrollen or less a ffec ted by components such as l ig n in and s i l ic a . Hem icellu loses: These are amorphous polysaccharides made up o f r e la t iv e ly short chains o f xylose or other pentoses (Figure 2.1b) or o f a mixture o f glucose and mannose, linked as with c e llu lo se , in beta-1, 4 structures. The hemicelluloses have many side chains but those in straws are almost en tire ly glueurono-arabino-xylans with side chains o f D-glucuronic acid r and L-arabinose. Hemicelluloses ex is t in c lose associa tion with ce llu lo se and l ig n in and vary w idely in content from one type o f plant material to another with a range o f about 6 to 40%. Like ce llu lo se , the in d iges tib le hemicellulose fra c t ion is la rg e ly encrusted with lign in . Pectin : This is the th ird type o f polysaccharide in CW and is based on galactose in the form o f D-galaturonic acid residues joined in alpha-1, 4 linkages (F igure 2 .1 c ). L ign in : Accompanying the structural polysaccharides is lig n in , an in e rt and complex polymer that is based on deriva tives o f phenyl propane (Figure 2 .I d ) . L ign in is encrusted in to the CW and establishes covalent bonding to hem icellu loses, forming so -ca lled ligno-carbohydrate complexes. L ign in may also be linked to other CW constituents by covalent bonds. Straw lign in s have not been studied in i great, d e ta il but in vestigations o f ligno-carbohydrate complexes | i in iw>|Od have shown that l ig n in is bound to d if fe ren t types o f sugar,units and to uronic acid residues in the hem icellu lose. University of Ghana http://ugspace.ug.edu.gh Lign in has a number o f functions essen tia l to the plants, the major one o f which is to supply strength and r ig id ity . I t s nu tritiona l s ign ifican ce l i e s in i t s in d iges tib le nature. By way o f i t s c lose physcial and/or chemical assocation with the CW polysaccharides, i t frequently acts as a physical ba rrier and impedes the m icrobial breakdown o f these compounds. Cutin Cutin, the external sh eet-lik e material on plant surfaces is s im ilar to l ig n in in protecting CW carbohydrates from m icrobial d igestion . Minerals McManus, et a l (1979) estimated the mineral content o f CW to range from 2 to 20%. The s o lu b ility o f th is fra c t io n is important in determining the qua lity o f the roughage. Jones and Handrick (1965) reported that almost a l l the insoluble fra c t ion consists o f s i l ic a which is present as inclusions within the CW or as encrustations on the CW (Jones and Handrick, 1967) where i t might in fluence the d ig e s t ib i l i t y o f CW (Baker and Harris, 1947). Using a regression approach, Van Soest and Jones (1968) showed that each percentage unit o f s i l ic a reduced in v it r o DM and OM d ig e s t ib i l i t y by 3.0 and 1.4 percentage units respective ly . By contrast s i l ic a was found to have; no e f fe c t on in v ivo OM d ig e s t ib i l i t y o f Panicum spp. (MinSon, 1971) or legumes (Van Soest & Jones, 1968). These apparent d ifferences could be explained by the pos ition o f s i l id a w ithin the plant tissue. Mlnson (1976) reported that silica- could be contained In spec ia lized epidermal c e l ls where 12. University of Ghana http://ugspace.ug.edu.gh i t is l ik e ly to a f fe c t the d igestion o f other fra c tion s . I t is also possible that other in d ige s t ib le fraction s may a lso protect the CW from d igestion . The ash content o f r ic e straw has been reported to be about three times higher than in other straws (Van Soest & Jones, ■h 1968). This is associated w ith the higher s i l ic a content o f r ic e straw than other straws (see Table 2.2 and 2 .3 ). I t should be stressed that mineral contents vary w idely depending on factors such as agronomic fa c to rs , amount o f s o i l contamination and plant va r ie ty . Other physical and chemical CW factors which act as barriers to m icrobial degradation are suberin, waxes, ha irs, moisture content £ o f CW, surface area exposure o f c e llu lo se , phenolic acids anti s.cetyl groups. Table 2.2: Proximate Composition o f major crop residues 13. /■ % DM Crop Residue Moisture % Crude Protein Organic Matter Crude Fibre Ether Extract NFE Maize stover 10 2-8 85-91 28-46 1 -2 35-53 Sorghum stover 10 3-6 96 31-35 1-2 50-56 Rice Straw 10 2-9 75-90 20-45 1-4 29-48 Groundnut haulms 10-12 11-17 87-90 21-29 1.5-2.5 51-57 Cowpea tops 10-12 6-18 82-90 25-30 1-1.5 48-50 S i«e t Potato tops 70-80 17-27 89-94 8-26 3-8 35-60 Sugarcane tops 90 20-22 82-83 15 3-3.5 42-46 Banana leaves 80 5-8 81-95 28-34 1.5-2.5 44-54 Banana Pseudostems 90 10-15 91 24 12 45 Coqoa Pods 75 2-9 86-91 i 21-32 2-3 61 O il Palm 56 2-9 75-90 20-45 1-4 33-56 Fruit bunch 3-4 95 - 6-8 - 987). University of Ghana http://ugspace.ug.edu.gh 14. Table 2.3: Detergent f ib r e content and in s itu degradab ility o f major crop residues Crop Residue % DM C ell Wall (NDF) C e ll Content ADF L ign in Cellu­ lose Hemi- Cellu - lose S il ic a Tl/2 (Hr) % DM losses (24h) Maize stover 70-80 - - 7-9 43 24 5 70 30-80 Sorghum stover 75-75 26 - 8 -11 31 30 5 130 25 Rice straw 60-80 20 45-55 4-10 24-52 5-45 12-17 60-80 30-34 Groundnut haulms 42-45 - 39-40 7-9 32 7 - 38 36 Cowpea Vines 75 - - 5-6 - - - - - Cassava tops 30-45 20 - - - - - 30-50 45 Sugarcane top 65-75 - 43 5-6 - - - 50-128 10 Banana leaves 40-60 10 - - - - - 50-60 - Banana Pseudostems 35-40 10 - 9-10 35 18 - 40-50 50 Source: Smith, (1987). « V University of Ghana http://ugspace.ug.edu.gh Table 2.2. anil 2.3 ulww uomo valuaa for tho chemical composition of some crop residues. The very high T^/2 values ( i . e . time taken fo r ha lf the material in a sample to be degraded in the rumen) (Table 2 .3 ) o f most o f the residues confirm th e ir poor degradab ility in the rumen. Such slow rates o f degradab ility mean low rates o f uptake o f the material from the rumen and therefore low intake o f Tota l D igestib le Nutrients (Smith, 1987). 2.3.4 M icrobial Degradation o f f ib re in the Rumen Plant fragments entering the rumen or hindgut become extensively colonized by bacteria w ith in an hour (Cheng et al, m\. Treating plant fragments to detach bacteria shows that at lea s t as many organisms associate with p a rtic les as remain fre e in the rumen liqu or (Minato and Suto, 1978). Preference is always shown fo r damaged areas during primary co lon ization . Chewing by the animal and methods o f feed preparation which maximise damage thus promote co lon iza tion and have a marked e f fe c t on rates, i f not on the ultimate extent oi' degradation. The lig n o -c e llu lo s ic complex accounts fo r most o f the organic matter (OM), and hence, gross e ie rgy o f common roughages. N u trition a lly , Pigden and Bender (1972) divided lign o -ce llu lo se o f low qua lity roughages in to three d is tin c t ca tegories: the unavailable fra c t ion including compounds such as l ig n in which fo r p ra c tica l purposes, is not degraded by rumeq m icroflora; the d ig es tib le energy (DE) fra c t ion representing carbohydrates which are normally a va ilab le fo r 15. micro b ia l degradation and the po ten tia lly d ig es tib le energy University of Ghana http://ugspace.ug.edu.gh (PDE) which includes the carbohydrates not normally ava ilab le to rumen m icro flora due to chemical and/or physical associa tion with the lign a -ce llu lo se complex, but which can be made ava ilab le by appropriate treatment or by supplementation. in young forages the PDE fra c t io n is r e la t iv e ly in s ign ifican t because most o f the carbohydrate material is a va ilab le to the rumen m icroflora . As the plant matures and l ig n i f ic a t io n proceeds, more o f the carbohydrates is " t ie d up" and in unprocessed mature forages the PDE fra c t ion may be as la rge as the DE fra c tion . Urea ammoniation lik e sodium hydroxide treatment makes th is PDE fra c t ion a va ilab le to the animal. 2.4 IMPROVEMENT OF NUTRITIVE VALUE OF CROP RESIDUES 2.4.1 Introduction : In order to increase the nu tritiona l value o f straws and other low -quality roughages fo r the u t i l iz a t io n by ruminants a number o f processing methods, namely: physical, chemical, and b io lo g ica l (Table 2 .4 ) have been used to rupture the c e llu lo s e - lig n in complex by ex traction t or decomposition o f l ig n in and thus make structural carbohydrates more accesib le fo r breakdown by rumen microbes, and supplementation to overcome sp ec ific nutrient d e fic ien c ies . Two fundamental considerations to be made on the fe a s ib i l i t y o f processing roughages are (a ) whether the d ig e s t ib i l i t y , and therefore, the ME content o f the material is improved by the process and (b ) whether the intake o f the ' I product is increased. 16. University of Ghana http://ugspace.ug.edu.gh 2.4 .2 ' Physical Treatment Physical treatment has been found to increase intake o f crop residues (Chaturvedi, Singh and Ranjhan, 1973; Adu and Lapkini, 1983). Of the physical processes l is te d in Table 2.4 chose appropriate fo r small scale farming systems in Ghana include chopping and grinding. Chopping and Grinding I t has been found that such physical treatments o f straw increases th e ir da ily intake o f animal s. This is due pa rtly because the density o f the feed may, be increased and partly because chewing time required to reduce ingested material to a p a r tic le s iz e su itable fo r d igestion by rumen microorganisms is decreased considerably. However grinding produces more or less fin e material that may pass through the d iges tive tra c t too rap id ly fo r maximum nutrient u t il iz a t io n . 17. University of Ghana http://ugspace.ug.edu.gh 18. Table 2.4: Curren tly a va ilab le treatments fo r improving the n u tr it ive value o f crop residues Physical Chemical Physico/Chemical B io lo g ica l A lk a li Treatment 1. Soaking and/ or waiting 1. Sodium Hydro­ xide 1. Grinding/ Chemicals 1. Composting 2. Chopping 2. Calcium hydroxide 2. Pe lle tin g/ Chemicals 2. Ensiling 3. Grinding and p e lle t in g 3. Potassium hydroxide 3. Steaming/ Chemicals 3. Fungal growth 4. Boiling 4. Anhydrous ammonia 4. Enzyme addition 5. Ball m illin g 5. Ammo rW nm hydroxide 6 . Gamma ir ra d ia ­ t ion Acid treatment 1. Sulphuric acid 7. High pressure steaming 2. Hydrochloric acid Oxidation 1. Sulphur d io ­ xide 2. Oxone 3. Chlorine and ch lorinated compounds Source: Smith, (1987). 2.4.3 Chemical Treatment The three classes o f chemicals currently being used to trea t fibrous residues are a lk a lis , acids and ox id izing agents. A l l three are, capable o f weakening c e l l wall component complexes University of Ghana http://ugspace.ug.edu.gh (lign in -carbohydrates ), so lu b iliz in g the components ( l ig n in , ce llu lo se , e t c . ) and Increasing the sw elling capacity o f the c e l l wall thus fa c i l i t a t in g m icrobial enzyme entry (Smith, 1987). ti 2.4.4 Use o f Sodium Hydroxide . Sodium hydroxide is genera lly regarded as the most e f fe c t iv e a lk a li fo r improving the d ig e s t ib i l i t y o f crop residues. Increasing in v it r o d ig e s t ib i l i t y (up to 38% units) as w ell as in v ivo d ig e s t ib i l i t y (24-30% un its) and intake o f treated crop residues (about 30%) have been reported by Amaning-Kwarteng, 1991). The responses obtained with _in vivo d ig e s t ib i l i t y correspond with the in v it r o DM d ig e s t ib i l i t y (IVDMD) quite w ell at le v e ls up to 4-6% NaOH. Above th is le v e l , In v ivo d ig e s t ib i l i t y , voluntary intake and increased da ily livew eigh t gain a l l tend to le v e l o f f or even decrease while the IVDMD continues to increase. Jackson (1977) suggested that the lower in v ivo d ig e s t ib i l i t y may be related to high rate o f feed passage from the rumen at high le v e ls o f NaOH application . In sp ite o f the e ffec tiven ess o f NaOH in improving crop residues feeding value, i t can hardly be recommended fo r use on small scale farms because o f problems o f a v a ila b il it y , cost and handling. 2.4.[5 Use o f caustic ash o f some crop residues A number o f workers reported high le v e ls o f potash in the lash o f a number o f crop residues, (Adebowale, (1985), Smith I (1987), Smith and Osafo (1987). 19. University of Ghana http://ugspace.ug.edu.gh Adebowale (1985) found that potassium concentration in cocoa pod ash, fo r example was about 44mg/kg. The amount o f hydroxyl ions (OH) present in the ash so lu tion as NaOH and KOH t was 20.5 and 28.7 percent resp ec tive ly . He a lso reported that t itr im e tr ic and potentiometric analyses shovred that about 4.4 kg o f cocoa pod ash was equivalent to 1 kg o f NaOH. Even though the use o f crop residue ash so lu tion from some crop residues, e .g . cocoa husk, may sound a b e tter a lte rn a tive to NaOH treatment, these sources o f a lk a li are used extensively by lo c a l farmers fo r the production o f soap, an industry which is regarded as an a lte rn a tive source o f income fo r the farmers. 2.4.6 Use o f Ammonia Ammonia in various forms is used to trea t straws. These include anhydrous and aqueous forms, and in d ire c t ly generated ammonia through the use o f urea or urine. The use o f NH^ as an anhydrous gas or as aqueous NH^ OH has improved d ig e s t ib i l i t y and voluntary intake sim ilar to that achieved with NaOH when conditions fo r treatment were appropriate (Sundstol e t a l , 1978). The use o f NH^ a lso avoids the problems a ris in g from the use o f NaOH (e .g . accummulation o f residual a lk a l i ) . 2.5 UREA TREATMENT When urea is decomposed, i t releases NH^ according to 20. University of Ghana http://ugspace.ug.edu.gh 21. the formula: (NH2) 2C0 + H20 -------> 2NH3 + CO2 Molecular weight 60 1$ *H' ♦ Addition o f 6.3% (wt/wt) o f urea to straw Is equivalent to adding 3.5% NH ,^ assuming 100% conversion (Sundstol and Coxworth, 1984). The NH^ lib era ted from urea, in the presence o f water, produces the a lk a li NH^ OH which acts on the lign oce llu lose complex o f the straw and loosens the bond between the l ig n in and ce llu lo se . 2.5.1 Factors in fluencing the e f fe c t o f urea treatment According to C loete and K ritz in ger (1984) and Guessous et a l (1989), success with urea treatment depends on: a) Urea le v e l b) Length o f treatment c ) Moisture content o f straw d) Environmental temperature e) Urease a c t iv ity f ) Type and qua lity o f material being treated . ' Economides (1986) treated straw with a 10% urea solution at the rate o f 4001/t straw and stored in sealed containers fo r t , 1, 15, 30, 45 and 60 days. He observed that in v it r o organic ! f----------- matter d ig e s t ib i l i t y did not change s ig n if ic a n t ly a fte r 30 days of incubation. Sim ilar observations were made by Jayasuriya University of Ghana http://ugspace.ug.edu.gh and Perera (1982) who treated straw with 4% urea solution . Optimal resu lts were achieved a ft e r 3-4 weeks. Jayasuriya ( 1585 ) on the other hand reported no s ign fican t change beyond 10 :days o f incubation. Alhassan and A liyu (1991) also reported no s ign ifican t change beyond 7 days o f incubation o f maize straw with 4% urea so lution . The e f fe c t o f moisture le v e l on the ammoniation o f low qua lity roughages was investigated by Sundstol, CoxwDrth and Mowat (1978), Solaiman, Horn and Owsns (197f9) and Cloete and K ritz in ger (1984). Sundstol e t a l (1979) found that increasing the moisture content from 12 to 50% had a p o s it iv e e f fe c t on the in v it r o organic matter d ig e s t ib i l i t y o f ammoniated straw. C loete and K ritz in ger (1984) also observed a higher in v it r o organic matter d ig e s t ib i l i t y at 37.5% moisture le v e l than at 25% moisture le v e l . Excessive moisture content o f treated straw may horever increase mould formation and enhance handling problems. In general, chemical reactions run fa s te r a t high rather than at low temperatures. C loete and K ritz in ge r (1984) observed an increase in e ffec tiven ess o f ammoniation when temperature was increased from 4°C to 35°C. Sundstol et a l (19.79) also found a pos itive e f fe c t o f increasing temperatures from -20° to + 25°C, but the e f fe c t was more prominent at 8 weeks than at 4 weeks o f treatment. This indicated that, at leajst, part o f the temperature e f fe c t can be compensated fo r by t • increasing the time o f treatment. ! ! E ffic ien cy o f ammoniation has also been reported to be influenced by the a v a ila b il it y o f urease in the medium. 22. University of Ghana http://ugspace.ug.edu.gh The optimum temperature fo r urease a c t iv it y in s o i l as indicated by Du Preez (1983) is approximately 30°C. According to Orskov, et a l (1983) urease a c t iv it y tends to decrease at temperatures lower than 20°C. Sundstol and Coxworth (1984) cautioned that unless maximum urea decomposition was ensured, very high le v e ls o f urea could a remain in the straw, and be p o ten tia lly dangerous to liv e s to ck . Guesssous et a l (1989) working on Moroccan straws reported that the straws naturally contained urease enough to hydrolyse added urea even during the co ldest months o f w inter. Urea treatment was, however, found to be more e f fe c t iv e at ambient teperature o f about 12°C d a ily mean. * The importance o f an a ir t ig h t container (o r s i lo ) fo r storing the straw during urea ammoniation has been a matter o f debate (Sundstol and Coxvrorth, 1984). Ibrahim Fernando and Fernando (1983) compared various types o f s ilo s fo r urea r ammoniation o f straws. The resu lts , which have been presented in th e ir decreasing order o f e ffe c tiv en ess are shown in Table 2.5. . As the s ilo s became less a ir t ig h t , the degree o f mouldiness increased, DM intake decreased and apparent DM d ig e s t ib i l i t y also decreased. Saadullah, Hague and Dolberg (1981) as c ited by Sundstol and Coxworth (1984) observed that bamboo baskets seemed as good s ilo s fo r urea treatment o f straw as did the earthern p it . ! 23. University of Ghana http://ugspace.ug.edu.gh 24. Table 2.5: The e f fe c t o f s i lo type o f mould attack, d ig e s t ib i l i t y and intake o f urea ensiled r ic e straw (Ibrahim, Wyeratne and Costa, 1983) Moulded % DM D iges ti­ b i l i t y (%) DM intake g/kg.d 1. Earthern p it 3 61 55 2. Polythene bag 18 60 51 3. Coconut leaves 31 60 47 A 4. Urea bags 37 57 46 5. Big bag 41 58 38 6 . Open stack 36 53 40 2.5.2 E ffe c t o f urea ammoniation on feeding value o f straw and on animal performance Response parameters used to assess the e f fe c t o f urea ammoniation on animal performance include intake, live'weight gain and d ig e s t ib i l i t y . Mosi and Lambourne (1982) found that the intake andt d ig e s t ib i l i t y o f t e f ( E ragrostis t e f ) straw, oat straw and mixed legume haulms are approximately doubled ttfien such straws were ensiled fo r 3-6 weeks with 4% (w t/vol) fe r t i l iz e r -g ra d e urea. Sheep fed on the ensiled product gaired 80g/day during a 21 day feeding period compared with a gain o f 20g/day in the control animals. I , A l i (1986) dissolved 5kg urea and 10kg .ca ttle manure in 40 ljitres o f water. The mixture was poured over 100kg o f straw I 1 whic^i was covered with mud fo r between 4 and 6 weeks. He University of Ghana http://ugspace.ug.edu.gh observed that intake o f sheep fed th is treated d ie t rose from 400 to 800g/day. Liveweight gain o f the sheep was 5% more than animals on untreated straw. Studies by other workers (Dolberg, et a l 1982; and Wanapat et a l 1982) have indicated that en s ilin g straw with urea (3-5%) increased the d ig e s t ib i l i t y by 10-12% units The straw had a moisture content o f 50% and was incubated fo r 2-3 weeks. Saadullah et a l (1981), as c ited by Sundstol and Coxworth (1984), measured the intake and d ig e s t ib i l i t y o f r ic e straw* treated with urea, (Table 2 .6 ). Results ob ta iied indicated that urea ammoniation increased the feeding value o f Table 2.6: P rote in content, intake, (OMI) and d ig e s t ib i l i t y (OMD) o f urea-treated r ic e straw (Saadullah et a l, 1981) 25. Crude Proteih g/kg DM OMI g/kg Vf0*75.d OMD Untreated Rice Straw 33 46.2 45 Treated with 3% urea in earthern p it (20 days) 74 51.7 54 Treated with 5% urea in earthern p it (20 days) 80 60.9 56 Treated with 5% urea in earthern p it (40 days) + 10% molasses 78 63.4 57 Treated with 5% urea in bamboo basket (20 days) I 83 57.5 56 University of Ghana http://ugspace.ug.edu.gh straw to the same extent as that normally found in experiments w ith anhydrous or aqueous NH,j. Guessous et a l (1989) found that treatment with 6% urea at 30% moisture le v e l increased crude p rote in content o f straw from 6 to 8% and IVOMD from 51-59%. Intake o f straw also increased s ig n if ic a n t ly . 2.5.3 Supplementation According to Deverdra (1985), the ch aracteris tics o f a maintenance feed fo r adult ruminants are: a crude prote in le v e l o f 6-7%, a dry matter d ig e s t ib i l i t y o f 50-55% and a dry matter intake o f about 1.7% o f body ’weight. Data summarised in Table 2.7 show that crop residues ra re ly meet these requirements. Chemical or other treatments reviewed e a r l ie r may improve intake and d ig e s t ib i l i t y but unless adequate supplementation o f d e fic ien t nutrients is made, much o f the additiona l energy released w i l l be in e f f ic ie n t ly used (Smith, 1987). Adequate supplementation is therefore required fo r e f f ic ie n t u t i l iz a t io n o f crop residues. Preston and Leng (1987) have suggested that to optim ise the u t i l iz a t io n o f crop residues, nu tritiona l supplements should provide the fo llow ing in order o f preference: 1. High concentration o f fermentable carbohydrates (CHO). 2. Fermentable n itrogen (3gH/100g fermentatble CHO). f. 3. Adequate rumen ecosystem: ( i ) Roughage characteris tics i i ( i i ) M icro-nutrientsI ( i i i ) Control o f protozoal a c t iv it y 2 6 . University of Ghana http://ugspace.ug.edu.gh 4. By-pass nutrients ( i ) Protein ( i i ) Energy 5. Balance of end-products of digestion. Supply of: ( i ) Amino acids ( i i ) Glucose and glucogenic compounds in re la tion to total oxidative energy and tissue needs. Table 2.7: Voluntary intake and d ig e s t ib i l i t y o f selected crop residues 2 7. Crop Residue % CP Intake X BW Dry Matter d ig e s t ib i l i t y Sheep Goat Sheep Goat Maize stover 4.0 - 0.7 - 53 Sorghum stover 4.0 - 2.0 - 57 Rice straw 4.2 1.4 1.9 47 48 Cocoa pod 5.0 — — 20 - Source: Smith, 1987. The f i r s t four ensure an adequate rumen ecosystem, while the la s t 2 complement the needs o f the animal as a whole. Table 2.8 shows a l i s t o f some o f the p o ten tia lly valuable supplements. University of Ghana http://ugspace.ug.edu.gh 28. Table 2.8: Possib le sources o f nu tritiona l supplements to crop residues in Ghana r N u tritiona l Factor Supplement Fermentable Nitrogen Urea, urine, animal manure, ammonium sulphate. Fermentable Carbohydrate Molasses cane ju ic e , cassava chips, cassava peels , re je c t banana/plantain, r ic e bran, maize bran, starch. Roughage-miconutrients Forages, such as G lir ic id ia , leucaena, water hyacinth, cassava tops, sugar cane tops, sorphum tops, banana leaves and pseudostems. By-pass p rote in O il seed cakes, leucaena, G lir ic id ia , other tannin rich forages, f is h meal By-pass energy Starch, com , broken r ic e , r ic e polish ings University of Ghana http://ugspace.ug.edu.gh CHAPTER 3 EXPERIMENT 1 f 3. TITLE: Determination o f optimum urea concentration, moisture le v e l and treatment time fo r urea ammoniation o f r ic e straw in Ghana. 3.1 INTRODUCTIONr ------------------ Ammoniation o f straw by en s ilin g with urea, even though inexpensive and uncomplicated, requires a treatment period o f approximately s ix to eight weeks (K r itz in ge r and Franck, 1981). The e f fe c t o f moisture le v e l on the ammoniation o f straw was investigated by various workers with moisture le v e ls ranging from 8% to 54%. I t can be concluded in general that ammoniation was consisten tly fa s te r at higher moisture le v e ls . In th is study, the e f fe c t o f urea concentration anti moisture le v e l with various treatment periods and th e ir in teractions were investigated simultaneously. 3.2 MATERIALS AND METHODS 3.2.1 Location o f experiment: This experiment was carried out in the Nutrition Laboratory o f the Department o f Animal Science, University o f Ghana, Legon. Treatments; Rice straw ( lo c a l v a r ie ty ), obtained from Kpong farms, was chopped in to about 3cm length . Hundred grammes o f the r ice straw were weighed in to each o f 72 polyethylene bags and subjected to various treatments as indidated in Table 3.1. 29. University of Ghana http://ugspace.ug.edu.gh Table 3.1: Various treatment conditions affecting-ammon iation o f r ic e straw and the le v e ls studied in experiment 1 30. F a c t o r Level Amount added per lOOg DM r ic e straw 1. Urea concentration 3.5 4.05g (%) 5.0 . 5.78g 6.5 7.52g 8.0 9.25g 2. Moisture le v e l 40 44.10cm3 (%) 50 72.92cm3 60 116.17cm3 3. Treatment period 7 _ (days) 14 21 3.2.2 Experimental Design; The treatments constitu ted a 4 x 3 x 3 fa c to r ia l experimental design, the fa c to rs being urea concentration, moisture le v e l and treatment period. 3.2.3 Ammoniation process: The various amounts o f urea were dissolved in the respective amounts o f d is t i l le d water and sprinkled on the straw in the polythene bags. A fte r the contents o f each bag had been thoroughly mixed, the bag was made a ir t ig h t by sealing with masking tape. The bags were kept in a room with an average ambient da ily temperature o f 28°C. Bags wsre opened a ft e r 7, 14 and 21 days o f en s ilin g . Each sample was then divided in to 2 and a ired fo r 30 minutes and 24 hours respec tive ly . 3.2.4 Chemical Analysis: Residual N itrogen (N ) content o f the samples was determined by the K jeldahl analysis (AOAC, 1975). Samples were also analysed fo r Organic Matter (OM), Acid detergent f ib r e (ADF) and Neutral detergent f ib r e (NDF). University of Ghana http://ugspace.ug.edu.gh 3.2.5 In V itro D ig e s t ib i l i t y : Three sheep (wethers) with an average weight o f 24kg, obtained from the A gricu ltu ra l Research Station, Kade, were drenched with Rametin (N-diethoxy phosphoryloxy — naphthalimide, Bayer Levekusen, Germany) and N.C.A. (Cooper, The Wellcome Foundation L td ., London, Great B rita in ) and dipped with Gamatox (gamma B.H.C. 20% w/v, Cooper McDougall and Robertson L td ., Berkhamsted Herts, England) to render them fre e o f endo-and ectoparasites. They were ruminally fis tu la ted (Preston, 198t>) and kept in conventional metabolism crates at the A gricu ltu ra l Research Station , Legon. A recovery period o f about 3 weeks was allowed during which intramuscular in je c t io n o f 'P en n ic il l in ' a n tib io t ic (5ml) was administered d a ily fo r 5d. The animals were fed a d ie t o f Panicum maximum and urea-treated straw in the ra t io o f 1:2. This was to ensure that the desired microbes were a va ilab le fo r the in v it r o d ig e s t ib i l i t y t r i a l . Water was g iven ad lib itum . Rumen liquor was then co lle c ted from each sheep by means o f a suction pump and a stomach tube passed through the f is tu la . Coarse p a rtic le s o f food were removed by strain ing the liqu or over a muslin sheet in to a suction b o tt le . About 85ml rumen sample were removed from each animal and transported to the laboratory in a thermos fla sk fo r In v it r o analysis (T i l l y and Terry 1963). 31. University of Ghana http://ugspace.ug.edu.gh 32. 3.3 RESULTS Composition o f untreated straw; The mean chemical composition o f untreated r ice straw is shown in Table 3.2. Table 3.2: Chemical composition and In v it r o or organic matter d ig e s t ib i l i t y (IVOMD) o f untreated r ic e straw DM 88.10 N 1.03 NDF 86^32 ADF 48.91 Hem-1 ce llu lose 37.41 Cellu lose 30.04 L ign in« i 10.99 Org. Matter 76.89 IVOMD 40.09 Cellu lose and hemicellulose together formed about 67% o f the DM, 47% o f OM and about 78% o f the c e l l wall component. N itrogen content was 1.03% o f DM ( i . e . about 6% CP). Residual N content: N itrogen content o f straw a ired fo r 30 minutes and 24 hrs as influenced by le v e l o f urea, length o f treatment period and moisture le v e l is shown in Tables 3.3 and 3.4 resp ec tive ly . In terac tive e f fe c ts on qua lity Of ammoniated straw a fte r a irin g fo r 24 hours are shown in F ig. 3.1 to 3.6. University of Ghana http://ugspace.ug.edu.gh 33. Table 3 .3: Percent N itrogen content o f straw a ired fo r 30 minutes as Influenced by le v e l o f urea, length o f treatment and moisture le v e l Treatment period (days) Mean N Con­ tent (%) Urea le v e l (%) Mean N Content (%) Moisture le v e l (%) Mean N Content (%) 7 3.11a 3.5 2.15a 40 3.10a .14 3.02a 5.0 2.73b 50 2.96b 21 3.12a 6.5 6.41C 60 3.20a 8.0 4.05<* S.E. 0.07 S.E. 0.08 S.E. 0.07 Means in the same column with d iffe ren t superscripts d iffe r s ig n if ic a n t ly (P 0 .05 ). Table 3.4: Percent N itrogen content o f straw a ired fo r 24h as influeneed by le v e l o f urea, treatment period and moisture content Treatment period (days) Mean N Con­ tent (%) Urea le v e l (%) Mean N Content (%) Moisture le v e l (%) Mean N Content (X) 7 1.30a 3.5 1.31* 40 1.63a 14 1.35a 5.0 1.24* 50 1.24 b 21 1.42a 6.5 1.38ab 60 1.27b 8.0 1.60b S.E. 0.10 S.E. 0.11 S.E. 0.10 Means in the same column with d if fe ren t superscripts d i f f e r s ign if ic a n t ly (P 0.05). I I i University of Ghana http://ugspace.ug.edu.gh Urea Concentration (%) Figure 3A . Interactive effect of Urea Concentration and Moisture level on Nitrogen content of Urea - Ammoniated rice straw University of Ghana http://ugspace.ug.edu.gh Ni tro ge n co nt en t (% ) 3 4 5 6 7 8 9 Urea Concentration (%) Figure 3.2. Interactive effect of Urea Concentration and treatment period on nitrogen content of Urea - Ammoniated rice straw University of Ghana http://ugspace.ug.edu.gh Treatment Period (days) Figure 3.3. Interactive effect of moisture level and treatment period on Nitrogen content of Urea - Ammoniated rice straw University of Ghana http://ugspace.ug.edu.gh Di ge sti bil ity (% ) 5 6 7 Urea Concentration (%) 8 Figure 3.4. Interactive effect of Urea Concentration and Moisture level on the in vitro organic matter digestibility of Urea - Ammoniated rice straw M1 ■---- M2 ▲ ---- M3. ... • ----- LEGEND University of Ghana http://ugspace.ug.edu.gh Di ge sti bil ity (% ) 56 3 4 5 6 7 8 Urea Concentration (%) Figure 3.5. Interactive effect of Urea Concentration and treatment period on the in vitro organic matter digestibility of Urea - Ammoniated rice straw T1 ■---- T2 ▲ ---- T3 . • ----- LEGEND University of Ghana http://ugspace.ug.edu.gh Di ge sti bil ity (% ) 54 53 - 52 - 51 - 50 - 49 - 48 - 47 - 6 LEGEND 8 10 12 14 16 18 20 22 Time of treatment (days) Figure 3.6. Interactive effect of moisture level and treatment period on the in vitro organic matter digestibility of Urea - Ammoniated rice straw University of Ghana http://ugspace.ug.edu.gh The highest residual n itrogen at a l l urea concentrations was found when urea was applied at 40% moisture le v e l ; while 60% fnoisture le v e l recorded the lowest residual nitrogen content, (F ig . 3 .1 ). While 8% urea concentration and 40% moisture gave the highest residual nitrogen, 6.5% urea and 40% moisture gave the highest IVOMD, (F ig . 3 .4 ). IVOMD decreased a fte r 6.5% urea fo r 40% and 50% moisture while i t continued to increased a ft e r 6.5% urea fo r 60% moisture. In F ig. 3.2, residual n itrogen increased with increasing urea concentration and was highest when straw was stored fo r 21 days. IVOMD was also higher fo r 21 days than 7 and 14 days (F ig . 3 .5 ). The peak fo r a l l three periods was at 6.5% urea a fte r which there was a decrease in IVOMD. Figure 3.3 depicts a higher amount o f residual nitrogen at 40% moisture le v e l compared to 50% and 60% moisture le v e ls with t respect to treatment time. The highest IVOMD however was recorded at 21 days with 40% moisture. 3.4 DISCUSSION r Chemical composition o f untreated straw The chemical composition o f r ic e straw determined in th is experiment agrees with values quoted by Smith (1987). However, the crude protein (CP) content determined in th is experiment was higher than that reported by Otchere et a l (1977) (2.90% )). D ifferences such as thise in chemical composition could be attributed to d ifferences in cu ltu ra l practices during the : ! cu lt iva tion o f the crop, stage o f harvesting o f the crop, clim atic conditions p reva ilin g , va r ie ty o f crop and handling and storage o f the residue (McDonald Edward and Greenhalgh, 1986). 40. University of Ghana http://ugspace.ug.edu.gh Residual N: In ammoniating straw with urea solution r ------ gaseous ammonia is released which produces NH^ OH in the presence o f water. This NH^ OH reacts with the straw to improve i t s feeding value. The reaction appears to be s im ilar to that o f anhydrous or aqueous ammonia both o f which have been proved e f fe c t iv e In improving the nu tr it ive value o f low qua lity roughages (Sundstol e t a l , 1978). Straw incubated with urea and a ired fo r 30 mins contained more residual N than straw a ired fo r 24h. Thus more o f the excess NH^ escaped when straw was a ired fo r 24h. Even though N-content o f straw depends on the le v e l o f urea used to trea t i t , Verma and Jackson (1984) reported that a th ird to h a lf o f the nitrogen applied as urea is lo s t when treated straw is aerated before feed ing. Straw U tiliz a t io n P ro jec t (SUP, 1986) reported that intake o f straw increased when urea ammoniated straw was aerated fo r about 24h. Residual N and IVOMD: The residual N analysed a ft e r 24 hrs f aeration may g ive an ind ica tion o f the le v e l o f unhydrolysed urea remaining on the straw a fte r incubation; as the moisture le v e l reduces and urea concentration increases, the amount o f unhydrolysed urea increases (F ig . 3 .1 ). 8% urea concentration f i therefore gave the highest residual N at 40% moisture. IVOMD decreased a ft e r 6.5% urea (F ig . 3 .4 ) at 40% and 50% moisture probably because there was not enough ammonia to break up the lign oce llu lo s ic bonds to render the straw more degradable. This ‘was probably due to the presence o f more unhydrolysed urea In the straw at 40 and 50% le v e ls . Thus 6.5% urea and 40% moisture gave the most e f fe c t iv e condition fo r hydrolysation and production o f ammonia. 41. University of Ghana http://ugspace.ug.edu.gh The highest amount o f residual N which was recorded with shorter periods o f incubation (F ig . 3.2 and 3 .3 ) compared to the longer period o f incubation could be explained by the fa c t that the longer the incubation period the higher the chance fo r microbes to hydrolyse the urea and thereby lower the residual N content. This is associated with higher NH^ which is reflectUcJin the higher IVOMD shown in F ig . 3.6 at 21 days. IVOMD: Ammoniation in general increased the organic matter (OM) d ig e s t ib i l i t y o f straw by 10-15 units (Arnason and Mo, 1977). The untreated straw used in th is experiment had an OM d ig e s t ib i l i t y o f 40.09% (Table 3 .2 ) and en s ilin g with 6.5% urea fo r 21 days increased the d ig e s t ib i l i t y o f straw OM by almost 15% units (F ig . 3 .5 ). Ammonia is a slow reacting agent but the e f fe c t o f ammoniation could be accelerated by increasing temperature (C loete and K r itz in ger , 1984). However, under ambient temperatures o f between 15 and 30°C, length o f treatment wauld be 1-4 weeks (Sundstol e£ a l , 1978). In the present experiment, 21 days was found to be sa tis fa c to ry when ambient temperature during the experiment was 28°C. Sundstol et_ a l (1979) reported that increasing the moisture ? content o f straw up to 50% increased the IVOMD o f ammoniated straw, while C loete and K riz tin ge r (1984) also reported an increase in d ig e s t ib i l i t y o f straw when moisture content was increased up to 37.5%. The optimum moisture le v e l (40%) observed in th is study is close to that obtained by Cloete and K ritz in ge r (1984). 3.5 ' CONCLUSION . The optimum conditions fo r en s ilin g r ic e straw with urea determined in th is experiment are 40% moisture le v e l , 6.5% urea and 21 days treatment period. treated straw fo r 24h is recommended. 42. University of Ghana http://ugspace.ug.edu.gh 43. CHAPTER 4 EXPERIMENT 2 4.0 TlTT.y.: E ffe c t o f type o f s i lo on the nu tr it ive value of urea ammoniated r ic e straw. 4.1 INTRODUCTION Various types o f s ilo s are ava ilab le to farmers. These include the earthern p it , bamboo s ilo s , baskets, cement containers ai^ sheds. In Ghana the practice o f ammoniating straw in s ilo s is not popular with farmers. The types o f s i lo to recommend w i l l depend on resu lts abtained in evaluation studies. The e f fe c t o f type o f s i lo on the nu tr it ive value o f ensiled straw was investiged by Ibrahim £ t a l (1983). They found bamboo baskets to be s im ilar to the earthern p it with a respect to e f fe c t on nu tr itive value o f straw. The ob jective o f th is experiment was to determine the e f fe c t o f type o f s i lo on the nu tr itive value o f ammoniated straw. 4.2 MATERIALS AND METHODS This experiment was carried out at the University o f t Ghana's A gricu ltu ra l Research Station, Legon. 4.2.1 Materials and Experimental Design: Three earthen p its , (150 x 90 x 75cm)/ 3 baskets (1/2 x 50 x 100cm) and 3 cement cu lverts (1/2 x 50 x 100cm) vere randomly placed in an open f spa'ce and used to determine the e f fe c t o f type o f s i lo on the nu tritive value o f urea-ammoniated r ic e straw. The s ilo s were lined' with polythene sheets and f i l l e d with about 50kg chopped University of Ghana http://ugspace.ug.edu.gh (3cm long) r ic e straw. The straw was put in layers o f about 16kg. Each la ye r was sprinkled wLth urea solution at the rate oi 3 ,75g urea/441cm water/kg straw. These rates were the optimun rates observed in Experiment 1. The straw was then pressed dowi and covered with polythene sheets kept in place by stones tc ensure a irtigh tness. A fte r a treatment period o f 21 days, the s ilo s were opened and straw samples taken from the top, middle and bottom la ye r and bulked fo r each s i lo . Samples were then subjected to the fo llow ing chemical analyses OM, NDF, ADF and IVOMD (AOAC, 1975). S ta t is t ic a l Analyses: Data were analysed using a completely randomised design. D ifferences were determined using Least square d iffe rences (LSD) procedures (Snedecor and Cochran, 1981). 4.3 RESULTS Table 4.1 shows the chemical composition and IVOMD o f straw samples taken from the various s ilo s . ■# Table 4.1: Chemical composition and IVOMD o f straw samples taken from the various s ilo s 44. Type o f s ilo N % NDF % ADF Hemi ce llu lo se IVOMD Basket 1.86 79.96 46.66 33.27 50.03 P it 1.94 76.17 37.60 * 38.57 52.65 Culvert 1.77 79.08 43.83 35.25 50.55 S.E.i 0.99 3.77 12.04 11.72 2.91 D ifferences among s ilo types were N.S. (P>0.05) University of Ghana http://ugspace.ug.edu.gh There were no s ign ifican t d ifferences w ith in s ilo s fo r the various parameters tested . Howsver, the earthern p it recorded then highest IVOMD and highest %N, N itrogen content was higher than the normal recorded fo r r ic e straw o f 1.03% In a l l s ilo s tested . 4.4 DISCUSSION Results obtained In th is experiment are comparable to those obtained by Saadullah ^ t a l (1981) in Bangladesh, who found earthern p it and bamboo basket s ilo s to have sim ilar e f f ic ie n c ie s in terms o f OMD and CP content. A l l three s ilo s used In th is experiment, the basket, the cement cu lvert and the earthern p it , do not d i f f e r s ign if ic a n t ly in terms at OMD and % N. Even though there vere no s ign ifican t d iffe ren ces in the earthern p it had a higher N-content and IVOMD than the other s i lo s . Thus in making a choice o f which s i lo to use, the earthern p it which i s the cheapest and most p ra c tica l could be the obvious choice even through much a lso depends on how much the farmer can a ffo rd . 45. University of Ghana http://ugspace.ug.edu.gh CHAPTER 5 EXPERIMENT 3 t 5.0 TITLE: E ffe c t o f urea ammoniation on rumen the degradation o f r ic e straw incubated in nylon bags. 5.1 INTRODUCTION The nylon bag technique is useful in g iv in g information as to the possib le extent o f d igestion or degradation in the rumen and the events that led up to i t i . e . the rate at which degradation occurs. This measurement o f rate i s pa rticu la r ly important because i t provides information on factors that a f fe c t intake o f roughages (Orskov and McDonald 1979). The ob jec tive o f th is experiment is to study the rate and po ten tia l extent o f d igestion o f urea ammoniated r ic e straw and thus obtain information re la tin g to voluntary intake o f the straw. 5.2 MATERIALS AND METHODS Location : This experiment was also carried out at the University o f Ghana's A gricu ltu ra l Research Station , Legon. Animals: Three rumen-cannulated sheep were used. They «e re fed the basal d ie t o f urea ensiled r ice straw. Sample: Two grammes each o f a ir-d r ied urea-ammoniated r lc e ; straw (Straw ensiled in an earthern p it at the rate o f 75g 3 urea/44lcm water/kg straw fo r 21 days was used), and untreated r ic e straw, ground to pass through a 2.0mm screen, were^ weighed into nylon bags which had been oven dried and treigiied. DM, N and NDF analyses were performed on samples o f i 46. University of Ghana http://ugspace.ug.edu.gh the joateria l p r io r to incubation and on residues fo llow ing incubation. Nylon bags: used were 8 x 12xm with pore s ize o f 25^U • Incubation: Bags containing samples were soaked fo r 3 min in siater to displace a ir before insertin g in to the rumen. Two bags were incubated per animal per sample per incubation time. Four bags were t ied to a drop lin e consisting o f nylon cord (200mm x 2mm) and weighted with a 20g s te e l bo lt at one end. Tw> drop lin e s were incubated at a time in the rumen, attaching the wire hook at the end o f the drop l in e to the f is tu la cap. Removal o f bags: Sets o f bags ware withdrawn a fte r 0, 3, 6, i 12, 24, 36, 48 and 72h. Unopened bags were dipped in to ethanol a ft e r removal from the rumen to a rrest fermentation. Bags were ind iv idua lly washed gen tly fo r 3 mins under running tap water. These bags, s t i l l unopened were then dried at 50°C to a constant vreight. The dried residue was analysed fo r DM and NDF. To determine in i t i a l washout o f DM, duplicate samples o f each roughage *rere placed in the rumen o f each sheep concurrently with other samples and then immediately removed. This value was subtracted from the amount remaining in bags at the respective hourly in terva ls to ca lcu late the percentage o f o r ig in a l DM remaining in bags fo r determination o f extent o f degradation. Rate o f DMD (Dm Disappearance) was determined by regressing the natural logarithm o f the percentage o r ig in a l DM remaining vs time according to procedures outlined by M ille r , (1980)'. 47. University of Ghana http://ugspace.ug.edu.gh S ta t is t ic a l Analys is: Data were subjected to analysis o f variance fo r a randomised complete block design with the straws as treatments and sheep as blocks. Treatment means vrere compared by athe method o f Least S ign ifican t D ifference protected by a s ign ifican t F-value (Snedecor and Cochran, 1981). 5.3 RESULTS Rate o f DMD from 3 to 72h and extent o f DMD at 0, 12 and 72h fo r urea ammoniated straw (TS) and untreated (US) r ic e straw are reported in Table 5.1. ^ ' Table 5.1: Rate and extent o f Dry matter disappearance (DMD) o f untreated (US) and urea-ammoniated (IS ) r ic e straw 48. Roughage Rate o f DMD (3 to 72h) Extent o f DMD (%) %/h 0 hr 12 hr 72 hr US 0.48 11.32 16.46 44.64 IS 0.74 8.14 17.51 58.97 Urea ammoniated straw (TS) had a higher rate o f DMD (0.74%/hr) than untreated straw (0.48%/hr), a 21% increase between US and TS. Except at 0 hr, extent o f DMD was higher in TS than in US at the times tested ( i . e . 12h and 72h). N itrogen content (N) and reutra l detergent f ib r e (NDF) values fo r US and TS a fte r incubation fo r 0, 12, and 72h are shown in Table 5.2. University of Ghana http://ugspace.ug.edu.gh 49. Table 5.2: Nitrogen and NDF contents o f untreated (US) and urea-ammoniated (T S )r ic e straw a ft e r incubation in the rumen o f sheep Period o f Incubation (h )___________ _ 0 12 72 N 0.93 1.24 2.60 JJS NDF 62.47 59.08 39.35 N 1.11 1.16 3.14 TS NDF 59.00 57.86 27.85 NDF was genera lly higher fo r US than fo r TS fo r a l l hours tested . Amount o f NDF a fte r incubation decreased from 0 to 72h by about f 23% in US and about 36% in TS. N itrogen content o f straw was genera lly lower fo r US than TS N itrogen content increased with increase in time o f incubation t i l l 72h fo r both treated and untreated straw being 3.14% and r- 2.60% respec tive ly . 5.4 ■ DISCUSSION The nylon bag technique id en t ifie d d iffe rences in rate and exteint o f DMD between ammoniated and untreated straw. The resu lts which agree with observations o f Alhassan and A liyu (1991) showed that' chemical treatment (o r urea ammoniation) increases both the rate and extent o f fermentation o f straw in the rumen. The e f fe c t o f ammoniation has been to cleave linkages between lig n in and hemibelluloses to make the la t t e r and also Cellu lose (which is embedded in the lign in -hem icellu lose complex) jmore accessib le fo r hydrjolyzing enzymes. As a resu lt, in th is experiment, University of Ghana http://ugspace.ug.edu.gh urea-ammoniated straw (XS) was degraded a t 72h about 14% more than untreated straw (US). The e f fe c t o f m icrobial enzymes on degradation begins to show at 12hr, but e f fe c t at 0 hr cannot be explained. Orskov and Kowalczyk (unpublished) as quoted by Orskov and McDonald (1979) a lso investigated the in te rac tion of chemical treatments using the nylon bag technique. A l l treatments investigated (SO2 , NH ,^ SO2 + NHg) had higher rates and extents o f DMD than the con tro l (untreated straw ). The SO2 being a source o f sulphur had a lower DMD at 72h (62%) than NH^ (71%). The combination o f both gave a higher DMD (80%) than e ith e r treatments. The importance o f rate o f degradation to the host animal is due to the fa c t that i t determines the speed a t vAiich the d ig e s t ib le components are removed from feed stu ffs and thus the time which the feed occupies space in the gut. From the resu lts o f th is experiment, TS would therefore be expected to be digested fa s te r and therefore have a higher turnover rate than US. This is indicated in Table 5.2 where c e l l wall contents decreased fa s te r in TS than in US. The increase in N fo r both TS and US is probably due to th e ' increased adherence o f rumen microbes to the c e l l walls o f the straw to e f fe c t degradation. Chesson and Orskov (1984) observed that chewing by the animal and methods o f feed preparation which maximize damage ( l ik e chopping and grinding)1 promote co lon isation and have a marked e f fe c t on rates, i f not t 1 on the u ltimate extent, o f degradation. 1 50. University of Ghana http://ugspace.ug.edu.gh 51. CHAPTER SIX EXPERIMENT FOUR THE POTENTIAL OF UREA-AMMQNIAIED RICE STRAW FOR DRY SEASON FEEDING OF SHEEP IN GHANA 6.1 INTRODUCTION Die u nava ilab ility o f good qua lity forage, espec ia lly during the dry season, as a major constraint to liv e s to ck production in the trop ics , and in Ghana fo r that matter, has been wall documented (Rose-Innes, 1960, Larsen and Amaning-Kwarteng, 1976, Alhassan and A liyu , 1991, Amaning-Kwarteng, 1991). Growth o f ruminants, during the dry season is represented by a sawtooth curve (Rose Innes, 1960) and on the Accra p la ins, Rose Innes (1960) estimated TOight ■a loss in c a t t le over the dry season to be 11% o f body weight. De Leeuw (as c ited by Alhassan and A liyu (1991) put the weight loss as 15-20% in c a t t le in Northern N igeria . Many studies have been undertaken to devise means of overcoming the dry season feed ing problem in Ghana by the use o f crop residues and agro-industria l by-products (Larsen and Amaning-Kwarteng, 1976, Addae, 1988, Amaning-Kwarteng, 1991). Amaning-Kwarteng et a l (1986) reported that NaOH - treated straw d ie ts provided more energy than required fo r maintenance fo r sheep and c a t t le in that the animals consumed over 1.5 times metabolizable energy r e la t iv e to th e ir respective 1 maintenance requirements. Alhassan and A liyu (1991) have a lso { j found that urea-ammoniation s ign if ic a n t ly increased intake o f University of Ghana http://ugspace.ug.edu.gh maize stover by ca tt le even though the d ie ts did not prevent c a t t le weight loss . The ob jec tive o f th is experiment was to quantify the po ten tia l o f urea-ammoniated r ic e straw in reducing dry-season weight loss by ca lcu lating ME consumption by the sheep r e la t iv e to th e ir maintenance requirement. 6.2 MATERIALS AND METHODS 6.2.1 Animals and management Six Nungua Black. Head x Djallonke vet hers weighing about 20kg live -w e igh t were used. Three o f the sheep were " in ta c t" and housed in ind ividual pens in an open-sided shed with elevated concrete f lo o r in g . The remaining 3 sheep were f i t t e d with permanent rumen cannulae (6.4cm diameter) and housed in ind ividual metabolism cages. Two weeks p r io r to the commencement o f the experiment the sheep wave in jected with a suspension supplying vitamins A, •s D and E and treated fo r both ecto - and endoparasites. A l l animals were veighed at the beginning and end o f each period and the ind ividual mean body weight fo r each period used to scale the nu tritiona l characteris tics measured. Water was ava ilab le to each animal ad l i b . 6.2.2 Diets t Rice straw ( lo c a l va r ie ty from Kpong Farms) was coarsely chopped (2-4cm p ieces) and subjected to 3 separate treatments which constituted the three experimental diets/treatments, A, B and C. 'i ' Diet A: Straw was not treated with any chemical but sprayed with mineral solution which supplied (g/kg) 79 water, 14.2 urea 52. University of Ghana http://ugspace.ug.edu.gh N, 1.0 S, 0.9 P and (mg/kg) 1.8 Cu and 0.11 Co. Limestone was then sprinkled on the straw to supply (g/kg) 1.0 Ca. The straw was not ensiled but kept in ju te sacs fo r at lea s t 7 days before feed ing. D iet B: Straw was sprayed with NaOH so lu tion (4 5 .6g NaOH in 113g water) fo llowed by a mineral so lution and limestone as fo r d ie t A. Straw was also not ensiled but stored as in d ie t A. D iet C: Straw was spread in an earthern p it (lm x lm x 1.25m) lined up with polythene sheets and each la ye r o f 16kg straw sprayed with a urea so lu tion (62.5g urea in 625ml water/kg straw ). Each p it was f i l l e d with 112kg straw. F il le d p its were covered with polythene sheets, fo llowed by heaps o f s o il and l e f t fo r 21 days before "excavating". Ensiled straw was a ired fo r 24h sprayed with minerals as fo r d ie t A, before feed ing. The mineral so lu tion here was devoid o f nitrogen. 6.2.3 Experimental design and feeding Each o f the 3 d ie ts was o ffe red to each sheep in a two 3 x 3 la t in square design. Each period comprised 15 days adaptation fo llo ved by 7 days sample co lle c t io n . Feed intakes ’sere measured d a ily and lOOg samples co llec ted d a ily and bulked. Sub-samples vere taken at end o f t r i a l and dried at 50°C fo r chemical analyses. Total faeces w re co llected d a ily , in to fa eca l bags attached to the sheep, and dried at 50°C. Dried samples were bulked fo r each animal over the co lle c t io n period. 6.2.4 Chemical analysis Feed, refusals and faeces samples were analysed fo r DM by drying in forced drought oven to a constant weight at 53. University of Ghana http://ugspace.ug.edu.gh 50°C. OM was determined as DM less the residual ash obtained a fte r ashing at 550°C fo r 16h. N was analysed by m icro-K jeldehl technique. NDF and ADL ware determined by the method o f Goering and Van Soest (1970). 6.2.5 S ta t is t ic a l Analysis Data were subjected to an analysis o f variance fo r two 3 x 3 la t in squares. In teractions between treatments and squares were not s ign ifican t and e f fe c t o f treatment was tested against residual mean square (4 d . f . ) . Treatment means ware compared on the basis o f the lea st s ign ifican t d iffe ren ce (Snedecor and Cochran, 1981). 6.3 RESULTS The chemical composition o f untreated r ic e straw and experimental d ie ts is shown in Table 6.1. There was an improvement in the CP o f a l l experimental d ie ts over the untreated straw. Table 6.2 shows the dry matter in take, organic matter d ig e s t ib i l i t y and metabolizable energy intake o f sheep fed the experimental d ie ts . There was a s ign ifican t (P<0.05) increase in r ic e straw intake 23.1 g/kg BW to 31.4g/kg BW as a resu lt o f treatment with urea. Organic matter d ig e s t ib i l i t y also increased by 2.8 percentage units with urea ammoniation. The metabolizable energy intake o f urea ammoniated straw was higher than untreated straw but lower than NaOH treated straw. 54. University of Ghana http://ugspace.ug.edu.gh Table 6.1: Chemical composition o f Untreated r ic e straw and 55. experimental d ie ts A (sprayed with only mineral so lu tion ), B (trea ted with NaOH and sprayed with mineral so lu tion and C (en siled with Urea and then sprayed with Urea-N fre e mineral so lu tion ) (Values are means o f three analyses per sample) Chemical Untreated Test Diets Component Straw A B C % Dry Matter (DM) 90.9 88.6 83.3 68.8 Composition on DM basis (%) Organic Matter 84.3 81.8 78.1 76.5 Crude prote in 4.32 13.0 12.6 14.9 NDF 75.9 75.6 66.2 54.5 ADL 8.25 8.21 7.45 6.88 University of Ghana http://ugspace.ug.edu.gh 56. Table 6.2: Dry Matter (DM) intake, organic matter (OM) d ig e s t ib i l i t y and metabolizable energy intake (MED. re la t iv e to maintenance energy requirements (Mm) by sheep fed d ie ts A, B and C* (Values are means o f five"sheep per d ie t ) ' P a r a m e t e r D A i e t B C SE (4 d . f . ) Mean l i v e weight (kg) 19.9 20.1 20.0 DM Intake (g/d) 46.0 71.9 62.8 20.6 (g/kg BW) 23.1 35.7 31.4 2.35 Apparent OM D ig e s t ib il i t y (%) 53.8 60.3 56.6 0.82 DOMI (g/d) 20.2 33.9 27.2 12.6 DOMD (%) 43.9 47.2 43.4 3.15 MEI (MJ/d) 3.03 5.09 3.50 0.46 Mm (MJ/d) 3.79 3.81 3.80 0.63 MEI/Mm 0.80 1.34 0.92 0.081 DOMD = D igestib le organic matter In dry matter. MEI = Metabolizable energy intake = DOMD x 0.15 x Dry matter intake (MAFF, 1975) Mm = Maintenance energy requirement 1.2 + 0.13 BW (where BW is body weight in Kg. (MAFF, 1975). DOMI = D igestib le OM intake. University of Ghana http://ugspace.ug.edu.gh 6.4 DISCUSSION That NaOH - treated straw is able to support maintenance energy requirement has been reported by severa l workers (Jackson 1977, Kellaway e£ a l . , 1978, Amaning-Kwarteng, et a l . , 1986); Amaning-Kwarteng, 1991). t In the present study urea ammoniated straw could not provide a l l required maintenance energy but showed 15% improvement over the urensiled straw. In a s im ila r study in Northern N igeria Alhassan and A liyu (1991) observed that urea-ammoniated maize straw could not prevent weight lo ss , hovever, the w igh t decline in animals consuming the treated straw was 15-20% smaller than observed fo r c a t t le in the eco log ica l zone. The present study suggests that with l i t t l e supplementation, such as with leguminous shrubs (Amaning-Kwarteng, 1991) urea ensiled straw could supply maintenance needs o f ruminants during the dry season. 57. University of Ghana http://ugspace.ug.edu.gh CHAPTER 7 GENERAL DISCUSSION 58. Treatment conditions a ffe c t in g urea ammoniation as discussed by Guessous et a l (1989) are urea le v e l , length o f treatment, moisture content o f straw, environmental temperature, urease a c t iv ity and type and qua lity o f material e being treated . The optimum urea le v e l , moisture content and treatment time fo r en s ilin g straw in th is study ware found to be 6.5%, 40% and 21 days respec tive ly at an ambient temperature o f 28^C. These resu lts are s im ilar to those obtained by Guessous et a l (1989) whose optimum conditions were 6% urea concentration at 30% moisture. Jayasuriya (1985) also recommended 4-5% urea concentration and treatment period o f 3-4 weeks. Contrary to these resu lts however, Alhassan and A liyu (1991) obtained optimum conditions to be 4% urea concentration and incubation period o f 7 days. This d isparity could be due to the d iffe ren ce in straw type used in both experiments; while r ic e straw was used in the present study, Alhassan and A liyu (1991) used maize straw. Table 2.2 and 2.3 show d iffe ren ces in composition between straw types which could account fo r the d ifferences in optimum conditions fo r ammoniation. The optimum values obtained in th is study were used to en sile r ic e straw fo r nylon bag degradability studies (Chapter I I 5) and Intake D ig e s t ib il ity Studies (Chapter 6 ). University of Ghana http://ugspace.ug.edu.gh Ensiling with urea in the above experiments increased dry matter disappearance and increased dry matter intake and d ig e s t ib i l i t y o f r ic e straw because the l ig n o -c e llu lo s ic bonds had already been loosened by the presence o f ammonia from urep. This action therefore enhances the d ig e s t ib i l i t y . Residual-N is a lso more e f fe c t iv e ly u t iliz e d with the greater a v a ila b il it y o f easrgy in the ensiled materia l. Even though the equation used in Chapter 6 is used under temperate conditions, i t has been used here to estimate the po ten tia l o f urea ammoniated straw as a maintenance d ie t . This meets the requirements o f a maintenance feed given by Devendxa (1985) as a crude p rote in le v e l o f 6-7%, a dry matter d ig e s t ib i l i t y o f 50-55% and a dry matter intake o f about 1.7% o f body weight. Where th ere 's the need to turn over animals fo r marketting, urea ammoniated r ice straw could be used as an id ea l basal d ie t with some amount o f d ietary supplementation to provide extra energy and bypass protein . 59. University of Ghana http://ugspace.ug.edu.gh 60. CHAPTER 8 CONCLUSION The optimum conditions required to en s ile r ic e straw with urea in Southern Ghana are 6.5% urea concentration, with 40% moisture content and stored fo r 21 days. -Rice straw treated th is way changed i t from a poor qua lity feed to a medium qua lity , which has the po ten tia l to maintain livew eigh t o f sheep. The type o f s i lo to be used is determined by how much the ind ividual farmer can a ffo rd . University of Ghana http://ugspace.ug.edu.gh 61. REFERENCES Addae, M.K. (1988). A review o f current research in the use o f Agro-based by-product in feeding liv e s to ck in Ghana. B.Sc. D issertlon , Animal Science Department, University o f Ghana, Legon. Adebowale, E.A. (1985). Organic waste ash as possib le source o f a lk a li fo r animal feed treatment, Anim Feed Sc i. Technol. J l : 237-248. Adu, I .F . and Lakpini, C.A. (1983). 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(1986) Supplemented prote in degradation, bacter ia l p rote in synthesis and nitrogen retention in sheep eating sadium-hydroxide treated straw. B ritish Journal o f Nu trition , 55: 557-569. AmanLng-Kwarteng, K. (1991) Sustaining Dry-Season Feeding o f Ruminants in Ghana. The use o f crop residue and leguminous shrubs as Ruminant Feedstuffs in Ghana. In Animal Feed Resources Network Workshop (Ed ito r, John E.S. Stores, Abdullah N. Said Jackson A. K a te g ile ), Addis Ababa, , Ethiopia: PANESA/ARNAB. Anderson, D.C. (1978). Use o f Cereal Residues in Beef Cattle Production Systems. J. Animal Sci. 46: 849^861. Association o f O f f ic ia l Ana ly tica l Chemists (A .O .A .C .) (1975). O f f ic ia l Methods o f Analysis, 12th Ed ition . Washington, D.C.: Association o f O f f ic ia l Ana ly tica l Chemists. Arnason, J. and Mo, M. (1977). Ammonia treatment o f straw. . Report on Straw U tiliz a t io n Conference, Oxford 24-25 | February. M inistry o f A gric . F isheries and Food. 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S. A fr . J. Anim. S c i. 14: 55-58. Crabtree, J.R. and W illiams, G.L. (1971). The Voluntary intake and U tiliz a t io n o f roughage-concentrate d ie ts by sheep. Animal Production 13: 71-82. De Leeuw, P .N ., (1971). The Prospects o f L ivestock Production in the Northern Guinea Savanna Zone. Samaru Agric . Newsl. 13: i 24-133. Devendra, C. (1985). Forage supplements: Po ten tia l value in feeding systems based on crop residues and agro-industria l by-products i'n South East Asia, In : Proceedings o f an In ternational Workshop on relevance o f crop residues and animal feeds in developing countries (Eds. Wanapat and Deveddra) Thailand­ ' s .i University of Ghana http://ugspace.ug.edu.gh 6 3. Dolberg, F ., Saadullah, M., Hague, M. and Ahmed, R. (1981). Storage o f urea-treated straw using indigenous m ateria l. World A—m^ Res. ^8: 37-41. Doyle, P.T. (1982). Options fo r the treatment o f fibrous roughages in developing countries. A review In : The u t i l isa tion—of fibrous agricu ltu ra l resideus as animal feeds (Ed. Doyle, P .T .) Australian Government P rin ting Services, Canberra. Du Preez, M., (1983) H id ro lise , n it r if ik a s e en vervlungtig ing van uream onder gekontroleerde toestande in dominante grondtipes van d ie wes-keep. M.Sc. verhaudeling. Un iversitat van stellenbosch. Economides, S. (1986). By-product u t i l iz a t io n in ruminant d ie ts in Cyprus. In : Towards optimal feeding o f A gricu ltu ra l by-products to liv e s to ck in A fr ic a . Proceedings o f a workshop in Egypt by A frican Research Network fo r A gricu ltu ra l by-products (ARNAB). ILCA, Ethiopia. Fianu, F .K ., Atta-Krah, M.K. and Koram, K. (1972). Some aspects o f dry season nu trition o f small ruminants in Ghana. Proc. 5th Ani. S c i. Symp. pp. 96-103. Goering, H.K. and Van Soest (1970). Forage Fibre Analysis (Apparatus, Reagents, Procedures and Some Applications) Agricu lture Research Station , U .S.D .A., Agricu lture Handbook No. 379, Washington D.C. Guessous, F ., Rihani, N ., Kabbali, A. and Johnson, W.L. (1989). Improving feeding systems fo r sheep in a mediterranean . ra in -fed cerea ls/ livestock area o f Morocco. J. Anim. Sci. JiZ: 3080-3086. Ibrahim, M.N.M., Fernando, D.N.S. and Fernando, S.N.F.M., (1983). Evaluation o f methods o f urea-ammonia treatment app lication at v i l la g e le v e l . Australian-Asian Fibrous A grlc . Residues Research Network, Univ. Peradeniya, S ri Lanka, 18-22 A p r il. Jackson, M.G., (1977). The a lk a li treatment o f straws. Animal Food Sc i. & Technol. g : 105-130. Jackson, M.G. (1978). Treating Straw fo r animal feeding - an assessment o f i t s technical and economic fe a s ib i l i t y . World Ani. Rev. 28: 38-43. Jayasuriya, M.C.N. (1985). Po ten tia l fo r the better u t i l iz a t io n o f crop residues and agro-industria l by-products in animal feeding in Indian sub-continent. In : B etter U t il iz a t io n o f * crop residues and by-products in animal feed ing: research gu idelines. F.A.O. Paper 50. F.A .O ., Rome. University of Ghana http://ugspace.ug.edu.gh 64. Jayasuriya, M.C.N. and Perera, H.G.D. (1982) Urea-ammonia treatment o f r ic e straw to improve i t s nu tr it ive value fo r ruminants. Agric . Wastes 143-150. Jones, L.H .P. and Handrick, K.A. (1965) J. A gric . Sci. j|5: 129. Jonas, L.H.P. and Handrick, K.A. (1967). S il ic a in s o ils , plants animals. Advances in Agronomy. 19.: 107-149. Kellaway, R .C ., C ro ft, F .C ., Thiago, L .R .C ., Redman, R.G. and L e ib o lz , J.M.L. (1978). A New Technique fo r upgrading the nu tr it ive value o f roughages under f i e ld conditions. Animal Feed Sci. & Technol. J_: 201-210. K r itz in ge r , N.M. and Franck, F. (1981). Die e ffe k van ureuminkuiling op d ie in v i l r o verteerbaarheid van koringstroo i. E ls . J. 5 (1 ) , 15. Larsen, R.E. and Amaning-Kwarteng, K. (1976). Cassava peels with urea and molasses as dry-season supplementing feed fo r c a t t le . Ghana Journal o f A gricu ltu ra l Science J.: 43-47. Latham, M .J., Hobbs, D.G. and Harris, P .J . , (1979). Adhesion o f rumen bacteria to a lk a li- trea ted plant stems. Ann. Rech. Vet. 10: 244-245. McDonald, P. Edwards, R.A. and Greerihalgh, J.F.D. (1986). Animal Nutrition . Longman S c ien t if ic & Technical, Essex, England. P .416-429. McManus, W.R. (1981). Forage Evaluation Concepts and Techniques, p.103. [J .L . Wheeler and R.D. Mochrie, e d ito rs ]. Melbourne: Commonwealth S c ien t if ic and Indu stria l; Research Organisation. McManus, W.R., Grout, L .L . , Malin, A .S ., Robinson, V.N.E. Anthony, R .G ., (1979). Ensilage from a lk a li- trea ted roughages. Aust. J . Exp. A gric . Anim. Husb. i£ : 354-361. M ille r , E.L. (1980). In v ic ia Faba Feeding value Processing and viruses, p. 17 (D.A. Bond, E d ito r ). The Hague: Martinus N ijh o f. Minato, H. and Suto, T ., (1978). Technique fo r fra c tion a tion o f bacteria in the rumen m icrobial ecosystem. I I . Attachment o f bacteria iso la ted from bovine rumen to ce llu lo se in v it r o and e lu tion o f bacteria attached therefrom. J. gen. Appl. M icrobiol. 24: 1-16. t Minton, D.J. (1971). The D ig e s t ib il i t y and Voluntary Intake o f s ix Panlcum va r ie t ie s . Aust. J. Exp. A gric . Anim. Husb. 11; 18-25. -----------------— — :------------------------ Minson, D.J. (1976). R elation betwaen D ig e s t ib il i t y and Composition o f Feed - A review. Wageningen Miscellaneous Papers. 12: 101-114. ----- -----------------------------c = University of Ghana http://ugspace.ug.edu.gh 65. Mosi, A.K. and Lambourne, L .J ., (1982). Research experiences in the A frican Research Network on A gricu ltu ra l By-products (ARNAB). In : By-products u t i l iz a t io n fo r animal production. B. K iflewahid, G.R. Potts and Drysdale (ed s ). IDRC-206e. Ottawa, Canada. * Nour, A.M. (1986). U t ilis a t io n o f r ic e straw on small farm in Egypt:* In : Towards optimal Feeding o f A gricu ltu ra l By-products to liv e s to ck in A fr ica . Proceedings o f a Workshop held at the Un iversity o f A lexandria, Egypt, October, 1985 by ARNAB 72-78. O ji, U .I. Mowat, D.N. and Winch, J .E ., (1977). A lk a li treatments o f com stover to increase nu tr itive value. J. Anim. Sci. M : 798-802. Orskov, E.R. and McDonald, I . , (1979). The estimation o f protein degradab ility in the rumen from incubation measurements weighed according to rate o f passage. J. A gric . Sci. (Camb.) 12: 499-503. Orskov, E .R ., Reid, G.W., Holland, S.M., Ta it, C.A.G. and Lee, N.N. (1983). The feeding value o f straw and whole crop barley and oats treated with anhydrous or aqueous ammonia or urea, Ani. Fd. Sci. Techn. 8, 247. Otchere, E.O., Dadzie, C.B.M., Erbynn, K.G., and Ayebo, D.A. (1977). Response o f sheep to r ice straw or cassava peels f o r t i f ie d with urea and molasses as supplemental feeds to grazing. Ghana Jnl A gric . Sci. 10, 61-66. Pearce, G.R. (1984). Factors contributing to va r ia tion in the nu tr it ive value o f fibrous agricu ltu ra l residues. In : The u t i l is a t io n o f fibrous agricu ltu ra l residues as animal feeds. (Ed. Doyle, P .T .) Australian Government Printing Services, Caribera. Pigden, W.J. and Bender, F. (1972). U t il iz a t io n o f lign oce llu lo se by ruminants. World Anim. Rev. 7-10. Preston, T.R. (1986). Better U t iliz a t io n o f crop residues and by-products in animal feed ing: research gu idelines. 2. A p ractica l manual fo r research workers. F.A.O. Paper 50/2, * F.A.O. Rome. Preston, T.R ., and Leng, R.A. (1987). Manipulation o f feeding and the rumen ecosystem. In : Matching ruminant production systems with ava ilab le resources in the top ics and sub-tropics. The Technical Centre fo r A gricu ltu ra l and • Rural Cooperation (C .T .A .) publication. Penanbul Books, Armidale. Rees, M.C., and L i t t l e , D.A. (1980). D ifferences between Sheep and Cattle in D ig e s t ib il ity , Voluntary Intake and Retention Time in the Rumen o f Three Tropical Grasses. J. A gric . S c i., 94: 483-485. ~ University of Ghana http://ugspace.ug.edu.gh 66. Rose-Innes, R. (1960). F irs t Grassland Symposium, p .55. Accra, Ghana: M inistry o f Agricu ltu re. f Rose-Innes, R. and Marbey, G.L. (1964) Studies on browse plants in Ghana. 1. Chemical composition (a ) Monthly Chemical analyses o f seven species o f trees , shrubs and vines browsed by free-ranging c a t t le on the Accra P la ins. Empire J. Exp. A gric . 32: 114-124. Saadjollah, M., Hague, M. and Dolberg, G. (1981). E ffectiven ess o f ammonification through urea in improving the feeding value o f r ic e straw in ruminants Trop. Anim. Prod. 30-36. Smith, O.B. (1987). U t iliz a t io n o f crop residues in the nu trition o f sheep and goats in the humid trop ics o f West A fr ica . In : Sheep and goat production in the humid trop ics o f West A fr ica . F.A.O. Paper ZQ: 92-113. Smith, O.B. and Osafo, E.K. (1987). S trateg ies fo r improving the u t i l iz a t io n o f cocoa-pod based d ie ts by ruminants Anim. Feed Sc i. Technol. ( In P ress). Snedecor, G.W. and Cochran (1981). S ta t is t ic a l Methods. IOWA State University Press, Ames, Iowa. Solaiman, S.G., Horn, G.W. and Owens, F.N. (1979). Ammonium hydroxide treatment o f wheat straw. J. Amm. Sc i. 49: 802-808. Sundstol, F. and Coxworth, E.M. (1984). Ammonia Treatment. In : Straw and other fibrous by-products as feed . Eds. F. Sundstol and E. Owen. E lsev ie r Science Publishers, Amsterdam, pp. 146-247. Sundstol, F ., Said, A .N ., and Arnason, J. (1979). Factors in fluencing the e f fe c t o f chemical treatment on the nu tr itive value o f straw. Acta. A gric . Scand. 29: 179-190. Sundstol, F ., Coxworth, E. and Mowat, D.N. (1978). Improving the nu tr it ive value o f straw and other low qua lity roughages by treatment with ammonia. Wld. Anim. Rev. 26: 13-21. Suriyajantratong, W. and Senetas, U. (1985). Y ie ld and N u tritive value o f groundnut vines at the ped-harvesting stage. In proceedings o f an In ternational warkshop on relevance o f crop residues as animal feeds in developing countries (Eds. , Wanapat and Devendra) Thailand, 1985. S.U.P. (1986). Straw U tiliz a t io n P ro ject Report No. 11. Techniques o f straw treatment with urea. S ri Lanka. I University of Ghana http://ugspace.ug.edu.gh 67. T i l ly , J.M. and Terry, R.A. (1963). Tto stage technique fo r the in v it ro d igestion o f forage crops. Journal o f B ritish Grassland Society 18: 104-111. Van Soest, P .J. and Jones, L.H.P. (1968). E ffe c t o f S i l ic a in forages upon d ig e s t ib i l i t y . J. Diary Sci. 51: 1644. Verma, M.L. and Jackson, M.G. (1984). Improved U t il iz a t io n o f A gricu ltu ra l Waste Materials and Indu stria l By-products as L ivestock Feed. Research Progress Report, p .14. G.B. Plant Un ivers ity , Pantnagar. Wanapat, M., Praserdsuk, S ., Chanthai, S. and Sivapraphagon, A. (1982). Improvement o f r ic e straw u t i l iz a t io n by urea-ensiling and/or supplementation with cassava chip fo r c a t t le during the dry season. In P .T. Doyle (e d . ) : The U til iz a t io n o f Fibrous Residues as Animal Feeds, University o f Melbourne Prin ting Services. University of Ghana http://ugspace.ug.edu.gh APPENDIX 1 Calculation o f amounts o f urea and water added to straw in Experiment 1 Moisture le v e l DM content o f a ir dry straw = 86.4% . . moisture content o f straw = 13.54% To ra ise th is to 40% moisture le v e l , 40 = 135.4 + x 100 1000 + x per kg 4(1000 + x ) = 10(135.4 + x) 6x = 2646 x = 441cm^/kg straw i i . 50% moisture le v e l 50 = 135.4 + x 100 1000 + x 5000 + 5x = 1354 + lOx 5x = 3646 x = 729.2cm^/kg straw i i i . 60% moisture le v e l 60 = 135.4 + x 100 1000 + x 4x = 4646 x = 1161.5cm^/kg straw Urea concentration i ) 3.5% urea DM of straw = 0.8646 3.5 x 1000 100 0.8646 “ 40.48g urea/kg straw i i ) 5.0% urea 1 5/100 x 1000 0.8646 = 57.83g urea/kg straw 68. University of Ghana http://ugspace.ug.edu.gh 69. , i i i ) i v ) 6.5% urea 6.5 x 1000 100 0.8646 = 75.15g urea/kg straw 8.0% urea 8/100 x 1000 0.8646 = 92.53g urea/kg straw University of Ghana http://ugspace.ug.edu.gh 70. SUMMARY OF ANOVA FOR VARIOUS PARAMETERS STUDIED IN EXPERIMENT 1 APPENDIX II Source df N 2 M/S PROBABILITY NDF ADF Hemlcell. IVOMD n 2 NDF ADF !Hemlcell.1• IVOMD TIME (A ) 2 0 . 1 1 1.30 2.01 3.35 2.36 0.18 0.43 f 0.21 : 0.31 0.01 UREA (B ) 3 0.02 4.27 1.69 0.75 2.24 0.04 0.07 0.27 I 0.83 0.01 MOIST (C) 2 0.05 0.22 1.62 2.28 1.69 0.03 0.85 0.28 : 0.43 f 0.03 A x B 6 0.003 3.00 2.11 3.54 2.25 0.76 0.13 0.17 : 0.30 0.53 B x C 4 0.006 0.36 0.27 1.56 2.76 0.38 0.95 0.91 : 0.72 0.40 A x C 6 0.17 0.92 1.58 1.77 3.01 0.05 0.64 0.29 ' 0.61 0.37 A x B x C 12 0.05 1.4 1.14 2.59 2.53 t 1 T O T A L 35 * t t University of Ghana http://ugspace.ug.edu.gh 71. SUMMARY OF ANOVA FOR VARIOUS PARAMETERS TESTED IN EXPERIMENT 2 APPENDIX III M/S PROBABILITY Source df N2 NDF ADF Hemicell. IVOMD N2 NDF ADF Henri c e l l . IVOMD Rep. 2 0.067 5.207 26.510 24.206 0.821 0.727 0.133 0.473 0.473 0.457 S ilos 2 1.289 11.759 64.441 2i.521 3.962 0.053 0.041 0.218 0.508 0.061 Error 4 0.193 1.491 28.220 26.718 0.918 0.011 0.109 0.011 0.041 0.240 T O T A L 8 University of Ghana http://ugspace.ug.edu.gh