Bernice Sefakor _Studies on Various Treatment Conditions Affecting Urea-Ammoniated Rice Straw in Ghana

Abstract

Four experiments were undertaken to evaluate the e f fe c t of various treatment conditions on the nu tr itiv e value of 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 Nitrogen content, neutral detergent fib 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% re sp e c tiv e ly . In Experiment 2, the optimum conditions obtained in Experiment 1 were used to treat r ic e straw which was then stored in d iffe r e n t types o f s i lo (earthern p i t , cane basket and cement cu lv e r t) 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 culvert had 1.55% and 1.10% N and 50.03 and t 48.21 IVOMD respec tiv ely . The in situ rate of ruminal dry matter (DM) I , disappearance (DMD) (3-72h) and extent o f DM disappearance (72h) investigated in Experiment 3 indicated that urea ammoniated 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 ic e straw. Urea treatment s ig n ific a n t ly increased straw intake but did not prevent sheep freight los s 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.