Department of Animal Science
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Item Feed the Future Innovation Lab for Genomics to Improve Poultry: a holistic approach to improve indigenous chicken production focusing on resilience to Newcastle disease(World's Poultry Science Journal, 2024) Zhou, H.; Baltenweck, I.; Kayang, B.B.Small-scale poultry production in Africa plays a significant role in alleviating malnutrition and poverty in rural communities. Global climate change and infectious poultry disease such as Newcastle disease (ND) have had tremendous negative impact on poultry production and health due to limited biosecurity, cold chain, and inadequate extension service. Genetic selection for enhanced resis tance to ND virus (NDV) offers a promising complementary approach to vaccination and biosecurity in addressing constraints in village production systems. The Feed the Future Innovation Lab for Genomics to Improve Poultry (GIP IL) has led an effort on the identification of genetic markers, genes and signalling pathways associated with enhanced resistance to NDV by conducting NDV challenging experiments in diverse inbred, commercial, and African indigenous chickens. The GIP IL developed a comprehensive genetic selection platform focusing on improved survival time and reduced virus shedding in the face of NDV infection and on enhanced growth rate and egg production. The programme applied the platform for genetic selection and breeding of indigen ous chickens through velogenic NDV natural exposure trials. To improve our understanding of the epidemiology of NDV in Africa, we characterised circulating strains of the virus in Ghana and Tanzania and identified NDV risk factors among local chickens. These data contribute to a body of knowledge useful for guiding disease control efforts, informing vaccine strategies, enhancing biosecurity, and contributing to our overall understanding of NDV dynamics. To gauge the demand for genetically improvedItem Population Structure and Genomic Characterisation of the Ashanti Dwarf Pig of Ghana(Animals, 2024) Aryee, S.N.D.; Owusu-Adjei, D.; Osei-Amponsah, R.; et al.There is still limited information on the genomic structure and genetic diversity of African pigs. Genetic diversity studies can contribute significantly to the genetic improvement and conser vation of African pigs. This study presents a genetic diversity analysis and population structure of pig breeds in Ghana, with a focus on the Ashanti Dwarf pig (ADP), an indigenous pig breed of Ghana. A total of 167 pigs sampled in Ghana and populations consisting of Ashanti Dwarf pigs (n = 106), exotics (mostly European pigs) (n = 11), crosses (between indigenous and exotic breeds) (n = 44), and unknown breeds (nondescript) (n = 6) were genotyped using Porcine SNP60K BeadChip. Moderate heterozygosity levels, ranging from 0.28 for Ashanti Dwarf pigs to 0.31 for exotic pigs (mostly European pigs), were observed. Principal component analysis of the pig populations within Ghana resulted in two distinct clusters of pigs: (i) Northern and (ii) Southern regional clusters. The PCA based on breed also resulted in four clusters: (i) ADPs; (ii) exotics (iii) crossbreeds between ADP and exotics; (iv) unknown breed types. The PCA demonstrated that the clustering was influenced by genetics, geographical location, production systems, and practices. ADMIXTURE-based analysis also showed that the populations within Ghana are admixed. FST analysis revealed SNPs associated with QTLs for traits such as disease resilience and growth among ADP populations within the different regional and ecological zones of Ghana.Item Genetic architecture of body weight, carcass, and internal organs traits of Ghanaian local chickens(Frontiers in Front. Genetics, 2024) Kanlisi, R.A.; Amuzu-Aweh, E.N.; Naazie, A.; et al.Information on the genetic architecture of the production traits of indigenous African chicken is limited. We performed a genome-wide association study using imputed Affymetrix Axiom® 600K SNP-chip genotypes on 1,113 chickens from three agroecological zones of Ghana. After quality control, a total of 382,240 SNPs remained. Variance components and heritabilities for some growth, carcass and internal organ traits were estimated. The genetic and phenotypic correlations among these traits were also estimated. The estimated heritabilities of body weight at week 22 (BW22), average daily gain (ADG), dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight were high and ranged from 0.50 to 0.69. Estimates of heritabilities for head weight, shank weight, and gizzard weight were moderate (0.31–0.35) while those of liver weight, back weight, dressing percentage, and heart weight were low (0.13–0.21). The estimated heritabilities of dressed weight, breast weight, wing weight, drumstick weight, neck weight, shank weight, and gizzard weight, corrected for BW22, were moderate (0.29–0.38), while the remaining traits had low heritability estimates (0.13–0.21). A total of 58 1-Mb SNP windows on chromosomes 1, 2, 4, 5, 6, 7, 8, 9, 13, 18, and 33 each explained more than 1% of the genetic variance for at least one of these traits. These genomic regions contained many genes previously reported to have effects on growth, carcass, and internal organ traits of chickens, including EMX2, CALCUL1, ACVR1B, CACNB1, RB1, MLNR, FOXO1, NCARPG, LCORL, LAP3, LDB2, KPNA3, and CAB39L. The moderate to high heritability estimates and high positive genetic correlations suggest that BW22, ADG, dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight could be improved through selective breedingItem Dorper sheep in Africa: A review of their use and performance in different environments(CABI Reviews, 2023) Ojango, J.M.K.; Okpek, M.; Osei-Amponsah, R.; et al.The Dorper breed developed in South Africa is used either as a pure breed or crossbred with existing indigenous breeds by many countries across the African continent to improve sheep production. This article presents documented information on the adoption, use, and performance of Dorper sheep across the continent of Africa and opportunities for their more sustainable production under the changing climatic conditions in Africa. Apart from the well-documented information on the Dorper sheep in South Africa, published information on the performance of the sheep is mainly from Eastern Africa. Most countries initially retained purebred Dorpers in nationally owned institutions for multiplication and crossbreeding trials with different indigenous breeds prior to distributing the crossbreds to diverse livestock keepers. The offspring produced through crossbreeding programs with the Dorper have better growth rates than indigenous breeds in the different countries; however, the performance of Dorper sheep in South Africa has not been achieved in any of the other countries. Genomic studies including Dorper sheep have identified regions of interest for resistance to brucellosis and Mycoplasma ovipneumonia that imply adaptability to challenging environments within Dorper sheep. Unfortunately, limitations in systems for guided breeding and monitoring of sheep productivity in Africa have resulted in haphazard crossbreeding of the Dorper. Targeted efforts are required across the different countries to develop breeding programs for improving locally adapted Dorper sheep populations and their crosses with indigenous breeds. New science and technologies need to be innovatively packaged and used to identify and propagate more productive and resilient Dorper and Dorper-based breed-types for the increasingly challenging tropical African range environmentsItem Impact of heat stress on ruminant livestock production and meat quality, and strategies for amelioration(Animal Frontiers, 2023) Chauhan, S.S.; Zhang, M.; Osei-Amponsah, R.; et al.Climate change will continue to accentuate the negative impact of heat stress (HS) on ruminant livestock production, compromising animal welfare and meat quality. • Mitigation strategies, including providing shade on farms, modifications of animal housing (heat extractors, fans, water sprinklers, and cool drinking water), and nutritional interventions, are important short-term measures to reduce the negative effects of HS. • Climate-smart breeding for thermotolerance and matching of adapted ruminant breeds to appropriate production systems should be considered for more sustainable livestock production systems.Item Spatial variability of herbage yield, grazing capacity and plant diversity in a tropical savannah rangeland ecosystem(African Journal of Range & Forage Science, 2023) Anane, N.D.; Ayizanga, X.; Sarkwa, F.O.; et alTo improve ruminant livestock production, evaluation of rangelands must be a routine. Rangeland evaluation gives information about the vegetation structure, biomass yield and quality. The Guinea savannah rangelands of Ghana lack research that characterises the spatial variability of herbage yield and quality. It was hypothesised that there is spatial heterogeneity in herbage yield, grazing capacity and plant diversity in the Guinea savannah rangelands of Ghana. The objective was to evaluate the spatial structure of herbage production and grazing capacity in the Guinea savannah rangelands of Ghana for sustainable livestock production. Data were collected from 105 sampling sites and integrated into geo-statistics, using ordinary kriging interpolation to generate herbage yield and grazing capacity estimates. Herbage yield and grazing capacity ranged from 0.63 t ha−1 to 13.43 t ha−1 and 0.18 LU ha−1 to 3.79 LU ha−1 respectively. The root mean square error and the average standard error values were close (2.38 and 2.51 respectively for herbage yield and 0.67 and 0.71 respectively for grazing capacity). Species diversity using the Shannon’s index ranged from 1.13 to 2.40. There was spatial heterogeneity in herbage yield, grazing capacity and species diversity in Ghana’s Guinea savannah rangelands with some parts needing effective site-specific improvement strategies for sustainable livestock production.Item Herder-Farmer Conflicts Amidst Covid-19 Pandemic in West-Africa(Ghanaian Journal of Animal Science, 2021) Hagan, B.; Timpong-Jones, E.C.; Osei-Amponsah, R.n West Africa, transhumance has been a major system of cattle production in which herders trav el with their herds in search of adequate pasture and water. Unfortunately, the perennial conflicts between the transhumant herders and crop farmers have had negative effects on agricultural pro duction. The objective of this review was to document among others such negative impacts and how COVID-19 has influenced transhumance activities in West Africa. The review was carried out using published articles on the subject from journals, books, online sources and semi-formal inter action from key stakeholders. Climate change, diversification of land use, land tenure systems, perceptions about pastoralists, porous entry points, absence of grazing corridors and failure to ad here to the conditions of the ECOWAS protocol on transhumance were some of the major causes of herder-farmer conflicts. Destruction of crops and animals, loss of human life, rural-urban mi gration, poor living conditions and destruction of homes are some of the major impacts of the herder-farmer conflicts in West Africa. Public education on transhumance, government interven tion and the ability to monitor and adhere to the ECOWAS protocols on transhumance by all countries in the region would help minimize these conflicts. Furthermore, all stakeholders should play their roles and help find innovative and sustainable ways of feeding transhumant cattle in West Africa.Item Association of Phenotypic Markers of Heat Tolerance with Australian Genomic Estimated Breeding Values and Dairy Cattle Selection Indices(Animals, 2023) Osei-Amponsah, R.; Dunshea, F.R.; Leury, B.J.; Abhijith, A.; Chauhan, S.S.Dairy cattle predicted by genomic breeding values to be heat tolerant are known to have less milk production decline and lower core body temperature increases in response to elevated temperatures. In a study conducted at the University of Melbourne’s Dookie Robotic Dairy Farm during summer, we identified the 20 most heat-susceptible and heat-tolerant cows in a herd of 150 Holstein Friesian lactating cows based on their phenotypic responses (changes in respiration rate, surface body temperature, panting score, and milk production). Hair samples were collected from the tip of the cows’ tails following standard genotyping protocols. The results indicated variation in feed saved and HT genomic estimated breeding values (GEBVs) (p ≤ 0.05) across age, indicating a potential for their selection. As expected, the thermotolerant group had higher GEBVs for HT and feed saved but lower values for milk production. In general, younger cows had superior GEBVs for the Balanced Performance Index (BPI) and Australian Selection Index (ASI), whilst older cows were superior in fertility, feed saved (FS), and HT. This study demonstrated highly significant (p ≤ 0.001) negative correlations (−0.28 to −0.74) between HT and GEBVs for current Australian dairy cattle selection indices (BPI, ASI, HWI) and significant (p ≤ 0.05) positive correlations between HT and GEBVs for traits like FS (0.45) and fertility (0.25). Genomic selection for HT will help improve cow efficiency and sustainability of dairy production under hot summer conditions. However, a more extensive study involving more lactating cows across multiple farms is recommended to confirm the associations between the phenotypic predictors of HT and GEBVs.Item Poultry health constraints in smallholder village poultry systems in Northern Ghana and Central Tanzania(Frontiers in Veterinary Science, 2023) Ouma, E.A.; Kankya, C.; Kayang, B.B.; et al.Introduction: Smallholder poultry production is a major contributor to food security and rural livelihoods in low-and middle-income countries. However, infectious diseases limit improvements to smallholder poultry production and performance of the sector in general. Infectious diseases of poultry, especially viral diseases, have major impacts on the health and productivity of flocks and account for significant morbidities and mortalities of birds each year. Methods: This study utilized participatory epidemiology approaches to better understand the poultry health constraints and challenges faced by smallholder poultry producers in village poultry systems in Northern Ghana and Central Tanzania. Results: The results show dominance of small-scale semi-intensive and extensive scavenging poultry production systems in the study areas. Newcastle disease ranked as the highest cause of morbidity and mortality in chickens in the two countries. The disease occurred mainly during the months coinciding with the dry season in both countries. Other health challenges among poultry flocks included worm infestation, fowl pox, coryza, and coccidiosis. Producers, especially in rural locations, had poor access to veterinary services and critical inputs necessary for poultry production. In the Northern region of Ghana, producers lacked definitive diagnoses for sick poultry due to a shortage of veterinary personnel and diagnostic laboratories. Discussion: These challenges point to the need for increased investment in poultry disease control and prevention programs, particularly in rural areas. Interventions focused on expansion of veterinary and agricultural extension services and diagnostic laboratory capacity in rural areas and increased gender sensitive training to enhance smallholder knowledge in poultry husbandry and disease prevention measures will support the development of the smallholder village poultry systems. Tapping into the diverse genetic reservoir of local chicken ecotypes with enhanced resistance to Newcastle disease through genomic selection, coupled with models for enhancing ND vaccination supply and use in the rural areas are potential future avenues for addressing ND constraints to productionItem Smallholder poultry production in the context of increasing global food prices: roles in poverty reduction and food security(Animal Frontiers, 2023) Birhanu, M.Y.; Osei-Amponsah, R.; Obese, F.Y.; Dessie, T.Item Assessment of the reproductive performances of native sows in Southern Benin(Oxford university press, 2021) Djimènou, D.; Adoligbé, C.M.; Aboh, A.B.; Amagnidé, A.G.; Osei-Amponsah, R.; Edénakpo, A.K.; Tobada, P.C.; Koudandé, D.O.Native sows contribute to a large extent to food security and poverty alleviation in Benin. However, their reproductive performance particularly under extensive systems is poorly characterized. The objective of this study was to fill this knowledge gap by selecting 284 multiparous sows based on hair color and some re productive parameters. The results showed that native sows of Southern Benin can be clustered into three groups with group 3 showing the best reproductive performances including highest average litter size (LS, 10.31 piglets), live-born piglets (LBP, 10.31 piglets), number of functional teats (10.94), and shorter average farrowing interval (6 mo). The analysis of sows’ performances based on their origin revealed that sows from agro-ecological zone 8 have the highest number of LBP and the lowest age at first mating and first farrowing. The analysis of sows’ performances based on the hair color showed that those with black hair have the largest LS and the highest number of LBP. This study showed that Benin’s native sows have good reproductive ability with enough variation to develop a sustainable pig industry for a better contribution to food security and wealth creation.Item Strategies to Upgrade Animal Health Delivery in Village Poultry Systems: Perspectives of Stakeholders From Northern Ghana and Central Zones in Tanzania(Frontiers, 2021) Enahoro, D.; Galiè, A.; Abukari, Y.; Chiwanga, G.H.; Kelly, T.R.; Kahamba, J.; Massawe, F.A.; Mapunda, F.; Jumba, H.; Weber, C.; Dione, M.; Kayang, B.; Ouma, E.Village chicken production holds much potential for the alleviation of malnutrition and poverty in rural communities in Africa. Owing to their subsistence nature, however, such systems are rife with infectious poultry diseases such as Newcastle disease (ND). Strategies common for the management of ND and other poultry diseases in intensive production systems, including vaccination and biosecurity measures, have seen limited success in the village production systems. New approaches are needed that can successfully deliver animal health inputs and services for the effective management of poultry health challenges in low-input systems. Our study utilized focus group discussions with men and women farmers as well as other poultry value chain actors such as input suppliers, live bird traders and processed poultry meat retailers, to investigate potential options for delivery of animal health care to village poultry systems in northern Ghana and central Tanzania. ND was commonly reported as a major disease constraint in the study sites of the two countries, with resulting fatalities particularly impactful on men and women producers and on traders. We therefore also conducted interviews that focused specifically on the gender component of village chicken production. The key health related challenges prioritized by women and men participants included limited access to, and poor quality of, vaccines and veterinary drugs, a shortage of veterinary officers, and insufficient knowledge and training of farmers on flock management practices. Women, more than men, emphasized the difficulties of accessing poultry health services. Our assessments suggest that for poultry health care delivery in the studied communities to be effective, there is need to improve the supply of good quality drugs and vaccines in rural areas, respond to the needs of both men and women, and recognize the different incentives for farmers, traders and other value chain actors. Community-based approaches and increased use of ICT technology such as mobile phones have much to offer in this regard.Item Bulk‐up synchronization of successive larval cohorts of Anopheles gambiae and Anopheles coluzzii through temperature reduction at early larval stages: efect on emergence rate, body size and mating success(Malaria Journal, 2021) Zubair, Q.; Matthews, H.; Sougoufara, S.; Mujeeb, F.; Ashall, S.; Aboagye‑Antwi, F.; Tripet, F.Background: Malaria persists as a huge medical and economic burden. Although the number of cases and death rates have reduced in recent years, novel interventions are a necessity if such gains are to be maintained. Alterna‑ tive methods to target mosquito vector populations that involve the release of large numbers genetically modifed mosquitoes are in development. However, their successful introduction will require innovative strategies to bulk-up mosquito numbers and improve mass rearing protocols for Anopheles mosquitoes. Methods: The relationship between mosquito aquatic stage development and temperature was exploited so that multiple cohorts of mosquitoes, from separate egg batches, could be synchronized to ‘bulk-up’ the number of mos‑ quitoes released. First instar larvae were separated into two cohorts: the frst, maintained under standard insectary conditions at 27o C, the second subjected to an initial 5-day cooling period at 19o C. Results: Cooling of 1st instars slowed the mean emergence times of Anopheles coluzzii and Anopheles gambiae by 2.4 and 3.5 days, respectively, compared to their 27o C counterparts. Pupation and emergence rates were good (>85%) in all conditions. Temperature adjustment had no effect on mosquito sex ratio and adult fitness parameters such as body size and mating success. Conclusions: Bulk-up larval synchronization is a simple method allowing more operational fexibility in mosquito production towards mark-release-recapture studies and mass release interventionsItem Comparison of early growth and survivability in indigenous guinea fowls from Northern Ghana(Tropical Animal Health and Production, 2021) Ahiagbe, K.M.J.; Amuzu-Aweh, E.N.; Bonney, P.; Nyameasem, J.K.; Avornyo, F.K.; Adenyo, C.; Amoah, K.O.; Naazie, A.; Kayang, B.B.Three guinea fowl populations from Northern Ghana were compared in terms of their body weight, growth rates, and survivability during the first 11 weeks of life. Keets (n = 865) were hatched from eggs collected from 32 sampling areas divided into eleven subpopulations within three populations in Northern Ghana. Together with an experimental flock maintained at Animal Research Institute (ARI flock), these birds were raised and appraised for weekly body weights, weekly growth rates, and survivability. Weekly body weights did not differ significantly (p > 0.05) among the three populations, although ARI flock were significantly heavier (p ˂ 0.05) compared to the main populations until the fourth week. In contrast, among the subpopulations, significant differences emerged in body weights from the second week and were more pronounced from the sixth week. Growth rates measured as weekly weight gains also differed significantly among subpopulations beyond the second week, although differences in growth rates were not significantly different among whole populations. The mean values for total feed intake, daily feed intake, and feed conversion ratio (FCR) did not vary significantly (p > 0.05) between the populations. Therefore, although the variations in body weight and growth rates were limited among the populations, there existed significant variations among subpopulations, creating opportunities to establish genetically divergent populations for growth rate and to improve early growth rates and body weights in local guinea fowls by selection. High survivability observed in the ARI flock compared to keets from the three populations of Northern Ghana was likely due to good breeder stock management practices despite their common ancestry.Item Impact of heat stress on the growth performance and retail meat quality of 2nd cross (Poll Dorset × (Border Leicester × Merino)) and Dorper lambs(Meat Science, 2021) Zhang, M.; Warner, R.D.; Dunshea, F.R.; DiGiacomo, K.; Joy, A.; Abhijith, A.; Osei-Amponsah, R.; Hopkins, D.L.; Ha, M.; Chauhan, S.S.The present study investigated the impact of heat stress and genetics on lamb growth performance and meat quality. Forty-eight Dorper and 2nd cross [Poll Dorset × (Border Leicester × Merino)] lambs (38-–42 kg; 4–5 months old) were allocated to either thermoneutral [TN; 18–21 ◦C, 45–55% relative humidity (RH)], or heat stress (HS; 28 ◦C–38 ◦C, 40–60% RH) conditions in a 2 × 2 factorial design for 2 weeks. Compared with 2nd cross, Dorper lambs had a lower respiration rate (RR) and rectal temperature (RT), and exhibited less decline in body weight under HS. 2nd cross lambs showed a higher body weight gain than Dorpers under TN conditions. HS increased a* and chroma of the Longissimus thoracis et lumborum (LTL) from 2nd cross lambs over 10 days of display, but had no impact on Dorper LTL. In conclusion, Dorpers showed higher heat tolerance compared with 2nd cross lambs during the 2 weeks HS.Item Sustainable genomic research for food security in sub‑Saharan Africa(Agriculture & Food Security, 2021) Aryee, S.N.D.; Owusu‑Adjei, D.; Osei‑Amponsah, R.; Skinner, B.; Sowatey, E.Although traditional selective breeding has had a tremendous impact on both livestock and crop production in Africa, this has not kept pace with the high demand for animal and plant products on account of increasing urbanization, improved livelihoods and a rapidly growing human population. These challenges justify the need for more innovative and sustainable ways of improving animal and crop production to meet this demand. Over the last two decades the potential of genomics as a key tool to achieve improvement in desirable phenotypic traits has revolutionized the field of applied animal and plant biology. However, well informed use of such techniques has yet to be fully exploited within the context of local resources and capacity-building. The objective of this review is to highlight the rich agricultural biodiversity of sub-Saharan Africa, the potential of genomics in their sustainable use for food security, the challenges of genomic research and the strategies that can be adopted to overcome them in the implementation of agricultural genomic research in Africa. The lack of state-of-the-art laboratory research facilities, skilled human resources, poor funding and non-availability of scientific research resources, paucity of collaborative links between African researchers and a lack of engagement between key stakeholders in the agricultural value chain were identified as major barriers that affect agricultural genomic research in Africa. Finally, the recommended strategies to overcome these challenges will guide policy-makers, researchers, development partners and key stakeholders in the smooth advancement of sustainable agricultural genomic research for improved food security in Africa.Item Sustainable genomic research for food security in sub‑Saharan Africa(Agriculture & Food Security, 2021) Aryee, S.N.D.; Owusu‑Adjei, D.; Osei‑Amponsah, R.; Skinner, B.; Sowatey, E.; Sargent, C.A.Although traditional selective breeding has had a tremendous impact on both livestock and crop production in Africa, this has not kept pace with the high demand for animal and plant products on account of increasing urbanization, improved livelihoods and a rapidly growing human population. These challenges justify the need for more innovative and sustainable ways of improving animal and crop production to meet this demand. Over the last two decades the potential of genomics as a key tool to achieve improvement in desirable phenotypic traits has revolutionized the field of applied animal and plant biology. However, well informed use of such techniques has yet to be fully exploited within the context of local resources and capacity-building. The objective of this review is to highlight the rich agricultural biodiversity of sub-Saharan Africa, the potential of genomics in their sustainable use for food security, the challenges of genomic research and the strategies that can be adopted to overcome them in the implementation of agricultural genomic research in Africa. The lack of state-of-the-art laboratory research facilities, skilled human resources, poor funding and non-availability of scientific research resources, paucity of collaborative links between African researchers and a lack of engagement between key stakeholders in the agricultural value chain were identified as major barriers that affect agricultural genomic research in Africa. Finally, the recommended strategies to overcome these challenges will guide policy-makers, researchers, development partners and key stakeholders in the smooth advancement of sustainable agricultural genomic research for improved food security in Africa.Item Effect of slaughter age and post-mortem days on meat quality of longissimus and semimembranosus muscles of Boer goats(Meat Science, 2021) Abhijith, A.; Warner, R.D.; Ha, M.; Dunshea, F.R.; Leury, B.J.; Zhang, M.; Joy, A.; Osei-Amponsah, R.; Chauhan, S.S.This study investigated the effects of age of animal and days post-mortem (PM) on meat quality of Boer goats. Twenty-four (24) wether Boer goats of two age groups (2YO group: 2 years old and 9MO: 6–9 months, with 12 animals/group) were slaughtered in a commercial processing plant. The pH@Temp18 was estimated to be above 6 in both age groups with higher (P < 0.01) values in 2YO goats. The PM storage for 14 days reduced the shear force in both age groups (P < 0.01). 2YO goat muscles (longissimus and semimembranosus) exhibited higher (P < 0.01) Thiobarbituric acid reactive substance values (TBARS), indicating increased lipid oxidation. Glycogen (P < 0.01) and lactate content (20 min post-slaughter) in longissimus of 9MO were lower compared to 2YO, and total muscle glycogen concentration was lower (P < 0.01) in both age groups below the threshold levels. Hence, as hypothesized, age and days PM proved to play crucial roles on Boer meat quality.Item Heat Stress Impacts on Lactating Cows Grazing Australian Summer Pastures on an Automatic Robotic Dairy(animals, 2020-05-17) Osei-Amponsah, R.; Dunshea, F.R.; Dunshea, B.J.; Cheng, L.; Cullen, B.; Joy, A.; Abhijith, A.; Zhang, M.H.; Chauhan, S.S.The objective of this study was to measure the impacts of summer heat events on physiological parameters (body temperature, respiratory rate and panting scores), grazing behaviour and production parameters of lactating Holstein Friesian cows managed on an Automated Robotic Dairy during Australian summer. The severity of heat stress was measured using Temperature-Humidity Index (THI) and impacts of di erent THIs—low ( 72), moderate (73–82) and high ( 83)—on physiological responses and production performance were measured. There was a highly significant (p 0.01) e ect of THI on respiratory rate (66.7, 84.7 and 109.1/min), panting scores (1.4, 1.9 and 2.3) and average body temperature of cows (38.4, 39.4 and 41.5 C), which increased as THI increased from low to moderate to high over the summer. Average milk production parameters were also significantly (p 0.01) a ected by THI, such that daily milk production dropped by 14% from low to high THI, milk temperature and fat% increased by 3%, whilst protein% increased by 2%. The lactation stage of cow had no significant e ect on physiological parameters but a ected (p 0.05) average daily milk yield and milk solids. Highly significant (p 0.01) positive correlations were obtained between THI and milk temperature, fat% and protein% whilst the reverse was observed between THI and milk yield, feed intake and rumination time. Under moderate and high THI, most cows sought shade, spent more time around watering points and showed signs of distress (excessive salivation and open mouth panting). In view of the expected future increase in the frequency and severity of heat events, additional strategies including selection and breeding for thermotolerance and dietary interventions to improve resilience of cows need to be pursued.Item Administration of melatonin improves testicular blood flow, circulating hormones, and semen quality in Shiba goats(Theriogenology, 2020-01-30) Nyametease, P.; Samir, H.; Elbadawy, M.; Nagaoka, K.; Sasaki, K.; Watanabe, G.Despite the role of melatonin in the regulation of the sleep-wake cycle and seasonal-reproduction, the present study investigated, for the first time, the potential role of melatonin on testicular blood flow (TBF) in goats. Twelve sexually mature male Shiba goats were exposed to a single s.c. injection of either melatonin suspended in one ml of corn oil (melatonin group; 36 mg/goat; n ¼ 5) or one ml of corn oil (control group; n ¼ 7). Monitoring the changes in TBF was done one week before (W-1), at the time of injection (W0), and once a week for 8 weeks after injection using color-pulsed Doppler ultrasonography. Concentrations of FSH, LH, inhibin, testosterone (T), estradiol (E2), and insulin-like growth factor-1 (IGF- 1) in plasma were determined by radioimmunoassay. Melatonin and nitric oxide (NO) concentrations were measured using enzyme immunoassay kits. Moreover, semen collection and evaluation of some sperm parameters were performed once a week. Results revealed decreases (P < 0.05) in the Doppler indices (resistive index, pulsatility index) of the testicular arteries from W2 till W6 in the melatonin group. FSH, LH, and inhibin concentrations did not change between the two groups, while T, E2, IGF-1, NO, and melatonin concentrations increased (P < 0.05) in the melatonin group compared to the control. Estradiol and NO concentrations increased (P < 0.05), coinciding with decreases in the values of Doppler indices. Notable (P < 0.05) improvements in most parameters of semen quality were seen in the melatonin group. In conclusion, melatonin induced a stimulatory effect on TBF in Shiba goats and possibly, it could be a potential to improve male goats fertility