Scientific Journal of Review <p>Scientific Journal Review (SJR) an Open Access Journal, is an international interdisciplinary research journal on all aspects of science and technology. It provides a unique forum to place your ideas, articles of general interest, research article, commentaries, book reviews, review articles, and anything of interest to the scientific community. Articles from different branches of science and technology are promptly made available to the wide range of readers after peer review. Being an open access journal, articles are freely available online, and those interested may read online or download articles in pdf format.</p> SJournals en-US Scientific Journal of Review 2322-2433 Dam breed effect and other dam related non-genetic factors as determinants of growth traits in goats and sheep production <p>Ewes/does individual performance is a prime factor that influence the overall meat productivity and profitability in goat and sheep production. The number of kids/lambs born per ewe/doe per year, effectively weaned and marketed at a desirable weight are absolutely essential components for the viability of any commercial goat and sheep enterprise. Hence one principal source of substantial meat production inefficiency in commercial goat and sheep production is poor maternal effects which compromise high kid/lamb growth, where a larger proportion of kid/lamb crop fails to attain desirable marketable weight resulting in immense economic losses. There is apparent evidence accrued through extensive studies in goats and sheep which point to the fact that heredity of the dam and other dam related non-genetic factors such as parity order, dam nutrition, age and weight of dam at kidding/lambing and the dam’s body condition score influence kid/lamb pre-weaning growth trait and the actual weight at weaning. In this respect, birth weight, pre and post weaning weight gain of kids/lambs may vary with dams’ genotype, parity, dams’ nutrition, litter size as a dams’ trait, dam weight/age and parity order. The resultant effect of genotype of dam on kid/lamb growth can be direct or indirect, firstly there is a direct contribution of half of the dams’ genes to the progeny for potential growth of kids/lambs, and secondly the indirect effect comes from dam possessing genes for milk production enough to adequately nurse their kids/lambs hence promoting desirable growth. It is important to note that dam milking capacity is dependent on breed, in addition to being influenced by other environmental factors such as dam nutrition and parity order. Kid/lamb born to high milk producing dams are highly likely to outclass their counterparts in post weaning growth weight gain, as well as the actual weaning weight. Low birth weight kid/lamb are associated with poor nutrition of dams during pregnancy and its effects could be seriously felt in multiple birth which result in compromised post weaning growth. Genetics is a primary source of variation for prolificacy in goats and sheep hence litter size can be designated as a maternal trait. The higher the size of birth the lower the weaning weight because of nursing competition due to multiple birth in large litter size. Mature dams give birth to heavier kids and provide enough milk to nursed kids/lambs promoting faster growth rates subsequently enhancing survivability of kids/lambs. There is potentiality of manipulation of husbandry practices focusing on ensuring that all born kids/lambs are as close as possible to the acceptable birth weight average for that specific breed of choice which can sustain desirable weaning and post weaning growth. It should be noted that due to multifaceted nature of the dam determinants of growth traits it is reasonable to assume that appreciation of specific cause and occurrence of kids’/lamb growth could be advantageous to minimize retarded growth rates. A total control of kid/lamb growth is probably unachievable as a result partly targeting the control of both environmental and dam-related factors is critical. High kid/lamb growth rates necessitate for good management practices and improved dam nutrition to support nursing of multiple birth, in addition to the exploitation of crossbred’s heterosis to promote growth in kids/lambs. The present review gives an insight on the influence of dam related factors on pre and post-weaning growth, as well as actual weaning weight in goat and sheep production.</p> Never Assan Copyright (c) 2020 Never Assan 2020-03-20 2020-03-20 9 3 616 633 Sex, age of animal and weight at slaughter as explanatory variables for carcass and meat quality properties in goats and sheep production <p>Slaughtering kids/lambs at specified age and weight of specialized goat and sheep meat breeds might promote high muscle deposition and a desirable carcass fat cover, culminating into meat with a more adequate nutritional profile and health properties for human consumption. In this case, animal factors such as sex, age and weight at slaughter play a central role as the primary explanatory variables on meat yield and quality of carcass parameters in goat and sheep production. The discussion on determinants of carcass and meat quality properties is complex given that the diversity of goat and sheep meat breeds, both early and late maturing is considerable, over and above exploited as is the practice in non-identical production systems. Of interest goats and sheep in most cases are accordingly slaughtered at different weights and age, and on the other hand, specific markets have preferred sex of animal for slaughter. However, taking cognisance of the above, carcass and meat parameters are influenced by various non-genetic effects, hence the knowledge on these factors and their interactions becomes of paramount importance in order to produce desirable meat quality for specified markets and consumers’ preference. A linear relationship between carcass yield with age at slaughter has been reported in goats and sheep, there is a tendency of carcass weight increasing as the age of the animal increases. Sex dependency on carcass and meat parameters has been inconsistent in goats and sheep, however, most studies show that sex greatly influence carcass and meat quality properties. Compromised dressing percentage in goats and sheep due to higher slaughter weight, could be explained by the lightest animals lacking perfectly developed digestive tracts. Against this background, age at slaughter explicitly influences meat quality, particularly with regards to tenderness of meat derived from young animals. The differential carcass status in young and mature animals is due to increased fat deposition in older animals than in younger ones, while fat tissue increases with increased slaughter weights. Complexity of determination of desirable carcass and meat parameters is ascribable to interaction of many variables, hence it is imperative to appreciate the role of each component by appropriately factoring their influence in any slaughter decision, where animals could be slaughtered at given age and weight to meet specified objectives of a particular market requirements. Producers operating in different production systems might not duplicate factors such as age, weight and sex of slaughter because they utilise different genotypes, and the prescribed nutritional regime in non-identical production systems will weigh heavily on the outcome of carcass and meat parameters. The interaction of all these factors (genotype and non-genetic factors) at different levels as influenced by the market expectations will decide the economics of goat and sheep meat production. This present review will give an insight on some non-genetic effects that influence carcass and meat quality properties namely sex, age and weight at slaughter.</p> Never Assan Copyright (c) 2020 Never Assan 2020-03-20 2020-03-20 9 3 634 643