156 Scientific Journal of Review (2013) 2(7) 156-175 ISSN 2322-2433 Various factors influencing birth weight in animal production N. Assan* Department of Agriculture Management, Faculty of science and Technology, Zimbabwe open University. * Corresponding author; Department of Agriculture Management, Faculty of science and Technology, Zimbabwe open University. A R T I C L E I N F O Article history, Received 17 July 2013 Accepted 24 June 2013 Available online 30 July 2013 Keywords, Environmental Genetic parameters Birth Livestock A B S T R A C T This is a review article that looks at various factors that influence birth weight in animal production. Birth weight is an important indicator of potential growth of an animal and is affected by both genetic and non-genetic factor, and the birth size depends on their interaction. Environmental conditions such as kind and quality of feed and details of management may have an influence on birth weight in livestock production. In order to minimize the adverse effects of factors that influence birth weight, it is perhaps important to understand the implications of different mechanisms, how and why they affect birth weight. Low birth weight than optimum is the main factor that determine the pre weaning losses of young ones and large birth have been associated with difficult birth. Traditional measures to ameliorate birth associated negative effects should also focus on maternal dietary manipulation which may influence optimum birth weight. Nutritional programs designed to improve dam’s body condition during pregnancy will have a positive influence on birth weight of progeny. A good knowledge of genetic parameters is essential to develop accurate selection indices and to optimally design breeding programs and performance recording systems for maximum economic gain or profit from growth traits. Estimates of genetic parameters for birth weight is model dependent and ignoring of maternal genetic effect in the model leads to overestimation of direct heritability for birth weight. Estimates of direct and maternal heritability for birth Contents lists available at Sjournals Journal homepage, www.Sjournals.com Review article