Factors influencing the growth of meat animals

Growth in animals is an increase in the mass of diverse tissues that continues at various rates during the lifetime of an animal. The patterns and processes of growth will be briefly described. Methods to measure growth and the influence of “animal” factors including physiological age, gender and breeding on growth will be summarized. “Nonanimal” factors including systems for describing the nutrient requirements for growth and the use of exogenous substances such as steroid hormones, β2 agonists and gut-active compounds and the potential of gene manipulation to enhance growth will be reviewed. Growth in utero, with an emphasis on the impact of maternal nutrition during pregnancy and nutritional influences during postnatal growth together with evidence of epigenetic influences on animal growth will be discussed. The chapter will conclude with some comments on future developments in, and challenges to, meat animal production.