CHAPTER ONE
1.0 INTRODUCTION
The size and age of sheep and goats are normally related to their productivity (Solomon and Kassahun, 2009). Larger sized animals usually produce more meat than smaller animals. Size is commonly represented by weight, though other linear measurements can be used. The size of an animal should be considered in relation to its age allowing for evaluation of growth performance used as a component in deciding which animals to buy, sell, cull or mate. Body weight is measured not only to evaluate carcass yield (Afolayan et al., 2006) and condition of the animal as a selection criterion but also to determine suitable medication dosage during health care and required feed amount of the animal (Kunene et al., 2009). Goat farming has increased in the tropics and is important for economic and social livelihood of the large human population, contributing meat, milk and clothing in domestic markets (Kosgey et al., 2006).
The economic importance of goats and sheep in the livelihood of rural African people cannot be overemphasized. They play a pivotal role in the rural economy as sources of meat and milk and their processed products such as cheese, wool and hair (including monhair) and skins. Economic and environmental benefits are derived from dung (which improves soil fertility and structure) and from nutrient recycling, and also income generation (FAO, 2009). Goat production in Nigeria contributes significantly to the agrarian economy. Various factors are within the environment which dictates the performance of animals, and these factors include rainfall, temperature, relative humidity, wind movement, solar radiation. The effect of these environmental factors can mediate through reduction or increase in feed intake, weight gain, plane of nutrition, diseases, reproductive performance and feed efficiency (Imasuen and Otoikhian, 2004).