Journal of Biology, Agriculture and Healthcare www.iiste.org ISSN 2224-3208 (Paper) ISSN 2225-093X (Online) Vol.5, No.24, 2015 95 Relationship between Birth Weight and Body Growth of Awassi Lambs during Early Weaning Mysaa Ata 1 * 1 Department of Animal Production and Protection, Faculty of Agriculture, Jerash University P.O. Box 311, Jerash 26110, Jordan Hani Hamad 2 2 Department of Food Science and Nutrition, Faculty of Agriculture, Jerash University P.O. Box 311, Jerash 26110, Jordan Abstract A study was conducted to find the relationship between body weight of male and female Awassi lambs at birth with their body development at early weaning period. Sixty lambs were used and divided into two groups (I, II). Each group was consisted of 30 lambs and divided into two subgroups (15 male and 15 female). Groups formed according to body weight at birth as follows: Group I, lambs with less than 3kg of weight; and Group II, lambs with more or equal than 3 kg of weight. Lambs were kept with their mothers and suckling ad libitum throughout the experimental period and were weighed at birth day (1 day old), at 30 days, and at 60 days. Differences between groups of lambs at 60 days of age were significant (p<0.05). Correlations ranged from low to moderate among the respective traits and ranged between positive from 0.505 to 0.762 and negative from - 0.181 to -0.513. Highest correlation in this study found between age (1-60) in male lambs (0.762) and in female lambs (0.659) of group II. The correlation coefficient effect at 60 days of age was higher in males than females lambs (p<0.05) where the correlation coefficient was 66% for male and 50% for female lambs. Therefore, lambs with heavier birth weights, showed the best production results in the development of body weight during the period of 60 days of early weaning process, which indicated that selection of lambs with greater birth weight may contribute to increasing Awassi lamb body development and growth. Keywords: Awassi sheep, Body growth, Correlation, Early weaning. 1. Introduction Animal Production occupies a large area in agriculture production in Jordan since its accounts for 55% of the value of agricultural production. Moreover, sheep production has a huge importance in animal production as the number of sheep reached 2311105 head consisting about 132885 head of lambs from total number of sheep (DOS, 2014). Awassi sheep breed capable to adapt to different climate conditions. Its production is based on a semi-intensive system distinguished by low offspring production but by high milk and meat production (Pollot and Gootwine, 2004). This breed is native to the Mediterranean area and it’s the most important breed in Jordan (Abdullah and Tabbaa, 2011; Dikmen et al., 2007). Dual purpose ewes, such as Awassi breed ewes, produces a high amount of milk that may exceed the requirement of normal lamb development and growth (Bocquier et al., 1999; Pollot and Gootwine, 2004; Reiad et al., 2010). Higher daily milk production occurs mostly during the first month of lactation (Akçapinar, 2000), when this milk is being used in a traditional rearing system for lambs to suckle. Therefore, it will be hard on producers to get benefit of such milk. As a result, a sheep producer has to wait until weaning, which reduces the income from the sheep herd because of lower milk production (Gargouri et al., 1993; McKusick et. al., 2001). Weaning defined as the withdrawals of milk from lambs suckle their dams, while early weaning is the withdrawal of the milk supply before the time when weaning would normally occur. Early weaning may be achieved successfully by the speed of lamb’s rumen development (Wardrop, 1960). It was also reported that rumen function develops very fast after birth until about 8 weeks of age, lambs consumes solid feed can digest it efficiently as adults (Al-Laham, 2007). The objective of early weaning for lambs is to increase the efficiency of milk production by dams and fattening lambs most rapidly by offering solid feed. It appears on theoretical grounds that lambs can be successfully weaned at any time after about 8 weeks of age. This theoretical prediction has been experimentally verified by Ward et al., (2008) who found that lambs weaned at 8 weeks of age had the same growth rate as un-weaned controls. Many studies showed how lamb’s body growth and development affected by genetic and non-genetic factors. Unfortunately, little attention addressed to the connection between body weight of lambs at birth and their early weaning weight. To effectively define the selected criteria, it is important to know the following: How lamb’s weight at birth affects body growth and weight during the weaning process. Therefore, the aim of this study was to explore the relationship between body weight of male and female Awassi lambs at birth with their body development at early weaning (period of 60 days).