Portal de Periódicos da CAPES

Birth weight, and pre- and postweaning growth rates of lambs belonging to the Afec-Assaf strain and its crosses with the American Suffolk

2013; Elsevier BV; Volume: 113; Issue: 1 Linguagem: Inglês

10.1016/j.smallrumres.2013.02.015

1879-0941

A. Rosov, E. Gootwine,

Reproductive Physiology in Livestock

We evaluated the contribution of the American Suffolk, a known terminal sire breed, to growth traits of lambs born to Afec-Assaf ewes. By contemporaneous comparisons during 10 lambing periods, birth weight, preweaning and postweaning Average Daily Gain (ADG) of Afec-Assaf lambs (n = 1301), 1/2 Suffolk lambs (n = 98), 1/4 Suffolk lambs (n = 598) and 1/8 Suffolk lambs (n = 237) were compared. On average (mean ± SD) lambs' birth weight, weaning age, weaning weight, final weight and final age were 4.5 ± 1.2 kg, 35 ± 6 days, 14.7 ± 3.3 kg, 54.7 ± 8.2 kg and 153 ± 12 days, respectively. Preweaning, postweaning and overall ADG was: 294 ± 66, 343 ± 62 and 330 ± 53 g/day, respectively. Birth weight of 1/2 Suffolk, 1/4 Suffolk and 1/8 Suffolk lambs, all born to Afec-Assaf ewes, did not differ (P > 0.05) from that of Afec-Assaf lambs. Lambs belonging to the 1/2 Suffolk and 1/4 Suffolk crosses had higher (P < 0.05) preweaning and postweaning ADG than Afec-Assaf lambs. The difference in total ADG between Afec-Assaf and 1/2 Suffolk lambs was about 22 g/day, leading to an estimated body weight difference of 3.3 kg between lambs of the two genotypes at the age of 150 days. Genetic analysis suggested no significant (P > 0.05) differences between the Suffolk and Afec-Assaf in birth weight or in postweaning ADG. However, additive, heterosis and recombination effects significantly (P < 0.05) contributed to the difference between the two genotypes in preweaning ADG, and additive and heterosis effects significantly (P < 0.05) contributed to the difference between the two genotypes in total ADG.