Data on ewe body weights and on lamb birth and weaning weights and survival rates were recorded on a total of 557 multiparous Rambouillet, Hampshire X Suffolk and Synthetic I (composite of Finnish Landrace, Rambouillet and Polled Dorset) ewes in two experiments started after the first trimester of gestation. In Exp. 1, a 2 X 2 factorial arrangement of treatments included all combinations of low...

castration of male animal's leads to a reduction in aggressive behavior, which animals will avoid wasting energy resulting to economic production of the animal, grows. it also reduces damage and bruising animals and increases normed meat producing at slaughter. in this study, 20 lambs ghezel breed in four age groups, group 1: one month (n = 4), group 2: two months (n = 4) group 3: three months ...

The aim of this study was to evaluate the effects of premating ewe weight and age on ewe reproductive performance, lamb growth and survival in Central Anatolian Merino (CAM) sheep. The trial included 4935 ewes and 5548 lambs from 23 breeder flocks in Eskişehir Province. The live weights (LWs) and ages of the ewes were recorded 1 week before the mating season. The number of lambs born, fertility...

the aim of this study was to estimate the genetic trend and genetic parameters of survival traits in baluchi sheep using survival records from 27978 baluchi sheep, which were collected by the animal breeding center of iran during1979 to 2009. genetic parameters of lamb survival from 1 to 400 days of age and from 1 to the last recording date. traits were estimated using animal model (with or wit...

BACKGROUND Existing mathematical models for scrapie dynamics in sheep populations assume that the PrP gene is only associated with scrapie susceptibility and with no other fitness related traits. This assumption contrasts recent findings of PrP gene associations with post-natal lamb survival in scrapie free Scottish Blackface populations. Lambs with scrapie resistant genotypes were found to hav...

Lamb mortality remains a significant welfare and economic issue for sheep production. Lamb survival is to a degree dependent upon an easy delivery and the expression of appropriate behaviours from both mother and offspring, such as rapid standing, udder seeking and sucking by the lamb. Genetic solutions have the potential to improve birth assistance and lamb behaviour but large amounts of data ...