To investigate the influence of maternal Se supply and plane of nutrition on lamb morbidity, mortality, and passive transfer of IgG, pregnant ewe lambs were used in 2 experiments with 2 × 3 factorial treatment arrangements. Supplementation of Se began at breeding and was either adequate Se (ASe, 9.5 μg/kg of BW) or high Se (HSe, 81.8 μg/kg of BW) in Exp. 1 or ASe (11.5 µg/kg of BW) or HSe (77.0...

Data collected on 3256 lambs born to Horro and Menz breed ewes single-sire mated to 71 rams at the International Livestock Research Institute (ILRI) Debre Berhan station between September 1992 and June 1996 were analysed for rates of survival and growth from birth to weaning. A significantly lower proportion of Menz lambs died before 1 year of age (28%) than the Horro lambs (59%). Least squares...

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...

introduction lamb production is the largest part of income in sheep industry. therefore, the mortality rate of lambs is a key factor in profit of the sheep breeding. mortality rate of lambs (or lamb mortality rate) in different breeds of sheep under different climatic conditions is varying from 15% to 50% and an average of 9% to 20% has been reported. survival rate is a combination trait that i...

This paper examines the environmental and management factors affecting lamb survival on high-performing sheep farms in New Zealand. Improved lambing percentage is the biggest contributor to higher profits on New Zealand sheep farms. Many sheep breeders have selected and bred ewes for increased fecundity over the last 4 decades. The increased proportion of ewes having triplets is of concern to f...

The experiment measured lamb responses to supplementation of the pregnant ewe diet with vitamin E above requirement. Crossbred ewes were mated with either Suffolk or Texel rams. Twin-bearing ewes were randomly allocated (approximately 21 months of age at allocation) to one of four treatment groups (20 ewes per group, 10 mated with Suffolk and 10 with Texel rams). Treatments imposed were 50, 100...

In this paper perinatal mortality is defined as those deaths occurring before, during or within seven days of lambing. Extensive surveys on abortion and stillbirths in sheep from several flocks have been reported from Great Britain (Sellers and Leech 1955; Leech and Sellers 1959; Watson 1962cr), from U.S.A. (Bell 1944, 1947), from New Zealand (McFarlane 1955; Hartley and Boyes 1955, 1964; Hicke...

Lamb production was measured over an 18 month period from 30 Javanese thintail (JTT) and 30 Border Leicester x Merino (BLM) ewes run continually with rams of several breeds. The study was carried out in West Java, Indonesia. One hundred and forty-eight lambs were born to JTT and BLM ewes respectively, the difference being associated with both a larger number of lambings and a higher incidence o...