Supplementation of high fecundity Border Leicester x Merino ewes with a high protein feed: its effect on lamb survival

Abstract

Two hundred and fifty Border Leicester x Merino ewes (40% heterozygous for the Booroola Fec B gene) were used in an experiment, replicated over 2 years, to examine the effects of cottonseed meal-based supplementation on lamb survival, birth, marking and weaning weight, as well as, liveweight and fleece characteristics of ewes. From 50 to 100 days of pregnancy, half of the ewes were supplemented with 80 g/head.day. The supplemented group was then split according to litter size and, until 30 days after lambing, were offered pellets at 80, 160 and 220 g/head .day, respectively, for ewes bearing single, twin and triplet (or more) lambs. Over the 2 years, ewes averaged 2.11 lambs per parturition and supplementation significantly increased lamb survival to weaning (73 v. 58%) with no interaction with litter size. Although supplementation had a positive effect on birth weight of all but twins, the effects of supplementation on survival were independent of birth weight effects. Significant effects of year, sire breed and litter size on lamb survival and birth weight were also noted. No effects of supplementation were apparent on lamb growth while ewe age, sire breed, sex and rearing rank all significantly influenced growth rates. Ewe weights, fleece weights and staple strength were significantly influenced by year, ewe age and litter size but not by supplementation. These findings indicate the benefits to lamb survival of providing a 'bypass' protein supplement to high fecundity flocks even when ewes are grazing good quality pastures.

Age trends in economically important traits of Merino ewes subjected to 10 years of divergent selection for multiple rearing ability

“…Ewe permanent environmental correlations of greasy fleece weight with reproduction were, on the other hand, relatively high and unfavourable. The impact of reproduction on fleece production has been quantified in the literature (Charlick & Arnold, 1990;Lee & Atkins, 1995;Hinch et al, 1996). Compared to barren ewes, the penalty in fleece weight was 652 g in ewes rearing singles, and 846 g in ewes rearing twins (Charlick & Arnold, 1990).…”

Effect of plane of nutrition of 1- and 2-year-old ewes in early and mid-pregnancy on ewe reproduction and offspring performance up to weaning

“…Reduced lamb survival following maternal undernutrition during pregnancy has been previously described (Vincent et al, 1985;Holst et al, 1986;Hinch et al, 1996) and it may be related to different factors Nutrition provided: low (L), medium (M) or high (H) as compared to predicted metabolizable energy requirements for maintenance. Mean estimates and estimated standard errors (e.s.e.)…”

Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs

“…These differences in survival between lambs from litters of different sizes are predominantly due to differences in lamb birthweight (Hinch et al 1985(Hinch et al , 1996Kenyon et al 2007). There is a curvilinear relationship between lamb birthweight and survival in Merinos, with lamb mortality being highest at both low and high birthweights (Mullaney 1969;Atkins 1980;Hatcher et al 2009;Oldham et al 2011).…”