Effect of energy allowance to triplet-bearing ewes in late gestation on ewe performance, lamb viability, and growth

I Dønnem,E.G Granquist,E Nadeau,Å.T Randby

doi:10.1016/j.livsci.2020.104027

Abstract

The present study was conducted to evaluate the effects of offering Norwegian white sheep (NKS) ewes a ration of either 85 (85% net energy lactation (NEL)), 100 (100% NEL) or 120% (120% NEL) of recommended NEL requirements from gestation day 96 to lambing on ewe performance, lamb viability and growth. Twenty-seven triplet-bearing ewes were allocated to 1 of 3 dietary treatments based on INRA (Jarrige, 1989) recommendations. Ewes were individually fed and NEL requirements were individually calculated for each ewe. Diets consisted of a restricted portion of grass silage from early harvest and an adjusted level of concentrate. As expected, increasing NEL allowance increased the ewe body weight gain (=P = 0.0004) and body condition score (BCS) (=P = 0.003) prepartum. The 120% NEL ewes lost more body condition (BC) in lactation compared with the 100% NEL ewes. There was no effect of ewe nutritional treatment on behavioral scores of the lambs (birth assistance, lamb vigour and sucking assistance) or the lamb birth weight. There was a considerable reduction of number of lambs from birth to weaning, due to stillbirths, deaths, and life-support during this period. Early live weight gain and weaning weights of lambs increased nominally with increasing prepartum energy allowance of their mother. However, only lambs in complete triplet litters had significant increases in live weight gain until weaning (=P = 0.008). We conclude that it is possible for triple-bearing ewes to meet the increased nutritional demand via intake, and even gain BC, in late gestation when feed quality is high. The high energy intake in ewes during late gestation increased energy mobilization during lactation that seemed to benefit lambs in triplet litters with a growth advance until weaning.

Highlights

The Norwegian white sheep (NKS) is a productive and prolific sheep breed for meat and wool production
Only lambs in complete triplet litters had significant increases in live weight gain until weaning (=P = 0.008). We conclude that it is possible for triple-bearing ewes to meet the increased nutritional demand via intake, and even gain body condition (BC), in late gestation when feed quality is high
At gestation day 96, the 27 ewes were distributed into three groups, each of 9 ewes, that were balanced according to expected lambing date, body weight (BW), body condition score (BCS) and age

Summary

Introduction

The Norwegian white sheep (NKS) is a productive and prolific sheep breed for meat and wool production. An increase in litter size per ewe should offer greater financial gains, but is associated with high mortality rates (Scales et al, 1986; EverettHincks and Dodds, 2008; Holmøy and Waage, 2015), and is a potential welfare concern. For this reason, there is a growing interest in optimal feeding regimens for these prolific ewes given their higher theoretical nutritional requirements in the last trimester of gestation (Jarrige, 1989; NRC, 2007). Maternal undernutrition can adversely affect lamb neonatal behavior and the mothering ability of the ewe, and the establishment of the ewe–lamb bond (Dwyer et al, 2003)

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Conclusion