Effects of maize-meal supplementation before mating on the production of hill country sheep

Abstract

A flock of 1500 Romney ewes (8 selection lines and 4 ages) and 200 Border Leicester × Romney ewes (1 selection line and 4 ages) was divided into 2 treatment groups with the same range and mean liveweight within 36 sub-groups before mating in 1973 and 1974. One treatment group was grazed on hill country pasture unsupplemented; the other group was supplemented with pellets containing 50% lucerne and 50% maize meal at a rate of 0.55 kg/ewe/day for 6 weeks before mating in 1973 and at a rate of 0.45 kg/ewe/day for 12 weeks before mating in 1974. The pre-mating liveweights of the supplemented and control treatments were 47.3 and 44.6 kg in 1973 and 45.3 and 38.3 kg in 1974. There was no difference between the supplemented and control groups in reproductive performance in 1973; in 1974 however, supplementation increased the percentage of lambs born by 11%, and the percentage of lambs weaned by 6%, arising from increases in the percentage of ewes lambing (73% v. 68%) and in the multiple birth rate (15.5% v. 8.8%). In 1974 all 9 genotypes increased in weight in the supplemented treatment and lost weight in the control. The Border Leicester × Romney ewes had a larger liveweight gain in the supplemented treatment and a smaller liveweight loss in the control ewes than the mean of the Romney genetypes. Among the Romney selection lines the“easy care” Romney made the greatest gain as a result of supplementation and the smallest loss in the control treatment.

Keywords:

• Ewes
• Romney
• maize-meal
• fodder cereals
• hill country
• pastures
• food supply
• animal production
• lambs
• animal growth
• weight gain