EFFECTS OF RESTRICTION OF GROWTH AND DEVELOPMENT OF BRECON CHEVIOT EWE LAMBS ON SUBSEQUENT LIFETIME REPRODUCTIVE-PERFORMANCE

The effects on the Lifetime reproductive performance of female sheep o f two levels of nutrition before they were weaned or during their adul t life were investigated using 499 Brecon Cheviot sheep, a breed which exhibits only small reproductive responses to contemporary nutritiona l manipulations. Female sheep subjected to a restricted level of nutri tion prior to weaning had a significantly lower lifetime incidence of multiple births than those on a high plane of nutrition (P<0.05) but n ot when restriction took place in adult life. Nutritional restriction did not significantly affect the proportions of barren ewes, irrespect ive of the time at which it was applied. There were positive relations hips between the nutritional treatment in both, early (P<0.05) and adu lt life (P<0.01) and the birth weight of lambs born to these ewes. It is concluded that undernutrition of female lambs of this breed during the first months of life results in a reduction in lifetime reproducti ve performance, irrespective of nutrition during adult life, and that food resources should be diverted, where possible, to this phase of th e production cycle to ensure that subsequent reproductive performance is not compromised. (C) 1998 Published by Elsevier Science B.V. All ri ghts reserved.