THE EFFECT OF NUTRITION DURING EARLY-LIFE ON VOLUNTARY FOOD-INTAKE BYLAMBS BETWEEN WEANING AND 2 YEARS OF AGE

Two experiments were carried out with Scottish Blackface lambs to inve stigate the effects of restricted nutrition during pregnancy and lacta tion on voluntary food intakes (VFI) between weaning and 2 years of ag e. Ewes were given diets providing 0.7 (LP) or 1.0 (HP) of their estim ated metabolizable energy requirements during the last 6 weeks of preg nancy and subsequently grazed swards with mean sward surface heights o f approximately 3 cm (LL) or 6 cm (HL) during lactation. All lambs wer e weaned at 17 weeks of age. In experiment 1, four treatment combinati ons (LP-LL, LP-HL, HP-LL and HP-HL) were applied and female lambs were studied. In experiment 2, two treatment combinations (LP-LL and HP-HL ) were applied and male lambs were studied. In both experiments the la mbs received a common level of nutrition between weaning and 2 years o f age. In both experiments, mean live weights were proportionately 0 2 higher for HP-HL than for LP-LL lambs at weaning (P < 0.001) and in e xperiment 2 mean live weights and body condition scores were still hig her in HP-HL than in LP-LL lambs at 2 years of age (P < 0.05). Abomasu m weights were higher in HP than in LP lambs at birth and higher in HP -HL than in LP-LL lambs at weaning in experiment 1 and the weights of the rumen and dimensions of the rumen villi were greater in HP-HL than in LP-LL lambs at weaning in both experiments (P < 0 05). The treatme nts had no effect on lipid content or mean adipocyte diameter in the m ain fat depots at birth or weaning. There were no treatment effects on VFI in either experiment. It was concluded that restricted nutrition during late pregnancy and early lactation does not affect VFI between weaning and 2 years of age in sheep, even though there are differences in live weight and the development of the gastrointestinal tract at w eaning and there may be long-term effects on live weight and body cond ition, particularly in male animals.