Undernutrition of the Merino sheep and its sequelae. V.* The influence of severe growth restriction during early post-natal life on reproduction and growth in later life

Abstract

The growth of two groups of Merino lambs was severely restricted at different stages of early post-natal life so that at 420 days of age they weighed only 12 kg. When their normally grown sibs born 1 year later attained a similar weight at 53 days all groups were combined and moved to sown pastures, where they grazed together for 6½ years. During this period the ewe reproduction, growth and wool production of the experimental animals were compared. Nutritional deprivation in early life did not affect the reproduction performance of the ewes, or the birth weights and weaning weights of their progeny. The restricted lambs resumed normal growth for the first two years of the recovery period, but their growth potential was not sustained, and consequently the severe growth restrictions imposed in early life had as its sequel a smaller adult. Wool production, and the number of wool fibres per sheep, were both significantly reduced by growth restrictions in early life. ___________________ *Part IV, Aust. J. Agric. Res., , 19: 997 (1968).