New Zealand Journal of Agricultural Research abstracts

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Short communication

The influence of maternal IGF-1 genotype on birthweight and growth rate of lambs

P. R. Kenyon^1,3*

H. T. Blair^1,3

B. H. Breier^2,3

P. D. Gluckman^2,3

¹Institute of Veterinary
Animal and Biomedical Sciences
Massey University
Private Bag 11222
Palmerston North 4442, New Zealand

²Liggins Institute
University of Auckland
Private Bag 92019
Auckland 1142, New Zealand

³National Research Centre for Growth and Development
Private Bag 92019
Auckland 1142, New Zealand

^*Author for correspondence: P.R.Kenyon@massey.ac.nz

Abstract   The present study was designed to determine the effect of IGF-1 selection on lamb birthweight and to establish the role of the maternal IGF-1 genotype on foetal growth. Nineteen high (H) line ewes were mated to high line rams (HH), 21 low (L) line ewes were mated to H line rams (LH), 25 control (C) line ewes were mated to control rams (CC), 35 H ewes were mated to L rams (HL) and 24 L ewes were mated to L rams (LL); the resultant lambs were used in this study. HH lambs were significantly (P < 0.05) lighter at birth than both LL and CC lambs. HL and LH lambs did not differ in birthweight from either LL or HH lambs. HH lambs grew significantly (P < 0.05) faster than LH lambs and faster than LL lambs (P = 0.05). HH lambs had significantly (P < 0.05) higher IGF-1 concentrations than LL lambs post-weaning. HL and LH IGF-1 concentrations were intermediate and differed significantly (P < 0.05) from both LL and HH lambs. The results of this study suggest that the difference in foetal growth between the selection lines is not influenced by maternal genotype, but is instead influenced by foetal genotype, and this warrants further examination.

Keywords   ewe liveweight; IGF-1; sheep; weaning weight

A06049; Online publication date 2 July 2007; Received 21 August 2006; accepted 20 March 2007

New Zealand Journal of Agricultural Research, 2007, Vol. 50: 291–297
0028–8233/07/5003–291 © The Royal Society of New Zealand 2007

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