Dakhlan, A

Moghaddar, N

van der Werf, J H J

2019-05

This study explores the interaction between genetic potential for growth in Merino lambs and their birth type (BT) or rearing type (RT). Data on birthweight (BWT), weaning weight (WWT), post-weaning weight (PWWT), scan fat (PFAT) and eye muscle depth (PEMD) were used from 3920 single and 4492 twin-born lambs from 285 sires and 5279 dams. Univariate analysis showed a significant sire x BT interaction accounting for 1.59% and 2.49% of the phenotypic variation for BWT and WWT, respectively, and no significant effect for PWWT, PFAT and PEMD. Sire x RT interaction effects were much smaller and only significant for PEMD. Bivariate analysis indicated that the genetic correlation (r_g) between trait expression in lambs born and reared as singles versus those born and reared as twins were high for BWT, WWT, PWWT (0.91 ± 0.02 - 0.96 ± 0.01), whereas r_g for PFAT and PEMD were lower (0.81 ± 0.03 and 0.86 ± 0.02). The r_g between traits expressed in lambs born and reared as singles versus those born as twins but reared as singles were lower: 0.77 ± 0.08, 0.88 ± 0.03, 0.66 ± 0.06 and 0.61 ± 0.08 for WWT, PWWT, PFAT and PEMD, respectively. A different RT only affected the expression of breeding values for PFAT and PEMD (r_g 0.62 ± 0.04 and 0.47 ± 0.03, respectively). This study showed genotype x environment interaction for BWT and WWT (sire x BT interaction) and for PEMD (sire by RT interaction). However, sires' breeding value of a model that accounts for sire x BT interaction provides a very similar ranking of sires compared with a model that ignores it, implying that there is no need to correct for the effect in models for genetic evaluation.

Animal Production Science, 59(6), p. 1016-1021

1836-5787

1836-0939

https://hdl.handle.net/1959.11/26912

CSIRO Publishing

Genotype x birth type or rearing-type interactions for growth and ultrasound scanning traits in Merino sheep

Journal Article

Publication