Abstract

A catch phrase within animal genetics is that there is as much variation within a breed as there is between breeds. The New Zealand Perendale Progeny Test has been conducted on North and South Island sites since 2010 with the aim of investigating genetic variability for carcass traits. A total of 51 sires, from 27 studs have been assessed, with sires selected from the top 20% of the Perendale across-flock Dual Purpose Index SIL evaluation. Within each year/site lambs generated were born within a week (ewes naturally synchronised pre-mating), and slaughtered on the same day. A total of 2318 male progeny have been generated and slaughtered through Alliance with traits measured including weight traits, carcass dimensions, VIAscan® traits, carcass pH, carcass fat colour and, in some years, colour stability of chilled aged loins, subjective marbling score and meat tenderness. Genetic parameters were estimated with ASREML; carcass weight was fitted as a co-variate for carcass traits (excluding carcass weight). The heritability estimates for all traits were moderate to high, with the lowest of 0.22 ± 0.07 for VIAscan® GR, and the highest, for pH, of 0.44 ± 0.09, with the majority between 0.22 and 0.43. The high estimate for slaughter plant measured pH was supported by the 0.59 ± 0.17 estimate for pH measured in the laboratory on those samples which were measured for colour stability. The phenotypic correlations between traits were generally well estimated with small standard errors for the majority of trait combinations. The genetic correlations were not as well estimated with standard errors greater than 0.10 for most traits combinations, but despite the large standard errors some were still significant, and in general agreement with values the literature. The progeny test has therefore demonstrated significant genetic variability for the range of carcass traits assessed in this study within the Perendale breed.

Johnson, PL, EA Young, D Russenklau, T Anderson, and KG Dodds

Proceedings of the New Zealand Society of Animal Production, Volume 75, Dunedin, 106-110, 2015