Abstract

The increased emphasis on the Merino for meat production has heightened the need to quantify the variation across the breed for meat and carcase traits and to produce geneticcorrelations and heritabilities for these traits. This paper reports on strain effects (broad, medium and fine wool) on carcase and meat quality traits for 1934 rams. Rams (~19 months of age) were slaughtered over 4 years and data on animals from 272 sires were collected. Every year, the rams were fed a formulated pellet at pasture for 5 weeks before slaughter. All animals were slaughtered in commercial abattoirs. Hot carcase weights were recorded and the GR measured using a GR knife. After overnight chilling (4–5°C), carcases were cut between the 12th/13th ribs and the longissimus thoracis et lumborum (LL) was exposed to the air at chiller temperature for 30 min. Meat colour was measured on the cut surface using a Minolta Chromameter set on the L*, a*, b* system. The pH of the LL and the semitendinosus (ST) muscle was also measured. Fine wool rams were the fattest when compared at the same carcase weight. The broad wool strain had the lowest pH in both muscles and there were minimal differences between strains for meat colour. These real differences between Merino strains in meat quality traits require more detailed investigation in order to understand their biological bases and identify if potential markers exist that could be used in Merino breeding programs.

DL, Hopkins, SI Mortimer, DF Stanley, DC McMillan, and SL Anderson

Proceedings of the New Zealand Society of Animal Production, Volume 67, Wanaka, 28-31, 2007