Differences between P and Y export lamb carcass grades in M. longissimus dorsi area and shape

A.H. Kirton

Ruakura Animal Research Station, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1982, 42: 121-124

Data on M. longissimus dorsi (LD) area, width and depth were examined on 1957 lamb carcasses graded for export as either P (moderate to heavy fat cover) or Y (light fat cover) over 3 slaughter seasons. Lambs were sired by 1 of 11 different breeds mated to Romney ewes. Carcasses in the 2 grades differed in mean weight and LD measurements in the different seasons. After adjustment for differences in carcass weight and the effect of sire breed, LD area did not differ between the P and the Y grades. After adjusting the A (width) and B (depth) measurements of differences in carcass weight and sire breed, P grade LD's were significantly narrower and deeper than those from the Y grade, but the differences were small (maximum of 5% for depth in 1970/1 season) and of little practical significance. Thus if the leaner Y grade carcasses are desired, and this is done on a within breed basis, the LD area or shape should not be adversely affected provided carcass weights are not reduced.

Keywords: NZSAPAB;

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Last Updated 03-05-1997