Abstract

Serial measurements of the pH of the longissimus dorsi muscle were obtained from lambs of 22 sire groups of six sire breeds (Experiment 1) and in 14 sire groups of lines selected for Fast and Slow Glucose Clearance (Experiment 2). Lamb sex (ewe, wether) and carcass weight and leanness had little effect on meat pH. Sire breed had significant effects on pH at 1 and 24 hours post mortem, and selection line had significant effects between 1 and 4 hours post mortem. These effects were greater on slaughter dates when pH levels were higher. Variation between individual sires was sufficient to account for some differences between sire breeds and selection lines. Differences between sire breeds and selection lines were found from the time of first pH measurement after slaughter through until ultimate pH was reached. This suggests that there were differences in the rate of glycogen breakdown to lactic acid immediately after slaughter or during electrical stimulation, as well as differences in the amount of glycogen in the muscle at slaughter. These findings confirm that lamb genotype can influence meat pH and thus will affect commercially important meat properties.

AR, Bray, SR Young, and GH Scales

Proceedings of the New Zealand Society of Animal Production, Volume 54, , 201-204, 1994