Correlations among beef carcass composition and meat quality
traits from a genetic marker trial
C.A. MORRIS, C.C. DALY, N.G. CULLEN AND S.M. HICKEY
AgResearch, Ruakura Agricultural Research Centre, Private Bag
3123, Hamilton, New Zealand
E-Mail:
Proceedings of the New Zealand Society of Animal Production 2001. 61:
96-99
A collaborative beef cattle project between AgResearch and
Adelaide University is described, which had the aim of identifying
genetic markers (DNA markers) for carcass composition and meat quality
traits. Two extreme breeds were used, the Jersey and Limousin, and
first-cross Jersey x Limousin bulls were mated to cows of both breeds to
produce experimental animals in two herds, in New Zealand and Australia.
The present paper provides information on relationships among some
traits recorded in the New Zealand herd, with a total of 416 back-cross
cattle of both sexes slaughtered as 2- year-olds at Ruakura in the
springs of 1998 and 1999. The recorded data included hot carcass weight
and the butcher-dissected weights of meat, fat and bone in the right
side, expressed as percentages of side weight (MP, FP and BP
respectively). The pH decline in the right striploin, removed from the
carcass after dressing and maintained at a constant 15°C, was
monitored to derive the initial (pH1), ultimate (pHu), and the rate of
fall of pH. Average shear force (SAVG) and the half-life of the ageing
rate (SHLF) were measured in striploin steaks cooked immediately after
rigor and then at intervals until ultimate tenderness. Percentage weight
loss (PWL) during cooking was recorded. Also measured in the striploin
were the concentrations of three metabolic enzymes, lactate
dehydrogenase (LDH), isocitrate dehydrogenase (ICDH) and 3-
hydroxyacyl-Coenzyme A dehydrogenase (HAD), and the proteolytic enzymes
m- and milli-calpain, and their inhibitor calpastatin (CAST). Glycogen
concentration in the muscle at slaughter, expressed as the glycolytic
potential (GLYP), was estimated from the sum of the concentrations at
rigor of glucose, glucose-6-phosphate, lactate and residual glycogen.
The range of pHu values was small, probably because all animals were
regularly handled. Correlations, after adjustment for breed group, sire
and slaughter group, included: MP with FP, -0.82; PWL with MP, 0.20; PWL
with FP, -0.29; MP with enzymes LDH, ICDH and HAD, 0.22, -0.21, -0.03;
FP with ICDH, 0.16; SAVG with SHLF, 0.48; SHLF with CAST, µ-and
milli-calpain, 0.28, -0.14, 0.03; CAST with µ- and milli-calpain, 0.26,
0.38; GLYP with pH1 and pHu -0.01 and -0.17. Overall, HCW, MW and
composition traits were not correlated with pH traits or SAVG, or µ- or
milli-calpain concentrations; HCW and MW were positively correlated with
LDH and GLYP.
Keywords: NZSAPAB;
cattle; correlation; carcass composition; meat quality
Last Updated 7/08/01
