Effect of Texel muscling quantitative trait locus (TM-QTL) on carcass composition and weight distribution in Texel lambs
Take Home Message: Inclusion of TM-QTL in breeding programmes to produce homozygote carrier lambs could increase meat yield in carcasses of equal weight.
The effect of the Texel muscling trait on carcass weight is reflected in increased weight of all carcass areas, with no effect of the Texel muscling quantitative trait locus (TM-QTL) on weight distribution. Carcass composition was affected by TM-QTL – homozygote TM-QTL carriers had a greater proportion of lean meat yield compared to other groups.
And, in addition to previously identified benefits, if TM-QTL were included in breeding programmes to produce homozygote carrier lambs, meat yield could be increased in carcasses of equal weight.
A myriad of exciting results for sheep breeders and lamb producers from one study, which set out to examine TM-QTL effects on carcass composition and weight distribution in Texel lambs, the findings of which were presented to delegates at this year’s British Society of Animal Science’s annual conference, held at the University of Nottingham.
“TM-QTL is a QTL that increases loin muscling by between 4% and 11% in Texel lambs and Texel-sired crossbred lambs with a polar over-dominant action (phenotype is expressed only if one copy is inherited from sire) and has an additive effect on carcass weight,” explained the Scottish Agricultural College’s Jenny Macfarlane. Her team’s study involved purebred Texel lambs.
After slaughter, carcasses were chilled for seven, eight or nine days, weighed, split and each side cut into fore-quarter (FORE ¼), saddle (SADDLE) and hind-quarter (HIND ¼). These were weighed and butchered into lean meat (LMY), fat trim and bone. The proportion of total carcass weight contained in each region and proportion of LMY, fat trim and bone in the carcass were calculated.
Lambs were blood-sampled and TM-QTL genotypes assigned and is was found that there were 40 non-carriers (+/+), 17 heterozygote carriers inheriting TM-QTL from the dam (+/TM), 53 heterozygote carriers inheriting TM-QTL from the sire (TM/+), 34 homozygote carriers (TM/TM) and 65 with unknown genotype.
“Analysis of the results revealed that, when adjusted for CWT, there were no significant differences between genotypes for weights in each area or the proportion of total CWT contained in each carcass area,” said Dr Macfarlane. “LMY/CWT was 1.36 to 2.37% higher in TM/TM compared to the other groups although the difference was significant only for TM/TM vs. +/TM. FAT/CWT and BONE/CWT were not significantly different between genotypes,” she added.
Presented to the British Society of Animal Science Annual Conference, April 4 to 5, 2011, University of Nottingham University, UK.
Full details: MacFarlane JM, Lambe NR, McLean KA, Wolf BT, Haresign W and Bunger L: “Effect of the Texel muscling quantitative trait locus (TM-QTL) on fore quarter, hind quarter and saddle weights, weight distribution and carcass composition in purebred Texel lambs.”
Presented to the British Society of Animal Science Annual Conference, April 4 - 5, 2011, University of Nottingham, UK.
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