The effect of conditioning period on loin muscle tenderness in crossbred lambs with or without the Texel muscling QTL (TM-QTL).
A Texel muscling quantitative trait locus (TM-QTL) has been identified on chromosome 18, which increases loin muscling, but may also have a negative impact on mechanically-measured loin tenderness in crossbred lambs, depending on conditioning time. This study investigated the influence of a range of conditioning times (3, 5, 7 or 9 days) on the effect of TM-QTL on loin muscle tenderness. Using Texel rams heterozygous for TM-QTL, mated to non-carrier Mule ewes, heterozygous (n=45) and wild-type (n=50) crossbred lambs were produced. Weight of the valuable Longissimus lumborum muscle was higher in TM-QTL carriers than non-carriers, when compared at a fixed age (+11.5%; P=0.038), with the same trend at a fixed carcass weight (+10.2%; P=0.064). Toughness, measured by shear force, was significantly higher in samples from TM-QTL carriers than non-carriers, after conditioning for 3 days (P=0.002), 5 days (P=0.003) or 7 days (P=0.03), but was not significantly different after 9 days of conditioning (P=0.32). Compared to non-carrier lambs, the proportion of samples above consumer acceptability thresholds for toughness was greater in the TM-QTL carrier lambs after 3 and 5 days of conditioning, similar at 7 days, but lower at 9 days. The results suggest that the negative effect of TM-QTL on loin tenderness in crossbred lambs can be overcome by conditioning for more than 7 days. Marketing of TM-QTL carrier lambs through companies that use enhanced processing protocols could be beneficial, due to higher loin muscle weights, without negative effects on meat quality.
Lambe
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NR
Sustainable Livestock Systems Group, Scottish Agricultural College, King's Buildings, Edinburgh EH9 3JG, UK. Nicola.Lambe@sac.ac.uk
Haresign
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W
Macfarlane
J
J
Richardson
R I
RI
Matika
O
O
Bünger
L
L
D000818:Animals; D002874:Chromosome Mapping / Q000662:veterinary*; D033481:Chromosomes, Mammalian; D003433:Crosses, Genetic; D005260:Female; D005511:Food Handling / Q000379:methods*; D005524:Food Technology; D005838:Genotype; D006824:Hybridization, Genetic; D008297:Male; D008460:Meat / Q000592:standards; D018482:Muscle, Skeletal; D009929:Organ Size / Q000235:genetics; D040641:Quantitative Trait Loci; D012756:Sheep / Q000235:genetics*; D013314:Stress, Mechanical