The effect of the Texel Muscling QTL on live and carcass weight in Texel lambs

The Texel Muscling QTL (TM-QTL) is a QTL affecting loin muscling in Texel sheep with a paternal polar overdominant pattern of expression. This study on purebred Texel sheep used the first available data to include homozygote TM-QTL carriers in addition to homozygote non-carriers and both heterozygotes to assess the effect of TM-QTL on live weight throughout growth from birth to slaughter (at around 20 weeks of age) and carcass weight. TM-QTL was found to have an effect on most measures of live and carcass weight. Animals inheriting two copies of TM-QTL showed an increase of 1.5 kg or 9% in carcass weight and an increase in live weight across a range of ages from birth to slaughter of between 7 and 15% compared to animals carrying no copies of TM-QTL. The effect of TM-QTL on the weight traits studied appears to be additive but heterozygote weights did not always support this. If more data on lambs carrying TM-QTL become available in future it would be useful to validate this effect on live and carcass weight and the pattern of the effect.