Abstract

The growth and carcass traits of 774 lambs out of Romney ewes and sired by Suffolk (S), Landcorp Lamb Supreme (LS), Texel (T) and Romney (R) rams were compared when slaughtered on five occasions (groups 1 to 5): November 1995, February, March, May and July 1996. Forty carcasses per slaughter group were dissected into commercial cuts of saleable meat, fat trim and bone. S- and LS-sired lambs had heavier pre-slaughter liveweights than T-sired lambs (38.4 ± 0.27, 38.5 ± 0.26, vs 36.3 ± 0.27 kg respectively; P<0.001), which in turn were heavier than R-sired lambs (35.0 ± 0.29 kg; P<0.001). S-sired lambs had heavier hot carcass weights than both LS- and T-sired lambs in slaughter groups 4 and 5 (+0.9 to +1.9 kg; P<0.01); R-sired lambs were significantly lightest in all slaughter groups (-0.7 to -3.9 kg; P<0.05). S- and R-sired lambs had greater adjusted GR tissue depths than LS-sired lambs in later slaughter groups. T-sired lambs were generally intermediate between LS- and R-sired lambs. R-sired lambs produced less weight of saleable meat than S-, LS- and T-sired lambs (by 1.4 to 1.7 kg; P<0.01). Lambs sired by Landcorp’s terminal sire breeds out-produced those sired by the company’s maternal R sire breed. S-sired lambs exhibited rapid growth early in the season, but increased fat levels later in the season compared with LS-and T-sired lambs.

GB, Nicoll, JW Skerritt, JL Dobbie, and TJ Grimwood

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 136-139, 1998