Effect of sire breed on grass-based lamb production

Improvement of lamb performance in low-input operations may prove vital for the sustainability of eastern US sheep production. Maintaining growth while improving carcass conformation using terminal sire crossbreeding systems may increase value in a pasture-based system. Therefore, the aim of this study was to compare effects of terminal sire breed on parasitism, growth, marketability of grazing lambs. Suffolk (SU; n = 2) and Texel (TX; n = 2) sires were mated to commercial ewes at the WVU Organic Farm. April-born lambs were managed on pasture as one group until weaning (mid-June), then were separated into 3 replicates per sire breed. Lambs were rotationally grazed for 93-d with paddock movement every 10-d and supplemented at a rate of 2% (16% CP) bodyweight. Weights were collected at weaning and then weekly for the duration of the study. Fecal egg counts (FEC) and FAMACHA scores were collected bi-weekly. Ultrasound measures of ribeye area (REA) were obtained at study conclusion and lambs were marketed at a graded auction. Sire breed did not impact weaning weight or growth rate. However, TX-sired lambs required fewer deworming treatments than SU-sired lambs (39% vs. 12%; P \u3c 0.01). FAMACHA scores were numerically lower in TX vs. SU-sired lambs (1.58 vs. 1.96; P \u3c 0.01. Texel-sired lambs had greater REA (11.57 vs 9.42 cm2; P \u3c 0.01) and graded better at auction. Texel-sired lambs sold for $27/cwt. more than Suffolk-sired lambs. These data demonstrate that the desirable composition of TX-sired lambs translated into greater market value