Comparison of Texel-and Suffolk-sired lambs out of Finnish Landrace × Dorset Horn ewes under grazing conditions

Abstract

SUMMARYTwo hundred and ten Finn–Dorset ewes were mated to ten rams, five Suffolks and five Texels, in 2 years, to evaluate Texel rams as fat lamb sires. Three hundred and ninetyseven lambs were born and used in the study until the 6th week of age, after which 155 lambs were available for the rest of the experiment. From 6 weeks of age they were grazed with their dams and weighed weekly until slaughtered at 30 kg (females) or 36 kg (males) live weight. Carcasses were assessed by the Meat and Livestock Commission and a random sample of 16 left sides were fully dissected.Fertility and prolificacy of the ewes were 95 and 190% respectively, and were not affected by sire breed. Texel-sired lambs did not differ from Suffolk in birth weight, weight at 6 weeks, growth rate from 6 weeks to slaughter, overall growth rate or age at slaughter. Except for growth rate from birth to 6 weeks, sex difference was significant (P < 0·05) in all growth estimates.No significant breed or sex difference was found in dressing percentages or carcass weight for age. Mean dressing percentage was 47·4 ± 3·48 and 47·5 ± 3·78 for Texel and Suffolk crosses, respectively. Texel cross carcasses had significantly (P < 0·05) lower fat scores and males did not differ from females. Texel cross carcasses had significantly (P < 0·05) higher lean and bone percentages, but significantly (P < 0·01) lower total fat percentage.Apart from demonstrating the capacity to produce leaner lambs compared with Suffolk, the results suggest that Texel sires offer the possibility of producing heavier carcasses without excess fat production.