Effect of active immunization against luteinizing hormone on carcass and meat quality of Romanov lambs

Influence of extending the pre-slaughter interval after second vaccination on the carcass cutting yield and the quality of meat from immunocastrated lambs

The influence of extending the vaccination-to-slaughter interval of immunocastrated lambs on carcass cutting yield and meat quality of the Longissimus thoracis (LT) muscle was investigated in forty Dohne Merino lambs (8.5 months old; 53.7 ± 4.8 kg). Immunocastration booster vaccination intervals of six (IC6; n = 10) and four (IC4; n = 10) weeks prior to the slaughter age were used, with two weeks between primary and secondary vaccinations. A further 10 lambs were Burdizzo-castrated at 6.5 months old (B). The control treatment remained intact (R; n = 10). Prime cutting yields, LT muscle area, LT subcutaneous fat thickness and instrumental meat quality were accessed. Both castration methods increased LT fat thickness and decreased meat CIE a* (redness) values. Extending the vaccination-to-slaughter interval of immunocastrates increased the gastrointestinal tract fat and decreased meat redness. Immunocastration of male lambs can thus be used to manipulate backfat without negatively influencing carcass weight, cutting yield or meat quality.

Quantification of the effects of castration on carcass and meat quality of sheep by meta-analysis

After an extensive literature search, meta-analytic techniques (fixed effect, random effects and hierarchical Bayesian models) were applied to numerically describe sizes and precision of effects caused by castration of intact rams on several performance, carcass and meat quality response variables. According to random effects models, rams presented greater (P<0.05) average daily gain, loin muscle area (leaner carcasses) and instrumental meat tenderness (more tough), with lower feed conversion ratios, dressing percentages and backfat thickness (less carcass fat) compared to castrates. These results could be applied in further strategies on the use of castration in male sheep.