Extending the interval between second vaccination and slaughter: II. Changes in the reproductive capacity of immunocastrated ram lambs

摘要: Immunocastration improves the welfare of castrated commercial slaughter lambs; however, time-point at which this technique influences semen quality and sperm production has not yet been established for various vaccination schedules. Furthermore, effect extended intervals between second needs to be investigated regarding continued testosterone suppression in immunocastrated lambs. The extending interval immunocastration from four six weeks on reproductive capacity Dohne Merino lambs was examined. A total 40 were stratified according initial weight (45.4±3.68 kg) randomly assigned treatments that included intact control rams (R), Burdizzo-castrated (B) with either (ICS4) or (ICS6) slaughter. Blood samples collected throughout study period determine serum concentrations, evaluate assess viability. Semen R showed improvement over trial. Throughout collection period, B had low poor motility viability, as expected. However, a slight increase percentage live towards end indicated success rates some Burdizzo-castration also caused testes tissue necrosis abscessing, indicating physiological stress. appearance scores varied both treatments, but mass decreased time. ICS6 consistent continuous decline concentrations an increased dead abnormal study. ICS4 treatment successful interrupting reducing quality; consistently treatment. Primary influenced levels only realised after secondary vaccination. Although all castration size colour, six-week vaccination-to-slaughter greater decrease cut surface L* (lightness) colour values seminiferous tubule circumference. Extending resulted more reliable influence Thus, is suitable alternative interruption testis functioning.