Resultados económicos entre novillos Holstein inmunocastrados vs no castrados, en engorda intensiva

The study compared the economic results between two groups: non-castrated Holstein bulls and bulls castrated with the gonadotropin-releasing hormone vaccine Bopriva. 510 Holstein feedlot bull calves between 7 and 8 months with a 220±1.19 kg. initial live weight was included. 269 bulls were vaccinated and 241 received no treatment. The vaccinated group got four immunizations: 24 hours upon arrival and 21, 101 and 181 days after the first vaccination. Bulls in the control group received a placebo. The effects of the treatments on hot carcass weight, cold carcass weight, fat thickness, kidney, pelvic and heart fat, ribeye area, and marbling score were analyzed using the GLM procedure. The linear statistical model for this trial included the overall mean, the fixed treatment effect, the random pen within treatment effect (experimental error), and the random animal within pen component (sampling effects within experimental units). Profit was estimated by subtracting the total cost from the revenue. Hot carcass weight, fat thickness, kidney, pelvic and heart fat and ribeye area were obtained to estimate final cut yield and quality grade. The average weight of the carcasses from the treated group was higher (P<.05) and feeding costs lower, contributing to a greater profit for this group. The vaccinated group had a lower final cut yield and higher quality grade.