IMPACTO DA IMUNOCASTRAÇÃO NA TAXA DE CONDENAÇÃO DE SUÍNOS NO ABATE

Abstract

Immunocastration of pigs is a technology developed to replace surgical castration without anesthesia and analgesia used in the castration of piglets, to avoid sexual odor in the meat and fat of whole pigs. The technique consists of applying two doses of an anti-GnRH vaccine, to inhibit the secretion of gonadal steroids, and has shown promise. When slaughtering finished pigs, a supposed difference was observed in the condemnation rate of carcasses from immunocastrated pigs (IC), compared to non-immunocastrated pigs (NIC – females, and surgically castrated males) due to injuries to the reproductive system or caused for fights or sexual behavior before slaughter. This work aims to evaluate the condemnation rates of IC pig carcasses and anatomopathologically classify the main lesions observed in IC pig carcasses. In a retrospective study, from 2017 to 2021, were evaluated the inspection records of 2,045,226 carcasses of finished pigs IC, NIC and mixed batches (IC/NIC), raised in an integration system in the State of Mato Grosso do Sul – MS. Brazil, slaughtered in a slaughterhouse with the Federal Inspection Service - SIF. Carcasses from IC pigs had 2.46% condemnation, those from IC/NIC pigs 2,38% and NIC with 1.51%. The average weight (AW) was evaluated to analyze a possible correlation (r) with the condemnation rate, with a positive correlation being observed (P<0.05). In a prospective study, 30,706 carcasses of IC and NIC pigs were monitored, raised in the same integrated system in Mato Grosso do Sul, Brazil, and slaughtered in an industrial slaughterhouse with SIF, between November 2022 and February 2023. The pigs had an average age at slaughter of 170 days and average weight of 114 Kg. In this prospective study, the condemnation rate of carcasses from IC pigs was also higher than that of NIC pigs. The main causes of condemnation and injuries identified in the post mortem examination of IC pig carcasses were: thinness (17.63%), peritonitis (12.16%), jaundice (10.33%), pneumonia (9.12%), and abscess (7.3%). Lymphadenitis and muscular changes had the same frequency (6.38%), and osteitis and splenitis also showed similar frequencies (5.77%). The remaining injuries had less than 5% frequency under the monitoring conditions of this study. The anatomopathological diagnosis resulted in lesions in: lung (24.65%), genitals (17.22% - scrotal sac, testicles and epididymis), heart, spleen and intestine (5.58%), and others organs with less than 5% of the lesions observed. It is concluded that, under the monitoring and reduction conditions evaluated, immunocastration impacted levels by increasing carcass notifications. Lesions observed on carcasses of IC pigs are similar to those described in the literature, but hemorrhagic and necrotic lesions in the peri-testicular region occur almost exclusively in this category.

Keywords: carcasses, castration, injuries, inspection, pigs