Impact of replacing physical castration with vaccination against GnRF (Improvac~®) on carcass grading following the SEUROP system

摘要

Vaccination against GnRF (using Improvac, Pfizer Animal Health) is an alternative to physical castration for the control of boar taint. Studies have shown that the implementation of an Improvac regimen, and consequent avoidance of early physical castration, leads to an increase in carcass leanness. This in turn might be expected to influence the distribution of carcass grades. The objective was to examine the impact of Improvac vaccination on carcass grading through review of a multi-study database. The SEUROP system for grading carcasses is commonly used within Europe and 13 studies from 10 countries were identified where carcasses from comparable groups of vaccinated and physically castrated animals were graded in this way. In total information was available for 1234 Improvac vaccinated pigs and 1345 physically castrated pigs. Data pooled from the 13 studies that used the SEUROP system showed a significant shift in distribution of grading to the more superior grades in vaccinated animals. A total of 75.3 % of the Improvac vaccinated animals were graded S or E, typically the most valuable grades, compared to 50.6 % of carcasses from physically castrated pigs. In contrast 8.1% of physically castrated pigs and 4.1% of vaccinated pigs were in the lowest (O and P) grades.