Influence of Housing Conditions on Reliability of Immunocastration and Consequences for Growth Performance of Male Pigs

Abstract

Simple Summary: Surgical castration of male piglets is societally criticized as it is painful and violates the integrity of the animals. Pork production with boars and immunocastrates are possible alternatives. Even if immunocastration is an animal-welfare-friendly alternative, its market share is low and the reliability of this technique is discussed controversially within the pork chain. Currently, the number and the reason for non-responders to vaccination are not clear. Various factors may contribute to impaired immune response including adverse and stressful housing conditions. This study, therefore, examines the influence of different housing conditions on the immune response after two Improvac ® vaccinations. To determine vaccination success, testosterone concentrations, GnRH-binding, and boar taint compounds were evaluated. Furthermore, the growth performance of male pigs was compared. The results show that immunocastration is reliable under different housing systems and prevents boar taint. Moreover, the growth performance of immunocastrates is high and even superior to that of boars and barrows after the 2nd vaccination. Accordingly, immunocastration is not only animal-welfare-friendly but also economically attractive and suitable for different housing systems.Abstract: Immunocastration is a sustainable alternative to piglet castration but faces limited market acceptance. The phenomenon of non-responders has not to date been examined in detail, but adverse and stressful housing conditions (e.g., mixing of groups) might impair the success of vaccinations. Therefore, we evaluated the influence of housing conditions on the immune response after two Improvac ® vaccinations at an age of 12 and 22 weeks, respectively. Boars, immunocastrates and barrows (n = 48 each) were assigned to three different housing conditions (n = 36 enriched, n = 36 standard n = 72 repeated social mixing). Immune response was quantified by measuring GnRH-binding and its consequences for testosterone concentrations, development of the genital tract and boar taint. Growth performance was evaluated via average daily gain (ADG). GnRH-binding and testosterone levels revealed that immunocastration reliably suppressed testicular functions after the 2nd vaccination. Housing conditions did not modify testicular function but influenced ADG as animals under mixing grew slower than those under enriched conditions. Gonadal status had only a slight impact on ADG except in immunocastrates, which showed a temporarily higher ADG after the 2nd vaccination. The results show that immunocastration is a reliable procedure under different housing conditions and competitive in terms of growth performance.

Carcass Characteristics and Primal Pork Cuts of Gilts, Boars, Immunocastrates and Barrows Using AutoFOM III Data of a Commercial Abattoir

“…These studies, however, refer to standardized trials with fixed ages at slaughter. It is well known that the growth performance of immunocastrates increases significantly after the second vaccination [ 19 , 30 , 31 ], as immunocastrates consume significantly more feed after the second vaccination [ 32 ]. For this reason, the timing of the second vaccination has a decisive impact on growth performance and thus indirectly on the final hot carcass weight of immunocastrates with a fixed fattening period.…”

“…As described in the review by Olsson and Pickova [ 44 ], it is well known that management (housing conditions, age, genetics, sex and feeding) can influence various pork quality parameters such as water holding capacity, fat content, tenderness, color and aroma. We also know that stress and intensive housing conditions can have a negative impact on growth performance and hot carcass weight in pigs [ 31 , 45 ]. An experiment with organic housing conditions and organic feed showed that the feed had no influence on the lean meat content of pig carcasses, but the housing conditions did.…”

“…Animals that were fattened under organic housing conditions had a lower lean meat content than animals that were fattened under conventional conditions [ 46 ]. A recent study by Kress et al [ 31 ] also highlighted that animals housed under stressful conditions due to repeated social mixing had a higher proportion of lean meat than animals in the standard and enriched groups [ 47 ], which could be attributed to increased lipolysis caused by stress [ 48 ]. An increasing animal/feeding-place ratio can also lead to more social stress in pigs and thus to a higher proportion of lean meat [ 49 ].…”

Quality of Dry-Cured Ham from Entire, Surgically and Immunocastrated Males: Case Study on Kraški Pršut

“…The hams for this study originate from a wider study evaluating immunocastration (for more details see [12]). We compared hams from surgical castrates (SC), immunocastrates (IC) and entire males (EM) of one crossbreed (Pietrain x German Landrace), which were fattened with the same diet ad libitum.…”

Animal Welfare and Production Challenges Associated with Pasture Pig Systems: A Review

“…An objection to the use of intact males would be the increased stress due of aggressive and mounting behavior during the finishing period [187]. Contrastingly, good results can be obtained by employing immuno-castration with pigs managed in different housing systems [188]. However, economical comparisons conducted in Germany showed that barrows performed better than boars and immunocastrates [189].…”