Performance of male pigs immunized against GnRH is related to the time of onset of biological response1

115

102

Meta-analytical approach was used to quantitatively synthesize the effect of immunocastration on growth, carcass, meat quality, reproductive organs and boar taint compounds. Altogether, 41 papers were collected for effect size (θ) calculation and the comparisons were made with entire males (EM) and surgical castrates (SC). The data for reproductive organs and growth performance are numerous enough to draw firm conclusions. In contrast, data for carcass and meat quality are more limited. Results of meta-analysis show efficient immunocastration with the magnitude of the response being by far the largest for reproductive organs (θ= −2.8 to −5.0) and boar taint substances (θ= −2.8 and −0.8 for androstenone and skatole, respectively). However, compared with SC, the immunocastrates exhibit larger bulbourethral glands (θ= 1.3) and slightly higher concentrations of androstenone and skatole (θ= 0.1 andθ= 0.2, respectively). The impact of immunocastration is also remarkable on performance, where the main advantage of the immunocastrates is their boar-like performance until revaccination. In the period following the second vaccination, they eat much more than EM (θ= 2.1), resulting in large effect size for growth rate compared with both EM and SC (θ= 1.1 andθ= 1.4, respectively). Considering the whole fattening period, their feed conversion ratio is higher compared with EM (θ= 0.6) and much lower than that of SC (θ= −1.3), although exhibiting moderately faster growth compared with both (θ= 0.6 andθ= 0.2, respectively). With regard to carcass quality, the immunocastrates take intermediate position between EM and SC. Besides, our analysis suggests no difference in meat quality with SC and some meat quality advantages of immunocastrates over EM because of higher intramuscular fat content (θ= 0.4) and lower shear force (θ= −0.6).

Section: Immunocastrates -Entire Malesmentioning

confidence: 73%

“…This could be explained with an early response to the vaccination. Indeed, Turkstra et al (2002) observed that in some pigs (qualified as early responders), LH and testosterone levels were reduced after V1. After the second vaccination, IC produce a large quantity of antibodies, sufficient for the neutralization of all secreted GnRH.…”

Section: Discussionmentioning

confidence: 99%

Meta-analysis of the effect of immunocastration on production performance, reproductive organs and boar taint compounds in pigs

Batorek

Čandek-Potokar

Bonneau

et al. 2012

115

102

“…This could be due to a rapid immunocastration effect in these pigs. In a study by Turkstra et al (2002), where a different anti-GnRH vaccine was used, 50% of the pigs had low levels of plasma testosterone and diminished testicular function already before the second vaccination. Before slaughter, mounting was also absent in standard vaccinated pigs, but was still present among the entire male pigs at the same level as previously.…”

Section: Resultsmentioning

confidence: 99%

Early vaccination with Improvac®: effects on performance and behaviour of male pigs

Andersson

Brunius

Zamaratskaia

et al. 2012

The aim of this study was to investigate the effect of giving a two-dose regimen of gonadotropin-releasing hormone vaccine, Improvac R (Pfizer Ltd), earlier than currently recommended, on performance and behaviour of growing/finishing pigs. Cross-bred male pigs (n 5 192) were randomly allocated, within a litter, into four groups at birth: one group of pigs surgically castrated without anaesthesia before one week of age, a second group of early vaccinated pigs given Improvac at 10 and 14 weeks of age, a third group of standard vaccinated pigs given Improvac at 16 and 20 weeks of age, so that the second vaccination was given 4 to 6 weeks before slaughter as recommended by the manufacturer, and a fourth group of entire male pigs. The experiment started when the pigs were 12 weeks old and lasted until 25 weeks of age, when the pigs were slaughtered. The pigs were fed restrictedly. Daily weight gain and feed conversion during the entire raising period did not differ significantly between groups. Estimated lean meat content of early vaccinated and surgically castrated pigs was lower when compared with entire male pigs, whereas standard vaccinated pigs did not differ from entire males. Dressing percentage was higher in early vaccinated and surgically castrated pigs than in standard vaccinated and entire male pigs, partly because of lower size and weight of reproductive organs. For both groups of vaccinated pigs, both problematic and non-problematic behaviours decreased after their second injection, from the levels of entire males to those of surgically castrated pigs. After the second injection, pigs of both vaccination groups performed no mountings, in contrast with entire male pigs of the same age. Skin lesions at slaughter were fewer and less severe for vaccinated pigs compared with entire male pigs. No difference in income per carcass was observed for surgically castrated or vaccinated pigs. However, for entire male pigs the income was lower, as the payment system in Sweden also takes into consideration the additional cost for boar taint analyses and reduced payment for tainted carcasses. Under our experimental conditions, early vaccination with Improvac can be used as an alternative to the recommended schedule to minimise problematic behaviour with unaffected profitability.Keywords: male pigs, early vaccination against GnRH, performance, behaviour ImplicationsThis study showed that an earlier than recommended vaccination of male pigs with a gonadotropin-releasing hormone vaccine, Improvac, yielded results similar to surgical castration and the recommended vaccination schedule regarding production and behaviour. This implies that the vaccination can potentially be administered at a younger age, and the flexibility of vaccination increased for pig farmers who find the manufacturer's recommended vaccination schedule impractical. Although early vaccination is a potential alternative to the currently recommended vaccination schedule, it needs to be more extensively studied for different breeds under different practical...

“…It also offers welfare advantages due to the absence of castration pain and stress (Prunier et al, 2006). Results of some studies also report higher growth rates for entire males than for C (Andersson et al, 1997;Turkstra et al, 2002). However, responses of anabolic steroids production by entire males are inconsistent because performance differences between entire males and castrates depend on genotype and housing conditions.…”

Section: Introductionmentioning

confidence: 99%

Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet

Pauly

Spring

O’Doherty

et al. 2008

In Europe there is increasing concern about the common practice of surgical castration of piglets without anaesthesia. One possible alternative to completely avoid castration is entire male pig production. Thus, the objective of the study was to compare the growth performance, carcass characteristics, organ weights, meat quality traits, fat score and boar taint compounds in the adipose tissue of group-penned entire male pigs and castrates. Furthermore, the effect of raw potato starch (RPS) fed for 7 days prior to slaughter was determined. Pigs (n= 36) were blocked by BW into 12 blocks (3 littermates/block) and assigned to three experimental groups: surgical castrates (C); entire males (EM); and entire males offered RPS (30 g RPS/100 g diet) for 7 days prior to slaughter (EM+). Pigs hadad libitumaccess to the feed from 22 to 107 kg, individual feed intake was recorded daily and BW once a week. Entire males grew slower (EM: 771, EM+: 776v. C: 830 g/day;P< 0.01), consumed less feed (EM: 1.87, EM+: 1.89v. C: 2.23 kg/day;P< 0.01) and were more efficient (feed conversion ratio: EM: 2.42, EM+: 2.44v. C: 2.69 kg/kg;P< 0.01) than C. Compared to C, carcass dressing percentage was lower (EM: 79.4, EM+: 79.4v. C: 81.6%;P< 0.01) and percentage of valuable cuts was higher (EM: 57.3, EM+: 56.5v. 52.6%;P< 0.01) in entire males. The hearts (EM: 426, EM+: 425v. C: 378 g), kidneys (EM: 387, EM+: 378v. C: 311 g), bulbourethral (EM: 200, EM+: 195v. C: 7 g) and salivary glands (EM: 99, EM+: 94v. C: 42 g) were heavier (P< 0.001) in entire males than in C. Meat quality traits did not (P> 0.05) differ among experimental groups but the adipose tissue was more unsaturated in entire males than in C as indicated by the higher fat scores (EM: 69.1, EM+: 67.2v. C: 63.6;P< 0.01). Feeding RPS reduced (P= 0.04) the skatole tissue concentrations (expressed in μg/g lipid) in EM+ (0.22) compared to EM (0.85), whereas androstenone and indole levels were not (P⩾ 0.60) affected (EM: 1.7 and 0.10, EM+: 2.0 and 0.09, respectively). Although the current results confirmed the high efficiency of entire males compared to castrates, the observed high androstenone levels represent a major challenge to implement entire males production.