The effects of immuno- and surgical-castration on the behaviour and consequently growth of group-housed, male finisher pigs

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.

Section: Discussionsupporting

confidence: 81%

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

“…This is in agreement with a positive influence of male sexual hormones on aggressiveness, provided that male pigs with the highest levels of aggressiveness are also those that received the highest number of aggressions in response to their own attacks. This is in good agreement with the lower levels of aggressive behaviours in groups of pigs after suppression of the testicular hormones due to surgical castration (Cronin et al, 2003) or due to vaccination against GnRH (Cronin et al, 2003;Baumgartner et al, 2010). Such relationship between androgens and aggressive behaviour has been demonstrated in numerous species including humans (Soma et al, 2008).…”

Section: Indicators Of the Pubertal Developmentsupporting

confidence: 86%

Influence of housing and season on pubertal development, boar taint compounds and skin lesions of male pigs

Prunier

Brilloüet²,

Merlot³

et al. 2013

Rearing entire pigs may lead to meat quality and welfare problems in relation to pubertal development. A better knowledge of the sources of variation of pubertal development, behaviour and boar taint is needed before generalizing entire male pigs. From 84 days of age, entire male pigs were reared in groups of 10 either in a conventional (C, 1 m²/animal, slatted floor) or an enriched (E, 2.5 m²/animal, straw bedding, outdoor run) housing during spring or autumn and fed ad libitum (n = 10/housing/season). Mounting behaviour was observed for 3 h during the third (M3), fourth (M4) and fifth (M5) months of age. The total number of skin lesions was counted on both sides of the pigs 1 day before the behavioural recordings. The time spent in the outdoor run was also recorded during 3 days per month. The animals were slaughtered at 161 ± 1 days of age (122 ± 9 kg live weight). Blood samples were collected at 89 (M3), 119 (M4) and 152 (M5) days of age and at slaughter for the testosterone and oestradiol measurements. The testes were collected at slaughter, freed from the surrounding tissues and weighed. The fat samples were collected for the androstenone and skatole concentration measurement. Plasma testosterone and oestradiol-17β (oestradiol), fat androstenone and skatole and weight of the testes did not differ between the housing systems. Plasma testosterone (8.3 v. 3.9 nmol/l, P < 0.05) and oestradiol (12.0 v. 9.2 pmol/l, P < 0.1) at M3, fat skatole (0.124 v. 0.043, P < 0.03) and weight of the testes (587 v. 512 g, P < 0.05) were higher in the autumn than in the spring trial, suggesting that the pubertal development was accelerated. The number of received mounting behaviours was slightly higher in the autumn ( P = 0.08) trial and was markedly higher in the E than in the C environment ( P < 0.003). Skin lesions were more numerous in the C than in the E housing at M4 and M5 and in the spring than in the autumn trial at M3 and M4 ( P < 0.05). Fat androstenone and the number of performed mounting behaviours were significantly correlated between each other and with numerous indicators of the pubertal development ( P < 0.05). The number of skin lesions was correlated with plasma testosterone and live weight ( P < 0.05). Overall, this study suggests the effect of season on sexual development, the effect of the housing system on behaviour, and demonstrates the links between sexual hormones, behaviour and boar taint.Keywords: pig, season, housing, testosterone, androstenone ImplicationsFinding solutions to rear entire male pigs without drawbacks on the meat quality and welfare during fattening are essential for the EU pig industry that is engaged in a process of stopping surgical castration. The present study evaluates the housing system and the season as two possible sources of variation of pubertal development, behaviour and boar taint. We found a positive effect of enriching the environment on the number of skin lesions but not on the other parameters. Decreasing day length seems to accelerate the pubertal development. The m...

“…The largest effect is a drastic increase in feed intake compared with EM, in relation with the sharp reduction in the production of androgens and oestrogens, which are known to negatively affect feed intake (Claus and Weiler, 1987). Cronin et al (2003) observed that IC had spent more time eating after V2, possibly in relation with their reduced sociosexual behaviour. Our analysis shows that feed intake after V2 is also slightly higher in IC compared with SC.…”

Section: Immunocastrates -Entire Malesmentioning

confidence: 93%

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

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).