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The aim of this study was to assess the effect of GnRH vaccination in boars (BO), barrows (BA), and gilts (GI) slaughtered at an average BW of 133 kg. Forty BO, 40 BA, and 40 GI were housed individually, fed ad libitum, and divided into 2 groups of 20 pigs per sex, a control group (CON) and a GnRH vaccinated group (IC). The IC group received 2 injections of GnRH vaccine (Improvac) at 70 and 105 kg. In BA, GnRH vaccination had minor effects on performance. Observed effects in BO and GI are therefore probably not caused by the GnRH vaccination itself but by the subsequent withdrawal of gonadal hormones. In BO, the increased feed intake after GnRH vaccination (P < 0.001), accompanied by a fall in estradiol and testosterone levels, led to faster growth (P = 0.014), increased back fat thickness (P = 0.021), and a tendency for a decreased meat percentage (P = 0.052). GnRH vaccination of BO decreased the boar taint-related sensory attribute scores similar to the levels of BA and GI (P < 0.001). In GI, the increased feed intake after GnRH vaccination (P < 0.001), accompanied by low progesterone levels, led to faster growth (P < 0.001), increased back fat thickness (P = 0.018), decreased meat percentage (P = 0.032), and a decreased shear force (P = 0.002) without significant differences in the sensory profile. [ABSTRACT FROM AUTHOR]

The Asp298Asn polymorphism of the melanocortin-4 receptor (MC4R) in pigs is known to affect economically important traits such as growth rate and backfat thickness. We have assessed the possible use of this polymorphism as a molecular marker to perform genetic selection toward lower boar taint levels without compromising growth performance and carcass and meat quality in commercial boars and gilts. Homozygous boars and gilts of the AA genotype and GG genotype were compared in an intervention study with a 2 × 2 design to assess main effects and possible interactions between sex and MC4R genotype. The concentrations of the 3 boar taint compounds androstenone (P = 0.044), skatole (P = 0.049), and indole (P = 0.006) were significantly higher in fat of AA boars compared to GG boars. However, no effect on the sensory analysis of the fat samples could be observed. Between 20 and 115 kg BW, AA pigs showed higher ADFI than GG pigs (P < 0.001). An interaction between genotype and sex was observed for ADG (P = 0.044): AA boars had a significantly higher ADG than GG boars but there was no significant difference between the gilts. Daily lean meat gain tended to be higher in boars compared to gilts (P = 0.051), independent of genotype. Similarly, boars showed higher G:F compared to gilts (P < 0.001), without effect of genotype. Genotype and sex affected several carcass quality parameters but there was no interaction. Pigs of the AA genotype displayed a lower dressing percentage (P = 0.005), lower ham width (P = 0.024), lower muscle thickness (P = 0.011), and higher fat thickness (P < 0.001), resulting in a lower lean meat percentage (P < 0.001) in comparison with GG pigs. Gilts had a significantly higher dressing percentage (P < 0.001), higher muscle thickness (P < 0.001), higher ham width (P < 0.001), and lower ham angle (P < 0.001) compared to boars. Other than the boar taint compounds, meat quality was not affected by genotype. Pork of gilts was darker (P = 0.014) and less exudative during cooking (P < 0.001) and contained more intramuscular fat (P = 0.013). These results indicate that genetic selection against boar taint is possible using this marker. This will also result in lower feed intake and ADG and, consequently, better carcass quality. [ABSTRACT FROM AUTHOR]

Abstract: This study evaluates 1) carcass quality, meat quality and palatability for barrows, immunocastrates and boars and 2) the effect of chicory supplemented feed during 10days before slaughter on boar meat quality. At comparable carcass weights, estimated carcass lean meat percentage was higher in immunocastrates and boars than in barrows. Muscle thickness was higher for immunocastrates and barrows compared to boars, while fat thickness was lowest for immunocastrates and boars. Barrows, immunocastrates and boars differed in water holding capacity and boar taint. Home consumer panels were conducted to evaluate palatability. The consumers did detect differences in tenderness and juiciness, but not for boar taint. The chicory feed supplemented in boar feed decreased skatole concentration in backfat, without largely influencing meat quality or palatability. Not only boar taint, but also carcass and meat quality should be considered when evaluating alternatives for surgical castration. [Copyright &y& Elsevier]

Abstract: Three potential early-age predictors of which boars are likely to develop boar taint (testes volume, skin lesions and dirtiness) were measured on 102 boars every fortnight from 10weeks of age until slaughter. These predictors were correlated with the level of boar taint according to the hot iron method and the concentrations of skatole and androstenone as determined by chemical analysis. The chance of no/low boar taint according to the hot iron method decreased with higher testes volume (weeks 22 and 24) and increased with skin lesion score (weeks 12, 16 and 18). For the concentrations of androstenone and skatole, the strongest correlation was found with testes volume in week 12. Skin lesions in week 16 were negatively correlated with skatole levels. Dirtiness was negatively correlated with skatole concentrations (week 18) but positively correlated with androstenone concentrations (weeks 20 and 22). Testes volume has the greatest potential for predicting the likelihood of developing boar taint. [Copyright &y& Elsevier]

This study was performed to investigate meat quality traits of loin and ham of commercial pigs as affected by genetic differences in carcass and growth traits of the parent lines. Three hybrid sow lines were crossbred with two types of Belgian Piétrain with different breeding goals (BP growth and BP carcass emphasizing daily growth and carcass conformation, respectively). Pig live performance and carcass quality of 270 offspring were measured, and meat quality of the loin and (cooked) ham was evaluated on 216 animals. Despite the differences in pig live performance and carcass quality for sow line, little effect on meat quality was observed. Only a lower (p < 0.05) intramuscular fat content of ham and a tendency (p < 0.1) toward lower cooking yield was observed in offspring of the sow line with the highest versus the lowest carcass lean content. Loin traits were only weakly associated with fresh and cooked ham quality traits. • The effect of growth and carcass traits in crossbred pigs on ham and loin quality was studied. • Differences in pig live performance according to sire type or sow line were of economic importance. • Meat quality did not differ between sire type or sow line. • Loin quality was only weakly associated with cooked ham meat quality. [ABSTRACT FROM AUTHOR]

Performance (from 10 weeks until slaughter), carcass and meat quality, and effectiveness of immunocastration was compared in crossbred offspring of stress positive (BP+) and negative (BP-) Belgian Piétrain and Canadian Duroc (CD) given the second vaccination of Improvac® at different times (4, 6, 8 weeks before slaughter). CD offspring had a significantly higher daily gain (DG) and feed intake (DFI), and lower predicted lean meat percentage (LMP) and dressing yield compared to BP+ and BP-, while feed conversion ratio (FCR) did not differ. CD offspring had significantly lower drip loss and higher pH i, intramuscular fat content than BP+ and BP- (except for pH i). No significant effect of vaccination time on DG nor FCR was observed. Predicted LMP tended to increase as time-post injection decreased, while meat quality was minor affected. Earlier vaccination had no effect on the effectiveness of immunocastration based on testosterone and GnRH-binding. • Evaluation of CD, BP- and BP+ as sire line when time of second vaccination to slaughter varied from 4 to 8 weeks • Earlier vaccination had negative effects on FCR and lean meat content and minor positive effects on drip loss and IMF • Effect of breed was lower than one copy of the RYR1 gene on lean meat content, dressing yield, meat pH and drip loss • CD had the lowest lean meat content and dressing yield and best meat quality compared to BP+, with BP- intermediate • No negative effect of earlier vaccination on effectiveness of immunocastration was observed [ABSTRACT FROM AUTHOR]

This study was designed to compare performance, carcass and meat quality of crossbred of a hybrid sow x three sire lines, i.e. stress positive Belgian Piétrain (BP), stress negative French Piétrain (FP) and Canadian Duroc (CD). BP offspring had a significantly higher carcass yield (p <.001) and lean meat content (p <.001) in comparison with FP, which was higher than CD. BP offspring had significantly lower pH (p <.05), water-holding capacity (WHC) (p <.001) and intramuscular fat (IMF) (p <.001) content in the loin compared to FP and CD, but these meat quality parameters, with the exception of pH, were superior for CD as compared to FP. In accordance with loin quality, pH i , pH u , WHC and IMF of BP were significantly lower (p <.05) compared to CD in the fresh and cooked ham. Most often, FP offspring could not be differentiated from the other offspring, with the exception of cooking loss of the cooked ham. Trained and consumer taste panels resulted in no significant differences (p >.1) in sensory attributes, however, consumers preffered CD based on ranking. • Effect of sire line on performance, carcass and meat quality of the loin and (cooked) ham was evaluated. • BP offspring tended to have a lower feed conversion ratio compared to offspring from FP and CD. • BP offspring had the best carcass quality, followed by FP and worst for CD. • CD offspring had the best meat quality scores, BP the worst and FP intermediate. • CD offspring ranked best for consumer preference. [ABSTRACT FROM AUTHOR]