Castration Of Piglets Research Articles

Chestnut wood extract in boar diet reduces intestinal skatole production, a boar taint compound

Abandoning traditional practice of piglet castration will impact the pigmeat sector. As a consequence, there is a need for research aiming at reducing boar taint caused by androstenone and skatole. Skatole is metabolized by cytochrome P450 enzymes (CYP450) in the liver. Skatole hepatic clearance is believed to be hindered by androstenone. Diet ingredients may modify skatole metabolism. Therefore, we tested the effect of hydrolysable tannins. We fed 51 young boars with 1–3 % chestnut wood extract as supplementary diet. After slaughter, the tissues were collected to assess androstenone and skatole accumulation in fat and to measure CYP450 activities, gene, and protein expression in the liver and intestine. Protein expression of two enzymes involved in androstenone metabolism, 3-beta-hydroxysteroid dehydrogenase (3β-HSD) and sulfotransferase family 2A member 1 (SULT2A1), was assessed, and feces collected to evaluate skatole production. Results show that intestinal skatole production in boars supplemented with 3 % of chestnut wood extract was more than halved. The intestinal catalytic activities of CYP450 were tenfold lower than hepatic and were mainly unaffected by tannins. Findings indicate a potential effect of tannins on steroidogenesis, which in the absence of effect on 3β-HSD and SULT2A1 expression suggests lower synthesis of androstenone due to tannins.

Rapid method for the simultaneous detection of boar taint compounds by means of solid phase microextraction coupled to gas chromatography/mass spectrometry

Because of animal welfare issues, the voluntary ban on surgical castration of male piglets, starting January 2018 was announced in a European Treaty. One viable alternative is the fattening of entire male pigs. However, this can cause negative consumer reactions due to the occurrence of boar taint and possibly lead to severe economic losses in pig husbandry. In this study, headspace solid phase microextraction (HS-SPME) coupled to GC–MS was used in the development and optimization of a candidate method for fast and accurate detection of the boar taint compounds. Remarkably fast extraction (45s) of the boar taint compounds from adipose tissue was achieved by singeing the fat with a soldering iron while released volatiles were extracted in-situ using HS-SPME. The obtained method showed good performance characteristics after validation according to CD 2002/657/EC and ISO/IEC 17025 guidelines. Moreover, cross-validation with an in-house UHPLC-HR-Orbitrap-MS method showed good agreement between an in-laboratory method and the new candidate method for the fast extraction and detection of skatole and androstenone, which emphasizes the accuracy of this new SPME-GC–MS method. Threshold detection of the boar taint compounds on a portable GC–MS could not be achieved. However, despite the lack of sensitivity obtained on the latter instrument, a very fast method with run-to-run time of 3.5min for the detection of the boar taint compounds was developed.

Weight gain, behavioral and cortisol changes after orchiectomy with or without local anaesthesia in piglets

The aim of this study was to investigate the effect of intratesticular local anesthesia on weight gain and behavioral and cortisol changes in piglets submitted to castration. Study design was a randomized controlled trial. Twenty-nine male Landrace crossbred piglets aged 3 to 6 days were used. The piglets were randomly divided into two groups: orchiectomy with anesthesia (A, n = 15) and orchiectomy without anesthesia (NOA, n = 14). Piglets in the A and NOA groups were treated with 0.5 mL of intratesticular 2% lidocaine with a vasoconstrictor in each testicle and 0.5 mL of intratesticular 0.9% sodium chloride, respectively. Blood samples were collected from all animals immediately after surgery and at 3 and 6 days postoperatively for measurement of the serum cortisol concentration. Behavior was assessed daily for 6 days by two observers blinded to the treatment. Weight was measured at the same time as cortisol measurement. Analysis of variance followed by the Student-Newman-Keuls test was used to investigate differences in time within and between the two groups. Mean times of six evaluations done for 90 minutes during 6 days of each behavior were compared by Tukey t test. The level of statistical significance was 5%. The serum cortisol concentration was higher immediately after surgery than at 3 and 6 days postoperatively in both groups. Weight gain was greater at 3 and 6 days postoperatively in the A group than in the NOA group. Intratesticular local anesthesia before castration in piglets is technically practical, is in accordance with good welfare practice, and improves short-term weight gain in piglets submitted to castration.

Towards entire male pigs in Europe: A perspective from the Spanish supply chain

In pig production, surgical castration is primarily performed to avoid boar taint and for management purposes. The European Commission plans to end surgical piglet castration voluntarily by 2018. The aim of this study was to assess the opinions and attitudes of Spanish stakeholders from the entire pork chain regarding this plan. Two methodologies were used: focus groups with 26 participants (qualitative method) were conducted with representatives of farmers, the meat industry, government institutions, retailers (including butchers), HORECA and consumers, and 127 face-to-face surveys at butchers (quantitative method) were carried out. These include an analytical hierarchical process to assess the determining factors when purchasing fresh pig meat. The results showed that a potential end of pig castration in Europe is not anticipated to affect conventional pig production in Spain. However, butchers are worried of negative effects on high quality meat and meat products, where surgical castration of pigs plays an important role.

Consumers' perception and acceptance of boiled and fermented sausages from strongly boar tainted meat

Characteristic off-flavours may occur in uncastrated male pigs depending on the accumulation of androstenone and skatole. Feasible processing of strongly tainted carcasses is challenging but gains in importance due to the European ban on piglet castration in 2018. This paper investigates consumers' acceptability of two sausage types: (a) emulsion-type (BOILED) and (b) smoked raw-fermented (FERM). Liking (9 point scales) and flavour perception (check-all-that-apply with both, typical and negatively connoted sensory terms) were evaluated by 120 consumers (within-subject design). Proportion of tainted boar meat (0, 50, 100%) affected overall liking of BOILED, F (2, 238)=23.22, P<.001, but not of FERM sausages, F (2, 238)=0.89, P=.414. Consumers described the flavour of BOILED-100 as strong and sweaty. In conclusion, FERM products seem promising for processing of tainted carcasses whereas formulations must be optimized for BOILED in order to eliminate perceptible off-flavours. Boar taint rejection thresholds may be higher for processed than those suggested for unprocessed meat cuts.

Evaluation of CO2 anaesthesia applied by a commercial device for the castration of male suckling piglets under field conditions.

The aim of this study was to describe clinical and behavioural parameters of piglets castrated with the use of CO2 anaesthesia by using the commercial available device MS Pigsleeper. 80 male piglets with three to six days of age were allocated to four groups, and were castrated or left uncastrated either after receiving 70% CO2/30% O02, or without anaesthesia. Defensive movements and heart rates were measured during induction and castration phase. At castration phase the dewclaw reflex was tested and piglets were monitored for vocalisation. During recovery and the subsequent five minutes conspicuous behaviours were recorded. Intensity of defensive movements was significantly higher in groups with CO2 anaesthesia during induction phase. Defensive movements were significantly lower in groups with CO2, but also not fully absent, during castration phase. Surgical tolerance was only reached by 20% (4/20) of piglets castrated under anaesthesia. Heart rates were above physiological levels at the beginning of induction phase and dropped significantly thereafter. Dropping of heart rates was more pronounced in anaesthetised groups leading to significant differences compared to non-anaesthetised groups. A minimum heart rate of 20 beats per minute was measured. Conspicuous behaviours as spasms, gasping and licking were described for pigs after CO2 anaesthesia. Measured parameters implicated stress and discomfort during induction and recovery phase and severe cardiovascular depression during CO2 anaesthesia. Surgical tolerance was reached by only a small proportion of anaesthetised piglets. Therefore, welfare aspects were not met using CO2 anaesthesia for piglet castration in general and especially by applying the gas anaesthesia with the commercial device MS Pigsleeper.

Immunocastrated male pigs: effect of 4 v. 6 weeks time post second injection on performance, carcass quality and meat quality

Immunocastration or vaccination against boar taint can be used as alternative for surgical castration of male piglets. The vaccine is administrated twice. After the second vaccination (V2), the pigs behave like barrows instead of boars and their feed intake increases which may result in a lower lean meat percentage. The timing of V2 is therefore crucial to find the right balance between the advantages of entire males and barrows. In this study, we evaluated the effect of time post second injection within the advised time frame (4 v. 6 weeks before slaughter) on behaviour, performance, carcass and meat quality of immunocastrated male pigs. In total, 180 animals (hybrid sow×Piétrain): 60 gilts, 60 male pigs vaccinated 6 weeks before slaughter (IM-6) and 60 male pigs vaccinated 4 weeks before slaughter (IM-4), all slaughtered at comparable slaughter weights. After 20 weeks of age, IM-6 showed more inactive behaviour at the expense of playing and aggressive behaviour. Daily feed intake (DFI), daily gain (DG) and feed conversion ratio (FCR) did not differ significantly between IM-6 and IM-4. Gilts had a lower DFI and DG in the late finishing phase and a higher FCR overall compared with both IM groups. Gilts showed a higher lean meat content compared with both IM groups. Earlier vaccination increased dressing percentage, which could partly be explained by the lower weight of the gastrointestinal tract, but not by testes weight. Meat quality traits and palatability did not differ significantly between IM-6 and IM-4. Vaccination of immunocastrates at 6 compared with 4 weeks before slaughter improved the calmness in the stable and the dressing percentage, while maintaining performance and carcass characteristics.

Concentrations of neopterin, biopterin, and cortisol associated with surgical castration of piglets with lidocaine

The effect of surgical castration with local anesthesia using lidocaine on neopterin, biopterin, and cortisol blood plasma concentrations in piglets was studied. Three groups of 12 piglets were investigated: one group castrated without lidocaine, one group castrated with lidocaine, and one group left as an uncastrated control group handled in the same way as castrated piglets. Blood samples were collected 4 min before castration, and 1 h and 24 h after castration. The time × treatment interaction (P < 0.01) was detected for neopterin concentrations, yielding the result that neopterin was higher (P < 0.01) in castrated piglets without lidocaine 1 h after surgical castration compared with all other groups. The time effect (P < 0.05) was detected for biopterin concentrations. The time × treatment interaction (P < 0.01) was detected for plasma cortisol concentrations, yielding the result that neopterin was higher (P < 0.01) in castrated piglets without lidocaine and in castrated piglets with lidocaine 1 h after surgical castration compared with pre-treatment and concentrations 24 h after surgical castration. The study showed that the use of lidocaine for the surgical castration of piglets may significantly influence the activation of the immune system. This is corroborated by a significant difference in blood plasma neopterin concentrations between piglets castrated with anesthesia and those castrated without it. The use of lidocaine had no effect on cortisol concentrations in comparison with the group castrated without lidocaine.

Influence of hands-on experience on pig farmers' attitude towards alternatives for surgical castration of male piglets

This study evaluates the influence of practical experience with alternatives for surgical castration (SC) on farmer attitudes. Nineteen farmers in Flanders were surveyed before (ex-ante) and after (ex-post) performing each of five treatments on farm: 1) SC with analgesia (SCAN); 2) SC with CO2 anaesthesia (SCCO2); 3) immunocastration (IM); 4) production of entire males (EM); and 5) SC without pain relief (SCN). For SCCO2 and SCAN, farmers mainly experienced disadvantages in terms of increased labour, costs and complexity. Hands-on experience promoted EM as a valid alternative for SCN due to the actual and perceived improvement in performance and profitability as well as the reduced labour demands. Experience with IM did not fully fulfil the favourable ex-ante expectations resulting in a level of dissatisfaction and a less favourable general attitude ex-post.

Agonistic behaviour, skin lesions and activity pattern of entire male, female and castrated male finishing pigs

Fattening of intact boars is the least invasive alternative to the detrimental welfare effects of surgical castration of piglets. However, beside problems such as boar taint the divergent agonistic and sexual behaviour of boars may impair the pigs’ welfare during fattening. To evaluate the effect of sex on agonistic interactions a total of 108 female, 108 castrated male and 108 entire male German crossbred pigs with an initial average body weight of 25kg were kept in nine pens during three replicates with 12 pigs per pen respectively (1.2 m2 per pig) separated by sex. Pigs were slaughthered at about 115kg body weight. Agonistic behaviour was recorded 24h before and 24h after, and skin lesion scores (from 0 to 3) were recorded four days before and three days after half of the pigs have been removed in each pen for slaugthering. In addition, the daily activity pattern of groups was examined by a motion sensor system during 72h before removing half of the pigs of a group. The frequency of mounting, knocking and fighting was significantly higher in entire males both before and after removing half of the pigs from groups. Disturbance of social structure by removing half of the pigs per group did not affect the total number of agonistic interactions in any sex. Entire males showed a higher incidence of skin lesions at the neck and the ham before, and at the shoulder after half of the pigs were removed for slaughtering. However, the severest lesion score 3 was not found in any group and for score 2 the highest incidence of 3.7% was found at the shoulder of entire males after removing half of the pigs per group. The activity pattern of the pigs was not affected by sex. It was concluded that under housing conditions used in the present study (ad libitum feeding and low stocking density) fattening of entire male pigs can be done without severe detrimental effects on their welfare.

Comparison of entire male and immunocastrated pigs for dry-cured ham production under two salting regimes

Due to the initiative to stop piglet castration, meat from entire male pigs is expected to take important share on the European market which can affect dry-cured ham industry. In the present study, hams of entire males (EM) and immunocastrates (IC) were submitted to dry-curing process. Sex category and salting regime were evaluated using standard (18days; HS) and shortened salting (6days; LS). At the end of processing, compared to HS, LS hams had lower (40%) salt content, were more proteolysed, were less salty, and had softer texture and different volatile profile. Sex effect was less evident; still, hams from EM exhibited higher processing losses and salt intake, and were drier, less marbled, harder, and more intensively coloured than IC hams. The panellists perceived higher off-flavours in hams with high boar taint compounds (correlation 0.67 and 0.53 for skatole and androstenone, respectively). The effect of sex category on volatile profile was negligible.

Genetic relationships between measures of sexual development, boar taint, health, and aggressiveness in pigs.

Breeding intact boars is a promising alternative to surgical castration of piglets. Genetic selection should enable farmers to solve problems due to boar taint and aggressiveness while taking into account potential consequences on other traits of interest. The aim of the study was to estimate genetic relations between sexual development, boar taint, health, and aggressiveness. About 1,600 Pietrain (purebred) or Pietrain × Large White (crossbred) boars were raised in a testing station. Blood samples were collected at about 105 kg BW for measuring sex hormones (testosterone and estradiol) and indicators of the inflammatory status (C-reactive protein [CRP], pig major acute-phase protein [pigMAP], and blood formula). Animals were slaughtered 9 d later and measured for boar taint compounds present in fat (androstenone and skatole) and skin lesions on carcass, an indicator of aggressiveness. For both genetic types, heritability was moderate for sex hormones (from 0.17 to 0.29) and skatole (0.24 for purebred and 0.37 for crossbred) and high for androstenone (0.63 and 0.70 for purebred and crossbred, respectively). Genetic correlations between sex hormones and boar taint compounds were moderate to high (from 0.31 to 0.95). Heritability was moderate for CRP (0.24 and 0.46 for purebred and crossbred, respectively) and very low for pigMAP (0.06 and 0.05 for purebred and crossbred, respectively. Numbers of leukocytes had moderate to high heritabilities according to the genetic type (from 0.21 to 0.52). Heritability of skin lesions was moderate for both genetic types (0.31). Genetic correlations were negative between sex hormones and inflammatory measures (from -0.46 to -0.05), positive between testosterone and number of lesions (0.43 and 0.53 for purebred and crossbred, respectively), and low between androstenone and lesions (-0.06 and -0.17 for purebred and crossbred, respectively). Overall, both breeds of pigs had very similar estimations of heritabilities, but estimates of genetic correlations were different for some pairs of traits. It would be possible to select boars based on their plasma concentration of sex hormones to decrease boar taint and aggressiveness without important consequences on the immune response. However, because of the strong links between boar taint and reproductive function, the possible consequences on the reproductive performance should be evaluated.

The effect of the MC4R gene on boar taint compounds, sexual maturity and behaviour in growing-finishing boars and gilts

Societal pressure to ban surgical castration of male piglets is rising due to animal welfare concerns, thus other methods to prevent boar taint need to be explored. Genetic selection against boar taint appears to be a long-term sustainable alternative. However, as boar taint is linked to reproductive hormones, it is important to consider possible negative side effects such as delayed sexual maturity or changes in behaviour. We reported earlier that the melanocortin-4 receptor (MC4R) marker can be used to reduce boar taint levels in fat of boars. The objective of this study was to evaluate whether MC4R marker-assisted selection for lower boar taint prevalence affects plasma levels of boar taint compounds and testosterone; sexual maturity; behaviour; skin lesions; and lameness in boars and gilts. Using an intervention study with a 2×2 design, 264 boars and gilts differing on position 893 of the MC4R gene (AA v. GG) were compared. The MC4R polymorphism did not affect the plasma concentration of either androstenone or testosterone at different time points, whereas the concentration of skatole was significantly lower (P=0.003) and the concentration of indole tended to be lower (P=0.074) in GG compared with AA boars. A higher percentage of gilts of the GG genotype were in puberty at slaughter age compared with AA gilts (P<0.001). The age of the boars at sexual maturity (as indicated by the first positive preputial smear test) did not differ between AA and GG boars. In contrast, weight of GG boars at sexual maturity tended to be lower (P=0.065). During the period from 6 weeks of age to slaughter, boars and gilts of the GG genotype showed more playing behaviour (P=0.015) and less passive and feeding behaviour (P=0.003). They showed more skin lesions on their back and caudal area (P=0.022), and tended to show more skin lesions on their head and anterior area (P=0.093) compared with AA animals. In conclusion, the polymorphism in the MC4R gene can be used as a marker without negative effects on reproduction characteristics in boars and gilts. Genetic selection towards a lower prevalence of boar taint will lead to more active pigs with more skin lesions. Management strategies may therefore be necessary to reduce skin lesions in the selected animals.

Raising Entire Males or Immunocastrates – Outlook on Meat Quality

European pig production faces a big challenge in the near future due to a strong initiative to abandon surgical castration of piglets. However, prior to ending of this widespread traditional practice in pig husbandry, a lot of potential problems need to be addressed in view of the adaptation of pig sector. It means that not only must boar taint issue be solved but also that meat technological quality will not be deteriorated. Two most viable alternatives to surgical castration will be reviewed with special emphasis on meat quality assurance.

Entire male pig production in Europe

In Europe the proportion of male pigs that are left ‘entire’ has been high for many years in the British Isles and Iberian Peninsula, and has recently increased in The Netherlands and to a lesser extent in Germany and France. Various European Union partners agreed in 2010 on a road map to abandon piglet castration by 1 January 2018. Despite significant commercial in-confidence research on instrumental methods for detecting boar-tainted carcasses at slaughter plants, nothing is currently being adopted at an industrial scale. A few abattoirs sort out the most heavily tainted carcasses, using human nose methods. However, there are major concerns with their accuracy, which is currently not documented in any publicly available technical report. The importance of androstenone and skatole for boar taint is still debated but a recent study (CAMPIG; G Backus, H Snoek, MA Oliver, M Font i Furnols, M Aluwé, F Tuyttens, M Bonneau, P Chevillon, MD Aaslyng, D Moerlein, L Meier-Dinkel, J Trautmann, J-E Haugen, unpubl. data) has established preliminary equations relating consumer dissatisfaction to androstenone and skatole levels. These equations still need further consolidation to integrate the impact of very high and very low androstenone levels on consumer acceptability. Reducing the incidence of boar taint at a production level and at the same time overcoming possible greater aggressive behaviour of entire male pigs are also critical for abandoning castration. Genetic selection is the most efficient way to reduce androstenone, but the selection of boar-taint-free genetic lines without any adverse consequence on the reproductive and growth performance will take time. Skatole levels can be efficiently reduced via feeding specific feedstuffs and good control of the animals’ environment. Provided that the incidence of boar taint can be reduced to an acceptable level and the residual tainted carcasses can be sorted out at a reasonable price by mutually recognised methods, the abandonment of castration will result in high benefits, up to one-billion euros for both the pork industry, via a drastic reduction of production costs, and society at large, through improved animal welfare and reduced impact on the environment.

Quality attributes of ready to eat bison meat snack during 40 °C accelerated storage

Since surgical castration of male piglets without anaesthesia is under heavy societal pressure, finding a sustainable solution to reduce boar taint has become urgent. One way to circumvent this animal welfare violation is raising entire male pigs whilst selecting against the tainted phenotype through marker-assisted selection. Since slaughtering at a lower weight is often suggested to reduce boar taint, selection using a marker for that trait could be a promising strategy. Therefore, in this study a melanocortin 4 receptor (MC4R) mutation, frequently described in different pig breeds as marker for fat content, weight gain and feed intake, was examined in relation to boar taint in pig breeds used in Belgian pig farms. Although results suggest an association between this mutation and a boar taint odour score assigned by experts, no association was found between the mutation and the concentration of the individual chemical boar taint components androstenone, skatole and indole.

An ethical case study: Castration of piglets without anesthesia

Depending on which ethical theory is adopted as policy, different responses to the dilemma may result. The moral case for prohibiting castration without anesthesia, in the interests of preventing unnecessary animal suffering, is certainly strong. Against this rests the financial interests of members of a large industry. The legislator faces a dilemma that could perhaps best by resolved by an appeal to impartial science. That is certainly the stance adopted by EUROGROUP FOR ANIMALS, which relies heavily on the EFSA findings to advance their cause. It is important, however, that we remain cognizant of the fact that ethical assumptions do underpin objective scientific findings (Sandoe, 2012). Despite the specific mandate of the EFSA, a hedonistic view of the need to avoid animal pain, even where this would limit natural behaviors, has clearly influenced their opinion on the welfare aspects of piglet castration. Such ethical assumptions might well be justified, but they should also be made transparent.

Evaluating the performance of sensory quality control: The case of boar taint

Detection of malodours referred to as ‘boar taint’ in entire male pigs is essential for quality control when refraining piglet castration. This study analysed the sensitivity and specificity of sensory evaluation by trained assessors (n=18) compared to chemical analysis of two marker compounds (androstenone, skatole) in backfat (n=794). Taking the measurement uncertainty into consideration, several cut-off thresholds for chemical analysis were exemplarily evaluated. Using the panel average score, sensitivity and specificity of sensory analysis ranged from 61 to 69% and 77 to 85%, respectively. Performance of individual assessors varied highly (sensitivity: 47 to 86%; specificity: 45 to 88%) and correlated to olfactory acuity to the compounds. According to receiver operating characteristic-curves, the average panel performed better than single assessors regardless of the sensory criterion shift. Agreement plots illustrate that high skatole levels are better detected than high androstenone levels (useful for assessor feedback). The agreement between sensory and chemical analyses was moderate. Assessors need to be selected carefully.

The MC4R c.893G > A mutation: A marker for growth and leanness associated with boar taint odour in Belgian pig breeds

Since surgical castration of male piglets without anaesthesia is under heavy societal pressure, finding a sustainable solution to reduce boar taint has become urgent. One way to circumvent this animal welfare violation is raising entire male pigs whilst selecting against the tainted phenotype through marker-assisted selection. Since slaughtering at a lower weight is often suggested to reduce boar taint, selection using a marker for that trait could be a promising strategy. Therefore, in this study a melanocortin 4 receptor (MC4R) mutation, frequently described in different pig breeds as marker for fat content, weight gain and feed intake, was examined in relation to boar taint in pig breeds used in Belgian pig farms. Although results suggest an association between this mutation and a boar taint odour score assigned by experts, no association was found between the mutation and the concentration of the individual chemical boar taint components androstenone, skatole and indole.

Comparison of immune and health markers in intact and neonatally castrated male pigs

Stress and sex hormones are known to regulate immune function. Castration of male piglets is used to avoid boar taint in the meat, but its consequences on immunity and health...