Effect of vaccination against gonadotrophin-releasing hormone, using Improvac®, on growth performance, body composition, behaviour and acute phase proteins

Carcass quality of immunocastrated boars - A retrospective analysis of slaughterhouse data

The aim of the study was to analyze the meat quality of immunocastrated (Improvac®, IC) male in comparison with female (GI), surgically castrated (BA) and entire male (EM) fattening pigs. In contrast to previous experimental studies, this analysis is based on slaughter data from routine slaughtering from one slaughterhouse (Germany), which offered farmers since 2018 the option of voluntarily supplying IC without the usual financial deduction for boars. Carcass parameters were assessed using AutoFOM III™. Until 2022, data from 1,736,684 pigs from 203 farms were available. After checking for completeness, plausibility and gender balance, slaughter data of 1,613,660 pigs with 434,479 IC from 182 farms remained for analysis. Number of IC slaughtered per year increased to 48 % during the study period and largely replaced BA animals (5.4 %) in 2022. Sex had the largest influence on the most important carcass parameters (e.g. lean meat percentage), while carcass weight was mainly influenced by the farm, but also by the change in the price mask. The carcass parameters of IC ranked mainly between GI and BA and within the acceptable range of slaughterhouse requirements, with IC tending to have values closer to GI. The analysis shows that the meat quality of IC animals can meet slaughterhouse requirements comparable to GI and BA. Considering the carcass parameters analyzed in this study immunocastration appears to be a sustainable and future-proof solution to the castration controversy and should be promoted through fair accounting of IC via the standard price masks for BA and GI.

Short-term associations between ambient ammonia concentrations and growing-finishing pig performance and health

Using sensors, the health and welfare of growing-finishing pigs can be continuously monitored by detecting deviations from pigs' normal behaviour, but the validity of such algorithms requires improvement. As changes in the environment influence pig behaviour, monitoring temporal changes in environmental factors may help identify periods with a higher risk of welfare issues. The real-time relationships between pig welfare and many environmental factors are, however, not well-understood. This study examined the short-term associations of ambient ammonia with indicators of pig production and health. Ambient ammonia concentrations were monitored with sensors during the growing-finishing period of three rounds at a German (farm G, n = 110 pigs/round) and one round at a Danish farm (farm D, n = 144 pigs). Body weight was estimated daily using 3D cameras (both farms), feed intake was recorded using electronic feeding stations (only farm G), and health indicators were recorded during twice- (farm G) or thrice-weekly (farm D) farm visits. Using splines (generalised additive models), ammonia concentrations were linked to indicators of pig production and health in real time and, for body weight, at a lag of 1, 2, 3 and 7 d. We found a range of relationships between ambient ammonia (5 - 50 ppm) and production or health indicators (i.e. body weight (real-time and lagged), feed intake, coughing, sneezing, pen fouling, diarrhoea, and tear staining), but they were highly inconsistent between farms and pig rounds. Part of this inconsistency may be due to differences in manure management and sensor locations, or could be explained by age or seasonal effects (e.g. heat stress). More robust relationships were identified for clinical measures related to pig behaviour, where tail damage and skin lesions linearly increased with ammonia from low concentrations (5 - 10 ppm) onwards, hence suggesting more tail biting and aggression at higher ammonia concentrations. In conclusion, ambient ammonia did not clearly associate with pig performance and health in the short term, while higher ammonia concentrations were related to higher occurrences of clinical signs reflecting undesirable behaviours. Therefore, daily ammonia measurements using sensors may be of limited value in identifying health issues in pigs, but they may aid in detecting periods with high risk of aggressive or tail biting behaviours that require interventions. As ambient ammonia was confounded with other environmental measurements, such as ambient temperature or carbon dioxide concentrations, identified associations should be interpreted cautiously or with ammonia as general indicator of air quality.

Assessing salivary cortisol and testosterone as non-invasive biomarkers for GnRH-immunocastration efficiency in heavy pigs

BACKGROUND

Efforts to enhance animal welfare have led to the investigation of alternative methods of performing surgical castration on young pigs that induce stress and anxiety. This study was conducted to establish the efficacy of immunocastration in heavy pigs, with non-invasive diagnostic indicators being salivary cortisol and testosterone levels.

RESULTS

At 225 days, a significant difference was noted in the cortisol levels of pigs in the treatment groups, with the immune-castrated (IC) recording higher levels than the surgically castrated (SC) animals. Furthermore, 196-day and 225-day-old IC pigs had remarkably elevated testosterone amounts. The changes that were seen to be significant after immunocastration indicate that the use of salivary tests can be a good way of evaluating how effective this alternative method is. Among SC pigs, a significant positive relationship was found between salivary cortisol and salivary testosterone concentrations at 225, 240, and 268 days. Moreover, no association was observed in IC animals. These findings signal that the hormonal levels and their interactions are related to different physiological reactions of pigs to immunological and surgical castration.

CONCLUSIONS

The results underline the significance of salivary cortisol and testosterone as stress and hormonal balance indicators in heavy pigs with immunocastration. This study provides insights into the complex hormonal reactions to stress post-castration and emphasizes the need for further research to enhance animal welfare practices. Overall, salivary testing offers a practical approach to evaluating immunocastration efficacy and monitoring pig health and well-being.

Pork quality and histological properties of longissimus muscle from boars and early and late immunocastrated pigs

Immunocastration has been introduced in pig production to reduce boar taint. However, there is not much information on how different schedule of immunocastration affects meat quality, especially muscle histological properties. In this study, carcass and meat quality characteristics, histological properties of the longissimus dorsi muscle, sensory characteristics and fatty acid composition of meat and fat from entire males (EM), late immunocastrated (LIC, first dose 8 weeks before slaughter, second dose 4 weeks before slaughter) and early immunocastrated pigs (EIC, first dose 13 weeks before slaughter, second dose 8 weeks before slaughter) were compared. Fat thickness was greater in EIC than in LIC and EM. Meat quality parameters differed mainly between EIC and EM, as EIC had a higher pH 45, lower electrical conductivity, lighter and more yellowish loins and lower drip loss than EM. EM had a higher protein and moisture content and a lower fat content than EIC and LIC. No major effect on histological properties was observed, however, the percentage of fast-twitch oxidative fibres tended to be lower in both LIC and EIC animals compared to EM. Pork from EM had higher boar taint and lower pork odour and flavour scores and higher pig and boar taint flavour scores. The results of this study show that the immunocastration schedule influences some carcass, meat and fat quality traits and, because of that, it can be modified to obtain the desired final product.

Circadian rhythms and diurnal patterns in the feed intake behaviour of growing-finishing pigs

The feeding behaviour of growing-finishing pigs is an important indicator of performance, health and welfare, but this use is limited by its large, poorly-understood variation. We explored the variation in basal feed intake of individual pigs by detecting circadian rhythms, extracting features of diurnal patterns and assessing consistency over time, from day-to-day and across age. Hourly feed intake data of individual pigs (n = 110) was obtained during one growing-finishing phase, using electronic feeding stations. We applied wavelet analysis to assess rhythms and a hurdle generalised additive model to extract features of diurnal patterns. We found that circadian rhythms could be detected during 58 ± 3% (mean ± standard error) of days in the growing-finishing phase (range 0-100%), predominantly at older ages. Although the group diurnal intake pattern was alternans (small morning peak, larger afternoon peak), individual pigs showed a range of diurnal patterns that changed with age, differing mostly in the extent of night fasting and day-to-day consistency. Our results suggest that the type, day-to-day consistency and age development of diurnal patterns in feed intake show general group patterns but also differ between pigs. Using this knowledge, promising features may be selected to compare against production, health and welfare parameters.

A matter of body weight and sex type: Pig carcass chemical composition and pork quality

This study compares minced carcass chemical composition and meat quality of castrated (CM), immunocastrated (IM) and entire male (EM), and female (FE) pigs at 70, 100 and 120 kg target body weights (TBW) (n = 80; 20 per sex). Sex affected fat, protein, and moisture content of the minced carcasses. Carcass fatty acid (FA) composition was affected by sex, with higher saturated and monounsaturated FA content in CM than in FE, IM and EM, and higher polyunsaturated FA in CM than in EM, with FE and IM in between. Except for intramuscular fat, which was higher in CM than in FE and EM, no significant differences between sexes were found in meat quality. TBW affected carcass chemical composition and some meat quality traits. An interaction between sex and TBW was found with IM approaching EM or CM depending on TBW.

The capacity of inspection on farm and at the abattoir to predict post-mortem outcomes in slaughter pigs: A study at animal level

The aim of this study was to investigate associations between ear, tail, and skin lesions, hernias, bursitis, and rectal prolapses at the abattoir and meat inspection outcomes in slaughter pigs, including carcass condemnations and trimmings, carcass weight, and carcass quality. This was an observational study whereby pigs were managed according to routine practices in a single abattoir. Data were collected from 1816 pigs. The relationship between animal-based welfare and post-mortem outcomes was analyzed using generalized mixed models (Proc Glimmix). Our findings showed that tail lesions were associated with entire carcass condemnations and trimmings (P < 0.001), a reduction in carcass weight (P < 0.05), and a potential to impair carcass quality by reducing muscle pH (P < 0.05), especially in carcasses from male pigs (P < 0.05). Additionally, hernias were associated with viscera condemnation (P < 0.05) and a reduction in carcass weight (P  < 0.05). Therefore, our findings confirm that ante-mortem inspection could be useful to predict post-mortem outcomes in the same pigs, especially in cases of tail lesions and hernia, which might trigger attention of the veterinary inspector in charge of the post-mortem inspection.

Does Immunocastration Affect Behaviour and Body Lesions in Heavy Pigs?

Simple Summary

Castration of piglets is routinely practiced to prevent the presence of boar taint. In Europe, around 61% of pigs are surgically castrated, 54% of which do not receive any pain-relief therapy. The increasing public awareness towards animal welfare and the ethical characteristics of animal-derived products has led to the necessity of finding more animal-friendly alternatives. Among them, immunocastration, a process of active immunisation leading to the suppression of testicular function, has shown promising results in light pig production, both in terms of animal welfare and productivity. Besides, no study has yet investigated animal welfare in immunocastrated males intended for Italian heavy pig production. This study aimed at evaluating the effect of immunocastration on the welfare of heavy pigs by monitoring behaviour and body lesions in immunocastrated and surgically castrated pigs. Salivary testosterone levels and productive traits were also evaluated. Our results confirmed that immunocastration is a suitable alternative to surgical castration with profitable productive performance, whereas the higher activity of animals and the higher presence of body lesions before the effective immunisation caused an impairment of animal welfare, which should be further investigated as a critical aspect in heavy pig production.

Abstract

Immunocastration has been pointed out as an alternative to surgical castration; though, most of the scientific studies were performed in light pig production. This study aimed to evaluate the effect of immunocastration on animal welfare in heavy pig production through the evaluation of behaviour and body lesions. A total of 188 commercial-hybrid pigs were randomly allocated into two treatment groups: surgical castration (SC) and immunocastration with Improvac^® (IC). Data on behaviour, body lesions, and salivary testosterone levels were collected the day before each vaccination at 15, 22, 32, and 36 weeks of age. IC and SC pigs were slaughtered at 40 and 41 weeks of age, respectively; productive and carcass traits data were also collected. Considering productive performance, our results confirmed that IC pigs grew faster and presented a higher weight at slaughter. A critical period for pig welfare was observed before 32 weeks: testosterone concentration and body lesion score were significantly higher in IC pigs compared to SC pigs; active behaviours were significantly more frequent in IC at 15 weeks. Immunocastration may represent a suitable alternative to surgical castration with profitable productive performances, whereas the impairment of welfare during the period before the effective vaccination should be further investigated as a potential critical aspect in heavy pig production.

EFSA Panel on Animal Health and Welfare (AHAW), Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Schmidt G, Herskin M, Michel V, Miranda Chueca MÁ, Mosbach‐Schulz O, Padalino B, Roberts HC, Stahl K, Velarde A, Viltrop A, Winckler C, Edwards S, Ivanova S, Leeb C, Wechsler B, Fabris C, Lima E, Mosbach‐Schulz O, Van der Stede Y, Vitali M, Spoolder H. Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

Productive performance and in vivo body composition across the growing and finishing period and carcass traits in pigs of four sex types

This study compares performance, body and carcass composition among castrated (CM), immunocastrated (IM) and entire males (EM), and females (FE) at 30, 70, 100 and 120 kg of body weight (total of n = 92; 20-24/sex type). Overall, IM had similar growth and feed intake to CM and greater than EM and FE. At each slaughter stage, IM had a lower killing-out percentage than CM and FE, in line with their heavier liver and kidneys. Flare fat proportion and backfat thickness on the ham and at the last rib level were similar for IM, EM and FE, and these were lower than CM. In EM and FE, backfat between the 3rd and 4th last ribs was lower and carcass lean content was higher than in CM, whereas IM were intermediate and not different to the other sexes. Females showed the largest ham proportion, this cut being leaner and less fatty than in CM. Belly proportion was higher in CM than in EM.

Animal Welfare Consequences of Organic Boar Fattening and Occurrence of Boar Taint on Five Commercial Farms

Simple Summary

The usual castration of male fattening pigs is under discussion, especially in organic farming, because of the negative effects on the pig’s welfare and integrity. Nevertheless, it is feared that boars show more aggressive and mounting behaviours, resulting in stress, painful injuries and lameness, and that their meat has an unpleasant odour/taste (called “boar taint”). Therefore, it was examined to which extent these concerns come true under commercial organic conditions. Additionally, influences from management and husbandry were investigated, in order to identify conditions in organic fattening systems with low risk to welfare and meat quality. Despite more agonistic and mounting behaviours in boars compared to castrates, especially if housed next to females, no increased numbers of skin lesions, lame pigs, disease treatments or deaths were observed. Less skin lesions occurred when more space was provided. A moderate rate of wounds on penises was found, but not on farms with bulky straw bedding. A small number of carcasses (1.44%) were excluded from processing because of boar taint. In conclusion, boar fattening under the examined organic conditions appears to be a feasible alternative to castration, but penile injuries should be monitored at slaughter.

Abstract

The welfare of male fattening pigs may be improved by refraining from castration, but may be compromised, in turn, by harmful social behaviour in groups of boars. In addition, boar taint may be problematic. This study aimed to evaluate these potential problems in boar fattening under commercial organic conditions. In total, 625 boars were compared with 433 barrows and 83 gilts regarding their social behaviour, lesions and lameness at 80 kg, before and after split marketing. The mixed-model analysis showed that significantly more short agonistic interactions, fights and mounting behaviours were observed in groups of boars. Agonistic interactions were reduced in spring/summer and when boars grew older. Fights and mounts were increased when boars had contact to female pigs in the neighbouring pen. No effect of split marketing, growth rate, homogeneity of groups, group size, feeding space and illumination hours could be detected. Increased interaction frequencies did not result in significantly more skin lesions, lameness, treatments or mortality. Increased space allowance reduced skin lesions. On 9.8% of the dissected boars’ penises, wounds were detected; they were absent on two farms with generous litter provision. Boar taint prevalence, as detected by human nose method, was 1.44%. Under the studied organic husbandry conditions, boar fattening appears to be practicable, although penile injuries should be monitored at slaughter.

Detection of Local Tissue Reactions after Anti-GnRF Injection in Male Pigs Assessed Using Magnetic Resonance Imaging

Simple Summary

Local tissue reactions after injection are known in animals and humans. This study analysed the local tissue reaction after injection of the so-called immunologic castration in pigs using magnetic resonance imaging to achieve insight into the reaction site. Long-lasting reactions, which can be traced to inflammatory reactions, were detected. Further studies are needed to evaluate the impact of these reactions on animal well-being and carcass quality.

Abstract

This study aimed at evaluating the local tissue reaction of an anti-GnRF product, which is used for the so called “immunocastration” in male pigs. A total of 34 pigs were injected two times (including a booster injection) with an anti-GnRF product. Injection was performed using the prescribed safety vaccinator. Injection sites were evaluated three times post injection using magnetic resonance imaging. Two examinations were performed after the first injection and one after the booster. The local tissue reaction was evaluated three-dimensionally by semi-automatic analyses, by linear measurements of injection depth and length, and by scoring the kind of tissue affected. Results showed a long-lasting reaction in affected muscle tissue. Therefore, needle length should be discussed, and an evaluation of the injection site after slaughter should be performed include behavioural scorings post injection to evaluate the impact on animal well-being and carcass quality.

Non-destructive evaluation of carcass and ham traits and meat quality assessment applied to early and late immunocastrated Iberian pigs

Castration is a common practice in Iberian pigs due to their advanced age and high weight at slaughter. Immunocastration (IC) is an alternative to surgical castration that influences carcass and cut fatness. These traits need to be evaluated in vivo and postmortem. The aims of the present work were (a) to determine the relationship between ham composition measured with computed tomography (CT) and in vivo ultrasound (US) and carcass fat thickness measurements, (b) to apply these technologies to early (EIP) and late (LIP) immunocastrated Iberian pigs in order to evaluate carcass fatness and ham tissue composition and (c) to assess meat quality on these animals and to find the relationships between meat quality traits (namely, intramuscular fat (IMF)) and fat depot thicknesses. For this purpose, 20 purebred Iberian pigs were immunocastrated with three doses of Improvac ®, at either 4.5, 5.5 and 9 or 11, 12 and 14 months of age (EIP or LIP; respectively; n = 10 each) and slaughtered at 17 months of age. Fat depots were evaluated in vivo by US, in carcass with a ruler and in hams by CT. Carcass and cut yields, loin meat quality and loin acceptability by consumers were determined. Also, IMF was determined in the loin and three muscles of the ham. Carcass weight was 14.9 kg heavier in EIP vs LIP, and loin backfat thickness (US- and ruler-measured) was also greater in EIP. Similarly, CT-evaluated ham bone and fat contents were greater and smaller for EIP vs LIP, respectively. Loin and ham IMF were also greater in EIP, but the other meat quality parameters were similar. The acceptability of meat by consumers was high and it did not differ between IC protocols. Correlations between several fat depots measured with the different technologies were high. In conclusion, all these technologies allowed fat depot measurements, which were highly correlated despite being obtained at different anatomical locations.

Adipose Tissue Gene Expression of Entire Male, Immunocastrated and Surgically Castrated Pigs

Differences in adipose tissue deposition and properties between pig male sex categories, i.e., entire males (EM), immunocastrates (IC) and surgical castrates (SC) are relatively well-characterized, whereas the underlying molecular mechanisms are still not fully understood. To gain knowledge about the genetic regulation of the differences in adipose tissue deposition, two different approaches were used: RNA-sequencing and candidate gene expression by quantitative PCR. A total of 83 differentially expressed genes were identified between EM and IC, 15 between IC and SC and 48 between EM and SC by RNA-sequencing of the subcutaneous adipose tissue. Comparing EM with IC or SC, upregulated genes related to extracellular matrix dynamics and adipogenesis, and downregulated genes involved in the control of lipid and carbohydrate metabolism were detected. Differential gene expression generally indicated high similarity between IC and SC as opposed to EM, except for several heat shock protein genes that were upregulated in EM and IC compared with SC. The candidate gene expression approach showed that genes involved in lipogenesis were downregulated in EM compared with IC pigs, further confirming RNA-sequencing results.

Effect of terminal sire line and timing second vaccination on effectiveness of immunocastration, performance, and carcass and meat quality

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.

Shortening the immunocastration-to-slaughter interval from 3 to 2 weeks reduced carcass backfat and weight, increased sexual behaviour and carcass skin blemishes in group-housed male pigs sold at fixed age

Context Pig producers require strategies to temporarily slow growth rate, particularly when markets impose penalties on over-weight and fat carcasses. Immunocastrated pigs usually have higher feed intakes (e.g. during the 3–5-week immunocastration-to-slaughter interval, which is commonly used in Australian pig industry), resulting in higher carcass weight and backfat thickness. Shortening the immunocastration-to-slaughter interval by delaying the second vaccination by a week may be a fine-tuned strategy to reduce carcass backfat and weight of male pigs. However, postponing the age receiving immunocastration as a method to achieve a shorter immunocastration-to-slaughter interval may increase aggressive and sexual behaviours of pigs. Aims The experiment aimed to quantify the effects of shortening the interval between the second dose of immunocastration and slaughter from 3 weeks to 2 weeks on growth performance, carcass traits, aggressive and sexual behaviours, and carcass skin blemishes in group-housed male finisher pigs slaughtered at a fixed age. Methods Pigs (n = 58 pens; 45 pigs per pen) were selected into the experiment at 16 weeks of age. Half of the pens received the second anti-GnRH vaccine (V2) as a means of immunocastration at 19 weeks (a common immunocastration age used in Australian pig industry; control group), and the remaining half of the pens received V2 at 20 weeks of age. All the pigs were slaughtered at 22 weeks of age. Growth performance was recorded between 16 and 22 weeks of age. Behavioural observation was conducted at 20 and 21 weeks of age. Carcass weight, backfat thickness and severity of skin blemishes on carcasses were recorded in the abattoir. Key results Results showed that shortening the immunocastration-to-slaughter interval from 3 to 2 weeks reduced average daily feed intake by 9%, growth rate by 8%, carcass weight by 3%, and backfat thickness by 7% (all P &lt; 0.05), but the percentage of pigs that displayed sexual behaviour and carcasses with &gt;25 lesions both increased (both P &lt; 0.05). Conclusions Shortening the immunocastration-to-slaughter interval from 3 to 2 weeks by delaying V2 is an effective strategy to reduce feed intake, growth rate, carcass weight and backfat in group-housed male pigs, but at a risk of increasing carcass skin blemishes. Implications The increased sexual behaviour and carcass skin blemishes will need to be managed when using a shortened immunocastration-to-slaughter interval to temporarily reduce carcass weight and backfat.

Reproductive status effects of pair-housed male pigs on natural, agonistic and sexual behaviours

Boar rearing, which avoids pain and suffering caused by surgical castration, provides better performance, a greater deposition of muscle tissue and leaner carcasses and thus has beneficial effects on both animal welfare and the product. Some countries that do not slaughter boars must consider their boar taint and aggressive and sexual behaviours. Considering that pigs are housed in large groups, which may complicate the formation of social hierarchies and increase fighting and mounting behaviours, some studies have conducted research with reduced numbers of pigs per pen, but these behaviours continued to be observed. However, a study of the reproductive status of pair-housed male pigs has yet to be reported. The aim of this study was to determine whether the reproductive status of uncastrated, immunocastrated and surgically castrated pair-housed male pigs alters their natural, agonistic and sexual behaviours. A total of 48 male pigs from Agroceres PIC™ genetics were assigned to three groups: surgically castrated (barrows), immunocastrated and uncastrated (boars). Natural, aggressive and sexual behaviours of the pigs were assessed by direct observations during four periods of 12 h each (six, five and three weeks before slaughter and the slaughter week). The pigs were housed in pairs from the growing phase until slaughter. Animal behaviour was observed from the finishing phase to slaughter. Carcass lesions were assessed according to five different classes (one: no injury; two to five: severely injured). Overall, boars spent more time lying and less time eating and drinking than barrows. In total of all the periods (48 h), boars expressed more aggressive and sexual behaviours than barrows, whereas immunocastrated pigs displayed similar behaviours to boars, before and after the second vaccine dose. No differences in carcass lesions between treatments and no prevalence of carcasses with severe injuries were observed. In conclusion, the reproductive status of pair-housed male pigs did not change the natural behaviour of boars, immunocastrated pigs or barrows. The agonistic and sexual behaviours of boars and barrows remained unchanged. When housing pigs in pairs, immunocastrated pigs presented similar agonistic and sexual behaviours to boars before and after the second immunocastration vaccine dose. The use of pair-housed uncastrated male pigs has generated welfare benefits for these animals, as the number of carcasses with injuries did not differ from barrows and immunocastrated pigs.

FSH promotes fat accumulation by activating PPARγ signaling in surgically castrated, but not immunocastrated, male pigs

Follicle-stimulating hormone (FSH) was recently implicated as a novel regulator of fat accumulation. Surgical castration causes high FSH concentrations and increases fat accumulation, whereas immunocastration results in low FSH concentrations and less fat in immunocastrated boars versus barrows. However, detailed information regarding the role of FSH in regulation of fat accumulation in male pigs is unclear. First, expression of FSH receptor was confirmed (real-time quantitative PCR) in subcutaneous and visceral adipose tissues (SAT and VAT, respectively) of boars. Then, surgical castration (high FSH model) was compared to immunocastration (low FSH model) to investigate potential roles of FSH in adipogenesis and fat accumulation. High FSH concentrations after surgical castration activated PPARγ signaling by upregulating expression of CREB (P < 0.05), and then recruited an array of PPARγ target adipogenic genes, including transcription factor (C/EBPα), long-chain fatty acid uptake (LPL), fatty acid de novo synthesis (FASN, ACACA) and lipid droplet formation (PLIN1) in both SAT and VAT, promoting fat accumulation in barrows. In contrast, much lower serum FSH concentrations in immunocastrates attenuated (P < 0.05) expressions of PPARγ and PPARγ target genes in both SAT and VAT, resulting in less fat accumulation in immunocastrated boars versus barrows. We concluded that the substantially elevated FSH concentrations in barrows promoted fat accumulation by activating the PPARγ signaling pathway in adipose tissues, whereas immunocastrates accumulated less fat due to low FSH.

The Use of Pork from Entire Male and Immunocastrated Pigs for Meat Products-An Overview with Recommendations

Due to the strong public initiative in Europe and increased regulator focus to mitigate pain, surgical castration of pigs is being gradually abandoned, while the importance of other sex categories like entire males (EM) and immunocastrates (IC) increases. Although beneficial for animal welfare and economics, their use also brings forward several quality problems. Besides the occurrence of boar taint in EM, these include excessive carcass leanness, softer fat, meat color and pH deviations, inferior water holding capacity and increased meat toughness. In this paper, the raw material differences between the male sex categories and their influence on product quality are reviewed, and possible solutions are presented. Using EM for dried or thermally processed products may result in lower processing yields and inferior sensory quality, which may partially be prevented by applying specific processing adaptations. Immunocastration is a viable solution, especially when prolonging the vaccination to slaughter interval. Low to medium levels of boar taint can be effectively managed in most of the meat products, applying procedures like cooking, microbial inoculation or masking (by spices and especially smoking), while highly tainted material can be valorized only by combining various methods and/or with dilution of the tainted meat.

Effect of immunocastration and housing conditions on pig carcass and meat quality traits

The present study investigated the effects of immunocastration and housing conditions on carcass, meat, and fat quality traits. Immunocastrates (IC, n = 48), entire (EM, n = 48), and surgical castrates (SC, n = 48) male pigs were reared under three different housing conditions. The conditions were standard (n = 36), enriched (n = 36, twice as much space as standard and additional outdoor access), or standard with repeated social mixing (n = 72). Pigs of the IC group were vaccinated at the age of 12 and 22 wk. The animals were slaughtered in four batches, balanced for sex category and housing, at the age of 27 wk reaching 124.7 ± 1.0 kg. Immunocastration led to increased fat deposition (i.e., thicker subcutaneous fat at different anatomical locations, more leaf fat, fatter belly in IC than EM, P < 0.05) but did not affect muscularity traits. As a result, EM exhibited higher and SC lower (P < 0.05) carcass leanness than IC. Fatty acids composition of either subcutaneous or intramuscular fat (IMF) agreed with general adiposity, that is, IC were intermediate between EM and SC exhibiting the lowest and highest fat saturation (P < 0.05), respectively. Compared to SC, EM exhibited higher (P < 0.05) levels of muscle oxidation and collagen content than SC, with IC taking an intermediate position in the case of the level of peroxidation and collagen content, or closer to SC as regards to oxidation of muscle proteins (i.e., carbonyl groups). Meat quality (including marbling score, cooking loss, subjective color redness, and chroma) of IC was similar to EM, and both differed (P < 0.05) from SC. However, IC and SC had less (P < 0.05) tough meat than EM, consistent with protein oxidation. The effect of housing was less evident. Mixing of pigs resulted in lower (P < 0.05) carcass weight and fatness in all sex categories with lower (P < 0.05) oleic and higher (P < 0.05) arachidonic acid in IMF of EM.

Influences of Immunocastration on Endocrine Parameters, Growth Performance and Carcass Quality, as Well as on Boar Taint and Penile Injuries

Simple Summary

Surgical castration of male pigs is associated with pain. Improvac^®, a GnRH vaccine induces an endogenous immune reaction that leads transiently to a decrease in testicular steroid synthesis after second vaccination. Investigating consequences of different vaccination schemes revealed that GnRH vaccination reliably prevents boar taint, if the manufacturers’ recommendations are applied. It had beneficial effects on animal welfare as it reduced penile injuries. Animals showed improved feed efficiency, leaner carcasses, and lower PUFA (polyunsaturated fatty acids) percentages than surgically castrated animals. Thus, immunocastration offers a reliable and animal friendly alternative to surgical castration.

Abstract

Castration of male pigs without anesthesia is a significant welfare issue. Improvac^®, a GnRH vaccine induces an endogenous immune response leading to a decrease in testicular steroids. Consequences of different vaccination schemes on testicular function and carcass quality were evaluated in immunocastrated boars (IC), surgical castrates (SC), and entire males (EM). Therefore, 128 male piglets were assigned to five treatment-groups and a long term follow-up group. IC groups received two vaccinations (V1, V2) with Improvac^® at 8 and 12, 12 and 16, or 12 and 18 weeks. Testosterone-concentrations decreased significantly two weeks after V2 in feces and dropped in serum from V2 to slaughter (S) except IC-8/12 without differing significantly. GnRH-binding results indicated the highest values for IC-12/18 animals. While IC-12/16 and IC-12/18 animals showed boar taint compounds below the threshold levels, two IC-8/12 animals had concentrations above the threshold level. Feed-efficiency was higher in EM than in SC with IC in between. In IC compared to EM, a decreasing amount of polyunsaturated-fatty-acids was obvious and GnRH-vaccination reduced penile injuries. The examined vaccination protocols reduce penile injuries, improve feed efficiency and carcass quality, and reliably prevents boar taint, if manufacturer’s recommendations concerning vaccination schedules are applied. Therefore immunocastration offers a reliable, animal friendly alternative to surgical castration.

Improvac induces immunocastration by affecting testosterone levels and disrupting spermatogenesis in male broiler chickens

Immunocastration (vaccination against Gonadotropin-releasing hormone (GnRH)) has been regarded as a friendly substitution to physical castration in animals. To date, a few studies have reported the use of Improvac for immunocastration in boar and one study in broiler chickens; however, there is an apparent dearth of scientific evidence regarding the application of Improvac for immunocastration in birds. In the present study, we evaluated the effects of Improvac-based immunocastration on testosterone levels and spermatogenesis in broiler chickens and the effects of Improvac on the expression of genes related to testosterone biosynthesis and metabolism as well as spermatogenesis. The birds were randomly divided into 4 groups (n = 30 each): Control group (non-immunized), Early group (immunized with Improvac at week 3), Late group (immunized with Improvac at week 6), and Early + Late group (immunized with Improvac at weeks 3 and 6). Immunization with Improvac significantly improved the average daily gain compared to the Control group. Of note, following Improvac vaccination, the reproductive efficiency was significantly decreased in male broiler chickens. Furthermore, parameters such as the serum testosterone concentration, spermatogenesis, and the expression levels of genes related to testosterone metabolism (Cyp17A1, Cyp19, HSD3B1, and HSD17B3) and spermatogenesis (Cyclin A1 and Cyclin A2) were significantly reduced in the immunized groups compared to the Control group. Taken together, these findings reveal that immunization against GnRH can be achieved, at least partially, in male broiler chickens. The results of our study also support the hypothesis of using Improvac as an alternative solution to caponization, with considerably improved animal welfare.

Physiological and economic benefits of abandoning invasive surgical procedures and enhancing animal welfare in swine production

Food-animal welfare is a major ethical and social concern. Pork is the most consumed meat worldwide, with over a billion pigs slaughtered annually. Most of these pigs routinely undergo painful surgical procedures (surgical castration, tail docking, teeth clipping), which farmers often reluctant to avoid, claiming it would increase cost and reduce production efficiency. Herein, this study indicates that these procedures compromise pigs' health and condition. Replacing surgical castration with immunocastration, avoiding tail docking and teeth clipping, and providing environmental enrichment, resulted in significant increase in weight gain, lowered risks for injuries and death, and reduced saliva and hair cortisol, both biomarkers for stress. Testosterone and DHEA analyses confirmed that immunocastration was an effective alternative to surgical castration. Economic models for the entire US swine market revealed that following across-the-board acceptance of this management, pork meat price is expected to drop, while the total annual social welfare (combined consumer and producer surplus) is expected to increase by $US 1.48 to 1.92 billion. In conclusion, sustainable swine farming management can be beneficial for both animals and farmers. Applying such welfare-friendly management is expected to reduce stress, enhance piglet/pig welfare and production, and improve the economics of swine operations in the global agro-food system.

Towards the Abandonment of Surgical Castration in Pigs: How is Immunocastration Perceived by Italian Consumers?

Simple Summary

The European Declaration on alternatives to surgical castration of pigs was aimed at abandoning surgical castration and switching to alternative techniques. Immunocastration (a vaccination against Gonadotropin Releasing Hormone) can be a viable alternative method. This technique offers some advantages in terms of animal welfare compared to surgical castration. Nevertheless, the main obstacle to the diffusion of immunocastration seems to be related to consumers’ acceptance, since the use of new technologies in the food chain often generates mistrust. The objective of this research was to assess how immunocastration is perceived by Italian consumers, and how complex and complete information (on advantages and disadvantages of the technique) can influence their perception. The results show that immunocastration is perceived in a predominantly positive manner (54.5%), with a relatively low level of risk perception (34.2%) and a good willingness to pay more for meat from immunocastrated pigs (+18.7%). However, there were no statistically significant differences between the control group (receiving only a neutral technical information) and groups to which complete and complex information was provided.

Abstract

Immunocastration of pigs represents an alternative method to surgical castration, being more respectful of animal welfare. However, this new technology may not be accepted by consumers due to their perception of possible risks tied to the use of the product, thus representing a concern for the production sector. The study aimed at verifying the attitude of Italian consumers towards immunocastration and to assess whether their perception can be affected by science-based information on advantages and disadvantages of immunocastration. A total of 969 consumers (divided in three groups representative of the Italian population) were contacted and asked to complete an online questionnaire. Only technical (neutral) information on immunocastration was provided to the first group; the second and the third group received information on the advantages (+) and disadvantages (-) of the technique, shown in reverse order (+/- and -/+, respectively). The level of information did not affect consumers’ perception of immunocastration. Overall, immunocastration is perceived in a predominantly positive manner (54.5%), with a relatively low level of risk perception (34.2%), and a good willingness to pay more for meat deriving from immunocastrated pigs (+18.7%).

Effect of immunocastration on growth performance, gonadal development and carcass and meat quality of SuHuai female pigs

The present study was aimed to compare growth performance, gonadal development, carcass characteristic and meat quality among SuHuai entire, immunocastrated and surgically castrated female pigs. Eighty 12-week-old SuHuai gilts were randomly assigned to the following four treatment groups with four pigs per pen and five replicate pens per treatment: control (PBS injection), two-dose Improvac regimen (V2), three-dose Improvac regimen (V3) and surgical castration (S). All pigs had ad libitum access to standard diets and water. The performance and occurrence of oestrus were recorded in the trial. Backfat thickness and loin eye muscle area were recorded ultrasonically. The pigs were slaughtered to measure the weight and size of the uterus, and the weight and activity of the ovaries, to determine the serum concentrations of progesterone, and to evaluate the quality of carcass and meat. There were no significant differences in growth performance among the four groups, except for the V2, which had a better average daily feed intake (P &lt; 0.05). Carcass and meat quality were comparable among the four groups; however, the intramuscular fat in control was higher than the V2 and V3 (P &lt; 0.01). Mean ovary and uterus weights and oestrus of female pigs in V2 and V3 were significantly (P &lt; 0.01) lower than in control, but the difference between the V2 and V3 was not significant. The concentration of progesterone in the control was significantly higher than that in the V2, V3 and S (P &lt; 0.05). These results indicated that immunocastration successfully suppressed gonadal development and had no adverse effects on growth performance, or carcass or meat-quality traits in Chinese SuHuai female pigs.

Dietary lecithin improves feed efficiency without impacting meat quality in immunocastrated male pigs and gilts fed a summer ration containing added fat

The aim of this study was to investigate the effects of sex and dietary lecithin on growth performance, meat quality, muscle collagen content and gene expression of key genes involved in collagen synthesis in finisher pigs. A total of 256 pigs (Large White × Landrace) were allotted to a 2 × 2 factorial arrangement involving sex (gilt or immunocastrated [IC] male) and dietary treatment (0 or 5 g/kg of dietary lecithin). All diets were formulated to contain 4.6% tallow with relatively high total fat of 6.3%. After 5 weeks of dietary treatment, pigs were slaughtered and Longissimus dorsi muscle was obtained for evaluation of meat quality and collagen content. Rectus abdominis muscle was analysed for gene expression of key genes involved in collagen synthesis namely, type I (α1) procollagen (COL1A1), type III (α1) procollagen (COL3A1), α-subunit of prolyl 4-hydroxylase (P4H), lysyl oxidase and metalloproteinase-1 (MMP-1). The results showed that lecithin improved feed efficiency of all pigs (P < 0.05) but it had no effect on feed intake, average daily gain and dressing percentage (P > 0.05). Lecithin also had no effect on meat compression, shear force, collagen content and gene expression (P > 0.05). Immunocastrated male had higher growth rate and increased COL1A1 expression than gilts. However, sex had no effect on fat depth at the P2 site (65 mm from the midline over the last rib), collagen content and expression of other genes (P > 0.05). In conclusion, lecithin improved feed efficiency in finishing pigs without impacting pork quality. Thus, inclusion of lecithin in diets containing high amount of tallow during the summer period could be beneficial.

Penile Injuries in Immunocastrated and Entire Male Pigs of One Fattening Farm

Penile injuries in boars have been discussed as a relevant welfare problem in pork production with entire males (EM). The incidence of penile injuries with immunocastrated boars has not been described so far. Thus, it was the aim of this study to systematically compare frequency and severity of penile injuries in EM and IC. Incidence and size of penile injuries (wounds, scars, hematomas) were evaluated in 192 IC and 215 EM from one farm after slaughter (120 kg live weight; four batches (BA) in at least weekly intervals over five weeks). 75.8% EM and 48.4% IC showed injuries at the pars libra of the penis. Scars were observed in 71.2% EM and 44.8% IC. Scars/animal were significantly influenced by treatment (IC vs. EM), B and treatment x B and increased with age in EM (BA1: 2.61 ± 3.05; BA4: 3.59 ± 3.47), but not in IC (BA1: 2.00 ± 3.02; BA4: 1.22 ± 1.91). Wounds were obvious in 17.2% EM and 8.3% IC. Wounds/animal were only influenced significantly by treatment and were lower in IC than in EM. Thus, it is concluded that immunocastration reduces the frequency and severity of penile injuries in IC when compared to EM of same age and weight.

Comparison among gilts, physical castrates, entire males, and immunological castrates in terms of growth performance, nitrogen and phosphorus retention, and carcass fat iodine value

The main objective was to determine the nitrogen and P retention and energy digestibility of immunological castrates (IC), entire males (EM), physical castrates (PC), and gilts (G) during 3 growth phases. A second objective was to compare growth performance among the sexes. The final objective was to determine the carcass iodine value (IV) among the sexes. Twelve individually housed pigs (PIC 337 × C22/29) of each sex with an initial mean BW of 35.7 ± 0.6 kg and a final BW of 145.0 ± 1.3 kg were evaluated. Anti-gonadotropin-releasing factor injections were administered at d 23 and 15 for groups 1 and 2, respectively. The second injection was given on d 56 of the 98-d experiment. Nitrogen, P, and energy digestibility were measured the last 3 d of the 10-d metabolism period starting at mean BW of 39.5 ± 0.6, 73.7 ± 0.8, and 105.5 ± 0.9 kg for periods 1, 2, and 3, respectively. The third collection started 14 d after the second injection. Entire males and IC had superior overall ADG compared to PC and G ( < 0.05). Entire males and G had the lowest overall ADFI, and PC had the greatest, with IC being intermediate ( < 0.05). Entire males were overall the most efficient, followed by IC, with PC and G being the least efficient ( < 0.05). Immunological castrates and EM had similar nitrogen retention (g/d) for the first 2 collection periods ( > 0.05). In the third collection period, nitrogen retention of IC was similar to that of both EM and PC ( < 0.05). Phosphorus retained (g/d) was not different among the sexes in the first collection; during the second collection, EM retained the greatest amount of P, G and PC retained the lowest, with IC being similar to all sexes. For the third collection, IC had P retention similar to that of EM, EM had retention similar to that of PC, and PC had retention similar to that of G ( > 0.05). However, G retained less P than EM or IC ( < 0.05). Apparent total tract digestibility of DM and GE and the DE of the diet did not differ among the sexes in any of the collection periods ( > 0.05). The jowl IV was the lowest in IC and PC and highest in EM, with G being similar to all sexes ( < 0.05). For the belly, EM had the highest IV, with the other 3 sexes being similar. In conclusion, 2 wk after the second injection, IC transition to become more similar to PC in terms of nitrogen utilization but are still similar to EM in P utilization. These data suggest a feeding program for IC that is intermediate between EM and PC is required to meet their nutritional requirements.

Effect of an anti-gonadotropin-releasing factor vaccine on sexual and aggressive behaviour in male pigs during the finishing period under Australian field conditions

OBJECTIVE

The objective of this study was to evaluate the effectiveness of an anti-gonadotropin-releasing factor vaccine in controlling sexual and aggressive behaviour of male pigs in the late finishing period under Australian field conditions.

METHODS

Male pigs from four consecutive batches over a 4-month period were randomly assigned to two groups: an untreated control group (n = 434) or a group treated with Improvac® (n = 433). The vaccine was administered at 10 and 16 weeks of age. Pigs were housed under commercial conditions in ecoshelters, a commonly used housing system in Australia in which pigs are kept in large pens often containing >100 animals. The occurrence of sexual and aggressive behaviours was recorded and evaluated after second vaccination until slaughter at 22 weeks of age.

RESULTS

Male pigs treated with Improvac demonstrated significant reductions in mounting, fighting, pushing, head butting and tail manipulation when compared with control animals.

CONCLUSION

This study confirms that vaccination with Improvac can improve the welfare of entire male pigs by inhibiting sexual and aggressive behaviour.

Effects of ractopamine administration and castration method on muscle fiber characteristics and sensory quality of the longissimus muscle in two Piétrain pig genotypes

Single and combined effects of ractopamine supplementation (RAC, 7.5 vs. 0 ppm), castration method (surgical castration: SC vs. immuno-castration: IM) and genotype (genotype A: GA vs. GB containing 25% or 50% Piétrain) were determined on longissimus muscle (LM) fiber traits and quality of pork (n=512). RAC increased fiber IIX cross-sectional area (P=0.009) and decreased glycolytic potential (P=0.02) and pork tenderness (P<0.001). Fiber traits indicated that LM of IM pigs was more oxidative (P<0.05) and meat had slightly higher (P=0.04) off-flavor score and WBSF than SC. LM from GB pigs was paler (P<0.05) and had greater (P<0.05) glycolytic potential, IIX fiber cross sectional area and pork off-flavor than GA. RAC supplementation, castration method and genotype or their combination affected some fiber traits and some quality parameters but differences reported were small indicating these treatments or their combination could be used without major prejudice to meat quality.