Consumer response to the possible use of a vaccine method to control boar taint v. physical piglet castration with anaesthesia: a quantitative study in four European countries

In most European countries, male piglets being reared for meat are physically castrated without anaesthesia in order to avoid boar taint and to safeguard sensory meat quality. This method is increasingly criticised for its violation of piglet welfare. Alternative methods are being researched and castration with anaesthesia or analgesia and vaccination (immunisation) against gonadotropin-releasing hormone (using Improvac®, Pfizer GmbH) have been proposed as possible solutions. In addition to efficacy, the successful introduction and adoption of the vaccine method by stakeholders in pig supply chains are expected to depend on a favourable reception by consumers. This large-scale quantitative cross-country study (n = 4031) involving representative samples of consumers in France, Germany, the Netherlands and Belgium does not support the reserved attitude of stakeholders who fear potential low market acceptance. The vaccine method was actually preferred by the majority of consumers surveyed (69.6% of the participants) and it was perceived as equally effective in terms of avoiding boar taint; 43.8% of the consumers reported an intention to seek out pork from pigs where the vaccine had been used to control boar taint, whereas 33.7% reported an intention to avoid pork from pigs physically castrated with anaesthesia. Consumers’ favourable dispositions to the vaccine method were independent of dominant ethical, health or price orientations when purchasing pork.     

Consequences of concurrent Ascaridia galli and Escherichia coli infections in chickens

   

The principal aim of this study was to evaluate dissociative anaesthesia for castration of colts during field conditions. Three dissociative anaesthetic protocols were evaluated during castration of colts in an animal hospital. The protocol considered to be the most suitable was thereafter evaluated during castration of colts under field conditions. Respiratory and haemodynamic parameters and the response to surgery were determined during anaesthesia. All horses breathed air spontaneously during anaesthesia. Under hospital conditions 26 colts were randomised to receive one of three anaesthetic protocols: Romifidine and tiletamine-zolazepam (RZ); acepromazine, romifidine and tiletamine-zolazepam (ARZ); or acepromazine, romifidine, butorphanol and tiletamine-zolazepam (ARBZ). The surgeon was blinded to the anaesthetic protocol used and decided whether supplemental anaesthesia was needed to complete surgery. Under field conditions 31 colts were castrated during anaesthesia with the ARBZ protocol. All inductions, anaesthesia and recoveries were calm and without excitation under both hospital and field conditions. Surgery was performed within 5–20 minutes after the horses had assumed lateral recumbency during both hospital and field castrations. Under hospital conditions some horses needed supplemental anaesthesia with all three anaesthetic protocols to complete surgery. Interestingly, none of the horses castrated with protocol ARBZ under field conditions needed additional anaesthesia. Cardiorespiratory changes were within acceptable limits in these clinically healthy colts.     

Castration-induced changes in microRNA expression profiles in subcutaneous adipose tissue of male pigs

MicroRNAs (miRNAs) are class of molecular regulators found to participate in numerous biological processes, such as adipogenesis and obesity in mammals. To determine the roles of miRNAs involved in castration-induced body fatness, we investigated the different miRNA expression patterns in subcutaneous adipose tissue between intact and castrated male pigs. Our results showed that castration led to decrease serum testosterone but increase serum Leptin levels (P?<?0.01). Moreover, castration also increased adipocyte size, body fat content and backfat thickness in male pigs (P?<?0.01). Meanwhile, miRNA expression profiles in adipose tissue were changed by castration, and 18 miRNAs were considered as the differentially expressed candidates between intact and castrated male pigs. Furthermore, functional analysis indicated that the differential expressed miRNAs and their target genes are involved in the regulation of fatty acid metabolism. In brief, our present study provides a comprehensive view on how miRNAs works in subcutaneous adipose tissue with castration. These results suggested that miRNAs might play an important role in the castration-induced fat deposition in male pigs.     

Sexual differentiation of reproductive behavior in pigs: defeminizing effects of prepubertal estradiol

The present study sought to determine (1) whether estrogen by itself can defeminize the behavior of pigs during the late juvenile-early pubertal period, and (2) whether the progressive late defeminization reported for pigs is a true organizational effect, as opposed to an artifact of the time between castration and testing. Male pigs were castrated at 19-22 days or left intact and females were ovariectomized at 3 months. Additional males castrated at 19-22 days and females ovariectomized at 3 months were implanted with estradiol benzoate (EB) from 3 to 5.5 months. After castration of the previously intact males at the age of 5.5 months, all subjects were tested beginning at 6.5 months for proceptivity (choice of a male versus a female in a T-maze) and receptivity (immobilization to a mounting male) following an injection of EB. EB administered during development significantly defeminized proceptivity and receptivity in both sexes. The decrease in proceptivity was more pronounced in males than in females and was more pronounced than the decrease in receptivity, as if differentiation ends earlier for proceptivity than for receptivity; the decrease in receptivity was more pronounced in females. To see whether the capacity to display female-typical behavior is a function of time since castration, we castrated additional males at 4 months and tested for receptivity 9 days later following an injection of EB, then tested again with the other subjects at 6.5 months. The proceptivity and receptivity scores for males castrated at 4 months fell between those for intact males and males castrated at 3 weeks, and thus these animals were not completely defeminized. They were more receptive at 6.5 months than at 4 months, but the difference was not significant. These results indicate that in pigs estradiol defeminizes both receptive and proceptive behavior and that this defeminization can occur relatively late in development.     

Resource efficiency and economic implications of alternatives to surgical castration without anaesthesia

This paper presents an analysis of the economic implications of alternative methods to surgical castration without anaesthesia. Detailed research results on the economic implications of four different alternatives are reported: castration with local anaesthesia, castration with general anaesthesia, immunocastration and raising entire males. The first three alternatives have been assessed for their impact on pig production costs in the most important pig-producing Member States of the EU. The findings on castration with anaesthesia show that cost differences among farms increase if the anaesthesia cannot be administered by farmers and when the veterinarian has to be called to perform it. The cost of veterinarian service largely affects the total average costs, making this solution economically less feasible in small-scale pig farms. In all other farms, the impact on production costs of local anaesthesia is however limited and does not exceed 1 €ct per kg. General anaesthesia administered by inhalation or injection of Ketamin in combination with a sedative (Azaperone, Midazolan) is more expensive. These costs depend heavily on farm size, as the inhalation equipment has to be depreciated on the largest number of pigs possible. The overall costs of immunocastration - including the cost of the work load for the farmer - has to be evaluated against the potential benefits derived from higher daily weight gain and feed efficiency in comparison with surgical castrates. The economic feasibility of this practice will finally depend on the price of the vaccine and on consumer acceptance of immunocastration. The improvement in feed efficiency may compensate almost entirely for the cost of vaccination. The main advantages linked to raising entire males are due to the higher efficiency of feed conversion, to the better growth rate and to the higher leanness of carcass. A higher risk of boar taint on the slaughter line has to be accounted for. Raising entire males should not generate more than 2.5% of boar taint among slaughter pigs, in order to maintain the considerable economic benefits of better feed efficiency of entire males with respect to castrates.     

Immunocastration reduces aggressive and sexual behaviour in male pigs

The aim of this study was to evaluate the effectiveness of a gonadotropin-releasing hormone (GnRH) vaccine, Improvac™ (Pfizer Ltd), in suppressing aggressive and sexual behaviour of male pigs. One hundred and thirty-six pigs were assigned to three treatments: entire male pigs (n = 64), immunocastration against GnRH (n = 48) and surgical castration (n = 24). Surgical castration was performed before the age of 1 week. Vaccination comprised two injections: the first injection was given 8 to 11 weeks before slaughter and the second injection 4 weeks before slaughter. After the second injection, immunocastrated pigs showed less non-violent social and aggressive behaviours than entire male pigs of the same age. Mounting was reduced to the same low level as observed in surgically castrated pigs, and more immunocastrated pigs were without skin lesions compared with entire male pigs. Pigs that received the second injection only 1 week before the observation day did not differ significantly in behaviour from those that received the injection 3 weeks before the observation day. Thus, the behaviour seems to change soon after the second injection and these changes remain until slaughter.     

Further regression of seminal vesicles of castrated guinea pig by administration of cyproterone acetate

It has been established that a low level of secretory activity persisted in seminal vesicles of guinea pigs long after castration and that this may be due to a higher extratesticular androgen level in this animal. A RIA study revealed that the normal serum testosterone concentration of the guinea pigs was comparable to that of the rats, but the basal serum testosterone level after castration was ten times higher than rats under a similar condition. It was also shown that cyproterone acetate did not significantly lower the basal serum testosterone concentration in the castrated guinea pigs. The higher basal serum testosterone level is believed to be responsible for the slow and incomplete regression of this gland in the guinea pigs. There was a significant reduction in wet weight of the seminal vesicles after the treatment of castrated guinea pigs with cyproterone acetate. Ultrastructural study showed that there were both qualitative and quantitative changes in the cytoplasmic organelles. The Golgi apparatus further reduced in size and in the number of associated vesicles and vacuoles. There was a marked decrease in the number and size of secretory granules and lysosomes and an increase in the degree of undulation of the basement membrane. Accumulation of lipid droplets and glycogen was commonly observed. All these morphological evidences showed that further regression of the castrated guinea pig seminal vesicles can be achieved by cyproterone acetate treatment.     

Considerations on the performance of immunocastrated male pigs

With the ongoing social pressure on surgical castration of pigs, an increase in the population of pigs that are either not castrated or immunocastrated (IC) can be expected. In both cases, their nutrient requirements and performance will differ from surgically castrated pigs and will require changes in their management. Immunocastration is performed by giving two injections of a modified gonadotrophin-releasing hormone component along with an adjuvant, at least 4 weeks apart. This paper describes the reported differences in growth performance and carcass quality of IC male pigs in comparison with boars (BO) and barrows (BA). Theoretically, IC pigs remain physiologically boar until the second vaccination and therefore, growth may be comparable with BO until this second vaccination. From then on, IC male pigs consume more feed than BO and grow faster when fed ad libitum. IC showed a faster growth and better feed conversion ratio than BA. When fed restrictedly, BO grow faster and more efficiently than BA and IC. IC have a lower carcass yield than BA and BO, whereas meat percentage is intermediate.     

Acute physiological responses to castration-related pain in piglets: the effect of two local anesthetics with or without meloxicam

Methods to reduce castration-related pain in piglets are still issues of concern and interest for authorities and producers. Our objectives were to estimate the effectiveness of two protocols of local anesthesia (lidocaine and the combination of lidocaine+bupivacaine) as well as the use of meloxicam as a postoperative analgesic in alleviating castration-related pain, measured by acute physiological responses. Eight groups (15 piglets/group) were included in the study: (1) castration without anesthesia or analgesia, without meloxicam (TRAD WITHOUT), (2) castration without anesthesia or analgesia, but with meloxicam (TRAD WITH), (3) handling without meloxicam (SHAM WITHOUT), (4) handling with meloxicam (SHAM WITH), (5) castration after local anesthesia with lidocaine but without meloxicam (LIDO WITHOUT), (6) castration after local anesthesia with lidocaine and meloxicam (LIDO WITH), (7) castration after local anesthesia with lidocaine+bupivacaine without meloxicam (LIDO+BUPI WITHOUT), (8) castration after local anesthesia with lidocaine+bupivacaine and meloxicam (LIDO+BUPI WITH). Acute physiological responses measured included skin surface temperature and serum glucose and cortisol concentrations. On days 4 and 11 post-castration BW was recorded and average daily gain was calculated over this period. Furthermore, piglet mortality was recorded over the 11-day post-castration period. Administration of local anesthetic or meloxicam did not prevent the decrease in skin surface temperature associated with castration. Lidocaine reduced the increase in glucose concentration associated with castration. For castrated pigs, the joint use of lidocaine and meloxicam caused a significant decrease in cortisol concentration; the combination of intratesticular lidocaine and bupivacaine did not seem to be more effective than lidocaine alone. No effect of treatments on mortality and growth were detected.     

Behavioural responses of piglets to castration: the effect of piglet age

It has long been assumed that neonatal animals are less sensitive than older animals to pain, and this reasoning has been used to recommend that routine surgical procedures be performed at an early age. In this study we tested if vocal and other behavioural responses to castration increase with piglet age. Piglets (n=84) from 14 litters were assigned to one of six treatment groups: castration or sham castration at 3, 10 or 17 days of age. During the procedure castrated piglets produced high-frequency calls (>1000Hz) at more than three times the rate of piglets in the sham-castrate group. The rate of low-frequency (<1000Hz) calls was also higher for piglets in the castrate group. The rate of high-frequency calling was lower for the youngest pigs but there was no relationship between age and the effect of treatment for any of the vocal responses measured (i.e. no age by treatment interaction). During the first 2h after castration, castrated piglets spent more time sitting or standing and less time lying. During the subsequent 22h, castrated piglets spent marginally more time at the udder and less time lying down. Older piglets missed more nursings. However, the effect of castration did not vary with the age of the piglet for any measure. We conclude that while the factors affecting both the shams and the castrates (e.g. distress due to restraint) may vary with age, the pain of castration is not affected by age within the range of ages that we tested.     

Pain and discomfort in male piglets during surgical castration with and without local anaesthesia as determined by vocalisation and defence behaviour

Surgical castration of male piglets without anaesthesia is routine in domestic pig production causing serious distress and impairment of welfare. Thus, the EU is seeking alternatives, with local anaesthesia being one of the possible candidates. The aim of the present study was to compare surgical castration without anaesthesia (castration by cutting the spermatic cords [C]) with castration under local anaesthesia (CL), the act of intratesticular anaesthesia (L), and the combined effect of local anaesthesia and the following castration (L + CL) under practical field conditions on a commercial farm. Distress was estimated according to a set of behavioural indicators derived from vocalisation and defence movements of the piglets. C had the overall worst effects on the indices, made up assumingly by the pain due to the intensity and duration of the procedure, although it was not possible to separate the effects of handling and the procedure of castration. Local anaesthesia reduces the intensity of pain experienced during castration as assessed by changes in the behavioural indicators used here. But this positive effect was partly obscured by additional distress due to prolonged handling. It is concluded that the welfare benefits of local anaesthesia for castration of piglets, as carried out and assessed here, may not fully meet expectations, and that further research is needed to find ways to reduce the suffering of male piglets, that it is necessary to castrate.     

Feedback regulation of gonadotropic hormone secretion in neonatal pigs

The effect of castration and of administration of charcoal-treated porcine follicular fluid (pFF) containing inhibin-like activity on plasma concentration of gonadotropic hormones was studied in neonatal pigs. Plasma follicle-stimulating hormone (FSH) concentration averaged 25.1 +/- 1.5 ng/ml (mean +/- SEM) in 1-wk-old females and gradually declined to 20.2 +/- 0.7 ng/ml 6 wk later. Ovariectomy did not significantly influence plasma FSH concentration. In males, concentration averaged 8.0 +/- 0.7 ng/ml before castration but rose significantly within 2 days after castration. Injection of luteinizing hormone-releasing hormone (LHRH) did not influence plasma FSH concentrations in intact males, but did in females and in 7-wk-old males castrated at 1 wk. Plasma luteinizing hormone (LH) concentrations in 1-wk-old females (2.2 +/- 0.4 ng/ml) gradually declined and were not influenced by castration. Concentrations of plasma LH in 1-wk-old male piglets (2.8 +/- 0.7 ng/ml) were not significantly influenced by castration within 2 days but were significantly higher 6 wk later. LHRH induced a significant rise in plasma LH concentrations in all animals. Injection of pFF resulted in a decline of plasma FSH concentrations in intact and castrated males and in intact females, but did not influence plasma LH concentrations. These data demonstrate a sex-specific difference in the control of plasma FSH, but not in plasma LH concentration in the neonatal pig. Plasma FSH concentrations, but not plasma LH concentrations, are suppressed by testicular hormones in 1-wk-old piglets. Plasma FSH concentrations can be suppressed in both neonatal male and female pigs by injections of pFF.     

Increase in epithelial cell growth by hyperprolactinemia induces delay of castration-induced involution of mouse seminal vesicle

Male (C57BL/6 x DBA)F1 hybrid mice were castrated on day 60 after birth; two pituitaries from 60-day-old female mice were immediately grafted under the capsule of the left kidney in half of the castrated mice to induce hyperprolactinemia. The seminal vesicles in the absence of androgen treatment were examined 15, 22, 30 and 60 days after castration with or without grafting. Significant increases in the weight (1.3-1.4-fold), DNA content (1.2-1.3-fold) and labeling index of epithelial cells (4-10-fold) of the seminal vesicles were found in mice with pituitary grafts compared to mice without grafts on days 15-30 after castration but not on day 60 after castration. Such stimulatory effects of hyperprolactinemia on mouse seminal vesicle cells were also observed on day 15 after castration plus adrenalectomy. Cell loss from the seminal vesicles was found to be similar in castrated mice with and without the grafts. The present findings demonstrate that hyperprolactinemia induces an increase in DNA synthesis of epithelial cells in the seminal vesicles until 30 days after castration and results in a significant delay of castration-induced involution of the weight and DNA content of the seminal vesicles for 1 month. However, the delay with increased epithelial cell growth by hyperprolactinemia disappeared 60 days after castration.     

Trends in incidence of AIDS associated with transfusion of blood and blood products in Europe and the United States, 1985-93.

OBJECTIVE--To quantify patterns and trends in incidence of AIDS associated with transfusion of blood and its products in 14 European countries and the United States. DESIGN--Data were derived from the World Health Organisation''s European non-aggregate AIDS dataset and, for the United States, from the Centers for Disease Control AIDS public information dataset. Rates were standardised by using the world standard populations and adjusted for reporting delays in each country. SUBJECTS--Cases of AIDS in patients with haemophilia and recipients of transfusions. RESULTS--Overall, between 1985 and 1993 almost 6000 cases of AIDS associated with transfusions were registered in the 14 European countries considered and over 8000 in the United States between 1985 and 1992. Most European countries had annual age adjusted rates lower than 0.5 per million children aged 12 or less and between 1 and 2 per million adults. The United States had rates around 1 per million children and 5 per million adults in the most recent period. For children, the highest rates were generally reached in 1985-7, whereas in adults the highest rates were in the late 1980s. France had the highest overall incidence of AIDS related to transfusion in Europe (3.3 per million). Romania had a major epidemic in children (over 30 cases per million children in 1988-90). Incidence rates of AIDS associated with transfusion were still increasing in some southern European countries in the early 1990s. CONCLUSIONS--Apart from in France and Romania it is clear that rates of bloodborne AIDS in European countries are lower than those registered in the United States.     

Potential sensitivity of pork production situations aiming at high-quality products to the use of entire male pigs as an alternative to surgical castrates

The perspective of a possible ban on surgical castration of male pigs in the EU is a real challenge for pork production systems aiming at (very) high-quality products. Information was collected from a total of 272 situations in 16 European countries, including 170 situations related to EU protected designations (Database of Origin & Registration (DOOR) database) and 102 other situations related to high-quality products or differentiated production systems, in order to evaluate their potential sensitivity to the use of entire male pigs along four dimensions: BT_Inc, likelihood of increased levels of boar taint compounds compared with conventional production of entire males; BT_Per, extent to which (some of) the associated pork product(s) are susceptible to perception of boar taint by consumers; FatQQ, likelihood that the quality of (some of) the related products is decreased due to the lower fat quantity and quality in entire males; Manag, increased likelihood of animal management and welfare problems compared with conventional production of entire males. Situations corresponding to EU protected designations (DOOR situations) were on average more sensitive to entire male production but 11% of the non-DOOR situations were highly potentially sensitive, whereas one-third of the DOOR situations had low potential sensitivity. In total, 37% of the situations where castration is not formally specified as mandatory exhibited high potential sensitivity to entire male production. Three main patterns of situations were identified via ascending hierarchical clustering. A first pattern including 31% of the DOOR situations and 74% of the other ones, had potentially no increased risk compared with conventional production of entire males. A second pattern including 28% of the DOOR situations and 16% of the other ones had a high, moderate and low potential sensitivity for FatQQ, BT_Inc and Manag, respectively. The third pattern including 41% of the DOOR situations and 11% of the other situations had high potential sensitivity for BT_Inc and FatQQ, associated with moderate to high sensitivity for Manag. The approach used to evaluate the sensitivity to entire male pig production from the limited information collected for this study has many limitations. More precise approaches using more specific information are needed to evaluate the actual sensitivity of individual situations to the use of entire male pigs. Still, the present study provides a first global insight on the capacity of European production systems aiming at high-quality products to use entire male pigs as an alternative to surgical castration.     

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

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

Effects of castration, dietary fat and adipose tissue sites on adipocyte plasma-membranes cyclic AMP phosphodiesterase activity in the pig.

1. cAMP Phosphodiesterase activity and kinetic parameters (Km and Vmax) were measured in subcutaneous and perirenal adipocyte plasma membranes from Large White male and castrated pigs. The animals were fed a control low fat diet or a sunflower diet enriched with linoleic acid (C18:2 n-6). 2. Phosphodiesterase activity, low Km and Vmax were lowered by castration. 3. In animals fed the sunflower diet, phosphodiesterase activity decreased without affecting either Km or Vmax. 4. Phosphodiesterase activity was higher in perirenal sites than in subcutaneous ones, particularly in male pigs. This may be explained by a lower Km or a higher cAMP phosphodiesterase affinity to cAMP in perirenal sites. 5. Theophylline was a potent inhibitor of phosphodiesterase activity principally in perirenal sites. 6. The intermediate role of cAMP phosphodiesterase in adenylate cyclase activity and lipolytic processes is discussed.     

Reduction of flobufen in pig hepatocytes: effect of pig breed (domestic,wild) and castration

Knowledge of the biotransformation processes of veterinary drugs and food supplements in food-producing animals is increasingly important. Residual levels of parent compounds or their metabolites in food of animal origin may differ with the breed, breeding conditions, and gender of animals. The nonsteroidal antiinflammatory drug flobufen, 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (racemic or its individual enantiomers) was used as a model to evaluate differences in activity, stereoselectivity, and stereospecificity of reductases in primary cultures of hepatocytes from intact male or castrated male domestic pigs (Sus scrofa domestica) or male wild pig (Sus scrofa scrofa). Time-dependent consumption of flobufen enantiomers and formation of dihydroflobufen (DHF) diastereoisomers as their principal metabolites in hepatocytes were measured using chiral HPLC. Flobufen reduction in hepatocytes from all three experimental groups of animals was stereoselective ((+)-R-flobufen was predominantly metabolized) and stereospecific (2R;4S-DHF and 2S;4S-DHF diastereoisomers were preferentially formed). Flobufen reductases activity in male domestic pigs was 30 times higher compared to castrated pigs. Flobufen reductases activity was similar in domestic and wild pigs. The stereospecificity and stereoselectivity of DHF production did not significantly differ with breed or castration of animal. Chiral inversion of flobufen enantiomers was also studied and differences between castrated and intact male pigs were seen.     

Physiology and behavior of pigs before and after castration: effects of two topical anesthetics

Surgical castration of male piglets is a common management practice conducted on commercial swine farms to prevent the occurrence of boar taint and aggressive behavior. However, the procedure of surgical castration causes acute pain-induced distress, which is an animal welfare concern. The objective of this study was to evaluate the use of two topical anesthetics to alleviate the pain caused by castration in piglets as measured by physiological and behavior indices of stress. At 3 days of age, 40 weight-matched piglets were allocated to one of four treatment groups. Treatments included: (i) sham castration (CON), (ii) surgical castration (CAS), (iii) castration and short-acting local anesthetic applied topically to the castration wound (SHORT) and (iv) castration and long-acting local anesthetic applied topically to the castration wound (LONG). Blood samples were collected from piglets before and 30, 60, 120 and 180 min after castration to measure leukocyte and differential counts and cortisol concentrations. The above experiment was repeated without blood collection and behavior was recorded for 30 min before and 180 min after castration or handling. Stress vocalizations were recorded during castration and handling. All piglets were weighed before and 24 h after castration and wound healing was recorded daily for the first 14 days after castration. Leukocyte counts and differentials did not differ (P > 0.05) among any of the treatments. Cortisol concentrations were elevated (P < 0.06) in CAS, SHORT and LONG piglets compared with controls 30 and 60 min after castration. The percentage of stress vocalizations was greater (P < 0.05) among castrated piglets compared with CON piglets, regardless of anesthetic treatment. Piglets that were castrated and not given a topical anesthetic spent more time (P < 0.05) lying without contact compared with piglets castrated and given a topical anesthetic, regardless of the topical anesthetic administered. Body weight change did not differ (P > 0.05) among treatments 24 h after castration or control handling and wound healing scores were greater (P < 0.05) in SHORT compared with CAS and LONG piglets 9 to 14 days after castration. In this study, the use of a short- or long-acting topical anesthetic was not effective in reducing the pain-induced distress caused by castration in piglets. Further research is needed to evaluate alternative practical methods to reduce the pain caused by the on-farm castration of piglets.