Effects of castration and eucalyptus oil supplementation on growth performance, nutrient digestibility, and blood-immunity indicators of male Holstein calves

The purpose of this study was to investigate the effects of early castration and eucalyptus oil (EUC) supplementation on dry matter intake (DMI), growth performance, and immune response of Holstein calves. Fifty-six male Holstein calves 52 d old and with an initial body weight (BW) of 63.5 ± 5.27 kg were used. The animals were blocked by BW and randomly assigned into 1 of the 4 treatment groups in a randomized complete block design with a 2 (no castration vs. castration) × 2 (without vs. with EUC) factorial arrangement of treatments. The treatments were (1) uncastrated calves fed without EUC, (2) uncastrated calves fed 0.5 g/d EUC (EUC group), (3) castrated calves (steers) fed without EUC (castrated group), and (4) steers fed with 0.5 g/d EUC (castrated + EUC). The experiment was 8 wk long, including pre- and postweaning (weaned at 72 d). The EUC × castrated interactions were not significant for DMI, growth performance, nutrient digestibility, and immune response. Castration did not affect the DMI, final BW, average daily gain (ADG), or feed efficiency, except that the ADG was greater for bull calves than for steers at postweaning. Supplementation with EUC increased DMI pre- and postweaning and increased the ADG of weaned calves. Digestibility in the total digestive tract was not affected by castration (except for organic matter digestibility), whereas adding EUC improved the digestibility of dry matter, acid detergent fiber, and crude protein. Blood concentration of IL-6 at d 94 was decreased by feeding EUC. These results indicate that the EUC could be fed to either intact or castrated dairy calves to promote growth and health postweaning; castration before weaning may reduce ADG and cause inflammatory stress without affecting feed intake or feed efficiency.

Effect of knife castration on leukocyte cytokine expression and indicators of stress, pain, and inflammation in Korean cattle bull calves

OBJECTIVE

This study investigated the effects of surgical castration on behavior, physiological and inflammatory indicators, and leukocyte cytokine mRNA levels in Korean cattle bull calves.

METHODS

Nineteen Korean cattle bull calves (average body weight, 254.5 kg; average age, 8.2 months) were divided into two treatment groups: control (n = 9) and castration (n = 10). Surgical castration was performed using Newberry knives and a Henderson castrating tool. Blood was obtained just before castration (0 h) and at 0.5 h, 6 h, 1 d, 3 d, 7 d, and 14 d after castration. Plasma cortisol (PC), saliva cortisol (SC), plasma substance P, and plasma haptoglobin concentrations, and the leucocyte mRNA levels of the interleukin-1-alpha (IL1A), interleukin-1-beta (IL1B), interleukin-1 receptor antagonist (IL1RN), and interleukin-6 (IL6) genes were analyzed.

RESULTS

Castration decreased (p<0.01) the average daily gain and gain/feed ratio. Castration reduced the time spent eating (p<0.001) and the eating frequency (p<0.01) and increased (p<0.001) the lying frequency. Castration temporarily increased (p<0.05) circulating PC and SC concentrations at 0.5 h after castration. Castration temporarily increased (p<0.05) plasma substance P concentrations at 1 d after castration. Castration increased (p<0.05) plasma haptoglobin concentrations at 1 and 3 d after castration. Castration increased (p< 0.05) leukocyte mRNA levels of the IL1A, IL1B, IL1RN, and IL6 genes at 6 h after castration.

CONCLUSION

Castration temporarily induced stress and expression of leucocyte inflammatory cytokine genes in Korean cattle bull calves.

Pain in the weeks following surgical and rubber ring castration in dairy calves

Many male dairy calves are castrated when reared for beef production, but for dairy breeds the assessment of the longer-lasting pain associated with this procedure has received little scientific attention. In this study we assessed 2 methods: surgical (n = 10 calves) and rubber ring (n = 11). All calves were castrated at 28 d of age using multimodal pain control. During the 8 wk that followed, we recorded wound healing, local inflammation, body weight, milk and calf starter intake, lying time, and wound-directed behavior. Surgical wounds were fully healed on average 4 wk after the procedure, but only 1 calf in the rubber ring treatment fully healed within the 8-wk study. Inflammation was greater after rubber ring castration; skin temperature in the area around the lesion was 1.7 ± 0.35°C (mean ± standard deviation) higher than for the surgical treatment. Compared with surgically castrated calves, those castrated by rubber ring gained less weight over the study period (on average 11.9 ± 5.1 kg less), a difference due in part to lower intake of calf starter (on average 1.8 ± 0.6 kg less). Calves in the rubber ring treatment spent less time lying down (on average 4.2 ± 1.2% fewer scans per day) and licked their lesions more frequently (on average 16.0 ± 3.3 more licks per day). We conclude that the rubber ring calves experienced more pain in the weeks following the procedure and thus recommend that surgical castration be favored for preweaning dairy calves.

Analgesia for Sheep in Commercial Production: Where to Next?

Simple Summary

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on industry to alleviate pain associated with husbandry practices, injury and illness. Although a number of analgesic solutions are now available for sheep, providing some amelioration of the acute pain responses, this review has highlighted a number of potential areas for further research.

Abstract

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

Development and Validation of a Bovine Castration Model and Rubric

Veterinary students require deliberate practice to reach competence in surgical bovine castration, but animal availability limits opportunities for practice. We sought to create and validate a surgical bovine castration model consisting of a molded silicone scrotum and testicles to allow students to practice this skill without the use of live animals. We sought to validate the model and associated scoring rubric for use in a veterinary clinical skills course. A convenience sample of third-year veterinary students (n = 19) who had never castrated a bovine were randomized into two groups. The traditionally trained (T) group performed castration on a live bull calf after a 50-minute instructional lecture. The model-trained (M) group received the same lecture and a 2-hour clinical skills session practicing bovine castration using the model. All students were subsequently digitally recorded while castrating a live bull calf. Performance recordings were scored by an investigator blinded to group. Survey data were collected from the students and from expert veterinarians testing the model (n = 8). Feedback from both groups was positive. The M group had higher performance scores than the T group (M group, M = 80.6; T group, M = 68.2; p = .005). Reliability of rubric scores was adequate at .74. No difference was found in surgical time (M group, M = 4.5 min; T group, M = 5.5 min; p = .12). Survey feedback indicated that experts and students considered the model useful. Model training improved students' performance scores and provided evidence for validation of the model and rubric.

Effect of testosterone on the differentiation control of stromal vascular cells isolated from longissimus muscle of Hanwoo beef cattle

Testosterone, as an influential factor in marbling score, requires strict management for uniform development of adipocytes in-between muscle bundles. Present study investigated effect of castration timing and testosterone levels on adipocyte development using SVCs. Isolated SVCs exhibited classical MSC markers, CD31^-, CD34^-, CD45^-, CD90⁺, and CD105⁺. ELISA analysis indicated that serum testosterone concentration was highest in non-castrated calves while no significant difference was observed between female, early and late castrated calves. CCK-8 assay showed that concentration of testosterone had no effect on cell proliferation. However, the real-time PCR demonstrated that 20 ng/ml of testosterone suppressed expression of preadipocyte markers, pref-1 and zfp423, but encouraged expression of myoblast markers, myf5 and myoD, via the AR. Consequently, expression of adipogenic markers C/EBPα and PPARγ, as well as accumulation of triglyceride, were decreased in 20 ng/ml testosterone treatment under adipogenic conditions. These findings suggest that by castrating calves before level of testosterone increases, may improve marbling development in the Hanwoo beef industry.

Effect of a single dose of subcutaneous meloxicam before knife castration alone or combined with hot-iron branding on scrotal healing, inflammatory response, and behaviour in 2-mo-old beef calves over 42 d post procedure

The objective of this study was to evaluate the effect of a single subcutaneous injection of meloxicam on scrotal healing, inflammatory response, and behaviour in castrated or castrated and branded beef calves for 42 d post procedure. Seventy-two 2-mo-old Angus crossbred bull calves were used to assess the effects of procedure (Trt): (1) sham control, (2) knife castration, and (3) knife castration and hot-iron branding; and pain mitigation (Med): (1) nonmedicated and (2) medicated with meloxicam according to a 3 × 2 factorial design. Body weight, scrotal circumference (SC), and healing scores were collected weekly until day 42. Blood samples were collected weekly until day 42 to assess haptoglobin, serum amyloid-A, and complete blood cell count. Hair was collected on day −1 and day 42 to assess cortisol concentrations. Lying and standing behaviour were recorded for 42 d, whereas pain-related behaviours were recorded on days 7, 15, 22, 29, and 34 post procedure. The inflammatory response (SC) and duration of standing was greater (P < 0.05) in calves castrated and branded than those only castrated. However, meloxicam did not reduce inflammation or improve wound healing in either castrated or castrated and branded calves.

Zinc injection as a novel castration method in beef bulls: effects on performance, behavior, and testosterone and haptoglobin concentration

Crossbred beef bulls (n = 180) were blocked by initial BW (337 ± 10.9 kg; six blocks) and assigned randomly to one of three treatments on day 0: 1) INJ; received 1 mL (100 mg Zn) of a Zn solution in each testis, 2) BAN; received blood- restrictive rubber band placed around the dorsal aspect of the scrotum, 3) BUL; bulls with testicles remaining intact in a randomized complete block design (three treatment pens per block and 10 cattle per pen). A subset of 54 animals (n = 3 per pen) was fitted with accelerometers on day 0 to quantify behavior variables continuously for 28 d. Testis width and scrotal circumference, and serum haptoglobin (days 0, 1, 3, 5, 7, and 14) and testosterone concentrations (every 28 d until slaughter) were also determined for the subset. During the slaughter process, testes from INJ and BUL were collected to assess final testes weight and for histopathological evaluation. Data were analyzed using a mixed model (α = 0.05); pen served as the experimental unit for all dependent variables. Final BW was greater (P < 0.01) for INJ and BUL compared to BAN (672, 686, and 611 kg, respectively; SEM = 4.4). Overall ADG and G:F were greater (P ≤ 0.03) in INJ and BUL than BAN; whereas, DMI was similar between treatments for the study duration (P = 0.46). Histopathological evaluation (n = 13; INJ = 7; BUL = 6) indicated that INJ testes were degenerative and reproductively nonviable whereas BUL testes were normal. Serum testosterone concentrations on day 168 were similar (P = 0.14) between INJ and BUL whereas after day 14, BAN was nondetectable; however, initial serum testosterone concentrations were similarly low across treatments. Serum haptoglobin concentration was greater (P < 0.01) in INJ than BUL and BAN on days 1, 3, 5, and 7. Scrotal circumference (P = 0.08) and testis width (P = 0.07) on day 168 tended to be greater for BUL than INJ. Motion index (P ≤ 0.02) and step count (P = 0.04) was greater in BUL and INJ compared to BAN cattle during the 28 d monitoring period. No difference in standing time (P ≥ 0.85) or lying bouts (P = 0.35) occurred. Zinc injection resulted in sterilization but did not cause complete cessation of testicular function evidenced by testosterone concentrations more similar to BUL than BAN. This resulted in overall increased BW and G:F for INJ vs. BAN, yet the acute phase response was markedly greater directly after Zn injection. Collectively, Zn injection resulted in outcomes more similar to BUL than BAN, implying minimal efficacy of INJ as a castration method in older bulls arriving to the feedlot.

Effect of castration method and analgesia on inflammation, behavior, growth performance, and carcass traits in feedlot cattle

Our objective was to determine the effect of castration timing, method, and use of the analgesic meloxicam (MEL) on inflammation, behavior, performance, and carcass traits in feedlot cattle. This study was a randomized complete block design conducted over a 3-yr period. In total, 194 crossbred beef calves from a single ranch origin were randomized at birth to receive one of five treatments arranged as a 2 × 2 + 1 factorial: 1) bulls castrated within 48 h of birth (CON), 2) bulls surgically castrated on day 0 without MEL (SUR), 3) bulls surgically castrated on day 0 with MEL (SUR + MEL), 4) bulls band castrated on d 0 without MEL (BAN), and 5) bulls band castrated on day 0 with MEL (BAN + MEL). Upon feedlot arrival (day -11; average 287 ± 2.03 d of age), animals were blocked by initial BW (224 ± 4.5 kg) and assigned randomly to treatment pens in three consecutive years (n = 2 pens per treatment in each year). Oral MEL was administered at 1 mg/kg BW concurrent with applicable castration treatment on day 0. Data were analyzed using the MIXED and GLIMMIX procedures of SAS with pen (year) serving as experimental unit. From days 0 to 7, ADG was reduced (P = 0.01) for surgical (-0.42) compared to band (0.43 kg/d) castration. Conversely, ADG was increased for surgical (1.74) vs. band (1.46 kg/d) castration from days 14 to 32. There was also an overall (day 0 to final) improvement in ADG for MEL (P = 0.02), but no effect of castration method was observed (P = 0.81). The CON group had the greatest (P = 0.05) marbling score. Backfat thickness was increased (P = 0.01) for MEL. A treatment × day interaction (P = 0.04) existed for serum haptoglobin, with SUR having the greatest (P < 0.01) concentration on days 1 and 4. Meloxicam administered in the surgically castrated treatment reduced (P = 0.01) serum haptoglobin concentration on day 1. Relative to baseline, standing duration for surgical castration was increased 113 min (P < 0.01), while banding caused 6.7 more lying bouts (P < 0.01) immediately following castration on day 0. Step count was greatest for BAN, intermediate for CON, and least for surgical (P < 0.01). Results suggest that MEL mitigated the more pronounced inflammation observed for surgical castration, whereas behavior was differentially altered for castration method indicative of a divergent pain response. Castration, regardless of method, transiently reduced ADG, but MEL administration improved overall ADG for both methods.

A meta-analysis of cortisol concentration, vocalization, and average daily gain associated with castration in beef cattle

A systematic review and meta-analysis (MA) were performed to summarize all scientific evidence for the effects of castration in male beef cattle on welfare indicators based on cortisol concentration, average daily gain (ADG), and vocalization. We searched five electronic databases, conference proceedings, and experts were contacted electronically. The main inclusion criteria involved completed studies using beef cattle up to one year of age undergoing surgical and non-surgical castration that presented cortisol concentration, ADG, or vocalization as an outcome. A random effect MA was conducted for each indicator separately with the mean of the control and treated groups. A total of 20 publications reporting 26 studies and 162 trials were included in the MA involving 1814 cattle. Between study heterogeneity was observed when analysing cortisol (I²=56.7%) and ADG (I²=79.6%). Surgical and non-surgical castration without drug administration compared to uncastrated animals showed no change (P≥0.05) in cortisol level. Multimodal therapy for pain did not decrease (P≥0.05) cortisol concentration after 30min when non-surgical castration was performed. Comparison between surgical castration, with and without anaesthesia, showed a tendency (P=0.077) to decrease cortisol levels after 120min of intervention. Non-surgical and surgical castration, performed with no pain mitigation, increased and tended to increase the ADG by 0.814g/d (P=0.001) and by 0.140g/d (P=0.091), respectively, when compared to a non-castrated group. Our MA study demonstrates an inconclusive result to draw recommendations on preferred castration practices to minimize pain in beef cattle.

Effect of castration timing and oral meloxicam administration on growth performance, inflammation, behavior, and carcass quality of beef calves

Beef bull calves (n = 62) were assigned randomly, within sire breed, to 1 of 4 treatments at birth. Treatments were 1) surgical castration near birth, 2) surgical castration near birth with oral administration of meloxicam (1 mg/kg BW), 3) surgical castration at weaning (WNG), or 4) surgical castration at weaning with oral administration of meloxicam (1 mg/kg BW; WMX). A subset of calves (n = 7/treatment group) were selected randomly near birth for blood collection, behavioral analyses, and rectal temperature (RT) records for a 7-d postcastration period on d 0 (birth), 1, 3, and 7, and on d 214 (weaning), 214 + 6 h, 215, 217, 221, and 228. Calf standing and lying activity were monitored from the same subsets by recording x- and y-axis positions of an accelerometer attached to the right metatarsus for 7 d postcastration. Calf BW was recorded throughout the entire production cycle, and carcass data were collected at slaughter. For statistical analyses, bulls left intact at birth were considered a positive control (BUL) for observations that occurred before their treatment application at weaning; likewise, bulls castrated at birth were considered a negative control (STR) during postweaning observations. No difference (P > 0.88) occurred in ADG between treatments throughout the preweaning period (d 0 to 214); however, 56-d postweaning ADG was greatest ( P= 0.02) in STR, intermediate in WMX, and least in WNG. At weaning, haptoglobin (Hp) was greater (P ≤ 0.005) for WNG and WMX compared to STR on d 214+6 h, 215, and 217, and Hp was greater (P = 0.05) in WNG compared to WMX on d 217. Neutrophils increased (P < 0.001) and red blood cells decreased (P ≤ 0.03) for WNG and WMX on d 214+6 h and 217, respectively. Postweaning behavior observations indicated that STR calves spent the least proportion of time standing (P = 0.002) when compared to WNG and WMX. Furthermore, WMX calves exhibited a greater proportion of time spent standing (P = 0.03) compared to WNG. Grazing and finishing phase ADG and carcass measurements did not differ (P ≥ 0.24) across treatments. In this study, surgical castration at weaning, but not near birth, altered the acute phase response, behavior, and growth performance. Oral meloxicam reduced serum Hp and improved ADG briefly when administered to calves castrated at weaning. Oral administration of meloxicam may be efficacious for mitigating some of the stress and inflammation associated with castration of weaning-age bull calves.

Effect of anti-gonadotropin-releasing factor vaccine and band castration on indicators of welfare in beef cattle

Angus crossbred bulls (n = 60; 257 ± 5.4 d of age; initial BW 358.8 ± 3.78 kg) were used to study the effect of a vaccine against gonadotropin-releasing factor (GnRF) and band castration on behavioral and physiological indicators of pain. Cattle were randomly assigned to 1 of 3 treatments: bulls, band-castrated calves without pain mitigation (castrated), and immune-vaccinated animals administered an anti-GnRF vaccine (vaccinated). All animals were fitted with a radio frequency ear tag so that individual animal feed intake and feeding behavior were recorded daily over the entire trial using an electronic feed bunk monitoring system. Two doses of anti-GnRF vaccine were administrated on d -35 and 0 and band castration was performed on d 0. Animal BW was recorded weekly starting on d -36 until d 56. Visual analog scores (VAS) were measured on d -36 -35, -1, and 0, and salivary cortisol concentration was measured at -30, 0, 30, 60, 120, and 270 min on d -35 and 0 after castration. Saliva and blood were obtained on d 1, 2, 5, and 7 and weekly until d 56 for determination of cortisol and complete blood cell count. Video data were collected for pain, sexual, and aggressive behavior daily the first week and once a week until d 56. Data were analyzed with a mixed-effect model with castration, time, and their interactions as main effects. Vaccinated calves had reduced ADG and intake (P < 0.05 and P < 0.001, respectively) during the first week after vaccination. Band-castrated calves had reduced ADG and intake (P < 0.001) until the end of the study. No differences in salivary cortisol and VAS were observed among groups at d -35 after the first vaccination and before band castration. However, on d 0, castrated cattle had greater cortisol concentrations and VAS (P < 0.05 and P < 0.01, respectively) than bulls and vaccinated animals. Complete blood cell count did not differ (P > 0.05) between treatments on d 0, 1, and 2. At d 56, vaccinated calves had greater (P < 0.05) final BW than band-castrated calves and both had less final BW than bulls. There was no indication that vaccination caused any physiological or behavioral changes indicative of pain. In contrast, band castration resulted in elevated cortisol scores and VAS indicative of a pain response and behavior related to pain (P < 0.001) until d 42 of the study. The present study demonstrates that anti-GnRF vaccine is a viable animal welfare-friendly alternative to traditional band castration in beef cattle under North American feedlot practices.

Características de carcaça e da carne de bovinos mestiços não-castrados ou submetidos a diferentes métodos de castração

Objetivou-se com este estudo analisar os efeitos de diferentes métodos de castração de machos mestiços de raças de origem leiteira, sobre as características de carcaça e da carne, em comparação com animais não-castrados. Foram utilizados 84 machos, com idade média de dez meses, distribuídos em quatro grupos de 21 animais: castrados com o uso de burdizzo, por meio de incisão lateral na bolsa escrotal, por remoção do tampão (ápice da bolsa escrotal) ou não-castrados. O abate dos animais ocorreu em frigorífico comercial, aos 30 meses de idade. Animais não-castrados apresentaram maior peso de carcaça fria (208,0±6,2 kg) do que os castrados por diferentes métodos (média 192,0±6,4 kg). Não houve diferença para a espessura de gordura entre os grupos experimentais, mas quando a medida foi ajustada ao peso de carcaça, observou-se maior cobertura de gordura nos animais castrados com burdizzo (0,79±0,08 mm/100 kg) ou por incisão lateral (0,86±0,09 mm/100 kg) do que os não-castrados (0,61±0,05 mm/100 kg). A área de olho de lombo foi maior nos machos não-castrados (60,47±1,94 cm²) do que os castrados com burdizzo (50,41±3,18 cm²). Não houve diferença para as relações músculo/osso e músculo+gordura/osso entre os grupos, mas a relação músculo/gordura foi maior nos animais não-castrados em relação aos castrados pela remoção do tampão e estes superiores aos castrados por incisão lateral. Não houve diferença entre as características sensoriais da carne, mas o grau de marmoreio foi maior nos animais castrados com burdizzo (2,33±0,20 pontos) ou castrados pela remoção do tampão (2,39±0,20 pontos) do que os bovinos não-castrados (1,77±0,12 pontos). O método de castração em bovinos mestiços de origem leiteira abatidos com peso reduzido não promove alterações na qualidade da carcaça e da carne dos animais, mas animais não-castrados apresentam maiores peso de abate e peso de carcaça fria, alem de maior porcentagem de músculo na carcaça e melhor relação músculo/gordura do que os castrados.

Effects of castration and weaning conducted concurrently or consecutively on behaviour, blood traits and performance in beef calves

The objectives of this study were to evaluate the effects of Burdizzo castration and abrupt weaning on the behaviour, blood traits and performance of beef calves when weaning was conducted concurrently or consecutively to castration. In total, 64 male beef calves aged between 6 and 7 months were assigned to a 2×2 factorial design with the following treatment groups (n=16 animals per treatment): (1) castrated and concurrently weaned in week 0 (CAS-WEA); (2) castrated in week 0 and weaned in week 4 (CAS-CON); (3) bulls weaned in week 0 (BUL-WEA); and (4) bulls weaned in week 4 (BUL-CON). The behaviour of the calves was observed for 3 days following weaning. Blood was collected weekly from weeks 0 to 5 and analysed for the acute-phase protein haptoglobin, and neutrophil and lymphocyte percentages. BW was recorded weekly from weeks 0 to 7. Animals were slaughtered at 17 months and weight, dressing percentage and carcass classifications were recorded. On day 1 after weaning, the number of vocalizations (calls/10 min) was higher in BUL-WEA (7.2) and CAS-WEA (5.4) than in calves of CAS-CON (2.8) and BUL-CON (2.9) groups (P<0.05). From days 1 to 3 vocalizations decreased in all groups. CAS-CON and BUL-CON animals spent 20% lying on day 1 after weaning compared with 40% in CAS-WEA and BUL-WEA calves (P<0.05). The haptoglobin concentration decreased during the first 5 weeks after weaning in all groups independent of the castration, weaning group or its interaction (P>0.05). WEA groups showed an increased average daily gain (ADG) during weeks 0 to 3 and a reduced ADG during 4 to 7 weeks in comparison with CON animals. At slaughter, bulls were about 80 kg heavier than castrates and had a superior dressing percentage and carcass classification (P>0.05). In conclusion, weaning had a greater effect on the number of vocalizations, standing/walking and lying behaviour and ADG compared with Burdizzo castration. In comparison with undertaking the procedures separately, concurrent castration and weaning neither affected behaviour and haematological parameters nor impaired performance. There was no evidence that the concurrent application of both treatments markedly increased the stress response compared with their application at intervals of a few weeks.