Effect of intravenous sodium salicylate administration prior to castration on plasma cortisol and electroencephalography parameters in calves

Physiological, haematological and electroencephalographic responses to heat stress in Katjang and Boer goats

The present study aimed to determine the effect of repeated heat stress on serum levels of cortisol (CORT), acute phase proteins (APP) and heat shock protein (HSP) 70, haematological indicators, and electroencephalographic (EEG) response in the native Katjang and exotic Boer goats. Six female Katjang (15.7 kg ± 0.68) and six female Boer (16.8 kg ± 1.16) goats aged 5 to 6 months old were exposed to 38 ± 1℃ for 8 h, and the procedure was repeated at three different weeks (weeks 1, 2 and 3). Measurements of rectal temperatures and EEG activity and collection of blood samples were conducted before heat exposure (0 h), immediately after the heat exposure (8 h), and 8 h after completion of heat exposure (16 h) (recovery period). The current results revealed that the Boer animals had significantly higher rectal temperatures (RT), haemoglobin (Hb) and packed cell volume (PCV) counts than their Kajang counterparts. There were significant breed × stage of heat treatment (SHT) × week of heat treatment (WHT) interactions for neutrophil to lymphocyte ratios (NLR). In general, the Katjang animals had elevated NLR compared to those of Boer. The Boer goats had reduced capacity to express serum HSP70 compared to their Katjang counterparts following the heat challenge at week 3. Boer goats demonstrated higher delta waves than the Katjang group, which suggested the former were more stressed following the heat exposure. Breed had a negligible effect on CORT, APP, WBC counts and backfat thickness. Our findings suggested that the Katjang breed, as measured by RT, HB and PCV count, and EEG activity, could be more tolerant to heat stress than Boer. The Katjang goats showed higher HSP70 expression than their Boer counterparts, suggesting improved thermoregulation in the former.

Application of Electroencephalography in Preslaughter Management: A Review

Electroencephalography (EEG) can be reliable for assessing the brain’s electrical activity of preslaughter stress and pain. The duration between the ventral neck cut and induction of a state of unconsciousness/insensibility is crucial in the slaughtering of animals, reducing pain, fear, and distress. Various EEG variables, such as median frequency (F50), the total power of EEG spectrum (Ptot), waves patterns (amplitude and frequencies), epileptiform EEG, index of consciousness, and isoelectric EEG, are used to identify a valid indicator of the state of unconsciousness. Association among various behavioral, physiological, and hematological parameters with EEG variables could provide an overall assessment and deep insights into the animal stress levels or welfare status during various managemental and preslaughter operations, such as transport, stunning, and slaughtering operations. The application of EEG could help in further refining the stunning technologies and slaughter protocols in livestock, poultry, and fish. The present review analyzed the application of EEG as a neurophysiological tool for assessing animal welfare during the critical state of preslaughter handling and slaughter, thus ensuring proper compliance with animal welfare principles.

Physiological and electroencephalogram responses in goats subjected to pre-and during slaughter stress

A comprehensive stress assessment is vital in understanding the impact of the pre-slaughter procedure on animal welfare. The transportation and handling process was commonly reported to cause stress in animals. This research utilises electroencephalography (EEG) as an alternative stress indicator to non-painful acute stress measurement. EEG has been proved to be instantaneous and sensitive with specific results. Therefore, this study was aimed to determine the stress level of goats subjected to two different transportation duration and the effect of lairage based on their EEG activities and blood parameters changes. Eighteen adult male goats were divided into two transportation stress groups based on the transport duration: the two-hour (TS2) and six-hour (TS6) groups. Then, each group was then again divided into three smaller groups according to the lairage duration, which was three-hour (L3), six-hour (L6), and overnight (L12) groups. Blood was sampled before transport, after transport, and during slaughter while EEG was recorded before transport, after transport, after lairage, and during slaughter. Results revealed that there was a significant decrease in beta wave activity compared to baseline in TS2 goats (P < 0.05) after transportation, whereas no significant difference was detected in the TS6 goats. At the same time, goats from the TS2 group showed increase in creatine kinase (CK) and lactate dehydrogenase (LDH) compared to that in TS6 goats. Together with the observed cortisol concentration, these findings showed that the TS6 goats were fully adapted to the transportation stress while the TS2 goats were still under stress. As for the lairage duration, it was observed that the TS2L3 goats showed lower EEG activities than the values obtained after two-hour transportation, while lower EEG activities were found from the TS6L6 goats after six-hour transportation. Therefore, it can be concluded that three-hour lairage was adequate to lower the impact of two hours transportation stress, whereas six-hour lairage was required to reduce the impact of six hours transportation stress. Finally, it was also found that the TS6L3, TS6L6, and TS6L12 groups took a long time to die after slaughter than the TS2L3, TS2L6, and TS2L12 goats based on the time their EEG activity reached isoelectric.

Unmitigated Surgical Castration in Calves of Different Ages: Electroencephalographic and Neurohormonal Findings

Castration is a common management procedure employed in North American cattle production and is known to cause a pain response. The present study was designed to investigate the effect of unmitigated surgical castration on the electroencephalography (EEG) responses and plasma substance P (SP) concentrations in calves of different ages under the same experimental conditions. Thirty male Holstein calves in three age categories [<6 weeks (6W); 3 months (3M); 6 months (6M); 10 calves per age group] were used in the study. Calves were subjected to a simulated castration session (SHAM) followed 24 h later by surgical castration (CAST) without analgesia. An EEG analysis was performed before the procedure (i.e., baseline), at treatment, and 0-5, 5-10, and 10-20 min post-treatment for both SHAM and CAST, respectively. Blood samples were collected immediately prior to both treatments (time 0) and again at 1, 2, 4, 8, and 12 h after both treatments. The EEG results showed a three-way interaction between treatment, age, and time for delta and beta absolute power, beta relative power, total power, and median frequency (p = 0.004, p = 0.04, p = 0.04, p = 0.03, and p = 0.008, respectively). Following CAST, EEG total power decreased, and median frequency increased relative to SHAM in 6W and 3M calves only following treatment. For 6W and 3M calves, delta and beta absolute power increased at CAST and at later time points relative to SHAM. Marginal evidence for two-way interactions was noted between time and treatment and between age and treatment on the concentration of SP (p = 0.068 and p = 0.066, respectively). Substance P concentrations decreased in CAST treatment compared to SHAM at the later times (8 h: p = 0.007; 12 h: p = 0.048); 6W calves showed lower SP concentration at CAST relative to SHAM (p = 0.017). These findings indicate variation in EEG responses and in SP concentrations following unmitigated surgical castration in calves and that these responses may be age specific. These EEG findings have implications for supporting the perception of the pain associated with surgical castration in young calves and emphasize the urgency of pain mitigation strategies during routine husbandry practices such as castration, as typically implemented in North American cattle management.

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.

Vitamin E and Selenium Decreased Cortisol in Cattle

Twenty dairy cows with left abomasal displacement were used to investigate the effects of vitamin E and selenium treatment on blood cortisol in dairy cows stressed by omentopexy. The cows were randomly divided into two groups. Ten hours before surgery 6 g of DL-α-tocopheryl acetate (6 mg.kg−1) and 67 mg of natrium selenite (0.1 mg.kg−1) in a volume of 40 ml were administered subcutaneously to 10 cows; the control animals (n = 10) received an equivalent volume of injectable water (40 ml). The injection of vitamin E and selenium produced a rapid rise (P < 0.05) in blood α-tocopherol and selenium concentrations. The serum vitamin E increased several times ten hours after vitamin E and Se injection and raised continuously to the highest average concentration of 21.6 mg.l−1 at hour 24 after the surgery. The highest selenium concentration was seen ten hours after selenium administration with holding the increased concentrations in comparison to initial ones during the whole study. Serum cortisol increased in both groups after surgery. The highest cortisol concentrations were reached at one hour after surgery in the experimental and control group (56.7 ± 28.8 and 65.3 ± 26.1 μg.l−1, respectively). A return to the levels similar to the initial ones was recognized 24 hours after the surgery. The ANOVA revealed a significant effect of vitamin E and selenium injection on serum cortisol (P < 0.05). In conclusion, we have demonstrated that abdominal surgery resulted in typical stress changes with a weaker cortisol response to the abdominal surgery in animals treated with vitamin E and selenium.

The Effects of Sea and Road Transport on Physiological and Electroencephalographic Responses in Brahman Crossbred Heifers

Simple Summary

This study investigated the effect of sea and road transport on the physiological response of cattle. The animals were transported by sea (14 d) from Darwin Port, Australia, to Pasir Gudang Port, Johor, Malaysia. Thereafter, the animals were road transported (330 km) from Pasir Gudang Port to Universiti Putra Malaysia (UPM). From the results of the various blood stress indicators and brain activity of the animals, both sea and road journeys were found to be stressful to the animals. However, the animals recovered from the stressful transport journeys following 4 and 7 days post-transport.

Abstract

The objective of the current study was to evaluate the effects of sea and road transport on the acute phase proteins (APP), cortisol, metabolic, haematological and electroencephalographic (EEG) responses of Brahman crossbred heifers. Sixty Brahman crossbred heifers were subjected to 14 d of transportation by sea from Darwin Port, Australia, to Pasir Gudang Port, Johor, Malaysia, and 330 km of road transportation. Results revealed that the intensity of response for most blood biochemical parameters increased significantly and were different from the baseline values taken while the animals were in Darwin Port, Australia. Haematological results obtained also revealed a significant increase and were different from the baseline values. Cortisol and APP (bovine alpha 1-acid glycoprotein and serum amyloid-A) values increased significantly and were different from the baseline values. Haematological parameters, APP, cortisol and EEG data (alpha, beta, delta and theta waves, total power and median frequency) decreased significantly following 4 and 7 days post-transport, suggesting a recovery of the animals from the stressfulness of transport. In conclusion, the current results revealed that the concentrations of biochemical and haematological parameters, cortisol, APP and EEG data were affected by both sea and road transport as evidenced by the significant changes recorded from the parameters above.

Pharmacokinetics of Salicylic Acid Following Intravenous and Oral Administration of Sodium Salicylate in Sheep

Simple Summary

Scarcity of non-steroidal anti-inflammatory drugs (NSAID) to minimise the pain in sheep instigated the current study. The aim of this study was to know the pharmacokinetic parameters of salicylic acid in New Zealand sheep after administration of multiple intravenous and oral doses of sodium salicylate (sodium salt of salicylic acid). Results of the study suggest that the half-life of the drug was shorter and clearance was faster after intravenous administration as compared to that of the oral administration. The minimum effective concentration required to produce analgesia in humans (16.8 µL) was achieved in sheep for about 0.17 h in the current study after intravenous administration of 100 and 200 mg/kg body weight of sodium salicylate. However, oral administration of these doses failed to achieve the minimum effective concentration as mentioned above. This study is of significance as it adds valuable information on pharmacokinetics and its variation due to breed, species, age, gender and environmental conditions. As per the authors’ knowledge, this is the only study showing detailed information about absorption, distribution and elimination of salicylic acid in New Zealand Sheep. An intravenous administration of sodium salicylate at 100 and 200 mg/kg dose may produce analgesia in sheep, which requires further investigation using pharmacokinetic–pharmacodynamic (PKPD) integration or modelling techniques.

Abstract

The pharmacokinetics of salicylic acid (SA) in sheep was evaluated following intravenous (IV) and oral administration of sodium salicylate (sodium salt of salicylic acid) at different doses. Six healthy sheep were administered sodium salicylate (SS) IV at doses of 10, 50, 100 and 200 mg/kg body weight and another six sheep were drenched with 100 and 200 mg/kg of SS orally. Both studies were randomised crossover trials. A one-week washout period between each treatment was allowed in both studies. Blood samples were collected at 0, 15, 30 min and 1, 2, 4 and 6 h after IV and oral SS administrations. Plasma SA concentrations were determined using high-performance liquid chromatography (HPLC) with diode array detection method. Pharmacokinetic variables were calculated in a non-compartmental model. The elimination half-life (T_{1/2 el}) of SA after IV administration of 200 mg/kg SS was 1.16 ± 0.32 h. Mean bioavailability of SA was 64%, and mean T_{1/2 el} was 1.90 ± 0.35 h, after 200 mg/kg of oral SS. The minimum plasma SA concentration (16.8 µg/mL) reported to produce analgesia in humans was achieved after IV administration of 100 and 200 mg/kg SS in sheep for about 0.17 h in this study. Experiments on pharmacokinetic–pharmacodynamics modelling are required to determine the actual effective plasma concentration range of SA in sheep.

Effects of vitamin E and selenium supplementation on blood lipid peroxidation and cortisol concentration in dairy cows undergoing omentopexy

Twenty dairy cows with left abomasal displacement were used to investigate the effects of vitamin E and selenium treatment on thiobarbituric acid reactive substances (TBARS) and blood cortisol in dairy cows stressed by omentopexy. The cows were randomly divided into two groups. Ten hours before surgery 6 g of DL-α-tocopheryl acetate (6 mg/kg) and 67 mg of natrium selenite (0.1 mg/kg) in volume of 40 ml (Vitaselen^® ) were administered subcutaneously to 10 cows; the control animals (n = 10) received an equivalent volume of injectable water (40 ml). The injection of vitamin E and selenium produced a rapid rise (p < .05) in blood α-tocopherol and selenium concentrations. The serum vitamin E increased several times 10 hr after vitamin E and Se injection and raised continuously to the highest average concentration 21.6 mg/L at hr 24 after the surgery. The highest selenium concentration was seen 10 hr after selenium administration with holding the increased concentrations in comparison with initial ones during the whole study. Two-way ANOVA did not show significant treatment effect on plasma concentrations TBARS in the study. The plasma concentrations of thiobarbituric acid reactive substances reached the maximum value of 0.18 μmol/L in the control group 5 hr after the surgery. Twenty-four hours after the surgery, the TBARS values returned to the initial ones. Serum cortisol increased in both groups after surgery. The highest cortisol concentrations were reached at 1 hr after surgery in the experimental and control group (56.7 ± 28.8 and 65.3 ± 26.1 μg/L respectively). A return to the levels similar to the initial ones was recognized 24 hr after the surgery. The ANOVA revealed a significant effect of vitamin E and selenium injection on plasma cortisol (p < .05). In conclusion, we have demonstrated that abdominal surgery resulted in typical stress changes with no significant effects of a single vitamin E/Se injection on blood lipid peroxidation. In addition, a weaker cortisol response to the abdominal surgery was recognized in animals treated with vitamin E and selenium.

Mitigation of electroencephalographic and cardiovascular responses to castration in Bos indicus bulls following the administration of either lidocaine or meloxicam

OBJECTIVE

To investigate the mitigating effects of administration of local anaesthetic or systemic meloxicam on the electroencephalographic (EEG) and cardiovascular responses during surgical castration of Bos indicus bull calves.

STUDY DESIGN

Prospective, randomized, experimental study.

ANIMALS

Thirty-six 6-8 month-old Bos indicus bull calves, with a mean ± standard deviation weight of 237 ± 19 kg.

METHODS

Animals were allocated randomly to three groups of 12 (group L, 260 mg of 2% lidocaine subcutaneously and intratesticularly 5 minutes prior to castration; group M, 0.5 mg kg^-1 of meloxicam subcutaneously 30 minutes prior to castration; group C, no preoperative analgesia administered). Anaesthesia was induced and maintained with halothane (0.9-1.1%) in oxygen. Electroencephalogram, heart rate (HR) and mean blood pressure (MAP) were recorded for 300 seconds prior to (baseline, B) and from the start of surgery (first testicle removal, T1). HR and MAP were compared at 10 second intervals for 90 seconds from the start of T1. Median frequency (F₅₀), spectral edge frequency (F₉₅) and total power of the EEG (P_tot) were analysed using area under the curve comparing T1 to B.

RESULTS

All EEG variables were significantly different between B and T1 (p ≤ 0.0001). No differences in F₅₀ were found between groups during T1 (p = 0.6491). F₉₅ and P_tot were significantly different between group L and groups C and M during T1 (p = 0.0005 and 0.0163, respectively). There were transient significant changes in HR and MAP in groups L and M compared to group C during the 20-50 second periods.

CONCLUSIONS

The EEG changes indicate nociceptive responses in all three groups during surgical castration, greater in group L compared to groups C and M. Both analgesics attenuated the peracute cardiovascular response. Lidocaine and meloxicam administered prior to castration attenuated these responses in Bos indicus bull calves.

CLINICAL RELEVANCE

These findings provide support for the preoperative administration of lidocaine and potentially meloxicam for castration in Bos indicus bull calves.

Effects of local anesthesia and flunixin meglumine on the acute cortisol response, behavior, and performance of young dairy calves undergoing surgical castration

This study assessed the effects of flunixin meglumine (FM) and a local anesthetic block (LA) on postcastration performance, plasma cortisol concentration, and behavior in dairy calves. Thirty 2- to 3-mo-old Holstein-Friesian bull calves were allocated to 5 treatments: castration with LA (2% lidocaine injected into the testes and subcutaneously), castration with FM (1.1mg/kg, i.v.), castration with LA+FM, castration without drugs (CC), and sham castration (SC). Castration was performed using a Newberry knife and Henderson castrating tool. Feed intake and body weight gain were recorded for 10d postcastration. Plasma cortisol concentration and behavior frequency and duration were monitored for 8h postcastration. Variables with repeated measures were analyzed using PROC MIXED (SAS Institute Inc., Cary, NC); one-way ANOVA was used for nonrepeated measures. No differences in feed intake or body weight gain were detected among groups. Calves in the CC, LA, and FM groups had transient (<60, <60, and <45 min, respectively) increases in plasma cortisol concentration after castration, with a second increase at 120 min in the LA group, whereas cortisol concentration remained at baseline in the LA+FM and SC groups. Mean cortisol concentrations were lower for calves in the LA+FM and SC groups than in the CC group. The area under the plasma cortisol concentration curve during the first 3h postcastration was greater in CC- and LA-treated calves than in SC controls. Castration without drugs was associated with higher frequencies of crouching and statue standing and less oral activity compared with SC controls. Administering LA alone before castration was associated with higher frequencies of head turning, statue standing, and postural changes, and less feeding behavior compared with SC controls. More leg lifting to groom was seen in LA+FM-treated calves than in SC controls. Calves administered FM alone before castration exhibited less crouching than CC calves, fewer postural shifts, and more feeding behavior than LA-treated calves. In summary, FM alone tended to shorten the duration of cortisol response and reduce crouching after surgical castration. Combining LA+FM eliminated the cortisol response to castration but was associated with more leg lifting behavior. Treatment with LA alone did not mitigate the cortisol response and was associated with several behavioral differences compared with SC, FM-treated, or FM+LA-treated calves. Results suggest that LA alone did not effectively control discomfort in young dairy calves castrated using the Henderson castration tool.

Effect of castration method on neurohormonal and electroencephalographic stress indicators in Holstein calves of different ages

As public concern for food animal welfare increases, a need to validate objective pain assessment tools exists in order to formulate animal welfare policies and facilitate regulatory approval of compounds to alleviate pain in livestock in the United States. The aims of this study were (1) to compare the physiological response to pain induced by surgical and nonsurgical (band) castration in calves and (2) to elucidate age-related differences in pain response of calves subjected to different castration methods. Seventy-six Holstein bull calves were blocked by age (≤8-wk and ≥6-mo-old) and randomly assigned to 1 of 4 treatment groups: control (n=20), castration by banding (n=18), cut-and-clamp surgical castration (n=20), and cut-and-pull surgical castration (n=18). Measurements included electroencephalogram, heart rate variability, infrared thermography, electrodermal activity, and concentrations of serum cortisol and plasma substance P before, during, and within 20min following castration. Electroencephalogram recordings showed desynchronization for all treatments, consistent with increased arousal; yet the magnitude of desynchronization was greatest for 6-mo-old calves castrated by cut-and-clamp. Additionally, older calves in the cut-and-pull group showed greater desynchronization than younger calves in the same group. Based on the heart rate variability analysis, 6-mo-old calves in the control or cut-and-pull castration groups showed greater sympathetic tone than younger calves in the same treatment groups. Overall, younger calves showed lower electrodermal activity than older calves. Regardless of treatment, concentrations of cortisol and plasma substance P were greater in 6-mo-old calves relative to their younger counterparts, indicating a more robust response to all treatments in older calves. In summary, neurohormonal and electroencephalographic stress responses of calves to castration were age-specific. Castration by cut-and-clamp showed the most pronounced stress response in 6-mo-old calves. These findings provide evidence that support welfare policies recommending castration at an early age and the use of analgesic compounds at the time of surgical castration especially in older calves. However, the potential long-term negative consequences of early untreated pain must be considered and warrant further investigation.

The pharmacokinetics and effects of meloxicam, gabapentin, and flunixin in postweaning dairy calves following dehorning with local anesthesia

Approved analgesic compounds in cattle are not currently available in the United States due to the lack of validated pain assessment methods and marker residue depletion studies. In this study, we compared the pharmacokinetic parameters and effect of preemptive analgesics administered to calves subjected to dehorning with local anesthesia. Holstein steers were randomly assigned to receive one of the following treatments per os (PO) or intravenously (IV) (n = 8/group): meloxicam (1 mg/kg PO), gabapentin (15 mg/kg PO), meloxicam (1 mg/kg), and gabapentin (15 mg/kg) PO, flunixin (2.2 mg/kg IV), or a placebo. Plasma drug, haptoglobin, substance P (SP) concentrations, serum cortisol concentrations, ocular thermography, mechanical nociceptive threshold (MNT), and average daily gain (ADG) were evaluated. Data were analyzed using mixed-effects models and noncompartmental pharmacokinetic analysis. Meloxicam, gabapentin, and meloxicam with gabapentin at the present doses did not reduce cortisol concentrations. Analgesic-treated calves had significantly lower plasma SP concentrations and improved ADG compared with controls. Flunixin calves had reduced circulating cortisol compared with controls. Meloxicam-treated calves showed an increase in MNT at two horn bud sites compared with the other treatments. Analgesics improved ADG and reduced biomarkers of pain, but effects differed by compound and route of administration.