Cortisol responses of calves to two methods of disbudding used with or without local anaesthetic

Cattle are disbudded or dehorned using a variety of methods. In this study, plasma cortisol concentrations were used to monitor distress in 6-week-old Friesian calves during the 9 hours following disbudding. Disbudding was carried out with a cautery iron or a dehorning scoop, with or without local anaesthetic. Cautery caused a transient rise in cortisol concentrations which returned to control values within 3 hours. The cortisol response to the scoop was more prolonged, as the plasma cortisol concentrations did not return to control levels until 7.5 hours after disbudding. The administration of a local anaesthetic reduced the cortisol response during the first 2 hours after scoop dehorning. This reduced response was followed by a delayed rise in cortisol concentrations between 2 and 7.5 hours. Cautery caused less distress than the scoop. The administration of local anaesthetic had little effect in alleviating distress in calves disbudded using the cautery iron.     

Cortisol responses of calves to two methods of tail docking used with or without local anaesthetic

Tail docking of dairy cows to facilitate milking is carried out on calves or on heifers before calving. By monitoring changes in plasma cortisol concentrations, this study evaluated the distress in calves when docked by a rubber ring or docking iron (cautery) with or without local anaesthetic. The cortisol responses indicated that in most calves docking using a rubber ring or docking iron was no more distressing than control handling and simulated docking. A small proportion of calves in control and tail docked groups exhibited larger cortisol responses, the magnitudes of which suggested that they experienced some mild distress. There was no detectable benefit with either method of docking when local anaesthetic was used. The rubber ring is the preferable method, as there was some haemorrhage after docking with the docking iron.     

Effects of a local anaesthetic and a non-steroidal anti-inflammatory analgesic on the behavioural responses of calves to dehorning

AIMS: To evaluate the use of local anaesthesia and systemic analgesia for alleviating the distress associated with dehorning by monitoring stimulated behaviours in calves. METHODS: Eight behaviours were monitored in 3-4 month-old calves dehorned with and without local anaesthesia and/or a non-steroidal anti-inflammatory drug, from 2 hours after treatment. RESULTS: Four of the behaviours, lying, grazing or ruminating, tail shaking and ear flicking, were significantly different during the first 4-6 hours of observation in control calves, which were not dehorned, compared to calves dehorned without anaesthesia or analgesia, which suggests that these behaviours are useful indices of the acute pain experienced by calves after dehorning. The behaviour of calves dehorned after both a local anaesthetic and a non-steroidal anti-inflammatory agent had been administered was similar to control calves. The behaviour of calves given only local anaesthesia or systemic analgesia prior to dehorning was similar to that of calves dehorned without any pain relief. CONCLUSION: These results suggest that calves should be given both a local anaesthetic and a systemic analgesic before dehorning to alleviate the pain associated with this procedure.     

Effects of a local anaesthetic and a non-steroidal anti-inflammatlory analgesic on the behavioural responses of calves to dehorning

Aims. To evaluate the use of local anaesthesia and systemic analgesia for alleviating the distress associated with dehorning by monitoring stimulated behaviours in calves.

Methods. Eight behaviours were monitored in 3-4 month-old calves dehorned with and without local anaesthesia and/or a non-steroidal anti-inflammatory drug, from 2 hours after treatment.

Results. Four of the behaviours, lying, grazing or ruminating, tail shaking and ear flicking, were significantly different during the first 4-6 hours of observation in control calves, which were not dehorned, compared to calves dehorned without anaesthesia or analgesia, which suggests that these behaviours are useful indices of the acute pain experienced by calves after dehorning. The behaviour of calves dehorned after both a local anaesthetic and a non-steroidal anti- inflammatory agent had been administered was similar to control calves. The behaviour of calves given only local anaesthesia or systemic analgesia prior to dehorning was similar to that of calves dehorned without any pain relief.

Conclusion. These results suggest that calves should be given both a local anaesthetic and a systemic analgesic before dehorning to alleviate the pain associated with this procedure.     

Behavioural responses of calves to amputation dehorning with and without local anaesthesia

OBJECTIVE: To assess the pain elicited by amputation dehorning and evaluate the effect of local anaesthesia by using changes in calf behaviour. METHODS: The behaviour of 6-month-old Friesian calves (n = 60), subjected to control handling, dehorned or dehorned after local anaesthesia treatment, was monitored in this study. The proportion of calves displaying particular behaviours was recorded using instantaneous scan sampling during the first 10 h and between 26 and 29 h after treatment. RESULTS: The three behaviours of tail flicking, head shaking and ear flicking displayed similar features with time according to treatment and appeared to occur in an inverse relation to rumination. Dehorned calves were highly restless for the first 6 h after treatment. A significantly greater proportion of them displayed tail flicking, head shaking and ear flicking than the control calves, which, by contrast, stood still and ruminated (P < 0.05). The behaviour of calves given local anaesthetic prior to dehorning was similar to that of the control calves for the first 2 h. Thereafter the proportion of calves displaying tail flicking, head shaking and ear flicking increased, rumination decreased, and the behaviour was similar to that of the dehorned calves. CONCLUSIONS: These results suggest that dehorning is a painful experience that lasts about 6 h and that local anaesthetic alleviates that pain during its period of action. It is recommended that local anaesthetic be administered when conducting amputation dehorning.     

Effect of local anaesthetic combined with wound cauterisation on the cortisol response to dehorning in calves

OBJECTIVE: To reassess whether local anaesthesia before dehorning and wound cauterisation after dehorning eliminates the cortisol response to dehorning. METHODS: A control group was compared with three dehorned groups (dehorned alone, dehorned after local anaesthesia, dehorned after local anaesthesia then cautery of the amputation wounds). The local anaesthetic regimen used produced nerve blockade for about 5 h. Blood samples were taken before and after dehorning and plasma cortisol concentrations were determined. RESULTS: Dehorning caused a marked cortisol response lasting for about 7 h. Local anaesthetic reduced the plasma cortisol concentrations to control values for 5 h, after which they increased for a further 5 h. Subsequently in both groups, cortisol concentrations remained at control values until at least 24 h after treatment. Local anaesthetic combined with wound cautery virtually abolished the cortisol response until at least 24 h after dehorning. CONCLUSION: Combining local anaesthesia with cautery of the amputation wounds substantially reduced the cortisol response until at least 24 h after dehorning.     

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound

Objective To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.
Design A physiological study with controls.
Procedure There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.
Results Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.
Conclusions If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.     

The effect of different combinations of lignocaine,ketoprofen, xylazine and tolazoline on the acute cortisol response to dehorning in calves

AIMS: The aims of this study were (a) to evaluate the effect of xylazine and tolazoline, with and without lignocaine, on the cortisol response of calves following amputation dehorning and (b) to assess the effect of a non-steroidal anti-inflammatory drug (ketoprofen) and local anaesthesia on the cortisol response of calves to amputation dehorning.

METHODS: Plasma cortisol concentrations were measured in 100 dehorned or non-dehorned 3-month-old calves over an 8-h period following five different sedative/analgesic or control treatments. Sedative/analgesic treatments were: control (no anaesthesia); local anaesthesia and ketoprofen; local anaesthesia and xylazine; local anaesthesia, xylazine and tolazoline; and xylazine only. Within each sedative/analgesic treatment group, half the calves (n=10 per group) were amputation dehorned and half were not dehorned.

RESULTS: The change in plasma cortisol concentrations in calves dehorned after being given ketoprofen and local anaesthesia did not differ significantly from that of non-dehorned control calves for at least 8 h. In contrast, the cortisol response of dehorned calves not given analgesic drugs peaked 30 min after dehorning and lasted >4 h. Xylazine injected before dehorning significantly reduced but did not eliminate the peak of the cortisol response. When both xylazine and local anaesthesia were administered before dehorning the peak in the cortisol response was virtually eliminated. In the dehorned calves that received xylazine with or without local anaesthesia, cortisol concentration increased significantly 3 h after dehorning and did not return to baseline until at least 5 h later. When tolazoline was administered shortly after xylazine, it caused a marked cortisol response, higher than the response to any other treatment.

CONCLUSIONS: Combining ketoprofen and local anaesthesia minimised the cortisol response, and by inference the pain- induced distress, following amputation dehorning in calves. Xylazine reduced the initial cortisol response to dehorning but not as much as when local anaesthesia was also given. The increase in cortisol concentration from 3–8 h after dehorning in calves given xylazine alone or in combination with local anaesthesia suggests that calves experienced pain-induced distress during this time and that xylazine had no long-term analgesic effect. Tolazoline, used to reverse the sedative effects of xylazine, caused a marked cortisol response in calves via a mechanism which remains unclear.     

The effect of different combinations of lignocaine, ketoprofen, xylazine and tolazoline on the acute cortisol response to dehorning in calves

AIMS: The aims of this study were (a) to evaluate the effect of xylazine and tolazoline, with and without lignocaine, on the cortisol response of calves following amputation dehorning and (b) to assess the effect of a non-steroidal anti-inflammatory drug (ketoprofen) and local anaesthesia on the cortisol response of calves to amputation dehorning. METHODS: Plasma cortisol concentrations were measured in 100 dehorned or non-dehorned 3-month-old calves over an 8-h period following five different sedative/analgesic or control treatments. Sedative/analgesic treatments were: control (no anaesthesia); local anaesthesia and ketoprofen; local anaesthesia and xylazine; local anaesthesia, xylazine and tolazoline; and xylazine only. Within each sedative/analgesic treatment group, half the calves (n=10 per group) were amputation dehorned and half were not dehorned. RESULTS: The change in plasma cortisol concentrations in calves dehorned after being given ketoprofen and local anaesthesia did not differ significantly from that of non-dehorned control calves for at least 8 h. In contrast, the cortisol response of dehorned calves not given analgesic drugs peaked 30 min after dehorning and lasted >4 h. Xylazine injected before dehorning significantly reduced but did not eliminate the peak of the cortisol response. When both xylazine and local anaesthesia were administered before dehorning the peak in the cortisol response was virtually eliminated. In the dehorned calves that received xylazine with or without local anaesthesia, cortisol concentration increased significantly 3 h after dehorning and did not return to baseline until at least 5 h later. When tolazoline was administered shortly after xylazine, it caused a marked cortisol response, higher than the response to any other treatment. CONCLUSIONS: Combining ketoprofen and local anaesthesia minimised the cortisol response, and by inference the pain-induced distress, following amputation dehorning in calves. Xylazine reduced the initial cortisol response to dehorning but not as much as when local anaesthesia was also given. The increase in cortisol concentration from 3-8 h after dehorning in calves given xylazine alone or in combination with local anaesthesia suggests that calves experienced pain-induced distress during this time and that xylazine had no long-term analgesic effect. Tolazoline, used to reverse the sedative effects of xylazine, caused a marked cortisol response in calves via a mechanism which remains unclear.     

Effects of ketoprofen alone or in combination with local anesthesia during the castration of bull calves on plasma cortisol,immunological, and inflammatory responses

To determine the effects of the anti-inflammatory ketoprofen, alone or with local anesthesia (LA) during castration on cortisol, immune, and acute phase responses, 40 Friesian calves (215 +/- 3.5 kg) were assigned as follows: 1) control, 2) surgical castration (SURG), 3) SURG following ketoprofen (3 mg/kg BW i.v.; SURG + K), 4) SURG following LA (9 mL of 2% lidocaine hydrochloride to each testis; SURG + LA), or 5) SURG following LA and K (SURG + LA + K). Total cortisol response was greater (P < 0.05) in SURG, SURG + LA, and SURG + K + LA calves than in control calves and was not different between control and SURG + K calves. The interval to peak cortisol was longer (P < 0.05) for SURG + K + LA calves than for either SURG or SURG + K calves. On d 3, KLH-induced interferon-gamma production was lower (P < 0.05) in SURG calves than in control calves, whereas concanavalin A-induced interferon-gamma production was lower (P < 0.05) in all castration groups than in control. On d 1 after surgery, fibrinogen was higher (P < 0.05) in SURG and SURG + LA calves than in control calves, whereas SURG + LA + K calves had lower (P < 0.05) fibrinogen than did SURG calves. Haptoglobin was higher (P < 0.05) in SURG calves on d 1, 3, and 7 than in control calves. On d 1 after surgery, SURG + K and SURG + LA + K calves had lower (P < 0.05) haptoglobin concentrations than SURG calves, whereas SURG + K calves had lower (P < 0.05) levels than SURG calves on d 3. In conclusion, surgical castration induced a significant elevation in cortisol secretion; the rise in cortisol was reduced to control levels by the administration of ketoprofen but not local anaesthetic. Thus, systemic analgesia using ketoprofen is more effective than local anesthesia during castration to alleviate the associated stress response.     

Acute cortisol responses of lambs to castration using a rubber ring and/or a castration clamp with or without local anaesthetic

Changes in plasma cortisol concentrations during the first 4 hours after castration of 6-week-old lambs by one of four methods were measured. The methods were application of a rubber ring above the testes, application of a ring to shorten the scrotum below the testes, use of a castration clamp plus a ring, and use of a castration clamp alone. The efficacy of local anaesthetic in reducing or abolishing the cortisol responses to castration by all these methods except short scrotum was assessed. Local anaesthetic was injected into the neck of the scrotum, both spermatic cords, the scrotal neck plus spermatic cords, or into both testes. The combined clamp plus ring method was used to test whether or not clamp damage to afferent nerves from the testes would reduce the cortisol response to ring castration. The short scrotum method elicited a significantly lower cortisol response than that caused by ring castration. Injection of local anaesthetic into both spermatic cords marginally reduced the cortisol response to ring castration, but the response was virtually abolished by prior scrotal neck, or scrotal neck plus spermatic cords, or intra-testicular local anaesthetic injections. The clamp plus ring method, where each spermatic cord and the associated scrotal tissue were crushed separately for 1, 5 or 10 seconds with no overlap between the two crush lines, did not elicit lower cortisol responses than the ring-only method. Local anaesthetic injected into the scrotal neck virtually abolished, and spermatic cord injections markedly reduced, the cortisol responses to combined clamp plus ring castration. The IO-second clamp application caused a more protracted cortisol response than did ring-only castration, whereas the cortisol responses to 1-second clamp application and to ring-only castration were similar. Local anaesthetic injected into the scrotal neck or spermatic cords did not affect significantly the cortisol response to the IO-second clamp application. The following conclusions were drawn from this work: the testes as well as the scrotum were sources of noxious sensory input after ring application; the clamp plus ring method used here was ineffective in reducing the pain-induced distress (as indicated by cortisol concentrations) caused by ring-only castration; injection of local anaesthetic into the scrotal neck or into the testes prior to ring application blocked most noxious sensory input from both the scrotum and the testes; and on the basis of the present cortisol responses the 10-second clamp applications method could not be recommended in reference to the ring-only method, but the l-second clamp application method might be equally acceptable for castrating 6-week-old-lambs. Of the methods examined, injections of local anaesthetic into the scrotal neck or both testes were the most effective in reducing the pain-induced distress caused by ring-only castration.     

Effects of a topical anaesthetic formulation and systemic carprofen, given singly or in combination, on the cortisol and behavioural responses of Merino lambs to castration

Objective   To determine the effectiveness of a topical anaesthetic formulation (Tri-Solfen) with or without the administration of a non-steroidal anti-inflammatory drug (carprofen) on the pain and distress response associated with ring or surgical castration of ram lambs.
Procedures   Merino ram lambs (n = 78) were allocated to 10 treatment groups: 4 groups of knife-castrated lambs and 4 groups of ring-castrated lambs received carprofen (4 mg/kg SC) and Tri-Solfen; 2 control groups (sham) received carprofen at 0 or 4 mg/kg SC. Measurements included plasma cortisol and haptoglobin concentrations, haematology, and behaviour, including posture.
Results   Knife-castrated lambs had higher peak cortisol and integrated cortisol responses for the first 6 h after treatment and greater concentration s of circulating acute phase proteins than ring-castrated lambs, both of which were significantly different from the sham controls. Tri-Solfen applied to the knife castration wound significantly reduced both the peak plasma cortisol concentration and the integrated cortisol response for the first 6 h and improved lying behaviour in the first 12 h. Carprofen reduced the cortisol response to knife castration at 30 min, but elevated the cortisol responses at 24 and 48 h. Carprofen nearly halved the number of acute pain behaviours associated with ring castration. There were no significant additive or synergistic effects from combining the analgesic treatments. Tri-Solfen applied to the tail wound provided no detectible benefits during ring castration + tail docking.
Conclusions   The physiological and behavioural responses suggest that ring castration has less impact on the lamb than knife castration. The specific analgesic treatments can provide modest amelioration of the pain and discomfort associated with castration. Alternative doses or application methods may enhance their efficacy.     

Effects of local anaesthesia or local anaesthesia plus a non-steroidal anti-inflammatory drug on the acute cortisol response of calves to five different methods of castration

The cortisol response of calves to different methods of castration (ring, band, surgical, clamp) with or without local anaesthetic, or local anaesthetic plus a non-steroidal anti-inflammatory drug were recorded. All methods of castration caused a significant cortisol response and by inference pain and distress. Band castration caused a greater cortisol response than ring castration but the responses were eliminated by local anaesthetic. The cortisol response to surgical castration, by traction on the spermatic cords or by cutting across them with an emasculator, was not diminished by local anaesthetic but when ketoprofen was given with local anaesthetic the cortisol response was eliminated. Local anaesthetic did reduce the behavioural response to cutting the scrotum and handling the testes. Clamp castration caused the smallest cortisol response which was reduced or eliminated by local anaesthetic or local anesthetic plus ketoprofen respectively, but this method of castration was not always successful.     

Effects of a topically applied anaesthetic on the behaviour,pain sensitivity and weight gain of dairy calves following thermocautery disbudding with a local anaesthetic

ABSTRACT

Aims: To compare the effect of a topically applied anaesthetic to no pain relief or meloxicam on the behavioural responses, pain sensitivity and weight gain of calves following disbudding with or without sedation.

Methods: A total of 364, 2–6 week-old calves from three commercial farms were systematically allocated to one of six treatment groups. All calves received a cornual nerve block prior to disbudding, with half restrained in a crate and half sedated with xylazine. Within these groups one third received no further treatment (control), one third were treated with meloxicam >10?minutes prior to disbudding and one third received a topical anaesthetic applied to the horn bud wounds following disbudding. The frequency of ear flicks, head shakes, head scratches and pain sensitivity of the wound were recorded on up to eight occasions over 24 hours after disbudding. Calves were weighed before, and 7 and 28 days after, disbudding to determine average daily weight gain (ADG).

Results: Compared to calves in the crate-control group, all other groups had reduced ear flicks at all times following disbudding (p?<?0.01). Treatment with meloxicam and topical anaesthesia in addition to sedation reduced head scratches compared to calves in the crate-control group (p?≤?0.013). At 22 hours after disbudding head shakes were reduced in sedated calves treated with topical anaesthetic compared to calves in the crate-control group (p?<?0.001). Pain sensitivity was lower in all sedated calves than unsedated calves (p?<?0.001). The ADG between Days 0–7 was 0.14 (95% CI?=?0.015–0.274) kg/day greater in sedated calves treated with meloxicam than calves in the crate-control group (p?=?0.03), and the ADG between Days 0–28 tended to be 0.06 (95% CI=?0.01–0.13) kg/day greater in sedated calves treated with topical anaesthetic than calves in the crate-control group (p?=?0.09).

Conclusion and clinical relevance: Sedation of calves for disbudding reduced the pain experienced in the following 24 hours. There was a benefit to providing calves with topical anaesthetic following disbudding on behavioural responses and pain sensitivity, which was similar to that of treating calves with meloxicam.     

Effect of iodine,selenium and cobalt rumen boluses given to dry dairy cows on the immunoglobulin and thyroid hormone status of calves

The objective was to determine the effect of rumen boluses containing 6800 mg iodine, 1000 mg selenium and 1000 mg cobalt given to dry dairy cows on the efficiency of colostral immunoglobulin G (IgG) absorption in calves. Thirteen cows received the bolus approximately 58 days before calving. A further 12 cows received no bolus and were used as controls. The cows were housed as one group. Calves were prevented from suckling for the first 24 h of life, and were given three feeds of a fixed quantity of colostrum. At 24 h, the average plasma concentrations of IgG in the calves were 15.5 and 13.4 g/L for the control and bolus groups, respectively; these were not significantly different (P = 0.212). Bolus treatment was associated with higher levels of free and total tri‐iodothyronine (T3) and thyroxine (T4) in the dams (all P < 0.001), although it had no effect on thyroid hormone levels in the calves. There were nevertheless positive and negative relationships between the efficiency with which colostral IgG was absorbed at 24 h and, respectively, total T3 at 24 h (P < 0.05) and total T4 at 1 h of age (P < 0.05). The underlying basis for these relationships remains to be established.     

The effect of a topical anaesthetic formulation, systemic flunixin and carprofen, singly or in combination, on cortisol and behavioural responses of Merino lambs to mulesing

OBJECTIVE: To determine the pain responses of lambs to mulesing, and the effectiveness of potential analgesic treatments. PROCEDURES: Merino lambs (n=64) were allocated at 5 weeks of age to eight treatment groups: 1) sham mules; 2) conventional mules; 3) topical anaesthetic, incorporating lignocaine, bupivicaine, adrenaline and cetrimide, applied immediately after mulesing; 4) flunixin + topical anaesthetic, with flunixin administered 2.5 mg/kg s.c. 90 min before mulesing; 5) carprofen + topical anaesthetic, with carprofen administered 4 mg/kg s.c. 90 min before mulesing; 6) carprofen, administered as above; 7) flunixin, administered as above; and 8) carprofen + flunixin, administered as above. Plasma cortisol was measured at 0, 0.5, 6, 12 and 24 h relative to mulesing. Animal behaviour, including posture, was recorded for 12 h after mulesing. RESULTS: The conventional mules lambs exhibited large increases in plasma cortisol, reduced lying and increased standing with a hunched back compared with sham mules animals. Topical anaesthetic reduced the cortisol peak to mulesing and hunched standing, and increased lying compared with the conventional mules treatment, but generally did not result in values equivalent to sham mules animals. Carprofen, flunixin, and carprofen + flunixin treatments did not reduce the cortisol response to mulesing but substantially ameliorated some changes in behavioural postures. Flunixin + topical anaesthetic reduced the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. Carprofen + topical anaesthetic abolished the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. All mulesed animals lost weight in the week after mulesing regardless of analgesic administration, but there were no significant differences in growth rate between any of the eight treatments over the 3 weeks after mulesing. CONCLUSIONS: Analgesics can moderate the pain response of lambs to mulesing. The welfare outcome for lambs of mulesing could be improved by use of a combination of local anaesthetic and long acting non-steroidal anti-inflammatory drug.     

Evaluation of radiology as a tool to diagnose pulmonic lesions in calves, for example prior to experimental infection studies

The aim of the study was to evaluate radiology as a technique to visualize pulmonary lesions in young calves, e.g. as a selection criterion for research animals in order to eliminate animals with lung lesions prior to experimental studies of pneumonia. Five calves with acute clinical signs of pneumonia were included in a direct comparative study of radiological and post mortem findings. Also, a number of animals with no signs of pneumonia were included as controls. The study revealed good agreement between the radiological and post mortem findings. Thus, in conclusion, radiology should be considered as a useful objective tool to predict the presence of pulmonary lesions in young calves.     

Luteolysis, onset of estrus, and ovulation in Holstein heifers given prostaglandin F2α concurrent with, or 24 hours prior to, removal of an intravaginal, progesterone-releasing device

The objective was to determine the effects of giving prostaglandin F2alpha (PGF) concurrent with, or 24 h before, removal of an intravaginal, progesterone-releasing (controlled internal drug release [CIDR]) device, on luteolysis, the synchrony of estrus and ovulation. Eighteen postpubertal Holstein heifers were given a CIDR and 100 microg gonadotropin releasing hormone (GnRH) and equally allocated to 3 groups. The PGF was given concurrently with CIDR removal after 7 or 8 d (groups D7/D7 and D8/D8, respectively) or given 1-d before removal of CIDR after 8 d (group D7/D8). There was no difference (P > 0.75) among groups in the intervals (h) from CIDR removal to onset of standing estrus and to ovulation (49.3 h+/-6.2 h and 77.5 h+/-9.0 h, respectively; least squares means+/-standard error of means). We also determined if stage of the estrus cycle influenced the synchrony of estrus or ovulation. In heifers in metestrus at CIDR insertion (versus those at estrus or diestrus), intervals from CIDR removal to estrus and to ovulation were longer by 33.4 h (P < 0.05) and 38.5 h (P = 0.01), respectively. However, the interval from standing estrus to ovulation was not affected. Giving PGF concurrent with CIDR removal did not affect luteal regression, the synchrony of estrus, and ovulation; but heifers in metestrus at the initiation of treatment had longer intervals from CIDR removal to estrus and ovulation.     

Effect of pinealectomy on prolactin, testosterone and luteinizing hormone concentration in plasma of bull calves exposed to 8 or 16 hours of light per day

Pineal tissue was removed from eight 6-wk-old bull calves (PX), whereas eight similar calves received sham pinealectomies (SPX). Before and after surgery, calves received 8 h of light (L):16 h of darkness (D) daily until 20 wk of age (wk 0 of experiment), at which time eight calves (four PX and four SPX) were maintained under 8L:16D for 12 additional wk, whereas the remaining eight calves received 16L:8D. At 0, 4, 8 and 12 wk of experiment, blood was collected from each animal for 26 h at 30-min intervals. Melatonin in SPX calves at wk 12 increased from 16.2 pg/ml of plasma when lights were on to 81.6 pg/ml during lights off, whereas in PX calves the nocturnal increase was absent. However, the nocturnal surge did occur in three PX calves on 8L:16D treatment, and those animals were excluded from calculations and analysis. At wk 0, prolactin (PRL) averaged 47 ng/ml among all calves. By wk 4 PRL increased (P less than .01) to 80 and 96 ng/ml in PX and SPX calves receiving 16L:8D, respectively; PRL averaged 53 and 48 ng/ml, respectively in PX and SPX calves maintained on 8L:16D. Prolactin was greater (P less than .05) through wk 12 in PX (64 ng/ml) and SPX (64 ng/ml) calves receiving 16L:8D than in calves exposed to 8L:16D, which remained unchanged (54 and 48 ng/ml). Testosterone was unaffected by photoperiod, but tended to be less (P = .13) in plasma of PX than of SPX calves at wk 0 (.90 vs 1.45 ng/ml of plasma).(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute cortisol responses and wound healing in lambs after ring castration plus docking with or without application of a castration clamp to the scrotum

OBJECTIVE: To test whether the cortisol response to ring castration plus docking is reduced by additional application of a castration clamp across the full width of the scrotum distal to the ring. DESIGN: A physiological study with controls. PROCEDURE: Lambs, 3 to 6 weeks of age, were castrated using a ring or ring plus castration clamp applied for 6 or 10 s and docked using a ring. Blood samples were taken before and regularly for about 4 h after treatment and analysed for plasma cortisol concentrations. The healing of the scrotal wounds was monitored for 6 weeks after castration. RESULTS: The plasma cortisol concentrations were lower only at 60 min after treatment in lambs castrated with a clamp placed on the scrotum for 10 s after ring castration and docking than in lambs castrated and docked by ring alone. Scrotal wounds healed more quickly after ring plus clamp than after ring only castration. CONCLUSIONS: The castration clamp had at most a marginal effect on the cortisol response to ring castration and docking of 3- to 6-week-old lambs, but it did seem to improve the rate of healing.