Beef Research News
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Evaluation of Substance P and Cortisol following castration
The study reported here was conducted to evaluate plasma concentrations of substance P (SP) and cortisol in calves after castration or simulated castration. Ten Angus-crossbred calves were acclimated for 5 days, assigned to a block on the basis of scrotal circumference, and randomly assigned to a castrated or simulated-castrated (control) group. Blood samples were collected twice before, at the time of (0 hours), and at several times points after castration or simulated castration. Vocalization and attitude scores were determined at time of castration or simulated castration. Plasma concentrations of SP and cortisol were determined by use of competitive and chemiluminescent enzyme immunoassays, respectively. Data were analyzed by use of repeated-measures analysis with a mixed model. Mean ± SEM cortisol concentration in castrated calves (78.88 ± 10.07 nmol/L) was similar to that in uncastrated control calves (73.01 ± 10.07 nmol/L). However, mean SP concentration in castrated calves (506.43 ± 38.11 pg/mL) was significantly higher than the concentration in control calves (386.42 ± 40.09 pg/mL). Mean cortisol concentration in calves with vocalization scores of 0 was not significantly different from the concentration in calves with vocalization scores of 3. However, calves with vocalization scores of 3 had significantly higher SP concentrations, compared with SP concentrations for calves with vocalization scores of 0. Similar cortisol concentrations were measured in castrated and control calves. A significant increase in plasma concentrations of SP after castration suggested a likely association with nociception. In the study reported here, we were unable to detect an increase in plasma cortisol response specifically associated with castration that has been described in the literature. However, a significant increase in plasma SP concentration was detected after castration, but additional research will be required to characterize this response. Considered together, these results suggest that simultaneous determination of plasma concentrations of SP and cortisol may be useful to differentiate between acute stress attributable to handling and prolonged distress associated with nociception. These results may have important implications for the assessment of pain in farm animals and the development of novel science based variables used to assess animal well-being in livestock production systems. Further characterization of objective pain measurements is needed for the development of less painful management practices and effective analgesic drug regimens.
Coetzee, J., B. Lubbers, S. Toerber, R. Gehring, D. Thomson, B. White, M. Apley. Plasma Concentrations of Substance P and Cortisol in Beef Calves after Castration or Simulated Castration. Am J Vet Res June 2008 69(6): 751-762
Evaluation of NSAIDS after castration
The purpose of this study was to compare efficacy of flunixin meglumine versus carprofen in controlling pain under field conditions following castration by use of an external clamping technique (Burdizzo) in calves that received epidural anesthesia. Forty male 5- to 6-month-old calves were allocated to 4 groups: castrated only (control calves; n = 8); castrated 5 minutes after epidural injection of 2% lidocaine (epidural-alone treated calves; 8), castrated after epidural anesthesia and SC administration of flunixin meglumine (epidural-flunixin treated calves; 12), and castrated after epidural anesthesia and SC administration of carprofen (epidural-carprofen-treated calves; 11 [1 calf not included]). Plasma cortisol concentration was measured before and 6, 24, and 48 hours after castration. Time of arrival at the feed trough at 24 and 48 hours was observed. Calves were observed at 24 and 48 hours for 4 pain-related behaviors. At 6 hours, control calves had significantly higher plasma cortisol concentrations, compared with baseline values and those of epidural-flunixin– and epidural-carprofen–treated calves. At 24 hours, epidural-carprofen–treated calves had significantly lower plasma cortisol concentrations, compared with control calves. At 48 hours, epidural-carprofen–treated calves had plasma cortisol concentrations that were similar to baseline values and significantly lower than epidural-flunixin– and epidural-alone–treated calves. At 24 and 48 hours, epidural-carprofen–treated calves were first to arrive at the feed trough and had fewer pain-related behaviors. Pain-related behaviors that indicated that all groups of calves in our study were affected were observed at 24 and 48 hours after castration. No calf group had a high correlation with immediate arrival at the trough (score 1) at 24 hours, suggesting that reluctance to move was increased in all calves. However, control calves and epidural-alone–treated calves had higher numbers of gait alterations and a significant delay (scores 3 and 4) in getting to the trough, compared with other calf groups. Epidural-carprofen–treated calves were the first to arrive at the feed trough and had fewer pain-related behaviors, compared with control calves, at 48 hours after castration. This finding supports the proposal, following the data on plasma cortisol concentrations, that calves that are reluctant to move are those that have more pain when forced to do it. We suggest that the reduced appetite of castrated cattle could be the consequence, among other factors, of this reluctance to move. No differences were found in the time of arrival at the feed trough and in the mean number of gait alterations between epidural-flunixin–and epidural-carprofen–treated calves. In conclusion, calves castrated by use of a castration clamp under field conditions in a feedlot have increases in plasma cortisol concentrations and pain related behaviors at 6, 24, and 48 hours after the procedure. In our study, SC carprofen administration in combination with epidural injection of lidocaine at 5 minutes before castration was efficient in improving the well-being of 5-month-old calves for at least 48 hours by reducing signs of pain. Further studies are needed to determine whether carprofen treatment alone is as efficacious as SC administration of carprofen in combination with epidural injection of lidocaine in reducing signs of pain following castration in calves.
Stilwell, G., M. Lima, D. Broom. Effects of Nonsteroidal Anti-inflammatory Drugs on Long-term Pain in Calves Castrated by Use of an External Clamping Technique Following Epidural Anesthesia. Am J Vet Res June 2008 69(6): 744-750
Effect of BVD on health and performance of feedlot cattle
The aim of this study was to investigate the effect of bovine viral diarrhea virus (BVDV) infections (unapparent acute infections and persistent infections) on the overall health and performance of feedlot cattle. Calves from 25 pens (7132 calves) were enrolled in the study. Overall and infectious disease mortality rates were significantly higher (P < 0.05) in pens categorized at arrival as positive for type I BVDV and lower in pens that were positive for type II BVDV than in negative pens. Mortality attributed to BVDV infection or enteritis was significantly more common (P < 0.05) in the pens containing persistently infected (PI) calves than in pens not containing PI calves (non-PI pens). There were no statistically detectable (P 0.05) differences in morbidity, overall mortality, average daily gain, or the dry matter intake to gain ratio between PI and non-PI pens. Although type-I BVDV infections in feedlots appear to contribute to higher mortality rates, the presence of PI calves alone does not appear to have a strong impact on pen-level animal health and feedlot performance.
Booker, C., S. Abutarbush, P. Morley, T. Guichon, B. Wildman, K. Jim, O. Schunicht, T. Pittman, T. Perrett, J. Ellis, G. Appleyard, D. Haines. The Effect of Bovine Viral Diarrhea Virus Infection on Health and Performance of Feedlot Cattle. Can Vet J March 2008 49(3): 253-260.
Cow-calf herds health associations with BVD, IBR and BVD-PIs
The objective of this research was to measure associations between health and productivity in cow-calf beef herds and persistent infection with bovine viral diarrhea virus (BVDV), antibodies against BVDV, or antibodies against infectious bovine rhinotracheitis (IBR) virus in calves.
There were 1,782 calves from 61 beef herds enrolled in the study. Calf serum samples were analyzed at weaning for antibodies against type 1 and type 2 BVDV and IBR virus. Skin biopsy specimens from 5,704 weaned calves were tested immunohistochemically to identify persistently infected (PI) calves. Herd production records and individual calf treatment and weaning weight records were collected. There was no association between the proportion of calves with antibodies against BVDV or IBR virus and herd prevalence of abortion, stillbirth, calf death, or nonpregnancy. Calf death risk was higher in herds in which a PI calf was detected, and PI calves were more likely to be treated and typically weighed substantially less than herdmates at weaning. Calves with high antibody titers suggesting exposure to BVDV typically weighed less than calves that had no evidence of exposure. BVDV infection, as indicated by the presence of PI calves and serologic evidence of infection in weaned calves, appeared to have the most substantial effect on productivity because of higher calf death risk and treatment risk and lower calf weaning weight.
Waldner, C.L., R.I. Kennedy. Associations between health and productivity in cow-calf beef herds and persistent infection with bovine viral diarrhea virus, antibodies against bovine viral diarrhea virus, or antibodies against infectious bovine rhinotracheitis virus in calves. Amer J Vet Res July 2008, Vol 69(7): 916-927.
Health effects in stocker calves after prophylactic administration of either tulathromycin or tilmicosin
Health and feed performance
parameters were compared on 293 beef stocker calves after metaphylactic
administration of antimicrobials with two different lengths of activity
(tulathromycin and tilmicosin) one day after arrival. Calves that
received metaphylactic tulathromycin displayed significant improvement
in morbidity, mortality, and first treatment success rates (P<0.05)
compared to tilmicosin calves. Tulathromycin-treated calves also showed
a significantly improved average daily gain and feed to gain ratio
(P<0.05) compared to tilmicosin-treated calves. Under conditions of this
study, calves receiving tulathromycin were healthier through a 43 day
growing phase compared to calves receiving tilmicosin. This health
difference likely accounted for the differences in feed performance
between treatment groups.
J. Nickell, B.J. White, R.L. Larson, D. Blasi, D. G. Renter. Comparison of short term health and performance effects related to prophylactic administration of either tulathromycin or tilmicosin to beef stocker calves. 2008 Vet Ther Summer 9(2) 147-156.
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