Julie Berry is a freelance science writer. In this week's blog, she shares her observations from the recent Center for Food Integrity's Food Summit held in Chicago, IL.
By Guest Blogger: Julie Berry, Science Writer, BS, Cornell University, MA, Johns Hopkins University
An article published recently in the American Journal of Veterinary Research evaluated practical and cost-effective ways to reduce pain and distress from castration and dehorning in Holstein calves.
“Negative public perception of procedures involved with castration and dehorning is mounting, with calls for the development of practices that minimize pain associated with common husbandry practices. Use of analgesic and anesthesia during painful procedures such as castration and dehorning has been suggested by organizations such as the AVMA, however, FDA-approved drugs labeled for the treatment of pain in animals do not currently exist,” wrote the study authors.
This study evaluated cortisol levels of 40 2-to-4 month old calves after dehorning and castration or sham dehorning and castration. Cows are prey animals, and will conceal pain, but plasma cortisol levels rise in response to pain or distress. Castration by surgery and hot iron dehorning are known to increase plasma cortisol concentration.
“The process of evaluating pain is especially complex in prey species, such as cattle, that inherently conceal pain,” wrote the study authors.
Plasma cortisol levels peak 30 minutes after dehorning, and plateau for 5 to 6 hours. Xylazine, ketamine, and butorphanol (XKB) administered intramuscularly had peak effectiveness at 10 minutes, but effectiveness decreases 1 hour after treatment. Salicylate (SAL) was dissolved in free choice water, mixed with molasses to increase palatability, at a concentration of 2.5 to 5 mg of SAL/ml.
“Results indicated that the treatment of cattle prior to castration and dehorning with SAL alone or in combination with XKB increased ADG and decreased circulating cortisol concentration,” wrote the study authors.
And, the study found that calves that received pain relievers grew better.
“ADG was significantly greater for 13 days after castration and dehorning in calves receiving SAL in drinking water provided ad libitum. This effect may in part be attributable to prolonged analgesic effects by the drugs but may also be due to the anti-inflammatory effects,” wrote the study authors. “Co-administration of XKB alone or in combination with salicylate in drinking water attenuated the cortisol response after castration and dehorning. Furthermore, ADG in calves that received free-choice salicylate was significantly greater than in the calves in the placebo and XKB groups, suggesting NSAID treatment in water may mitigate negative performance effects associated with castration and dehorning in calves.”
“Furthermore, possible production benefits resulting from that increase in ADG would likely make the addition of analgesic treatments to castration and dehorning protocols more cost-effective.”
According to the study, aspirin has a recommended meat and milk withdrawal of 24 hours, and further studies are needed to evaluate tissue withdrawals when SAL is used as it was in the study. Xylazine administered at a dose of 0.05 to 0.30 mg/kg has a recommended withdrawal of 4 days in meat and 24 hours in milk. The Food Animal Residue Avoidance Databank suggests withdrawal times for ketamine at dosages up to 10 mg/kg IM be 3 days for meat and 28 hours for milk. Butorphanol has a suggested withdrawal time of 48 hours. Pain management practices should be implemented under the supervision of a veterinarian.
“Use of SAL is only permitted in an approved formulation under the supervision of a veterinarian to alleviate suffering, provided use does not result in a violative tissue residue.”
“Pharmokinetics and physiologic effects of intramuscularly administered xylazine hydrochloride-ketamine butorphanol tartrate alone or in combination with orally administered sodium salicylate on biomarkers of pain in Holstein calves following castration and dehorning” was co-authored by Sarah L Baldridge, DVM, MS; Johann F Coetzee, BVSc, PhD; Steve S Dritz, DVM, PhD; James B Reinbold, DVM, PhD; Ronette Gehring, BVSc, MMedVet; James Havel, BS; and Butch Kukanich, DVM, PhD.
Are there other ways to make dehorning pain relief practical and cost-effective?