Author: Kristy

Pain — no gain

Fitness gurus are fond of the phrase “no pain, no gain,” but in animal agriculture, the opposite is closer to the truth. Across livestock production, we’ve seen growing acceptance of the relationships between stress, disease and lost performance. We’re also operating in a time when consumer perceptions are evolving rapidly and playing a growing role in how we raise food animals.

Along with those trends, we’re seeing a growing interest in pain mitigation in cattle, particularly in procedures such as dehorning and castration, for improving animal welfare, health and overall performance. Veterinarians and producers have faced a challenge though, with a lack of medications labeled for pain relief in cattle in the United States.

However, provisions of the Animal Medicinal Drug Use Clarification Act (AMDUCA) allow veterinarians some flexibility in using pain medications, while research and practical experience demonstrate benefits in doing so.

Gerald Stokka, DVM, MS, a livestock stewardship specialist at North Dakota State University, says that while the choices are limited, veterinarians today have several viable options for mitigating pain, depending on whether it results from injury, chronic conditions such as lameness or procedures such as castration and dehorning.

Veterinarians have had the option to prescribe local anesthetics such as lidocaine for procedures such as castration or dehorning, but effective and affordable options for longer-term analgesia have been limited. Various opioids, α2 adrenergic agonists, aspirin and other non-steroidal anti-inflammatory drugs (NSAID) have been used, but generally have short durations, moderate effects and, in the case of opioids, are highly regulated. Flunixin meglumine is an injectable NSAID that is labeled for use in cattle as an anti-inflammatory and antipyretic in the United States and has seen considerable extra-label use in pain management. Its duration is short, however, at about six to 12 hours and must be administered intravenously which limits its efficacy for relieving longer-term pain such as from dehorning or lameness.

Longer-acting option

In recent years, veterinarians have been using the NSAID meloxicam for pain relief following procedures such as dehorning and castration. Hans Coetzee, BVSc, Cert CHP, PhD, DACVCP, DACAW, has conducted considerable research on the drug, which is in tablet form for oral administration, and says it works well, with about five days of duration from a single dose, and is inexpensive.

While on the faculty at Kansas State University, Coetzee conducted two trials with meloxicam; one was evaluating its effects on weight gains following dehorning and another measuring the incidence of bovine respiratory disease (BRD) following castration.

In the dehorning study, 12 Holstein steers, at 16 weeks of age, received either meloxicam or a placebo prior to scoop dehorning with a Barnes dehorner and thermocautery. Measured at six and 10 days post-dehorning, the treated calves gained an average of 1.6 kg per day compared with 0.8 kg for the control calves.

The castration study involved 258 cross-bred male beef calves, including 145 bulls and 113 steers. The researchers allocated the calves to groups by gender status to receive either 1 mg per kg meloxicam or 1 mg per kg of lactose monohydrate placebo. About 24 hours after arrival all calves were blood-sampled to determine meloxicam concentrations and received a dose of ceftiofur crystalline free acid, a modified-live BRD viral vaccine and an anthelmintic injection at processing. At this time, bull calves were surgically castrated using a Newberry knife. Calves were monitored twice daily for signs of BRD. Calves were individually weighed on day 0, 14 and 28. In this trial, bull calves receiving meloxicam prior to castration were almost 50 percent less likely to develop BRD compared with placebo-treated controls. Among the steers in the trial, there was no difference in BRD incidence between the meloxicam-treated group compared with untreated control steers. Normally, Coetzee notes, BRD incidence in bulls castrated upon arrival in feedyards is three times that in steers, indicating that castration at the earliest age practicable is preferred although still not widely adopted in some segments of the beef industry.

Veterinarians have been using the product in extra-label applications under provisions of AMDUCA, but the implications were somewhat unclear. Coetzee says Ohio veterinarian Fred Gingrich, with Country Roads Veterinary Services, wrote to the FDA’s Center for Veterinary Medicine (CVM) for clarification. In response, CVM provided a letter indicating pain management is a legitimate extra-label use for the drug. The CVM letter states that extra-label use of drugs “is limited to treatment modalities when the health of an animal is threatened or suffering or death may result from failure to treat. We (the CVM) consider the use of analgesics and anesthetics for the purpose of alleviating pain…an acceptable justification for using approved drugs in an extra-label manner.”

Coetzee recommends using a local anesthetic to relieve short-term acute pain when dehorning cattle, and using an NSAID such as meloxicam to address longer-term pain following the procedure. He says dairies have had good success administering meloxicam to individual calves in milk replacement 12 hours or so prior to dehorning, but the product also can be administered at the time of the procedure, assuming a local anesthetic is used to address short-term pain, as the product begins taking effect within 30 minutes.

According to the American Association of Bovine Practitioners (AABP), meloxicam is available through several commonly used distributors. Current prices for a 1,000-count bottle of 15 mg tablets means you can medicate calves at 0.45 mg/lb (1mg/kg) for less than a dime per hundredweight.

Due to the convenience and low cost of meloxicam, Coetzee says producers are more receptive to implementing pain management as part of their dehorning and castration protocols. And, he adds, producers who have used the product in dehorning have noted that treated calves appear significantly more comfortable and feed more readily in the days following dehorning compared with past experiences with calves not treated with a long-acting analgesic.

Gingrich has seen similar results in his Ohio dairy practice. He routinely uses meloxicam when dehorning dairy calves at about 4 weeks of age, in combination with lidocaine for local anesthesia.  His observations, and those of his dairy clients, are that calves exhibit less pain and generally look better a day or two after dehorning when treated with meloxicam.

He administers meloxicam at the same time as the lidocaine, just prior to dehorning, and says it begins to take effect by the time the local anesthesia wears off. Some clients administer a second dose the day after dehorning.

According to Coetzee and AABP guidelines, a conservative meat withdrawal interval of 21 days is recommended, based on the terminal plasma half-life reported in dairy calves of 40 hours, with milk withdrawal of 96 hours. The Iowa State University Veterinary Diagnostics Laboratory can provide a residue test if there is any question on the withdrawal status of animals.

Coetzee and Gingrich remind veterinarians they must follow AMDUCA guidelines, including having a valid veterinarian-client-patient relationship (VCPR) and maintaining records on animals treated, treatment dates and dosage for extra-label use of meloxicam or other pain medications in cattle.

Other applications

While more research is needed, meloxicam could provide beneficial pain relief in situations other than dehorning and castration, particularly with young cattle. Gingrich says he occasionally uses the product to provide pain relief with injured calves. For pain management in adult cattle, such as lameness cases, he prefers to use flunixin meglumine, mainly due to the shorter milk and meat withdrawal times.

Coetzee says more research is needed, but he believes the product also could provide benefits at branding time. Some research has shown limited benefits of using flunixin meglumine intravenously at branding, but that product is relatively short-acting, with six to 12 hours of duration. The four- to five-day duration of meloxicam could provide more effective relief from the lingering pain from branding.

Lameness pain

At North Dakota State University, Sarah Wagner, DVM, PhD, has conducted research on lameness in dairy cattle and pain relief for lame cattle. With lameness prevalence reaching 20 to 25 percent in some herds, she stresses prevention as a first, critical step. But when lameness occurs, placing cattle on pastures or in pens with adequate bedding can improve welfare and speed recovery. Corrective trimming techniques and the application of a foot block to the healthy claw can significantly reduce pain associated with claw lesions. When necessary for trimming or surgical procedures, intravenous regional anesthesia or ring block relieves pain and reduces movement of the treated foot.

Stokka agrees, saying veterinarians and producers should work to manage environmental conditions, providing lame animals with a softer, bedded surface and limiting movement. In some cases of chronic lameness, such as “stifled” cattle with a ruptured crucciate ligament, Stokka says the best option is to provide the animal with as much comfort as possible, providing a soft pen surface to relieve pressure on the joint and limiting movement until the animal can be culled and shipped to slaughter.

As for analgesic drug treatments, Wagner states there is evidence that ketoprofen  is an effective analgesic for lame cattle, citing studies performed in Canada evaluating cattle based on locomotion scoring and weight-shifting behavior. The NSAID, administered in an IV injection once every 24 hours, appears to significantly reduce pain associated with lameness. The product is not approved for pain relief in cattle in the United States but has an approval in Canada and is approved for use in horses in the United States. At a dosage of 3 ml per 100 kg, each treatment will cost around $17 for a mature cow.

Coetzee says early research indicates meloxicam, in combination with gabapentin, could be effective in relieving pain in cattle suffering from various types of lameness. Most importantly, he says, veterinarians have an ethical obligation to mitigate pain when possible, using medications in accordance with AMDUCA provisions and within a valid VCPR.

For this article and more on metabolizable protein in dairy rations, disease diagnostics, the “value proposition,” antibiotic residues and bovine leukosis, see the digital edition of the March-April Bovine Veterinarian.

Posted in In The Industry |

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