Castration of Cattle
Castration of male calves intended for beef production is an ancient and common routine surgical procedure carried out in Australia and overseas. There are many reasons for castration and some of the benefits include facilitation of management, improved meat quality and fewer injuries in confinement operations by decreasing aggressive and sexual behaviours. A number of methods of castration are available but the application of rubber rings and surgery are the recommended practices in Australia. While castration may appear brutal and unnecessarily painful to the general public, the Cattle Standards and Guidelines Writing Group recently reviewed the reasons for castration and the methods used and agreed that the procedure is necessary for cattle husbandry.
Pain Management in Production Animals
Pain is a subjective experience that can only be measured indirectly and identification of pain responses can be difficult in animals such as calves as they are genetically wired to conceal pain as a survival mechanism. Studies in calves have shown that all methods of castration are acutely painful and induce pain related distress that can be divided into physiological responses, behavioural responses and a production response. Furthermore, the risk of local or systemic disease after castration is increased by stress and postsurgical immunosuppression (Coetzee et al. 2011). The assessment of pain, however, is an inexact science. The types of pain and their perception are often not understood and are known to vary at different ages and between individuals.
Meloxicam – The Drug of Choice
There is widespread acknowledgement from beef producers, consumers, and industry and government bodies that pain associated with surgical or non-surgical husbandry practices in cattle must be managed effectively (MLA website). NSAIDs prevent inflammation by inhibiting cyclooxygenase (COX) enzymes and thus the production of prostaglandins. Prostaglandins associated with the COX-2 enzyme are linked with pain and inflammation that result from tissue injury.
The NSAID meloxicam exerts anti-inflammatory, anti-exudative, analgesic and antipyretic effects. It inhibits leukocyte infiltration into the inflamed tissue and prevents bone and cartilage destruction. To a minor extent it also inhibits collagen-induced thrombocyte aggregation. Unlike traditional non-selective NSAIDs, meloxicam preferentially inhibits the activity of COX-2. The resulting decrease in prostaglandin synthesis is responsible for the therapeutic effects of meloxicam. This makes meloxicam the drug of choice for use in young calves with developing rumen function, as it will interfere less with normal homeostatic processes.
Ilium Buccalgesic OTM
Ilium Buccalgesic OTM is an APVMA registered ready-to-use formulation containing 10 mg meloxicam/mL and designed to provide pain relief in calves undergoing castration. Formulated for oral trans-mucosal (OTM) absorption, the dose volume is applied into the sulcus between the molar teeth and the inside of the cheek. A WHP of 14 days and an ESI of 21 days are approved. In a pharmacokinetic study, Ilium Buccalgesic OTM was found to be bioequivalent in area under the curve (AUC) to a meloxicam SC injection. Another study showed that there was a clear trend in the majority of variables assessed that Ilium Buccalgesic OTM resulted in pain mitigation in calves undergoing surgical castration.