All of these methods cause extensive wounds that need several weeks to heal and induce pain not only during the procedure itself but also in the longer term, impairing the well-being of calves. The most common method in Europe and the USA for disbudding of calves is the use of a hot iron other methods are using a scoop, caustic paste, rubber rings or surgical removal of the horn buds. Although the risk of injuries in herds of horned dairy cows is controllable and highly management-dependent, the keeping of horned dairy cows in loose housing is uncommon and most farmers prefer hornless cows. The most frequently used argument for disbudding calves is the protection against injuries to conspecifics and humans. In total, 94.3% in the USA and 81% of the dairy cattle in Europe are disbudded or dehorned.
The disbudding of calves is a routine intervention in dairy cattle farming. Regarding the effectiveness of isoeugenol to prevent horn growth, more studies are needed. Our results suggest that injection of isoeugenol causes less pain and thus seems to be beneficial compared to hot-iron disbudding, while clove oil was not advantageous. Tissue alterations such as swellings of the eyelids often occurred in CLOV, but less so in ISO. 12 weeks after the treatment, horn growth was prevented in about 50% of the horns in CLOV and ISO. MNT in CLOV was intermediate, with decreased values up to 3 weeks in some animals. For ISO, the decrease was less distinct and most calves’ values returned to baseline after 1–2 weeks. MNT decreased most strongly and for the longest time for BURN in most calves at least for 3 weeks. There was a treatment*time point interaction (linear mixed model, p < 0.05). MNT was measured using von Frey filaments and a pressure algometer at four locations around the horn bud. We investigated mechanical nociceptive threshold (MNT), possible tissue alterations and horn growth for up to 12 weeks after injection of 1.5 mL clove oil (CLOV), isoeugenol (ISO) or saline (CON) or after hot-iron disbudding (BURN with local anesthesia and sedation, n = 10/treatment).
Due to cytotoxic and anesthetic properties, the injection of clove oil or its component isoeugenol may be less detrimental to animal welfare. Further evaluation of the technique is warranted.Disbudding of calves is a common, painful intervention.
TOPCAT METROLOGY SKIN
The results of this study suggest that hypothermia has potential to provide distal limb analgesia in horses at skin surface temperatures below 7 ☌. Skin surface temperatures of <7 ☌ required water temperatures below 2 ☌. As the skin surface temperature decreased below 7 ☌, there was a rapid increase in the force required to elicit a response ( P = 0.036). Both forelimbs of each horse were tested one week apart.Īt skin surface temperatures above 7 ☌, there was little association between skin surface temperature and the mechanical force required to elicit a response. Limb surface temperature was measured after 30 min at each target water temperature and the mechanical force required to elicit a response (mechanical nociceptive threshold) was determined using a pneumatic actuator. A distal forelimb of each horse was cooled using water immersion at the following sequential target water temperatures: 34 ☌, 20 ☌, 10 ☌, 5 ☌, 1 ☌, 5 ☌, 10 ☌, 20 ☌. The study population consisted of eight healthy adult Standardbred horses, selected from a teaching herd. In this prospective study, the analgesic effects of regional hypothermia were assessed using mechanical nociceptive thresholds during distal limb cooling. Regional hypothermia has shown promise as analgesic in horses when used to manage painful conditions of the distal limb such as laminitis.