Modestly Improved Compliance and Apparent Comfort of Horses With Aversions to Mildly Aversive Routine Health Care Procedures Following Short-Term Alpha-Casozepine Supplementation

Alpha-casozepine, a decapeptide derived from bovine milk α-S1 casein, has well-documented anxiolytic properties in several species. To evaluate potential benefit of alpha-casozepine to horses' compliance and comfort with routine management and health care procedures, we blindly compared behavior of alpha-casozepine-supplemented and control-supplemented horses with known specific aversions to specific health care procedures. Twenty-six light horse mares were first screened for aversions based on compliance and apparent comfort during a standard battery of 12 health care examinations and treatment procedures. Based on quantitative behavioral analysis of video-recorded sessions, baseline compliance and/or comfort with each procedure was scored from 0 (unable to progress) to 10 (excellent compliance and relaxed comfort). Based on those results, 10 of the 26 horses were selected as five pairs that were matched for breed and the same two specific aversions. One of each pair was randomly assigned to alpha-casozepine supplementation (2,000 mg PO daily) and the other to control supplement for 5 days. On day 5 of supplementation, the standard battery of 12 procedures was repeated. For the five alpha-casozepine-supplemented subjects, compliance and/or comfort scores improved for seven of their 10 aversions compared with one of 10 for the five matched controls (P < .01, Fisher Exact). Average score increased 1.5 (standard error [SE] = 0.87) points for alpha-casozepine aversions compared with an average decrease of 0.92 (SE = 0.61) points for matched control aversions (P < .05, Wilcoxon signed ranks). These results indicate a modest benefit of alpha-casozepine supplementation to horses for improvement of compliance and apparent comfort with mildly aversive routine health care procedures.