Evaluation of the impacts of spaying by either the dropped ovary technique or ovariectomy via flank laparotomy on the welfare of Bos indicus beef heifers and cows.

The welfare outcomes for Bos indicus cattle (100 heifers and 50 cows) spayed by either the dropped ovary technique (DOT) or ovariectomy via flank laparotomy (FL) were compared with cattle subjected to physical restraint (PR), restraint by electroimmobilization in conjunction with PR (EIM), and PR and mock AI (MAI). Welfare assessment used measures of morbidity, mortality, BW change, and behavior and physiology indicative of pain and stress. One FL heifer died at d 5 from peritonitis. In the 8-h period postprocedures, plasma bound cortisol concentrations of FL, DOT, and EIM cows were not different and were greater (P<0.05) than PR and MAI. Similarly, FL and DOT heifers had greater (P<0.05) concentrations than PR and MAI, with EIM intermediate. Creatine kinase and aspartate aminotransferase concentrations were greater (P<0.05) in FL and EIM heifers compared with the other treatments, with a similar pattern seen in the cows. Haptoglobin concentrations were significantly (P<0.05) increased in the FL heifers compared with other treatments in the 8- to 24-h and 24- to 96-h periods postprocedures, and in cows were significantly (P<0.05) increased in the FL and DOT compared with PR in the 24- to 96-h period. Behavioral responses complemented the physiological responses; standing head down was shown by more (P<0.05) FL cows and heifers to 3 d postprocedures compared with other treatments, although there was no difference between FL and DOT heifers at the end of the day of procedures. At this same time, fewer (P<0.05) FL and DOT heifers and cows were observed feeding compared with other treatments, although in cows there was no difference between FL, DOT, and EIM. There were no significant differences (P>0.05) between treatments in BW changes. For both heifers and cows, FL and DOT spaying caused similar levels of acute pain, but FL had longer-lasting adverse impacts on welfare. Electroimmobilization during FL contributed to the pain and stress of the procedure. We conclude that: i) FL and DOT spaying should not be conducted without measures to manage the associated pain and stress; ii) DOT spaying is preferable to FL spaying; iii) spaying heifers is preferable to spaying cows; and iv) electroimmobilization causes pain and stress and should not be routinely used as a method of restraint.