Wound inflammation post-orchiectomy affects the social dynamic of Nelore bulls

BACKGROUND

Confinement of cattle imposes spatial restrictions and predisposes to aversive social encounters that can lead to contusions, wounds, pain, stress, fright, and reduced productivity. Although endogenous testosterone concentrations are linked to agonistic dominance behaviors in males, it is unknown whether decreased blood testosterone concentrations after castration alter social hierarchy rank in Nelore bulls. Therefore, in this study, we investigated the impact of the surgical would inflammation post-orchiectomy on social dynamics in a group of Nelore bulls (Bos indicus). Fourteen Nelore (Bos indicus) bulls were castrated and assessed pre- and post-surgically. Parameters evaluated were agonistic (mounting, headbutting, and fighting) and affiliative (head-play) behavior, plasma testosterone concentrations, average daily weight gain (ADG), and a score for severity of post-surgical infection. Exploratory statistics included social network analysis (SNA), hierarchy rank delta (Δ), and principal component analysis (PCA). Furthermore, statistical inferences included the Wilcoxon test, multiple logistic regression models, and Spearman's correlation.

RESULTS

The social dynamic of Nelore bulls was modified after castration based on the findings of the SNA and the PCA. The moderate correlation between the postoperative inflammation level with the Δ, and the significant effect of this level in the logistic model post-castration were partially attributed to effects of pain on social relations.

CONCLUSIONS

Our findings suggest the severity of post-surgical inflammation, which has an association with pain intensity, was closely associated with changes in the social hierarchy.

Morphine-induced pruritus after epidural administration followed by treatment with naloxone in a cat

Case summary

A young male domestic shorthair cat weighing 1.6 kg was admitted to a veterinary teaching hospital for elective orchiectomy. A lumbosacral epidural injection of preservative-free morphine (0.1 mg/kg) and lidocaine (0.25 ml/kg) was performed under general anesthesia. One hour after extubation, the cat became agitated. Severe licking and biting of the hindlimbs, tail and lumbar area were observed. Pruritus was suspected and likely to be caused by epidural morphine. Acepromazine (0.02 mg/kg IM) was administered but clinical signs did not cease. Naloxone (2 µg/kg IV) was administered and clinical signs resolved within 20 mins.

Relevance and novel information

Different therapeutic approaches are available for the treatment of morphine-induced pruritus. This case describes an additional treatment option using opioid antagonism with naloxone.