Acute post-orchiectomy pain does not reduce alpha rams' interest in feed resources

Area of Science:

• Animal Welfare Science
• Veterinary Ethology
• Sheep Husbandry

Background:

• Assessing sheep pain is crucial for animal welfare, often relying on behavioral indicators like appetite.
• Dominant (alpha) male sheep have feeding priority, but the impact of pain on their feed interest within a social hierarchy is not well understood.

Purpose of the Study:

• To investigate the effects of acute post-orchiectomy pain on the feed interest of alpha rams accessing a limited, desirable feed resource.

Main Methods:

• Eighteen rams were housed in groups of three, establishing social hierarchies (alpha, beta, gamma).
• Behavioral tests measured feed interest (latency, frequency, duration) before and after castration.
• The Unesp-Botucatu sheep acute pain scale (USAPS) was used to assess pain levels.

Main Results:

• Alpha rams exhibited the highest social hierarchical index.
• While pain scores increased in alpha rams post-surgery, their latency, frequency, and duration of feed access remained unchanged compared to beta and gamma rams.
• Acute post-orchiectomy pain did not decrease alpha rams' interest in accessing the limited feed resource.

Conclusions:

• Dominance dynamics may confound appetite-related behaviors when assessing acute pain in sheep.
• Routine feeding presents an opportunity for pain detection using the USAPS, but dominance needs consideration.
• Alpha rams' interest in limited feed was not affected by acute post-orchiectomy pain in this study.