Lumpy jaw in wild sheep and its evolutionary implications.

Area of Science:

• Veterinary Pathology
• Wildlife Biology
• Evolutionary Biology

Background:

• Mandibular osteomyelitis, commonly known as lumpy jaw, affects various Ovis species.
• Dental anomalies and their prevalence in wild and domesticated sheep populations are not well-documented globally.

Purpose of the Study:

• To investigate the distribution and prevalence of lumpy jaw in wild sheep populations.
• To assess the biological and evolutionary implications of lumpy jaw in Ovis spp.
• To compare lumpy jaw prevalence between North American and Eurasian wild sheep, and domesticated breeds.

Main Methods:

• Analysis of 3,363 wild sheep mandibles and 1,028 domesticated sheep mandibles.
• Geographical and subspecies-level prevalence assessment of lumpy jaw.
• Correlation analysis between subspecies evolutionary age and lumpy jaw susceptibility.

Main Results:

• Lumpy jaw is widespread in North American wild sheep (e.g., Dall's sheep 23.3%, Stone's sheep 29.3%) but rare in Eurasian wild sheep (0-7.1%).
• Thinhorn sheep (Ovis dalli) showed higher prevalence than bighorn sheep (Ovis canadensis).
• An inverse relationship observed between subspecies evolutionary age and lumpy jaw susceptibility in thinhorn sheep; females more susceptible than males.

Conclusions:

• Lumpy jaw poses a significant health issue for North American wild sheep, with varying prevalence across subspecies.
• Geographical and evolutionary factors appear to influence lumpy jaw susceptibility in wild sheep.
• Further research is needed to clarify the impact of lumpy jaw on sheep longevity and horn development.