Risk factors for dystocia in farmed red deer (Cervus elaphus)

Objective To analyse data from a study of deer herd health and productivity to identify potential risk factors for the occurrence of dystocia. Design A 2-year longitudinal observational study of 14 red deer farms was c arried out in New Zealand. About 2700 hinds were monitored each year for in dividual characteristics including body condition score (BCS), and reproduc tive performance. Grazing and calving management practices were recorded. D uring calving, farmers recorded carving difficulties (dystocia) that needed human assistance or caused the death of the hind. Risk factors potentially affecting the occurrence of dystocia were identified and analysed by multi variable statistical techniques. Results The percentage of hinds with dystocia was 0.52% (95% CI 0.32 to 0.7 8). Hinds with a post-winter BCS over 3.5 were 2.7 times as likely to exper ience dystocia as hinds scoring 3.5 or less. Given the same BCS class, body weight gain in late pregnancy was associated with an increased risk of dyst ocia. Grazing steep paddocks in the last trimester of pregnancy decreased t he risk of dystocia in hinds with a BCS over 3.5. Conclusions The risk of dystocia on red deer farms may be reduced if key in dividual animal, management and environmental factors are optimal.