Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: V Mob and individual-hind risk factors associated with calf rearing to weaning

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. Both years combined, 3364 adult and 653 yearling hinds were diagnosed pregnant in June by ultrasound scanning and monitored for reproductive success up to weaning. At weaning, pre-rut at ap proximately 100 days after calving, udders were palpated or observed by the farmer and hinds were categorised as lactating (wet) indicating survival o f calf, or not lactating (dry). Farm management practices during calving an d early lactation were recorded. Analysis of risk factors associated with p rogeny survival was done using path analysis (separately for adult and year ling hinds). Adult hinds >3 years old at calving, conceiving before 1 May a nd having a body-condition score >2 in September had 2.8, 2.4 and 2.9 times significantly higher odds of rearing a calf to weaning than other hinds, r espectively. Adult hinds had about 5 times lower odds of rearing a calf to weaning when they were mixed with mature stags during calving. When farmers visited calving paddocks and checked for calving problems, adult hinds had 1.7 times higher odds of rearing a calf to weaning. When the farmer entere d calving paddocks at least every second time they observed the hinds, year ling hinds had a twice higher odds of rearing a calf up to weaning. Sunny w eather and high maximum temperatures were positively and negatively associa ted, respectively, with the probability of an adult hind being in lactation at weaning. (C) 2000 Elsevier Science B.V. All rights reserved.