640
The Fertility of South African Holstein and Jersey heifers
ABSTRACT:Age at first calving is the standard fertility trait for dairy heifers. This trait is affected by growth rate and the managers’ attitude towards an early age at first calving. While age at conception for heifers could be derived from age at first calving, little information is available on the age at first service in heifers and first service success rate. Service records from 13072 heifers in 16 South African Holstein and Jersey herds were available. Average (±SD) age at first service for Holstein and Jersey heifers was 19.3±4.8 and 16.4±8.1 months of age respectively. The result is a high age at first calving, i.e. 29.4±5.2 and 26.4±8.6 months of age for Holstein and Jersey heifers respectively. Some effort should be put into improving reproduction performance of heifers to reduce rearing costs.
Keywords:
dairy heifers
fertility traits
conception age
days open
Keywords:
