Abstract:
The genetic relationship between conformation traits and functional herd life of the South African
Jersey population was investigated. Data on conformation traits (n = 46 238) and functional herd life (n =
90 530) on registered South African Jersey cows calving between 1989 and 2008 were obtained from the
Integrated Registration and Genetic Information System. Conformation traits were scored using a subjective
linear scoring system ranging from 1 to 9, except for foot angle, with a maximum score of 8. Conformation
traits included stature, chest width, body depth, dairy strength, rump angle, thurl width, rear leg side view,
foot angle, fore udder attachment, rear udder height, rear udder width, udder support, udder depth, front teat
placement, rear teat placement and front teat length. Genetic correlations between conformation traits and
functional herd life were estimated by a series of bivariate analyses. Significant moderate to strong positive
genetic correlations between most udder traits and functional herd life (0.23 to 0.63) were estimated. The
most important udder traits related to functional herd life were fore udder attachment, rear udder height and
udder depth. Most of the body structure traits had a low to moderate negative correlation with functional
herd life (-0.04 to -0.27). However, rump angle and foot angle were estimated to have a moderate positive
genetic correlation with functional herd life. The genetic relationships between functional herd life and
conformation traits in the South African Jersey breed indicate that conformation traits could be used to
enhance the accuracy of genetic evaluation for functional herd life. It is therefore recommended that current
national genetic evaluation for functional herd life in the South African Jersey breed should include
conformation traits.
