Reliability of dairy sire surveys in production recorded herds

Abstract

The results of production surveys of small numbers of daughters of 1878 Australian Illawarra Shorthorn and Jersey sires were used to classify sires into the categories of raising, maintaining and lowering herd production. In recorded commercial herds, production was raised or maintained by 73% of all sires surveyed. Results from the 2 breeds were similar. The accuracy of preliminary surveys was determined by comparing the preliminary and intermediate stages of 1024 surveys of sires used in commercial herds, and 237 surveys in purebred herds. The comparison indicated that 92-5% of the surveys in commercial herds showed only small changes. In purebred herds, 88-6% of Australian Illawarra Shorthorn and 90.6% of Jersey sire surveys showed only small changes. Significant positive correlation coefficients between preliminary and intermediate stages were shown. It is concluded that production records obtained for a normal completed lactation of each of 10 daughters are sufficient to assess a sire's capacity to transmit production characteristics.