Rate, Age, and Criteria for Disposal in a Herd of Registered Jersey Cattle

Abstract

Reasons for disposal of dairy cattle from a registered Jersey herd established in 1887, noted for high production, on supervised herd test since 1929, and classified annually since 1938, were analyzed for the period, 1948 to October, 1963. Average size of the milking herd was 108. 4 cows. Sixty-seven per cent of the 854 females, exclusive of free-martins, born during the period lived to enter the milking herd. Stillbirths and early post-natal mortality accounted for 23. 3% of the disposals. Sterility, undesirable type and unthrifti-ness, and pedigree were the major reasons for disposal of heifers between 6 and 24 months of age, accounting for 42. 7, 35. 3 and 9. 8% of the reasons for disposal in this age group, respectively. Five hundred-three milking cows were culled; annual disposal rate, 29%. The culled cows included 13 Excellent, 192 Very Good, 177 Good Plus, 26 Good, and 95 Unclassified. Criteria for disposal were: low production, 7. 7%; sterility, 4. 2%; mastitis, 4. 1%; other diseases, 3. 9%; type, 3. 0%; age, 1. 2%, and 4. 9% were sold for dairy purposes. Average age in years and number of lactations completed by all cows at time of disposal were 6. 79 and 3. 43, respectively.