Reasons for disposal of cows in a purebred Hereford and two multibreed synthetic groups under range conditions

Abstract

Reasons for disposal were determined for 983 cows from a purepred Hereford and two multibreed synthetic groups; all were born in the 1966–1975 period. One synthetic group (Beef Synthetic #1) was composed mainly of beef breeds, while the other synthetic group (Dairy Synthetic) had 64% dairy breeding. The cows were managed under a stringent culling policy under which any cow failing to wean a calf each year was culled. Cows were also culled for unsoundness and other defects. The mean longevity was 4.2 yr, with 16 yr being the maximum age attained by any cow. The highest percentage of cows was disposed as 2-yr olds (first calvers). Death losses accounted for 8.8%, while culling for reproductive failure, calf survival problems, calving problems and udder problems accounted for 51.3, 12.1, 10.9 and 7.7% of all disposals, respectively. Culling for reproductive failure was the major reason for disposal at all ages, although its relative importance diminished with advancing age. Culling for udder problems was of greatest significance in 6-yr-old and older cows. Culling for calf survival problems was higher (P < 0.05) in the Hereford than in the two synthetic groups. While mortality in the Dairy Synthetic group was higher (P < 0.05) than in the other two groups, the reverse was the case with respect to culling for severe calving problems, with Dairy Synthetic cows being culled the least (P < 0.05). Key words: Beef cattle, longevity, mortality, culling, breed