Dairy calf mortality rate: influence of management and housing factors on calf mortality rate in Tulare County, California.

Data on calf mortality, calving site, calf-rearing facilities, and calf-management procedures were collected from 16 dairy farms in Tulare County, California. Discriminant analyses were used to test if any significant differences in these factors existed between farms with higher than average and farms with lower than average death losses. The average mortality rate over a period of at least 2 years on individual farms varied from a low of 3.5 +/- 1.1% to a high of 30.6 +/- 3.1%. Calf management personnel was the only factor significantly related to the mortality rate, with considerably fewer death losses on farms where the owner managed the calves than on farms where employees performed these duties. In general, other factor categories relating to size of the cow herd, calving site, and calf housing were not related significantly to calf deaths. The average number of heifer calves born each year on individual farms was increasing year by year, and on some farms, there seemed to be a concomitant increase in death losses. This, together with the tendency toward greater number of deaths on the larger owner-managed farms, indicated that calf care was diluted under these conditions.