Inheritance of calf mortality for Brown Swiss cattle.

Worksheets with reports of calf mortality were voluntarily submitted by dairy producers to the Brown Swiss Cattle Breeders Association. Objective was to assess genetic and nongenetic factors influencing calf mortality of Brown Swiss. Multiple births were removed prior to analysis. Three traits recorded and analyzed were dead at birth, death through 2nd d after birth including dead at birth, and death from 1st to 7th d of life. Male calves were more likely to be dead at birth, to die through 2nd d, and to die from 1st to 7th d of life than female calves. Dead birth was greater for calves from primiparous than multiparous dams; however, death from 1st to 7th d did not differ by parity status of dam. Death from 1st to 7th d was greater from December to May than from June to November. Heritabilities for Brown Swiss were .05, .07, and .04 for dead at birth, dead through 2nd d, and death from 1st to 7th d, respectively. Mortality rates and heritabilities were similar to estimates for Holsteins from the literature. Rank correlations of sires for transmitting abilities of calf mortality and production were near zero.