Abstract
Effects of disease on the risk of removal in Holstein-Friesian cows were investigated in a two and a half year study. Records were available from 141 sold cows, 415 culled cows and 1452 comparison cows in 32 commercial dairy herds within a 50 mile radius of Guelph, Ontario.
Removals were subdivided into culls (cows sent to slaughter) and sales for dairy purposes. Discriminant analysis was used to identify disease conditions associated with an increased risk of removal before the 150th day or after the 150th day of the lactation. Age and herd effects were controlled in all analyses and the effect of level of production was controlled in analyses of removals after Day 150. Subclinical mastitis was associated with increased risks of culling and of being sold for dairy purposes after Day 150. Mastitis, milk fever, feet and leg problems, teat injuries and respiratory disease were associated with an increased risk of culling early in the lactation. No disease conditions were significantly associated with the risk of being sold for dairy purposes early in the lactation.
The survival experience of these cows was determined by the use of life table analyses, the median survival time being 5.6 years. Risk of removal was highest in cows aged 3.0–4.9 years and in cows over 7 years old. Survival was positively associated with level of milk production.
Effects of disease on the risk of removal in Holstein-Friesian cows were investigated in a two and a half year study. Records were available from 141 sold cows, 415 culled cows and 1452 comparison cows in 32 commercial dairy herds within a 50 mile radius of Guelph, Ontario.
Removals were subdivided into culls (cows sent to slaughter) and sales for dairy purposes. Discriminant analysis was used to identify disease conditions associated with an increased risk of removal before the 150th day or after the 150th day of the lactation. Age and herd effects were controlled in all analyses and the effect of level of production was controlled in analyses of removals after Day 150. Subclinical mastitis was associated with increased risks of culling and of being sold for dairy purposes after Day 150. Mastitis, milk fever, feet and leg problems, teat injuries and respiratory disease were associated with an increased risk of culling early in the lactation. No disease conditions were significantly associated with the risk of being sold for dairy purposes early in the lactation.
The survival experience of these cows was determined by the use of life table analyses, the median survival time being 5.6 years. Risk of removal was highest in cows aged 3.0–4.9 years and in cows over 7 years old. Survival was positively associated with level of milk production.
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