Descriptive epidemiological study on culling and deaths in eight dairy herds.
OBJECTIVE
To describe the production and reproduction characteristics of the population under investigation and to compare them with the target population of non-seasonally calving dairy herds, to describe the pattern of culling with respect to length of productive life and length of time after calving, and to identify stages of the production cycle that are associated with increased risk of culling from the dairy herd.


METHODS
A longitudinal population study of eight non-seasonally calving dairy herds in the Camden district of New South Wales.


RESULTS
The production and reproduction characteristics of this population were broadly similar to herds participating in the New South Wales Agriculture Dairy Herd Improvement scheme. In agreement with recent surveys, risk of culling increased with increased parity. This was accounted for specifically by increased risk of culling for calving disorders, reproductive tract lesions, and disorders of the udder. Risk of culling for failure to conceive appeared to remain constant throughout productive life. The overall risks for culling were greatest during the first 9 days after calving and 300 days after calving.


CONCLUSIONS
Reducing the incidence of calving-associated disorders, attention to reproductive management and control of herd mastitis offer opportunities to reduce involuntary culling rates in this population.
Department of Animal Science, University of Sydney, Camden, New South Wales.
M A
MA
Stevenson
I J
IJ
Lean
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000401:mortality; D003612:Dairying / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D015994:Incidence; D007247:Infertility, Female / Q000453:epidemiology / Q000662:veterinary; D007794:Lameness, Animal / Q000453:epidemiology; D008137:Longitudinal Studies; D008414:Mastitis, Bovine / Q000453:epidemiology; D009517:New South Wales / Q000453:epidemiology; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000662:veterinary; D011247:Pregnancy; D011336:Probability; D016016:Proportional Hazards Models; D012307:Risk Factors