Factors affecting the risk of euthanasia for cows in Danish dairy herds.

Information about the 7238 Danish dairy cows that died or were euthanized in April, May and June of 2008 was obtained from the Danish Cattle Database, and the herd-level factors affecting the risk of being euthanized (as opposed to dying naturally) were evaluated by logistic regression. In total, 16.6 per cent of the dead cows had been euthanized. The odds of euthanasia increased with increasing herd size, increasing herd-level milk yield and increasing morbidity in the herd. The odds ratio (OR) of euthanasia was 1.13 (P<0.0001) for the effect of an increase in herd size of 50 cows, 1.13 (P<0.0001) for an increase in herd-level milk yield of 1000 kg energy-corrected milk per cow per year, and 1.31 (P<0.0001) for an increase in the average number of diseases recorded per cow per year of 0.5. The cows' parity and stage of lactation had no effect on their risk of being euthanized.