Comparison of the breeding performance of cows in cold and warm loose-housing systems in Finland

Finland's cold loose-housing systems for dairy cows were compared with the more traditional warm loose-housing systems regarding the number of days from calving-to-first-service, the first-service-pregnancy risk and the repeated-service-conception hazard. 3131 calvings registered during the indoor periods in 1996 and 1997 on 208 farms were modelled using multilevel survival analysis and logistic regression in a retrospective cohort study. Compared to cows in a warm loose-housing system, cows in a cold loose-housing system had the same period from calving-to-first-service, a significant 6% lower first-service-pregnancy risk and the same repeated-service-conception hazard. (C) 2004 Elsevier B.V. All rights reserved.