Comparison of milk production of dairy cows kept in cold and warm loose-housing systems.
A retrospective cohort study was conducted to test whether the lactation curves of cows kept in cold loose-housing systems (CLHs) were the same as for cows in warm loose-housing systems (WLHs) in the Nordic countries. Approximately 40000 test-day records from 5366 Ayrshire or Black and White cows kept on 38 CLHs and 166 WLHs in Finland during 1996 and 1997 were used. Analysis used a random-coefficient model (correcting for parity, breed and calving-year-season and the correlation-structure between test-days of the same cow and cows of the same herd). Cows in a CLH produced up to 1l less milk per test-day, but this difference was not statistically significant. Surprisingly, the difference in milk yield was not affected by calving-year-season, parity or breed.
Schnier
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Department of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, FIN 00014 Helsinki, Finland. christian.schnier@hesinki.fi
Hielm
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Saloniemi
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D000818:Animals; D002417:Cattle / Q000502:physiology*; D015331:Cohort Studies; D003080:Cold Temperature; D003612:Dairying; D005260:Female; D005387:Finland; D006361:Heating; D006799:Housing, Animal; D008892:Milk / Q000502:physiology*; D008962:Models, Theoretical; D012098:Reproduction; D012189:Retrospective Studies; D012621:Seasons