Reproductive performance, general health, and longevity of dairy cows at a Swedish research farm with both organic and conventional production

Summary

Data from a 12-year longitudinal study was used to compare reproductive performance (RP), general animal health, and longevity in conventionally managed dairy cows and organically managed dairy cows. All cows were held at the same farm and managed by the same personnel. The management of the groups was basically alike, with the main exception being differences in feed composition and feeding regimes. Management of the organic group was done according to the Swedish standards for organic farming, which are certified by the International Federation of Agricultural Movements. The data for this study included all cows calving from September 1, 1990 to August 31, 2001; in total 154 organically and 156 conventionally managed animals. Calving-to-first insemination and calving interval were recorded to characterize RP. Animal health was studied by recording the number of veterinary treated cases of disease. Finally, we studied the length of productive life, from 1st calving to removal. Multivariable models were applied in the analyses to account for variables such as milk yield, parity, breed, calving season, and year of calving. Conventionally managed dairy cows in 3rd lactation or more were found to have longer time from calving-to-first service than organically managed dairy cows. Beside that difference, the groups did not differ in any aspect of RP. Comparisons of number of veterinary treated cases of disease per lactation and the length of productive life revealed no significant differences or trends. With this unique study design, applied in a well managed herd, we were not able to demonstrate any obvious differences in RP, general health or longevity between organically and conventionally managed dairy cows.