Body conditions scores of dairy cattle in organic farms

Dairy cows on organic farms may not be fed adequately because provision of concentrates (and thus energy and protein), minerals and vitamins is limite d. The hypothesis was therefore tested that the nutritional status of dairy cows in organic dairy production is insufficient. The nutritional status w as characterized by determination of body conditions scores (BCS) in 152 fa rms, which were a stratified sample of Swiss organic farms. In summer (July - September 1997) and the ensuing winter (January - March 1998) the BCS wa s evaluated in 1687 and 1867 dairy cows, respectively. Mean number of cows per farm was 12.3, 13.7% of farms were located in mountain zones and 26% in lowlands, and 26% of farms kept part or all of their herds on alpine pastu res during summer. Average 305-day milk yield was 5467 kg per lactation. De pending on breed, this was 5-12% less than the contemporary average annual milk yield of cows registered in herd books. Average milk protein and fat c ontents were lower than that of cows kept on conventional farms. Mean milk urea concentration was 3.2 mmol/l in summer and only 2.0 mmol/l in winter, indicating insufficient protein supply in winter. BCS were between 3.0 and 3.75 for 69% of the cows, and <2 and >4 for 3 and 4% of cows, respectively. Effects on BCS of cow characteristics (days post-partum, age and breed) an d effects of farm characteristics with emphasis on feeding procedures were assessed with linear models. Days post-partum, breed and several farm level variables had a significant influence on BCS. In conclusion, most dairy co ws on organic farms had opitimal BCS and thus an adequate nutritional statu s. However nutritional energy and/or protein deficits were apparent during the winter feeding period.