Associations between use of electric cow-trainers and clinical diseases, reproductive performance and culling in Swedish dairy cattle

The aims of this follow-up study were: (a) to evaluate the role of ECT tech nology as a risk factor for several diseases; and (b) to determine if the e ffects of these diseases on cows' reproductive performance and as risk fact ors for culling are influenced by exposure to ECTs. Diseases considered wer e retained placenta, metritis, ketosis, cystic ovaries, silent heat, milk f ever, clinical mastitis, and foot and leg problems. We used historical and contemporary controls (with control herds selected to match the experimenta l herds for size and location). Data consisted of 10264 Swedish Red and Whi te (SRB) and 5461 Swedish Friesian (SLU) lactation records in 150 herds of which 33 used cow-trainers. Logistic regression was used to estimate the ef fects of parity and exposure to electric cow-trainers on the risks of disea ses and the effects of diseases and exposure to electric cow-trainers on ri sk of culling. The least-squares procedure was used to estimate the effects of diseases on reproductive performance. The dominant effects associated with use of electric cow-trainers were an i ncreased risk for silent heat, clinical mastitis, ketosis and culling relat ive to cows in herds not using cow-trainers. Diseases had negative effects on reproductive performance anti the effects were larger for cows in herds using cow-trainers. In herds using electric cow-trainers, the largest incre ase in the interval from first service to conception (58 days) was caused b y the occurrences of silent heat, cystic ovaries and the combination of two or more diseases. Retained placenta, metritis, cystic ovaries, clinical ma stitis and a combination of two or more diseases increased the risk of cull ing about two times relative to healthy primiparous cows with the increase being greater for cows in herds using cow-trainers. Silent heat did not inc rease risk of culling in control groups, but was the largest risk factor fo r culling in the exposed group. We concluded that exposure to electric cow- trainers increased the incidence risk of silent heat, clinical mastitis, an d ketosis and changed silent heat from a neutral disease with respect to cu lling to a major risk factor. Finally, exposure to row-trainers increased t he general negative effect of diseases on the cows' reproductive performanc e and risk for culling. (C) 1998 Elsevier Science B.V. All rights reserved.