The effect of dry cow therapy and internal teat-sealant on intra-mammary infections during subsequent lactation

Dry cow therapy (DCT), an infusion of antibiotics into the mammary gland at the end of lactation, is widely used for the control of intra-mammary infections (IMI) in the dairy cow. However, increased public health concerns about the use of antibiotics, has led to the search for alternatives to the routine use of antibiotics during drying off. In the present study the effects of three dry cow treatments, two types of DCT and a teat-sealant, on the development of new IMI and clinical mastitis were investigated in 240 cows belonging to two herds (Herd A and Herd B). In Herd A, 60 cows were given one type of DCT (Cloxacillin) and the other 60 cows were given another type of DCT (Framycetin). In Herd B, 60 cows were given teat-sealant and the other herd were not given any treatment. There were significantly more new IMI at calving in control cattle compared to those given teat-sealants (p < 0.001) and there were more cases of clinical cases of mastitis in the control group. The number of clinical cases detected in cows given teat-sealant in Herd B were not significantly different from those detected in cows in Herd A given Cloxacillin or Framycetin.