Prevention and control of environmental pathogen-induced mastitis in dairy cows

The aim of this work was to determine the effect of the treatment of cows with infected udders upon the occurrence of bacterial mastitis in a dairy herd. The animals were housed in two production stables using conventional technology and were milked directly into the tubes of a DZ-100 milking machine (fi Agrozet, Pelhrimov, Czech Republic). In the last two months of 1999 an unfavorable development in the occurrence of secretory disturbances could be stated. The measures taken in January 2000 had not resulted in any improvement of the health state therefore the farm asked the team of the Research Institute of Veterinary Medicine to complexly examine the health state of the cows' udders. In March 2000 the udder secretion of all 215 dairy cows was subjected to three subsequent bacteriological and NK-test examinations as well as a clinical evaluation of herd health. On the basis of the bacteriological examination all cows with infected udders were subjected to treatment. Lactating cows were treated with Ganaret (fi Infuza, Horatev, Czech Republic), those not responding to this preparation were treated with Cefa-Lak (fi Fort Dodge, Iowa, USA). Effectivity of the treatment was examined monthly by complex udder examinations (bacteriological and NK-test examination of the secretion, clinical examination of the health state of the udder). Each mastitis agent isolated from the secretions was tested for sensitivity to ten antibiotics. From the results it follows: At the end of 1999, 67.4% of the dairy cows were bacteriologically positive. The antimastitis measures taken by the breeder were ineffective, since the infection rate decreased to 59.5% only. After introduction of preventive and control antimastitis measures and treatment of cows with an infected udder the rate of mastitis decreased to 10.7%. This relatively favourable state could be maintained for about four months. As a result of mistakes in the preventive antimastitis measures the number of infected cows increase to 27.4 %, later even to 40.9%. Throughout the observation period Streptococcus uberis and coagulase-negative staphylococci were the dominant pathogenic bacteria. By introducing preventive and control measures the originally high number of somatic cells (811) dropped under the standard limit (400 thous/ml)