The influence of laterality on mastitis incidence in dairy cattle--preliminary study

During summer (June to August) of continental weather conditions treated mastitis episodes at a large Hungarian dairy farm were studied to determine the relationship between the distribution of mastitis among quarters of the udder and the lying behaviour (laterality) of the cows. There was a significant difference in laterality between cows that developed mastitis and cows that did not. Cows that developed mastitis, had an increased left laterality in lying, which was related to the increased probability of a right-sided mastitis episode. However, the effect was not significant due to the large variation in the data. At the same time, significantly more cows with clinical mastitis had a somatic cell count (SCC) higher than that of cows without clinical mastitis. While a significant correlation was found between the occurrence of treated mastitis cases and SCC > 1,000,000, no statistically significant differences could be observed in milk production between the two groups.

The incidence of mastitis treated with antibiotics in large-scale Hungarian Holstein-Friesian dairy farms

Treated mastitis episodes at large Hungarian dairy farms were studied to determine the distribution of mastitis treated with antibiotics among quarters of the udder. Data were detailed records of all mastitis episodes that occurred during 1976 lactations in Farm A infected with Staphylococcus aureus (from May 1995 through July 1998) and 808 lactations in Farm B free from S. aureus (from January 1999 through March 2001). The distribution of treated quarters was compared with mathematical expectations based upon a random distribution in the case of Farm A. Results on mastitis incidences for different lactation stage groups showed an increasing incidence within subsequent lactation stage groups in Farm A. In contrast, in Farm B the mastitis incidence for lactation stage group between 35 and 100 days was the highest, but beyond 100 days the incidence decreased and reached the lowest value. Results gave strong evidence that the four quarters within the udder are not distributed randomly with respect to naturally occurring episodes of treated mastitis. More episodes than expected occurred in which only one or all four quarters were treated. Fewer episodes than expected with two or three treated quarters were observed. In both farms, the mastitis rate for rear quarters was higher than for front quarters, and the incidence of right quarter mastitis episodes was higher than that of left quarter mastitis episodes.