Mastitis and herd health in 15 dairy farms in Schleswig-Holstein, Germany - a field study.

摘要

The aim of the field study was to investigate factors influencing udder health and fertility in fifteen commercialdairy farms in Schleswig-Holstein (Northern Germany). From January 1997 to December 1998 sterile quarterforemilk samples of 960 +- 49 lactating cows were collected once monthly for cytobacteriological analysis.Antimicrobial susceptibility was tested in 791 strains of mastitis pathogens. A clinical examination of the udderswas carried out between the 14th and the 80th day of lactation. Data concerning management, milking routine,disease frequency and treatments, drying off, calving and culling were recorded every month. Prevalence of quarters infected with mastitis pathogens was 16.0 % in 1997, slightly increasing to 18.5 % in1998. Somatic cell count decreased from 78,462 (geometric mean) in 1997 to 70,272 in 1998. Staphylococcusspp. were the predominant mastitis pathogens with a quarter prevalence of 12.9 % in 1997 and 15.7 % in1998, resp., followed by Streptococcus spp. with 2.6 % and 2.9 %, resp. In both years less than 1 % ofquarters were infected with other mastitis pathogens including Sc. agalactiae. The percentage of ß-lactamaseproducing staphylococci strains decreased from 59.6 % in 1997 to 44.7 % in 1998. The incidence of clinicalmastitis decreased from 4.8 +- 1.4 % per 100 cows and month to 4.4 +- 1.1 % in 1998. During the study 673 ofall recorded 1990 cows (33.8 %) suffered at least once from clinical mastitis, 34.4 % of these cows had at leasttwo episodes of clinical mastitis.Throughout lactation 38.9 % of clinical cases of mastitis were observed during the first 50 days post partum.Somatic cell count of quarters was significantly influenced by herd x season, calving season, parity, stage oflactation, bacteriological status and milk yield. Udder and teat conformation had little influence on somatic cellcount. Factors with a significant influence on milk yield throughout lactation were herd x season, calvingseason, breed, parity, stage of lactation, subclinical and clinical mastitis.Clinical mastitis was detected in 11.2 % of multiparous and 7.4 % of primiparous cows during the first month oflactation. The risk of multiparous cows to develop clinical mastitis post partum was increased with higher parity,with subclinical mastitis before drying off, high prevalence of mastitis pathogens of the herd in the calvingmonth, high milk yield before drying off and with placenta retention. Primiparous cows had an increased risk todevelop clinical mastitis in the first month of lactation when calving occurred during winter. Greater teatdiameters, diseases during the early puerperium and high mean milk yields in the herd and deep udders werealso associated with an increased risk. The risk for placenta retention in multiparous cows was higher in cows infected with Streptococcus spp. beforedrying off than in cows without infection. Calving during winter, dry periods less than 40 days and high meanmilk yields in the herd were associated with an increased risk for retained placenta.Mean calving to first insemination interval was 81.1 ? 31.3 days and was significantly influenced by herd xseason, parity, fat and protein corrected milk yield, placenta retention, reproductive and metabolic disorders.In cows with subclinical mastitis the interval was prolonged by 11.7 days. Mean days open were 104.6. Factorswith significant influence on days open were herd x season, fat and protein corrected milk yield, as well asreproductive and metabolic disorders.