RESUMEN
Bovine viral diarrhea (BVD) is one of the most important infectious cattle diseases worldwide. The major source of virus transmission is immunotolerant, persistently infected (PI) calves, which makes them the key target of control programs. In the German federal state of Saxony-Anhalt, a very low prevalence was achieved, with more than 99.8% of the cattle herds being free from PI animals since the year 2013. In 2017, BVD virus was detected in a previously disease-free holding (herd size of ~380 cows, their offspring, and fattening bulls). The purchase of two so-called Trojan cows, i.e., dams pregnant with a PI calf, was identified as the source of infection. The births of the PI animals resulted in transient infections of in-contact dams, accompanied by vertical virus transmission to their fetuses within the critical timeframe for the induction of PI calves. Forty-eight days after the birth of the first PI calf, all animals in close contact with the Trojan cows during their parturition period were blood-sampled and serologically examined by a neutralization test and several commercial ELISAs. The resulting seroprevalence strongly depended on the applied test system. The outbreak could be stopped by the immediate elimination of every newborn PI calf and vaccination, and since 2018, no BVD cases have occurred.
RESUMEN
Staphylococcus (S.) aureus is an important mastitis causing pathogen in dairy cows worldwide. The aim of this controlled and randomized study was to analyze the effects of an antibiotic treatment on chronic subclinical S.aureus mastitis during lactation.The study was conducted between July 2011 and December 2011 in Northern Germany including 134 udder quarters (i. e. 103 dairy cows) infected with S. aureus. The animals were randomly divided into two groups (control and treatment group). Quarter foremilk duplicate samples were taken on days 0, 7, 32 and 39 from each infected udder quarter for microbiological analysis and somatic cell count determination. Treatment consisted of cephalexin (200 mg intramammarily 5 times every 12 h) plus marbofloxacine (2 mg/kg BM subcutaneously 3 times every 24 h). "Pathogen elimination" was assessed as the status, when no S. aureus was isolated from the quarter samples of days 32 and 39. "Cure" was defined as the status, when in addition to pathogen elimination the somatic cell count of the quarter in both milk samples was below 100 000/ml. Animals of the treatment group showed a pathogen elimination rate of 35.9% and a cure rate of 21.9%. The rates for the control group were 21.4% and 8.6%, resp. The differences between groups were statistically significant. These results indicate that pathogen elimination and cure rates of chronic subclinical S. aureus mastitis are low after an intramammary cephalexin and subcutaneous marbofloxacine treatment, but still significantly better than without any antibiotic treatment.