Field experience with a single intravenous injection of marbofloxacin 16% in lactating dairy cows with acute clinical mastitis

In a non-controlled multicentre field trial conducted on commercial farms in France and Germany, local and general tolerance of marbofloxacin (Forcyl (R), Vetoquinol SA) was evaluated after intravenous administration to 100 lactating dairy cows suffering from acute clinical mastitis. Clinical signs, concomitant therapy, disease evolution and bacteriological analysis of milk at inclusion were also monitored. All the 100 included cows presented local and general signs of acute clinical mastitis, involving one or two quarters. They were treated once with marbofloxacin (Forcyl (R)) at the dose rate of 10 mg/kg (i.e. 10 ml/160kg) by intravenous injection. Most of the included cows (83%) received a concomitant treatment. A clinical examination was performed before and immediately following treatment with the study product and 1, 2-3 and 7 days after this treatment, with some cases up to 14 days later (40%). Milk was sampled for microbiological examination before treatment in 81% of the cases. The time course of the target disease showed a rapid decrease of mean rectal temperature as well as mean score of all the local and general clinical parameters, whether the cows received concomitant therapy (83 cows) or not (17 cows). However, 8 cows were given a new treatment for mastitis during the study. The two main pathogens isolated before treatment were Escherichia coli and Streptococcus uberis. The most frequent side effects observed after injection were moderate and transient local reactions (swelling, slight pain at injection, hematoma). Diarrhoea was observed both before treatment and within the first days following treatment. Tremors, lameness and nervousness were also observed on rare occasions within the first days following injection. Intravenous administration of a high dose of marbofloxacin (Forcyl (R)) was efficacious and safe in cows suffering from acute clinical mastitis, in combination with various concomitant treatments (83% of the included animals) or alone (17%).