Treatment of clinical mastitis with cephalosporin-based intramammary products
Andrew Bradley and others, University of Bristol
Clinical mastitis is a considerable financial drain on the UK dairy industry with each case typically costing an estimated £200. There is significant variation in the cure rate achieved in different herds.
The authors compare the results in several international studies involving three cephalosporin-based intramammary preparations. From a total of 491 cases in three countries, it was apparent that there were no major differences in the cure rates achieved with a cefalexin-kanamycin combination compared with cefquinome treatment. But both groups were more likely to be pathogen free post-treatment compared with cattle treated with cefoperazone.
Pre-treatment rectal temperature, individual somatic cell counts and the presence of Staphylococcus aureus infections were useful indicators for pathogen-free status, while parity, yield, bulk milk cell counts and other management factors were not.
Cattle Practice 17 (1): 33-37.
Pharmacokinetics of tilmicosin following intramammary administration
Geoff Smith and others, North Carolina State University
Tilmicosin is a macrolide antibiotic approved in the US for the treatment of respiratory disease in cattle but which is sometimes used off-label as an intramammary treatment for mastitis. The authors assess its elimination kinetics in milk when infused into the glands of dairy cattle. Residues were found in high concentration in milk and the drug had a long half life, being detectable for the entire 40-day study period. Therefore they recommend that the compound should not be used by the intramammary route in lactating animals.
Journal of the American Veterinary Medical Association 234 (2): 245-248.
Potential value of Azadirachta indica extract in treating bovine mastitis
Ujjwalkumar De and Reena Mukherjee, Indian Veterinary Research Institute, Izatnagar
Neem (Azadirachta indica) is a shrub that is widely used in Indian traditional medicine. The authors prepared an extract of the seeds from this plant which was infused into the udders of cattle with clinical mastitis. Their findings showed a reduction in somatic cell count, total bacterial count and milk neutophil percentage. The cytokines interleukin 2 and gamma interferon were expressed in the milk cells of cattle following treatment. The extract may therefore have potential value as an alternative to conventional antibiotics.
Tropical Animal Health and Production 41 (2): 189-197.
Pharmacokinetics of enrofloxacin in cattle with mastitis
L. X. Fu and others, South China Agricultural University, Guangzhou, China
Enrofloxacin is a fluoroquinolone antibiotic with broad spectrum activity used widely for the treatment of mastitis. The authors investigate the population pharmacokinetics of the compound and its main metabolite ciprofloxacin in a group of 105 sick cows after a single intramuscular dose of 2.5mg/kg. Their results indicate that body weight and daily milk production have a significant influence on the clearance of both enrofloxacin and ciprofloxacin and on the volume of distribution of the parent molecule.
Journal of Veterinary Pharmacology and Therapeutics 31 (3): 240-245.
Pharmacokinetics of danofloxacin in lactating sheep and goats
Elisa Escudero and others, University of Murcia, Spain
Danofloxacin is a synthetic fluoroquinolone effective against a wide range of Gram-negative and some Gram-positive bacteria. It is not currently licensed for use in sheep and goats.
The authors examined the availability of the compound following a 6mg/kg dose delivered by the intravenous and subcutaneous routes in lactating animals of both species. Their findings show that the drug shows extensive absorption, high systemic availability and high distribution into the udder resulting in higher concentrations in milk than in plasma.
Journal of Veterinary Pharmacology and Therapeutics 30 (6): 572-577.
Susceptibility of enteric bacteria to chlortetracycline administered in feed
Tammy Platt and others, Texas A&M University
Animal agriculture is frequently blamed for the emergence of drugresistant bacteria. The authors examine whether chlortetracycline administered in feed is likely to select for tetracycline resistance in enteric bacteria. The drug was administered for 16 days in the feed of 20 steers. Treatment did cause a temporary increase in the likelihood of recovering resistant bacteria but exposure to chlortetracycline reduced the likelihood of recovering ceftiofurresistant E. coli isolates, even though isolates were co-resistant to tetracycline.
American Journal of Veterinary Research 69 (8): 988-996.
Unusual presentation of Mycoplasma bovis infection in dairy calves
Aiden Foster and others, Veterinary Laboratories Agency, Shrewsbury
Mycoplasma bovis is commonly isolated from mastitis cases in cattle and may also cause other clinical signs including pneumonia, arthritis and abortion. The authors describe unusual signs of severe otitis media attributed to this organism in a group of 20 dairy calves aged one to four weeks. The infection probably originated from cows in the milking herd based on evidence of seroconversion and the detection of M. bovis in a milk sample. Therefore this organism should be considered when investigating otitis problems in calves.
The Veterinary Journal 179 (3): 455-457.
Efficacy of a Salmonella enterica serotype Newport vaccine in healthy cattle
Dennis Hermesch and others, Kansas State University
Salmonella species infections may be the cause of a variety of clinical conditions in cattle and can also be transmitted to human consumers of infected milk and meat products from apparently healthy animals. A Salmonella enterica serotype Newport vaccine was administered to 180 female Holsteins before parturition. Inoculated cattle produced an average 1.14kg/day more milk than untreated controls, even in animals which had no detectable shedding of Salmonella Newport or clinical signs of salmonellosis.
American Journal of Veterinary Research 69 (9): 1,229-1,234.
Mycoplasma bovis mastitis in prepubertal heifers
Lawrence Fox and others, Washington State University
Prepubertal heifers from two neighbouring dairy herds were found to have mastitis due to Mycoplasma bovis infection. These were identified during routine examinations of six-monthold replacement calves when teat palpation revealed mammary nodes. The organism was cultured from samples of lacteal secretions. Both calves were euthanased and the organism cultured from various tissues. The same strain was found in dams and herd mates and so it suggested that the calves were infected by vertical transmission.
Canadian Veterinary Journal 49 (11): 1,110-1,112.
Mastitis caused by Bacillus anthracis in a beef cow
Ross Hawkes and others, Mohawk Animal Clinic, Melfort, Saskatchewan
An eight-year-old mixed breed beef cow with severe mastitis in midlactation was examined on a farm that was under anthrax quarantine after the disease was diagnosed on the premises 10 days earlier. The animal had mild depression and swelling of the front and hind left quarters. Direct examination and culture of the serosanguinous-like milk samples collected from these quarters were consistent with Bacillus anthracis infection. The cow was treated with florfenicol antibiotic but died shortly after the initial presentation.
Canadian Veterinary Journal 49 (9): 889- 891.
