ABSTRACT
The objective was to compare the prevalence of subclinical mastitis (SM) and of udder pathogens in 60 Swiss organic (OP) and 60 conventional production systems (CP). Cows (n=970) were studied for SM prevalence and udder pathogens at median 31 d and 102 d post partum. Cows showing a >or=1+ positive California Mastitis Test (CMT) in at least one quarter were considered to have SM. Cow-level prevalences of SM for visits at 31 d and 102 d post partum (39% and 40% in OP and 34% and 35% in CP) were similar, but quarter-level prevalences of SM were higher (P<0.02) in OP than CP (15% and 18% in OP and 12% and 15% in CP). Median somatic cell counts in milk at 31 d post partum were higher (P<0.05) in OP than CP cows (43000 and 28000 cells/ml, respectively), but were similar at 102 d post partum in OP and CP cows (45000 and 38000 cells/ml, respectively). In milk samples from quarters showing a CMT reaction >or=2+ the prevalences of coagulase negative staphylococci were lower (P<0.05) at 102 d post partum, whereas prevalences of non-agalactiae streptococci were higher (P<0.05) in OP than in CP cows at 31 d and 102 d post partum. In conclusion, under Swiss conditions, subclinical mastitis is a greater problem in organic than in conventional production systems, but differences are not marked.
Subject(s)
Dairying/methods , Mastitis, Bovine/diagnosis , Mastitis, Bovine/epidemiology , Animals , Cattle , Cell Count/veterinary , Female , Milk/cytology , Milk/microbiology , Prevalence , Switzerland/epidemiologyABSTRACT
Pharmacokinetic characteristics of benzylpenicillin and its benzylpenicilloyl (BPO)-derivatives were studied in serum and milk of health cows, using a classical biological assay ( Sarcina lutea test) and a competitive ELISA for BPO detection. The plasma level and passage into milk was determined after intramuscular administration of penethamate-hydroiodide and benzylpenicillin-procaine. In serum of cows receiving penethamate hydroiodide, BPO seemed to persist for a rather long time; the reason for this observation was not clarified. The effect of local (intramammary) application of penicillin G was followed with milk from cows having healthy and mastitic quarters. In all cases, it was found that BPO was not excreted any longer than active penicillin G in milk. In a further survey, 1015 bulk milk samples from two large dairy regions were examined with the ELISA and a biological assay using Bacillus stearothermophilus var. calidolactis . None of the samples showed detectable BPO or antibiotic residues. It is concluded that milk containing inactive penicillin derivatives, like BPO, is not an important source to cause allergies.
