Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies using ribosomal spacer (RS)-PCR, however, demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infections are genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. Furthermore, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. In addition to RS-PCR, other methods for subtyping Staph. aureus are known, including spa typing and multilocus sequence typing (MLST). They are based on sequencing the spa and various housekeeping genes, respectively. The aim of the present study was to compare the 3 analytic methods using 456 strains of Staph. aureus isolated from milk of bovine intramammary infections and bulk tanks obtained from 12 European countries. Furthermore, the phylogeny of animal Staph. aureus was inferred and the zoonotic transfer of Staph. aureus between cattle and humans was studied. The analyzed strains could be grouped into 6 genotypic clusters, with CLB, CLC, and CLR being the most prominent ones. Comparing the 3 subtyping methods, RS-PCR showed the highest resolution, followed by spa typing and MLST. We found associations among the methods but in many cases they were unsatisfactory except for CLB and CLC. Cluster CLB was positive for clonal complex (CC)8 in 99% of the cases and typically positive for t2953; it is the cattle-adapted form of CC8. Cluster CLC was always positive for t529 and typically positive for CC705. For CLR and the remaining subtypes, links among the 3 methods were generally poor. Bovine Staph. aureus is highly clonal and a few clones predominate. Animal Staph. aureus always evolve from human strains, such that every human strain may be the ancestor of a novel animal-adapted strain. The zoonotic transfer of IMI-and milk-associated strains of Staph. aureus between cattle and humans seems to be very limited and different hosts are not considered as a source for mutual, spontaneous infections. Spillover events, however, may happen.

Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies, however, have demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infection is genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. In addition, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. The aim of this study was to subtype strains of Staph. aureus isolated from bovine mastitic milk and bulk tank milk to obtain a unified view of the presence of bovine staphylococcal subtypes in 12 European countries. A total of 456 strains of Staph. aureus were subjected to different typing methods: ribosomal spacer PCR, detection of enterotoxin genes, and detection of gene polymorphisms (lukE, coa). Major genotypes with their variants were combined into genotypic clusters (CL). This study revealed 5 major CL representing 76% of all strains and comprised CLB, CLC, CLF, CLI, and CLR. The clusters were characterized by the same genetic properties as the Swiss isolates, demonstrating high clonality of bovine Staph. aureus. Interestingly, CLB was situated in central Europe whereas the other CL were widely disseminated. The remaining 24% of the strains comprised 41 genotypes and variants, some of which (GTAM, GTBG) were restricted to certain countries; many others, however, were observed only once.

BackgroundPrevious studies have shown a high prevalence of failure of passive transfer of immunity (FPT) in Swiss dairy calves.ObjectivesTo investigate risk factors associated with poor colostrum quality and FPT on Swiss dairy farms.AnimalsColostrum and serum samples from 373 dam‐calf pairs at 141 farms.MethodsThe gamma globulin (Gg) concentrations of the dams’ colostrum and the calves’ serum samples were determined by electrophoresis. Potential risk factors were assessed by logistic regression of questionnaire data.ResultsPrevalence values of 15.5% (95% confidence interval [CI], 12.0–19.6%) for low‐quality colostrum (<50 g Gg/L) in cows and 43.5% (95% CI, 38.4–48.8%) for FPT (serum Gg < 10 g/L) in calves were estimated. The main factors associated with low colostrum quality included colostrum leakage before or during parturition and a time lag > 6 hours between parturition and first milking. The results confirm that the occurrence of FPT in calves primarily was influenced by the quality of colostrum, the amount of ingested colostrum, and the time between birth and first feeding.Conclusions and Clinical ImportanceThese results confirm a large potential for improvement in colostrum harvesting and colostrum feeding procedures in the study herds. Control for colostrum leaking intra‐partum, early colostrum milking, and ensuring that the calves ingest a sufficient volume of colostrum within the first hours of life are measures that can be readily implemented by farmers to decrease the incidence of FPT without additional workload.

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Twu experiments were conducted to examine the relationship between sward surface height, herbage intake and liveweight gain in beef cattle grazed on pasture. In Experiment 1, two 'animal types" (18 Charolais x Angus steers and 18 Friesian bulls) were continuously grazed for 22 days during the late autumn on replicated swards maintained at sward surface heights of 6, 10 and 15 cm. Herbage intakes, assessed from the faecal concentration of chromium delivered from an intraruminal controlled release capsule and the in vitro digestibility of hand-plucked herbage samples, were curvilinearly related to sward height {r = 0-76. F<0-Ol). Average liveweight gains were 002, 0-61 and 1-31 kg d'^ (P<0-05) and increased linearly (r = 0'84. P < 0-001) with sward height. The maintenance organic matter intakes of the steers and bulls, with initial mean (± s.e.) live weights of 225 ± 15 kg and 172 ± 15 kg respectively, were estimated to be 3-6 and 3-5 kg d^' respectively. In Experiment 2 (spring) 36 cattle, including 35 of those used in Experiment 1, were reallocated to sward heights of 5, 10 and 15 cm using the same design as for Experiment 1. Average liveweight gains were