Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.

The aim of this study was to evaluate vaccine efficacy of a commercial vaccine (Startvac, Hipra Spain) aimed at reducing intramammary infections (IMI) with Staphylococcus aureus and coagulase-negative staphylococci under field conditions. During the 21-mo duration of the study, 1,156 lactations from 809 cows were enrolled in 2 herds. During the first phase of the trial, all cows that were due to calve were vaccinated until approximately 50% of cows in the milking herd were vaccinated (at ~6mo). At that point, when 50% vaccination coverage was reached, cows that were due to calve were randomly assigned to be vaccinated or left as negative controls. Cure rate, rate of new infection, prevalence, and duration of infections were analyzed. Vaccination resulted in a moderate reduction in incidence of new staphylococcal IMI and a more pronounced reduction in duration of IMI associated with reduction of the basic reproduction ratio of Staph. aureus by approximately 45% and of coagulase-negative staphylococci by approximately 35%. The utilization of vaccine in combination with other infection-control procedures, such as excellent milking procedures, treatment, segregation, and culling of known infected cattle, will result in an important reduction in incidence and duration of intramammary staphylococcal infections.

A repeat breeder cow (RBC) can be defined as an animal that after 3 or more inseminations cannot get pregnant because of fertilization failure or early embryonic death. If no cause is identified precisely, inadequate uterine receptivity is responsible for implantation failures. Since a large number of identified molecular mediators, such as cytokines, growth factors and lipids have been postulated to be involved in early feto-maternal interaction, in this study a different approach to the treatment of RBC syndrome has been employed using a platelet concentrate (PC) that contains a significant amount of growth factors accumulated in its α-granules. Three explorative studies were performed. Initially, PC was supplemented in the in vitro embryo culture medium to study its effect on embryo-development. After the pilot study, 4 RBCs were treated with intrauterine administration of PC to evaluate proliferative potential of endometrium by immunohistochemical expression of the antigen Ki-67. Lastly, the effect of intrauterine administration of PC at 48 hrs after artificial insemination in RBCs was evaluated. The in vitro results show that 5 % of PC and 5 % of fetal calf serum (FCS) increase the rate of blastocysts compared with the control containing 10 % FCS only (43.04 % vs 35.00 % respectively). The immunohistochemical study shows more proliferating nuclei in the treated uterine horn compared to the control one. After intrauterine insemination in RBCs, the percentage of pregnant cows in the control group was 33.33 % compared to 70 % of the treated animals. We suppose that when embryo descends in uterus could find a more appropriate environment for nesting and subsequent pregnancy.

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