It is well documented that heat stress (HS) causes subfertility in dairy cows. However, during the last ten years we have been observing that, under high temperature-humidity index (THI ≥ 75), despite the overall reduced fertility, some cows conceive at the first artificial insemination (AI). Here, we examined distinctive features of cows with conserved fertility under severe HS. From the databases of three herds, 167 lactating Holstein cows were selected; group TT cows (n = 57) conceived in the previous summer (THI ≥ 75) at the 1st AI, and group TS (n = 110) failed to conceive at the same period after at least 2 consecutive AIs. The animals calved in spring, and in August, blood samples were collected during a hot day (THI ≥ 81) for the determination of cortisol and HSP70 concentrations. In one farm, the validity of fertility data of the previous year was reexamined. In 28 cows from group TT and in 39 cows from group TS, the conception rate was examined during July and August. In 6 cows from each group (TT and TS) the oestrous cycles were synchronized, ovulation was induced with GnRH (THI = 80), and the concentration of the pre-ovulatory LH surge was determined in 9 blood samples. The progesterone concentration in the ensuing cycle was determined in blood samples collected every other day. Overall, cortisol and HSP70 were significantly lower in TT group compared to TS. More (p < .05) animals from group TT conceived at the first AI compared with those from group TS. The induced pre-ovulatory LH surge peaked at higher level (p < .002) in group TT than in group TS, while no difference was recorded among groups either in mean progesterone concentrations or in the duration of the ensuing oestrous cycle. These results are highly suggestive that thermotolerance in some dairy cows is an inherent characteristic, warranting further genetic investigation.

Our objective was to evaluate the efficacy of a vaccine against staphylococcal mastitis in 5 dairy sheep farms, with 316 ewes in the vaccinated (V) group and 307 in the control (C) group studied throughout a lactation period. Two administrations of the vaccine were performed during the last stage of gestation of ewes. Starting 15 d after lambing and at monthly intervals thereafter, up to 9 milk samplings were performed for bacteriological and cytological examinations. Staphylococcal isolates recovered were examined for biofilm formation. Blood samples were collected for measurement of IgG poly-N-acetylglucosamine-specific antibodies. The most frequently isolated bacteria were staphylococci: 56.4 and 76.1%, respectively, of total isolates recovered from ewes of group V and C, respectively; staphylococci as causal agents of mastitis were isolated less frequently from V (5.3%) than in ewes in C (10.3%). Among mastitis-associated staphylococcal isolates recovered from V ewes, a smaller proportion was biofilm-forming than among ones from C: 53.2% versus 74.9% of isolates; biofilm-forming staphylococci as causal agents of mastitis were isolated less frequently from ewes in group V (2.3%) than in ewes in group C (6.0%). Anti-poly-N-acetylglucosamine-specific antibody values increased in V ewes and were higher than in C; a greater proportion of ewes with low antibody titers developed staphylococcal mastitis (41.4%) than of V ewes with high antibody titers (17.0%). Incidence risk of mastitis, staphylococcal mastitis, and biofilm-associated staphylococcal mastitis was smaller in V than in C: 36.7, 17.1, and 8.0% versus 44.3, 30.9, and 18.9%, respectively. The first case of staphylococcal mastitis occurred later in V than in C: third versus second sampling point. Overall, efficacy of the vaccine was 44.6% for staphylococcal mastitis, 57.7% for biofilm-associated staphylococcal mastitis, 33.1% for staphylococcal intramammary infection, and 51.5% for biofilm-associated staphylococcal intramammary infection. Nevertheless, vaccination should not be the only means for controlling mastitis; other udder health management measures should be included therein to improve control of the infection.

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a b s t r a c tObjective of this paper was to review relevant work and to present a general account of the bluetongue outbreak, which occurred in Greece in 2014. In total, 2895 outbreaks of the disease have been reported by the veterinary authorities of Greece; sheep, goats and cattle were affected with officially reported morbidity rates of 11.0%, 2.0% and 3.5%, respectively. No vaccinations were allowed and conservative measures were implemented to attempt to limit the disease, which at the end had expanded throughout the country. In field investigations, a significantly higher bluetongue morbidity rate (27.5%) in sheep has been reported. During that work, clinical anaemia was encountered, which was characterised as macrocytic, hypochromic, regenerative and non-haemolytic. Other investigations, which are reviewed in this paper, have described an outbreak of Citrobacter freundii-associated enteritis in newborn kids, offspring of goats subclinically infected with Bluetongue virus, increased rate of early embryonic deaths, reduced conception rates, increased incidence risk of mastitis and reduced milk yield in herds of subclinicallyinfected cattle and detection of the virus from hunter-harvested tissue samples of roe-deer. In 2015, vaccines against the disease have been licenced; vaccinations started in May 2015. Then, in 2015, only one outbreak of the disease was confirmed, which could have been the result of a combination of reasons acting concurrently to prevent further cases.