In vivo and in vitro heat shock proteins gene expression in cattle.

The main purpose for this study was the quantification of the heat shock proteins HSPA1A and HSP90AA1, in cow lymphocytes, when subjected to heat stress directly - in vivo, or indirectly - in vitro. The aim was to identify differences between HSP expression in vitro and in vivo. The experiment was conducted in the Biometeorology and Ethology Laboratory of FZEA-USP. Were used three female Holstein Frisian, which were subjected to heat stress, by sun exposure. The blood samples were collected after sun exposure, with a temperature of 40 ± 2 º C, during three days. For in vitro tests, blood of the same animals was collected and placed for a period of 4 hours in a water bath at 40 º C, thus simulating the thermal stress. Total RNA of lymphocytes was extracted, treated with DNase I and submitted to cDNA synthesis for gene expression quantification of HSPA1A and HSP90AA1, by real time PCR (qRT-PCR). The data were tested for normality by Kolmogorov-Smirnov test and for homocedasticity by Levene test. Data were analyzed according to a general linear model procedure with 2 fixed factors treatment and genes expression. Significantly different means were submitted to post-hoc comparisons of means (LSD test) and regarded as significantly different when P<0.05. The results showed that there are no significant differences between the in vitro and the in vivo treatments

INFLUÊNCIA DA DISPONIBILIDADE DE SOMBRA A PASTO SOBRE A MORFOLOGIA ESPERMÁTICA DE TOUROS DA RAÇA BRAHMAN (Bos taurus indicus) CRIADOS NA REGIÃO SUDESTE DO BRASIL

Under heat stress conditions, testicular degeneration can occur, even on zebu animals. Therefore, the aim of this work was to verify the occurrence of any possible effect of shadow availability on pasture on spermatic morphology of Brahman Bulls on Brazil Southeast. Five animals were allocated on pasture with shadow availability, and five bulls were allocated on pasture without any kind of shadow. No difference was observed (P>0.05) in any of the characteristics analyzed when Brahman bulls were maintained on pastures with or without shadow availability

Influence of season on plasmatic cortisol and IGF -I in dairy cows under thermal comfort.

Objectives: Access to evaporative cooling system can increase production in dairy cows due to improve thermal comfort. The aim of this study was to evaluate the impact of ambient temperature on thermoregulation, cortisol and IGF-I, and determine the efficiency of evaporative cooling system on the physiological responses in different weather patterns. Materials and Methods: 24 Holstein cows were housed in two groups with or without access to cooling system with fans and mist in the free-stall. The parameters analyzed were: rectal temperature (TR ), body surface (TS ), internal base of tail (TC ), respiratory rate (FR), cortisol and IGF-I during the morning milking (700h) and afternoon (1430h) in five different weather patterns throughout the year (fall, winter, spring, dry summer and rainy summer). Results: TR , TS , TC and FR were lower in the morning (P<0.01). Cooling system did not affect rectal temperature, with both groups had values below 38.56 over the year (P=0.11). We observed an upward trend (P<0.05) in plasma cortisol concentrations between autumn and winter, starting the decline until the dry summer and a further increase during the rainy summer. A gradual increase of IGF-I happened between autumn until the dry summer, and decreased during the rainy summer (P<0.05). Cortisol and IGF-I may have been influenced by light hours. TR showed a moderate and positive correlation (P <0.001) with the TS (0.46) and FR (0.35). The air temperature and THI showed positive moderate to high correlations with TR , TC , TS and FR (P <0.001). Conclusions: The ambient temperature influences positively on the physiological variables, independent of the cooling system, but cooled animals kept milk production even during the summer. The plasma concentrations of cortisol and IGF-I may have been influenced by the seasons and the milk production

Evaluation of salivary proteins as potential biomarkers of milk production in hot climates

Evaluation of salivary proteins as potential biomarkers of milk production in hot climates Ana CAPM Geraldo1, Cristina Conceição 1,2, Liliana Cachucho2, Flávio Silva2, Catarina Matos2, Elsa Lamy1, Fernando Capela e Silva 1,3, and Alfredo Pereira 1,2 1 Institute of Mediterranean Agricultural and Environmental Sciences, University of Evora, Portugal; 2 Department of Zootechnics, University of Évora, Portugal; 3 Department of Biology, University of Evora, Portugal [email protected] Dairy cattle are particularly sensitive to high temperatures, lowering milk output as well as milk quality (fat, solid, lactose and protein). Given the trend of global warming, the joint selection for productivity and adaptability is an objective, i.e. greater heat loss without lowering the metabolism. So, to search and validate the xistence of non"invasive biomarkers that could allow selection of the animals best adapted is crucial to achieve such an objective. The interest of saliva as a source of biomarkers starts to increase in animal production. Salivary ortisol has been used in some studies, but it presents some limitations for thermal stress, which can be circumvent by salivary proteins. The hypothesis that cows presenting high potential for milk production under adverse thermal conditions also present differences in salivary protein profiles comparatively to the ones less productive, is actually being tested at ICAAM"University of Évora, Portugal, by our research team. The experiment was design to identify salivary proteins whose expression levels can be related to the potential for milk production under unfavourable thermal conditions. Twelve animals (6 high and 6 low milk potential production) were analysed for salivary protein composition at three different acclimation time points: first, during summer, under hot temperatures; second, under thermoneutrality; and third, during winter, under low temperatures. Whole saliva was collected directly from cow mouth, using cotton rolls (salivettes). At each time point, collection was performed in two different days, to avoid bias due to particular variations due to environment. One and two"dimensional electrophoresis are being performed to compare salivary proteomes from animals with different milk production potential, and to assess how differences between these groups are maintained through the different acclimation periods.COST FA1308- Dairy Care; ICAA