Dairy Response For Shade Associated To Cooling Equipment

Milk production in Brazil has been transformed lately due to the new worlds economical order and new technology has been adopted by the producers for improving productivity. To minimize the negative effect of the tropical environment in the dairy cows it is necessary to understand the relationships between the animal exposed to heat stress and its physiological response. This present research was carried out at Animal Science Institute, in São Paulo and had the objective to evaluate three different types of shade for milking cows lodged in open field. The tested treatments were: 1) artificial shade using a propylene screen 80% direct solar radiation reduction; 2) the same shade using a fan of 0.5 HP; and 3) the same shade structure using a fan 0.5 HP with fogging system. Eighteen milking cows were used in the treatments been 12 Holstein cows and 6 Brown Swiss equally distributed in the treatments according to their age and milk production level. The parameters analyzed were: milk production and fat content; body temperature, respiratory frequency, and cardiac frequency. Environmental parameters measured were dry bulb, black globe temperature and relative humidity, collect in each treatment and at a meteorological station at nearby site. The statistical package Software S-Plus 4.5 was used for evaluating the results. The results showed that the best treatment was the shade using forced ventilation associated to fogging system.246214628Head, H.H., Management of dairy cattle in tropical and subtropical environments (1995) Congresso Brasileiro de Biometerologia, Anais, SBBiomet, pp. 26-68. , JaboticabalBaêta, F.C., Instalações para gado leiteiro na região do mercosul (1998) Congresso Brasileiro de Biometeorologia, 2. Anais SBB, pp. 162-173. , GoiãniaHuber, H., Manejo de animais em sistema de estabulação livre visando maximizar o conforto e a produ̧ão (1995) Annis II Congresso Brasileiro de Gado Leiteiro, pp. 41-68. , PiracicabaHead, H.H., The strategic use of the fisiological potential of the dairy cow (1989) Anais Simpósio Leite nos Trópicos: Novas Estratégias de Proḑãuo, pp. 38-89. , BotucatuHead, H.H., The strategic use of the fisiological potential of the dairy cow (1989) Anais Simpósio Leite nos Trópicos: Novas Estratégias de Produ̧ão, pp. 38-89. , BotucatuFrazzi, E., Calamari, L., Calegari, Diferentes Systems of air conditioning for dairy cows housing in mediterranean climate (1998) Internacional Congress on Agricultural Engeneering, , 13 th MarrocosFrazzi, E., Calamari, L., Calegari, F., Maianti, M.G., Cappa, V., The Aeration, with and without misting: Effects on heat stress in dairy cows (1997) Proceeding of the Fifth International Symposium, pp. 907-914. , MinnesotaFolman, Y., Berman, A., Hertz, Z., Kaim, M., Rosemberg, M., Mamen, M., Gordin, S., Milk yeldand fertility of hight-yelding dairy cows in a subtropical climate during summer and inter (1979) J. Dairy Res., 46, pp. 411-425Fuquay, J.W., Heat stress as it affects animal production (1997) Livestock Environment V, 2, pp. 1133-1137Hall, A.B., Young, B.A., Goodwin, P.J., Gaughan, J.M., Davison, T., Alleviation of excessive heat load in the high producing dairy cow (1997) Livestock Environment V, 2, pp. 928-935Igono, M.O., Steevens, B.J., Shanklin, M.D., Johson, H.D., Spray cooling effects on milk production, milk and retal temperature of cows during a moderate temperature summer season (1985) J. Dairy Sci., 68, pp. 979-985Rodrigues, L.A., McKonnen, G., Wilcox, C.J., Martin, F.G., Krienke, W.A., Effects of relative humidity, maximum and minimum temperature, pregnancy and stage of lactation on milk composition and yeld (1985) J. Dairy Sci., 68, pp. 973-978Roman-Ponce, H., Thatcher, W.W., Buffington, D.E., Wilcox, C.J., Van Horn, H.H., Physiological and production responses of dairy cattle to a shade structure in a subtropical environment (1977) J. Dairy. Sci, 60, p. 42403

Imunidade celular em vacas Holandesas soropositivas para o Vírus da Leucose Bovina (BLV) durante o período de transição

RESUMO Esta pesquisa avaliou a dinâmica dos leucócitos e das subpopulações de linfócitos em vacas Holandesas soropositivas para o BLV no período de transição. Amostras de sangue (n=72) provenientes de 12 vacas foram coletadas entre as semanas -2 e +3 para a realização do leucograma, imunofenotipagem, dosagem de cortisol e haptoglobina (Hp). O perfil leucocitário foi caracterizado por leucocitose, neutrofilia, monocitose e eosinopenia próximo ao parto. Linfocitose e elevada proporção de linfócitos B CD21+ foram achados constantes entre as semanas -2 e +3; assim, as vacas foram testadas e confirmadas soropositivas para o BLV. Os valores das subpopulações de linfócitos T apresentaram-se baixos durante o período de transição, observando-se dois picos máximos que coincidiram com as elevações nas concentrações de cortisol no parto (2,11µg/dL) e semana +3 (1,97µg/dL). Hp apresentou aumento crescente de -2 (166µg/mL) a +3 (576µg/mL), provavelmente associada à elevada taxa de infecções uterinas observadas nas semanas +2 e +3. As vacas soropositivas para o BLV apresentaram leucograma de estresse próximo ao parto, exceto para linfócitos. A linfocitose e as elevadas proporções de células B CD21+, associadas com as baixas proporções de células T, podem ser indicativo de imunossupressão e predisposição aos processos inflamatórios no período pós-parto

Cellular immunity in Holstein cows seropositive for Bovine Leukosis Virus (BLV) during the transition period

<p></p><p>ABSTRACT This research evaluated the dynamics of leukocytes and lymphocytes subsets in seropositive Holstein cows for BLV during the transition period. Blood samples (n=72) from 12 cows were harvested from week -2 up to week +3 to perform leukogram, immunophenotyping, cortisol and haptoglobin (Hp). Leukocytes pattern was characterized by leukocytosis, neutrophilia, monocytosis and eosinopenia around calving. Lymphocytosis and high proportions of B cells CD21+ were a constant finding between week -2 and +3, thus cows were tested and confirmed seropositive for BLV. The values of T lymphocytes subsets were low during the transition period, observing two peaks that coincided with high levels of cortisol at delivery (2.11µg/dL) and week +3 (1.97µg/dL). Hp had gradual increase from week -2 (166µg/mL) until week +3 (576g/mL) probably due to high rate of uterine infection detected between week +2 and +3. The seropositive cows for BLV presented stress leukogram around delivery, except for lymphocytes. Lymphocytosis and the high proportions of B cells, associated with the low proportions of T lymphocytes, can be indicative of immunosuppression and predisposition to the inflammatory process observed in the post-partum period.</p><p></p

Benefits of automated acclimatization during the pre-milking phase of lactating girolando cows Benefícios da climatização automatizada na pré-ordenha de vacas girolando em lactação

The aim of this paper was to evaluate the automated acclimatization effects during pre-milking of cows on thermal conditioning, physiology, milk production and cost-benefit of the automated adiabatic evaporative cooling system (AECS). The treatments 20; 30; 40 min and control consisted of exposure time of pre-milking cows to the automated AECS. Sixteen cows were used with an average daily milk yield of 19 kg, distributed in a 4 x 4 Latin square design. The Tukey's test (P<0.05) was used to compare the means. The environmental variables, dry bulb temperature (DBT, ºC) and relative humidity (RH, %), were recorded every minute, which allowed the determination of the system efficiency through the Temperature and Humidity Index (THI). The respiratory rate (RR), rectal temperature (RT) and temperature of the coat (TC) were measured before and after the acclimatization. The 40 min treatment kept the environmental variables and the comfort indexes within recommended limits. The physiological variables (RR, RT and TC) were lower in the 40 min treatment and reflected positively on milk production, which increased 3.66% compared to the control treatment. The system was profitable, having a 43 days return on investment and a monthly revenue increase of R$1,992.67.<br>Objetivou-se com esta pesquisa avaliar os efeitos da climatização na pré-ordenha sobre o acondicionamento térmico, fisiologia, produção de leite e relação custo/benefício do sistema de resfriamento adiabático evaporativo (SRAE) automatizado. Os tratamentos adotados foram os tempos de exposição dos animais ao SRAE no curral de espera, 20; 30; 40 min e o tratamento-controle. Utilizaram-se 16 vacas com produção de 19 kg de leite dia-1, adotando-se delineamento em quadrado latino 4 x 4 e comparação entre as médias pelo teste de Tukey (P<0,05). Foram registradas as variáveis ambientais temperatura de bulbo seco (Tbs) e umidade relativa (UR) a cada minuto, o que permitiu determinar a eficiência do sistema por meio do índice de temperatura e umidade (ITU). A frequência respiratória (FR), temperatura retal (TR) e temperatura de pelame (TP) foram medidas antes e depois da climatização. O tratamento 40 min permitiu manter as variáveis ambientais e os índices de conforto entre os limites recomendados. As variáveis fisiológicas (FR, TR e TP) mostraram valores inferiores no tratamento 40 min, com aumento de 3,66$ 1.992,67 com tempo de retorno do capital de 43 dias