Evaluating The Relationship Between Superficial Body Temperature And Milk Yield In Lactating Jersey Cows Using Climatization At Pre-milking Parlor [avaliação Da Relação Entre A Temperatura Da Superficie Corporal E Produção De Vacas Jersey Submetidas à Climatização Na Pré-ordenha]

Jersey cows has been used in warm climates because they have better performance in dairy production. Generally milk production is reduced in warm climates due to the consequent reduction in feed intake because of the heat stress. When the heat stress occurs there is an increase in the body temperature, however it is not known if the skin temperature indicates a thermal discomfort or if it influences milk yield. The objective of this research was to verify if there was a correlation between skin temperature and milk yield using two treatments. Treatment (A) where the cows stayed for 30 minutes before the milking period, in a room with a shower and a fan; and treatment (B) where the cows did not had access to any cooling device (control). After milking the skin temperature were recorded in the places: forehead, back, leg and teats. Data were statistically analyzed and, even though in treatment (A) the skin temperature were reduced it was not found correlation between skin temperature and milk yield.1123537Baccari Jr., F., Manejo ambiental para produção de leite em climas quentes (1998) Congresso Brasileiro de Biometeorologia, II. Goiânia, 1998. Anais. Goiânia, Sociedade Brasileira de Biometeorologia, pp. 136-161Beede, D.K., Shearer, J.K., Nutritional management of dairy cattle during hot weather (1991) Agri-practice, 12, pp. 5-13Head, H.H., The strategic use of the physiological potential of the dairy cow (1989) Anais Simpósio "Leite Nos Trópicos: Novas Estratégias de Produção", pp. 38-89Johnson, H.D., Role of physiology in cattle production in the tropics (1982) New York: Praeger ScientificMacfarlene, J.S., Stevens, B.A., The effect of natural shade and spraying with water on the productivity of dairy cows in the tropics (1972) Trp. Animal Health Production, 4, pp. 249-253Maust, L.E., Macdowell, R.E., Hooven, N.W., Effect of Summer weather on performance of Holstein cows in three stages of lactation (1972) Journal of Dairy Science, 55, pp. 1133-1139Rodriguez, L.A., Mckonnen, G., Wilcox, C.J., Martin, F.G., Kriemke, W.A., Effects of relative humidity, maximum and minimum temperature, pregnancy, and stage of lactation on milk composition and yield (1985) Journal of Dairy Science, 68, pp. 973-97

Índice de previsão de produção de leite para vacas Jersey Index for predicting milk production in Jersey cows

No Brasil, o uso de vários modelos de criação intensiva e semi-extensiva desfavorece a adoção generalizada de métodos de manejo do gado bovino, principalmente do gado leiteiro. Mesmo assim, a produção leiteira pode ser melhorada a partir do uso de tecnologias que possam garantir o manejo adequado do rebanho. O objetivo deste trabalho foi desenvolver um índice de previsão de produção de leite para vacas Jersey em lactação, de genética de alta produtividade, em regime semi-estabulado, nas condições tropicais. Para a obtenção do índice, consideraram-se a temperatura e a umidade relativa do ambiente e a velocidade do ar, assim como valores de precipitação pluviométrica, temperatura do solo do pasto e a radiação solar como agentes estressores, os quais podem alterar a produção de leite. O experimento considerou dois tratamentos: A - as vacas permaneceram em sala de espera guarnecida com chuveiro e ventiladores, por um período 30 min antes da ordenha; B - as vacas não tiveram acesso a essa sala de espera (controle). Fora do período de ordenha, as vacas tiveram acesso ao pasto. Observou-se que as diferenças de médias de produção entre os tratamentos não foram estatisticamente significativas. Foram procedidas as análises para efeito de elaboração do modelo e chegou-se a um modelo factível, considerando a relação entre produção e a precipitação, assim como a temperatura máxima do solo do pasto.<br>In Brazil the adoption of several models of cattle confinement leads to special conditions for management methods in dairy production, which can be improved by the use of technology that assures better herd management. Indexes relating environmental variables to production are applied for the prediction of milk production. The values of temperature and relative humidity, rain index, solar radiation and pasture soil temperature are generally considered potential stress agents for cows. The objective of this research was to develop an index for predicting milk production for high productivity Jersey milking cows lodged in semi confinement in tropical conditions. The experiment considered two treatments: A - the cows waited for 30 minutes prior to milking in a room with a shower associated to a fan; B - the cows did not have access to this room (control). Other than the waiting period, the cows had access to pasture. Differences in the effect of average production were not statistically significant. The analysis for studying the effect of the variables and designing the model led to a statistical model relating the variables milk production and rain index, as well as the maximum soil temperature of pasture, and milk production