Department of Animal Science, State University of Acaraú Valley (UVA), 62040370, Sobral, CE, Brazil.
Department of Animal Science, Federal Rural University of the Semi-arid Region (UFERSA), 59625900, Mossoró, RN, Brazil.
Int J Biometeorol. 2020 Jan;64(1):105-113. doi: 10.1007/s00484-019-01797-9. Epub 2019 Sep 4.
The objectives of this study were to determine the main variables which act in the adaptive profile and the dynamic of the thermoregulatory responses of Sindi and Girolando dairy cows in tropical conditions using multivariate analyses as the auxiliary method. Thirty dairy cows were evaluated, in which the data were collected monthly during 12 months. Rectal temperature (R) and respiratory rate (R) were measured twice a day (morning and afternoon), along with meteorological variables (air temperature, relative humidity, and wind speed), and later the Black Globe and Humidity Index and Radiant Heat Load were calculated. Blood samples were collected for estimating the levels of triiodothyronine (T), thyroxine (T), hemoglobin concentration (HC), red blood cells (RBC), packet cell volume (PCV), mean corpuscular volume (MCV), white blood cells (WBC), glucose (GLU), cholesterol (CHO), triglycerides (TRI), creatinine (CRE), total protein (TP), urea (URE), albumin (ALB), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). The more active variables in the adaptive profile for Sindi cows were T, PCV, RBC, WBC, TRI, CRE, HC, T, and URE, while PCV, RBC, ALB, TP, R, R, URE, ALT, and AST variables were more active for Girolando cows. All animals were classified according to their corresponding group when considering all variables under study. The classification error percentage was > 40% in the Sindi cows when the physiological responses were considered, whereas an 80% success rate was observed in Girolando cows in the winter and summer seasons. The physiological responses of the dairy cows are similar in winter and distinct in summer in tropical conditions.
本研究的目的是利用多元分析作为辅助方法，确定作用于辛地和吉拉索奶牛在热带条件下适应特征和体温调节反应动态的主要变量。评估了 30 头奶牛，在 12 个月的时间里每月收集一次数据。每天测量两次直肠温度（R）和呼吸频率（R）（早上和下午），同时测量气象变量（空气温度、相对湿度和风速），然后计算黑球和湿度指数以及辐射热负荷。采集血样以估计三碘甲状腺原氨酸（T）、甲状腺素（T）、血红蛋白浓度（HC）、红细胞（RBC）、红细胞压积（PCV）、平均红细胞体积（MCV）、白细胞（WBC）、葡萄糖（GLU）、胆固醇（CHO）、甘油三酯（TRI）、肌酐（CRE）、总蛋白（TP）、尿素（URE）、白蛋白（ALB）、天门冬氨酸氨基转移酶（AST）和丙氨酸氨基转移酶（ALT）的水平。辛地奶牛适应特征中更活跃的变量是 T、PCV、RBC、WBC、TRI、CRE、HC、T 和 URE，而 PCV、RBC、ALB、TP、R、R、URE、ALT 和 AST 变量对吉拉索奶牛更为活跃。当考虑所有研究变量时，所有动物都根据其相应的组进行分类。当考虑生理反应时，辛地奶牛的分类错误百分比>40%，而在冬季和夏季，吉拉索奶牛的成功率为 80%。在热带条件下，奶牛的生理反应在冬季相似，夏季则不同。
