Castanheira Marlos, Paiva Samuel Rezende, Louvandini Helder, Landim Aline, Fiorvanti Maria Clorinda Soares, Dallago Bruno Stefano, Correa Patricia Spoto, McManus Concepta
Escola de Veterinária, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Trop Anim Health Prod. 2010 Dec;42(8):1821-8. doi: 10.1007/s11250-010-9643-x. Epub 2010 Jul 23.
The animal and its environment make up an integrated system, where each acts on the other. Tropical regions are characterized by high levels of solar radiation and environmental temperature which may adversely affect animal production. This study carries out a multivariate analysis of physical and physiological traits in sheep in the Federal District of Brazil to test the ability to separate groups of animals and determine which traits are most important in the adaptation of animal to heat stress. The variables studied included coat thickness, number and length of hairs, pigmentation of the skin and coat, number of sweat glands as well as heart and respiratory rates, rectal and skin temperatures, sweating rate, and blood parameters. Five groups of ten animals were used depending on breed (Bergamasca, crossbred, or Santa Inês) or coat color (Santa Inês--brown, white, and black). The data underwent multivariate statistical analyses including cluster, discriminate, and canonical, using Statistical Analysis System--SAS®. The tree diagram showed clear distances between groups studied and canonical analysis was able to separate individuals in groups, especially Bergamasca and white Santa Inês. The canonical correlation redundancy analysis showed that coat reflectance as well as hair length and number of hairs per unit area were the most useful in explaining changes in physiological traits. Skin and coat traits such as hair length, coat reflectance, percentage of epithelial area occupied by sweat glands, skin reflectance and thickness, as well as heart and breathing rates were the most important in separating these groups.
动物及其环境构成一个综合系统，其中二者相互作用。热带地区的特点是太阳辐射水平高和环境温度高，这可能对动物生产产生不利影响。本研究对巴西联邦区绵羊的身体和生理特征进行了多变量分析，以测试区分动物群体的能力，并确定哪些特征对动物适应热应激最为重要。所研究的变量包括被毛厚度、毛发数量和长度、皮肤和被毛的色素沉着、汗腺数量以及心率和呼吸率、直肠温度和皮肤温度、出汗率和血液参数。根据品种（贝加马斯卡羊、杂交羊或圣伊内斯羊）或被毛颜色（圣伊内斯羊——棕色、白色和黑色），使用了五组，每组十只动物。使用统计分析系统——SAS® 对数据进行了多变量统计分析，包括聚类分析、判别分析和典型相关分析。树形图显示了所研究群体之间的明显距离，典型相关分析能够区分群体中的个体，尤其是贝加马斯卡羊和白色圣伊内斯羊。典型相关冗余分析表明，被毛反射率以及毛发长度和单位面积毛发数量在解释生理特征变化方面最有用。被毛和皮肤特征，如毛发长度、被毛反射率、汗腺占据的上皮面积百分比、皮肤反射率和厚度，以及心率和呼吸率在区分这些群体方面最为重要。
