Tadesse Dereje, Patra Amlan Kumar, Puchala Ryszard, Hussein Ali, Goetsch Arthur Louis
American Institute for Goat Research, Langston University, Langston, OK 73050, USA.
Department of Animal Sciences, Debre Berhan University, Debre Berhan P.O. Box 445, Ethiopia.
Animals (Basel). 2023 Aug 16;13(16):2643. doi: 10.3390/ani13162643.
Physiological and blood measurement changes due to high heat load, restricted feed intake, and limited drinking water availability in 135 animals of three hair sheep breeds (Dorper, Katahdin, and St. Croix) were subjected to multivariate analysis techniques. The objective of this analysis was to evaluate the ability of these variables to separate individual hair sheep into groups based on adaptation characteristics in response to three physiological stressors and identify variables with greater discriminatory power. There were 16, 8, and 13 physiological and blood variables obtained from high heat load, restricted feed consumption, and water intake studies, respectively, for multivariate analysis. Physiological variables such as respiration rate, rectal and skin temperature, and panting score were measured only in the heat stress study. The results of the cluster and canonical discriminant analyses showed the presence of wide divergence ( 0.05) between St. Croix and other breeds in their responses to high heat loads and restricted-feed- and -water-intake conditions. Dorper and Katahdin were grouped ( 0.05) together based on the changes in physiological variables, which were separated ( 0.05) from those of St. Croix as a resilient group. The stepwise discriminant analysis indicated that skin temperature, panting score, rectal temperature, respiration rate, and blood urea nitrogen and oxygen concentrations were the significant ( 0.05) discriminating variables in clustering individual sheep into groups based on their responses to the high-heat-stress condition. Under the limited feed intake condition, the significant ( 0.05) traits responsible for the separation of St. Croix from Dorper and Katahdin were blood triglyceride and cholesterol concentrations, whereas blood hemoglobin, osmolality, protein, and albumin were most important discriminating variables under the limited water intake condition. In conclusion, the results of the present study suggest that the stress responses of Dorper and Katahdin are similar and different from that of St. Croix. This finding can be useful information for future decisions in developing climate-resilient sheep through selective breeding.
对三个毛用绵羊品种（杜泊羊、卡他丁羊和圣克罗伊羊）的135只动物，因高热负荷、采食量受限和饮水供应有限导致的生理和血液测量变化进行了多变量分析技术研究。该分析的目的是评估这些变量根据对三种生理应激源的适应特征将个体毛用绵羊分组的能力，并识别具有更大鉴别力的变量。分别从高热负荷、采食量受限和饮水研究中获得了16个、8个和13个生理和血液变量用于多变量分析。生理变量如呼吸频率、直肠温度和皮肤温度以及喘气评分仅在热应激研究中进行了测量。聚类分析和典型判别分析结果表明，圣克罗伊羊与其他品种在对高热负荷以及采食量和饮水量受限条件的反应上存在广泛差异（P<0.05）。根据生理变量的变化，杜泊羊和卡他丁羊被归为一组（P<0.05），而作为一个适应性强的群体，它们与圣克罗伊羊的生理变量变化存在差异（P<0.05）。逐步判别分析表明，皮肤温度、喘气评分、直肠温度、呼吸频率以及血液尿素氮和氧浓度是根据绵羊对高热应激条件的反应将个体绵羊聚类分组的显著（P<0.05）鉴别变量。在采食量受限条件下，导致圣克罗伊羊与杜泊羊和卡他丁羊分离的显著（P<0.05）特征是血液甘油三酯和胆固醇浓度，而在饮水受限条件下，血液血红蛋白、渗透压、蛋白质和白蛋白是最重要的鉴别变量。总之，本研究结果表明，杜泊羊和卡他丁羊的应激反应相似，与圣克罗伊羊不同。这一发现可为未来通过选择性育种培育适应气候变化的绵羊的决策提供有用信息。
