Presley S M, Knapp F W, Boling J A, Burg J G
Department of Entomology, University of Kentucky, Lexington 40546, USA.
J Econ Entomol. 1996 Feb;89(1):138-43. doi: 10.1093/jee/89.1.138.
Twenty-four Hereford-Angus crossbred beef steers were exposed to 0, 75, 150, and 225 horn flies, Haematobia irritans (L.), per head under controlled environmental conditions. The physiological and nutritional indices of all steers were recorded during a 14-d infestation period. Overall rectal temperature increased in steers exposed to 225 H. irritans was per head. Feed intake and nitrogen consumption by steers exposed to 225 H. irritans was lower than uninfested steers during the first 4 d. Overall serum cortisol was lower in steers exposed to 150 or 225 H. irritans per head compared with unexposed steers. Compared with unexposed steers, packed cell volume (percentage) was lower in steers exposed to 150 H. irritans on days 4, 7, and 14, lower in steers exposed to 225 H. irritans on days 7 and 14, and lower in steers exposed to 75 H. irritans on day 14. Blood urea nitrogen (BUN) was higher on day 1 in steers exposed to 75 H. irritans per head compared with uninfested steers, whereas BUN was lower in 225 H. irritans-exposed steers on days 7, 10, and 14 when compared with uninfested steers. Our data, in conjunction with previously published data, suggest that rectal temperature increases in beef steers exposed to > 150 H. irritans per head, and water consumption and urine production increases at infestation levels > 225 H. irritans per per head. Our data were unable to resolve H. irritans effects on steer heart rate, respiration rate, urinary nitrogen excreted, nitrogen retained, and serum cortisol levels.
在可控环境条件下，将24头赫里福德 - 安格斯杂交肉牛每头暴露于0、75、150和225只角蝇（嗜人血蝇）。在为期14天的感染期内记录所有肉牛的生理和营养指标。每头暴露于225只嗜人血蝇的肉牛总体直肠温度升高。在最初4天，暴露于225只嗜人血蝇的肉牛采食量和氮消耗量低于未感染的肉牛。与未暴露的肉牛相比，每头暴露于150或225只嗜人血蝇的肉牛总体血清皮质醇水平较低。与未暴露的肉牛相比，在第4、7和14天，暴露于150只嗜人血蝇的肉牛的红细胞压积（百分比）较低；在第7和14天，暴露于225只嗜人血蝇的肉牛的红细胞压积较低；在第14天，暴露于75只嗜人血蝇的肉牛的红细胞压积较低。与未感染的肉牛相比，每头暴露于75只嗜人血蝇的肉牛在第1天的血尿素氮（BUN）较高，而与未感染肉牛相比，暴露于225只嗜人血蝇的肉牛在第7、10和14天的BUN较低。我们的数据与先前发表的数据表明，每头暴露于超过150只嗜人血蝇的肉牛直肠温度会升高，且在感染水平超过每头225只嗜人血蝇时，饮水量和尿量会增加。我们的数据无法确定嗜人血蝇对肉牛心率、呼吸频率、尿氮排泄、氮保留和血清皮质醇水平的影响。
