Carvalho F A, Lammoglia M A, Simoes M J, Randel R D
West University of Sao Paulo (UNOESTE), Brazil.
J Anim Sci. 1995 Dec;73(12):3570-3. doi: 10.2527/1995.73123570x.
The objective of this study conducted in tropical Brazil was to characterize some physiological responses to heat stress in imported Bos taurus, native Bos taurus, and native Bos indicus cattle. Imported Simmental (n = 107) native Simmental (n = 99), and native Bos indicus cattle (n = 121) (42 to 80 mo of age) were evaluated. Animals were walked 7 km at 37 degrees C and 60 to 65% relative humidity during midday. Rectal temperatures and respiration rates were taken before and after the walk. A .01-cm2 sample of cutaneous tissue from the lateral cervical region was obtained from each animal. Slices were stained with hematoxylin-eosin solution, and the epithelial strata were counted. Perimeter of the sweat glands was also calculated. Rectal temperatures before the walk were greater (P < .001) in imported Simmental (40.52 +/- .04 degrees C) than in native Simmental (38.92 +/- .04 degrees C) or Bos indicus (38.90 +/- .04 degrees C). Rectal temperatures after the walk were greater (P < .001) in native Simmental (39.87 +/- .05 degrees C) than in Bos indicus (39.46 +/- .05 degrees C). Because of the heat, imported Simmental were not capable of finishing the drive, and rectal temperatures could not be taken. Respiration rates before and after the walk were greater (P < .001) in imported Simmental (64.3 +/- .6; 95.8 +/- .8) than in native Simmental (35.0 +/- .6; 56.8 +/- .8) or Bos indicus (15.0 +/- .2; 33.2 +/- .8). Sweat gland perimeter was greater (P < .001) in Bos indicus (540.5 +/- 19.1 mm) than in native Simmental (382.0 +/- 27.6 micrograms) or imported Simmental 497.2 +/- 17.4 micrograms). Native Bos indicus were environmentally adapted, native Simmental had elevated body temperatures and respiration rates, and imported Simmental had dramatically increased body temperatures and respiration rates. Native Bos indicus cattle were environmentally adapted and differed in skin histology, sweat gland histometry, and number of epithelial strata.
在热带巴西开展的这项研究的目的是，描述引进的欧洲牛、本地欧洲牛和本地瘤牛对热应激的一些生理反应。对引进的西门塔尔牛（n = 107）、本地西门塔尔牛（n = 99）和本地瘤牛（n = 121）（42至80月龄）进行了评估。在中午，让动物在37摄氏度、相对湿度60%至65%的条件下行走7公里。在行走前后测量直肠温度和呼吸频率。从每只动物的颈部外侧区域采集0.01平方厘米的皮肤组织样本。切片用苏木精-伊红溶液染色，并对上皮层数进行计数。还计算了汗腺周长。行走前，引进的西门塔尔牛的直肠温度（40.52±0.04摄氏度）高于本地西门塔尔牛（38.92±0.04摄氏度）或瘤牛（38.90±0.04摄氏度）（P < 0.001）。行走后，本地西门塔尔牛的直肠温度（39.87±0.05摄氏度）高于瘤牛（39.46±0.05摄氏度）（P < 0.001）。由于炎热，引进的西门塔尔牛无法完成行程，因此无法测量直肠温度。行走前后，引进的西门塔尔牛的呼吸频率（64.3±0.6；95.8±0.8）高于本地西门塔尔牛（35.0±0.6；56.8±0.8）或瘤牛（15.0±0.2；33.2±0.8）（P < 0.001）。瘤牛的汗腺周长（540.5±19.1毫米）大于本地西门塔尔牛（382.0±27.6微克）或引进的西门塔尔牛（497.2±17.4微克）（P < 0.001）。本地瘤牛对环境具有适应性，本地西门塔尔牛体温和呼吸频率升高，引进的西门塔尔牛体温和呼吸频率大幅增加。本地瘤牛对环境具有适应性，在皮肤组织学、汗腺组织测量和上皮层数方面存在差异。
