The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P < 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P < 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P < 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.

The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P < 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P < 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P < 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.

The productivity and well-being of animals can be substantially affected by stress. This is particularly true in the case of beef calves that are subjected to a multitude of stressors over a short period during the first year of life. Perhaps the most often studied stress-responsive variable has been blood corticosteroid concentrations. Factors such as age, gender, genetics, and degree of prior experience, can influence how an animal perceives and responds to a given stressor. Few studies have tried to control these variables, and accordingly, many conflicting results have been published regarding the impact of various stressors on cortisol response. We measured baseline plasma cortisol concentration over a 44-day study in Bos indicus and Bos taurus calves. Plasma cortisol values in Bos indicus calves were higher (32.60 +/- 0.66 ng/ml) than values in calves of Bos taurus (25.81 +/- 0.76) breeding. A precipitous decrease in cortisol concentration was observed 7 days after transport stress in all calves. Baseline cortisol concentration did not provide any indication of the intensity of the various stressors. However, significant differences were readily observed after ACTH administration. On the basis of cortisol secretion, stresses of transport and weaning were similar and were the most stressful to calves, regardless of genotype.

Chemotactic locomotion and luminol-dependent chemiluminescence of neutrophils, mitogen-induced lymphocyte blastogenesis, serum cortisol concentration, immunoglobulin quantification, and leukocyte counts were determined to evaluate the effect of a single strenuous exercise in horses. Increased serum cortisol concentration (P < 0.01) and an increased neutrophil-to-lymphocyte ratio P < 0.05) indicated that horses had been stressed. The chemotactic index and peak chemiluminescence production decreased significantly (P < 0.05 and P < 0.01, respectively) 1 day after exercise. Mitogen-induced blastogenesis of lymphocytes and serum immunoglobulin values remained unchanged in response to exercise. Results of this study indicated that a single bout of exercise may transiently impair neutrophil antimicrobial functions and nonspecific defense mechanisms, but not specific immunity in horses.

Sixty-eight cattle under general anesthesia were splenectomized. The transthoracic approach was used to provide better access to the spleen and to facilitate ligature of the major splenic vessels. The procedure was easier and less time-consuming, compared with other surgical approaches, and is considered to be less stressful to the animals. Postoperative recovery was complete in 67 of 68 cattle. After surgery, 1 animal developed respiratory tract disease that was thought to have been unrelated to the surgery.

Two test specimens of skin were cut from the lateral aspect of each hind limb of 9 rats. Specimens were contiguous, thereby providing matched pairs. One specimen was immediately placed in liquid nitrogen for 5 minutes, then stored at -70 C and tested within 3 to 4 weeks. Within 5 minutes of harvest, the second specimen was used for immediate material testing. Basic engineering material tests were used to measure strength, loading response, and elastic and viscous properties. Each matched pair of tissues was used for the same procedure. Quasistatic uniaxial tensile tests were used to apply deformations to the test specimens, and resulting loads were recorded. Stress and strain were calculated from the recorded data, providing information on yield strength, ultimate strength, fracture strength, and loading response. Each matched pair of specimens represented 1 repetition; 6 repetitions were made of each observation. Statistical analysis indicated that tissue freezing significantly (P<0.05) increased fracture strength, but did not affect strength, ultimate strength, or loading response. Dynamic vibration response tests were used to find mechanical mobility of the specimens, thereby providing information on elastic and viscous behaviors, which were quantified by calculation of spring and damping coefficients, respectively. As before, 6 repetitions were used. Statistical analysis indicated that tissue freezing did not affect these coefficients.