Abstract. Strawberry disease is a subchronic, non–debilitating, and non–fatal inflammatory skin disease of rainbow trout that has been recognized for the past 25 years. Morbidity ranges up to 80% and the disease affects fishes from 15cm in length to brood stock size. Epizootiological data indicate that strawberry disease usually appears, first in the autumn and reaches peak incidence during the following winter and spring. Data also indicate that the disease is found only in certain trout farms in the western and Pacific north–western regions of the United States. Although the cause of strawberry disease is unknown, the normal clinical course of 8 weeks can be reduced by oral treatment with oxytetracycline. Clinical signs include appearance of bright red, raised, circumscribed, ulcerated and indurated lesions in the skin that usually range up to 3 cm or more in diameter. Microscopically, the disease is characterized as a subchronic, focal, non–suppurative dermatitis with ulceration and extensive infiltration of mononuclear inflammatory cells.

Aortic blood pressure, ECG, electromyogram, and heart rate were recorded in cold-stressed and rewarmed young Holstein bull calves. The calves were anesthetized and then cold-stressed by immersion in cold water until their core body temperature (colonic) was lowered 10 C. Hypothermia was continued for 1 additional hour and then the calves were rewarmed by 3 external rewarming methods or were allowed to recover naturally (unassisted). Aortic blood pressure began to decrease in cold-stressed calves by the time their core body temperature had decreased 2 C and continued to decrease during cooling. Heart rate initially increased then decreased with cooling. Blunting of the systolic blood pressure peaks and appearance of extraneous waveforms that obscured the normal component waveforms of the ECG complex were also observed during cooling. Aortic blood pressure and heart rate of cold-stressed calves increased soon after the start of recovery and eventually returned to base line even though the rate of recovery varied depending on the method of rewarming. The component waveforms of the ECG complex became more discernible as rewarming of the cold-stressed calves progressed.

One- to 7-day-old Holstein bull calves were anesthetized and cold-stressed until their core body temperature (CBT; colonic) was lowered by 10 C. The calves were then rewarmed in warm water, by heat pads or heat lamps, or allowed to recover naturally (unassisted). Temperatures of peripheral tissues, muscles, and the body core were recorded. The time required to lower the CBT of the cold-stressed calves was 168 +/- 11.7 minutes (mean +/- SE). Cold exposure caused a linear decrease in blood, colonic, rectal, and oral temperatures, whereas temperature decreases in the thigh and pectoral muscles, dorsal and ventral thoracic regions, and the hock joint region were generally of greater magnitude and were curvilinear in pattern. By the time the CBT had decreased 1 C, tissue temperatures during cooling were less than (P less than 0.01) the respective temperatures obtained before cooling. The mean time required to rewarm the calves in warm water (47.1 +/- 3.5 minutes) was less than (P less than 0.05) that for the other rewarming methods. The mean rewarming times for the heat pad (128 +/- 12.8) and heat lamp (125.4 +/- 10.9) methods were greater than (P less than 0.05) that for the warm water method, but less than (P less than 0.05) that for the unassisted calves (190.7 +/- 23.1). In general, there was a linear increase in most of the tissue temperatures during recovery although temperatures in the hock joint region were variable. Temperature differences were observed between the thigh and pectoral muscles and between subcutaneous tissues during cooling and recovery. There was poor correlation between the ages of the calves and the time required to decrease their CBT during cooling and also the time required to increase their CBT, regardless of the rewarming method used.

Hematologic values were determined in cold-stressed and rewarmed 1- to 7-day-old Holstein bull calves. The animals were anesthetized and then cold-stressed by immersion in water until their core body temperature (colonic) had decreased by 10 C. They were kept at the hypothermic state for an additional 1 hour and then were rewarmed by 1 of 3 external rewarming methods or by natural (unassisted) recovery. Changes observed in the hematologic values of the cold-stressed calves during cooling represented a trend, rather than a direct effect of cold exposure because the values did not differ (P greater than 0.05) from those obtained from the noncold-stressed animals. Nevertheless, a linear decrease (P less than 0.05) in the total number of leukocytes was observed in the cold-stressed calves during cooling when compared with preimmersion values. The leukopenia resulted primarily from a neutropenia (P less than 0.05) and secondarily from decreases in the number of other leukocytes. Minor increases were noticed in the total number of erythrocytes, hemoglobin concentration, and PCV, whereas mean corpuscular values generally remained unchanged during cooling. A rapid and linear increase in the total number of leukocytes was noticed in all cold-stressed calves during recovery. The increase in total leukocytes occurred in all types of leukocytes and particularly in segmented and nonsegmented neutrophils.