Experimental infections of birds with Turlock virus.

Two experiments were conducted with five gallinaceous and one passerine bird species to determine their responses to Turlock (TUR) virus inoculations. Inoculation of TUR strain 847-32 into bobwhites, chukars, ring-necked pheasants, chickens, and Japanese quail did not product detectable viremias. The first four species, however, did respond with neutralizing antibody. Inoculation of chickens with strain 69V-1095 resulted in a viremia which lasted 5 days and had a peak mean titer of 2.0 log 10 PFU per 0.2 ml of blood on the third day after infection. The observation that viremic birds exhibited no noticeable virus-associated morbidity or mortality suggested that TUR virus does not have a detrimental effect on free-ranging populations of the avian hosts studied during this investigation.

Electrophoretic protein analysis in the conditioned captive wild coyote, Canis latrans.

Total protein, albumin and serum protein values were determined on 19 male and 14 female captive, vaccinated, wild coyotes. Male coyotes had significantly higher total protein, alpha 1 and alpha 2 globulin levels than female coyotes. Captive, wild coyotes had lower values for total protein, albumin and beta globulins, and higher values for alpha 2 and gamma globulins than similar values for laboratory dogs. Albumin values determined by bromcresol green were slightly higher than values derived by electrophoresis. This difference was non-significant.

Surgical procedure for intraamnionic inoculation of the bovine fetus.

A surgical procedure that ensures intraamnionic inoculation of the bovine fetus is described. Right flank surgical operation was performed, using a "grid"-type entry though the abdominal muscles. A portion of the uterus containing 1 fetal leg was presented for inoculating the test material between the hooves. The procedure was rapid and simple to do and was safe for both the dam and the fetus.

Inherited susceptibility of cattle to high-altitude pulmonary hypertension.

This study examines the hypothesis that susceptibility of cattle to high-altitude pulmonary hypertension and heart failure (high mountain disease) is genetically transmitted. Eight offspring of cattle recovered from high mountain disease were considered "susceptible." Eleven offspring of healthy cattle residing at high altitude were considered "resistant." At the resident altitude of 1,524 m, 10-day-old susceptible calves had higher pulmonary arterial pressures than did resistant calves (34 vs.21 mmHg), but at 90 days of age the pressures for the two groups were similar (26 vs. 24 mmHg). After 64 days of exposure to an altitude of 3,048 m, the susceptible calves (87 +/- 7 (SE) vs. 40 +/- 3 mmHg). By 124 days at 3,048 m, all susceptible but none of the resistant calves had developed heart failure. The results indicated that susceptibility to pulmonary hypertension at high altitude was inherited. Susceptible cattle may provide a useful model of human hypoxic pulmonary hypertension.

Correlation of acute with chronic hypoxic pulmonary hypertension in cattle.

We investigated acute and chronic hypoxic pulmonary pressor responses in two groups of calves, one bred to be susceptible, the other resistant to high-altitude pulmonary hypertension. Twelve 5-mo-old susceptible calves residing at 1,524 m increased their mean pulmonary arterial pressure from 26 +/- 2 (SE) to 55 +/- 4 mmHg during 2 h at a simulated altitude of 4,572 m. In 10 resistant calves pressure increased from 22 +/- 1 to 37 +/- 2 mmHg. Five calves were selected from each group for further study. When 9 mo old, the 5 susceptible calves again showed a greater pressor response to acute hypoxia (27 +/- 1 to 55 +/- 4 mmHg) than did 5 resistant calves (23 +/- 1 to 41 +/- 3 mmHg). When 12 mo old, the 5 susceptible calves also developed a greater increase in pulmonary arterial pressure (21 +/- 2 to 9 +/- 4 mmHg) during 18 days at 4,572 m than did the 5 resistant calves (21 +/- 1 to 64 +/- 4 mmHg). Acute and chronic hypoxic pulmonary pressor responses were highly correlated (r = 0.91; P less than 0.001) indicating that they were probably produced through a common mechanism.