Responses of calves to a simulated altitude of 5000 m

Abstract

ABSTRACT.-Six calves were exposed in succession 12 days at 400 m altitude (control), 12 days at a simulated altitude of 5000 m in a low pressure chamber (experimental), and 14 days at 400 m altitude (recovery). Exposure to 5000 m produced the following changes : intake of feed and water decreased by 47 and 35% respectively, and body weight gain ceased. Rectal temperature rose by 0.4oc. Heart rate increased by 65%. Respiratory rate and blood pH increased moderately. There was an S-shaped rise of haematocrit (from 33 to 45%), which was paralleled by blood viscosity. Plasma viscosity showed a sharp, but transient rise. Short term measurements made during ascent to and descent from 5000 m altitude, both lasting for four hours, showed that some of the changes developed rapidly.

Effect of diet type on performance and metabolic traits of Peruvian local and introduced cow types kept at 200 and 3600 m of altitude

“…Cows exposed to oxygen partial pressure equivalent to 4500 m a.s.l. responded with effective adaptation mechanisms (Bianca and Hays, 1975), but the time needed for sufficient adaptation was found to be too long to prevent massive depressions in performance (Christen et al, 1996;Kreuzer et al, 1998). This may be different in cows fully adapted to high altitude.…”