Physiological effects of altitude on cattle
Hays, F.L.; Bianca, W.
Schweizer Archiv für Tierheilkunde 118(4): 151-166
1976
ISSN/ISBN: 0036-7281 PMID: 959804 Document Number: 99820
Eleven heifers aged 6-15 months were housed at 400 m above sea level for 16 weeks, housed at 2000 m for 4 weeks, pastured at 1700-2600 m for 12 weeks, housed at 2000 m for 4 weeks, then housed at 400 m for 4 weeks. Blood haemoglobin, haematocrit and viscosity increased while the cattle were on the mountain, mainly during the first period of housing on the mountain, indicating that the cause was hypoxia; plasma viscosity also increased, this being attributed to a loss of plasma water or a modification of plasma proteins. Heart rate decreased by about 10 beats/min on the mountain pasture. Mean pulmonary arterial pressure and venous blood pH were unaffected. Body weight fell during the first half of the time on the mountain, but this was not caused by chronic mountain sickness.