Studies in the environmental physiology of cattle in Northern Rhodesia. I. The relation between the changes in the haemoglobin index with age and the development of the heat toleration coefficient

Abstract

An investigation has been made on the changes in the haemoglobin index with age in four breeds of indigenous African and two breeds of European cattle.1. Support is given to previous findings that the haemoglobin index was high and variable at birth and fell to an individual more stable adult level at between 2 and 3 years of age.2. The haemoglobin levels for mature animals of the four tropical breeds are higher than mean figures quoted for other tropical cattle, but still fall within the ranges quoted.3. The haemoglobin levels for the Friesian agreed with those quoted from temperate regions, but those for the Jersey were higher, agreeing most nearly with Jamaican figures. A reason for this is advanced.4. The haemoglobin levels of the tropical breeds were significantly higher than those of the two temperate breeds examined.5. Confirmation was given to the association of a high haemoglobin index with a high heat toleration coefficient.

Studies on the production of beef from zebu cattle in East Africa IV. Variation in blood haemoglobin and its response to the feeding of dicalcium phosphate

“…Haemoglobin levels after 12 months appear to align more closely with those of fully adult animals. This has also been found by Walker (1958).…”

“…found by Gourlay (1959) in a group of sixty normal, healthy zebu cattle of mixed sex and all over 1 year of age, the 12-5 g./lOO ml. for adult Boran (zebu) cattle in Rhodesia found by Walker (1958) and the average of 12-6 g. reported by Gonzaga (1939) for Red Sindhi cows in the Philippines. More variable results are reported from India where adult Hariana cows averaged only 10-9 g./lOO ml., whilst Hariana calves from 0 to 6 months old were as high as 16-0 g. for males and 15-5 g. for females (Mullick & Pal, 1943).…”

Interrelationships of Erythrocyte Characters and Other Characters of British and Zebu Crossbred Beef Cattle

“…Red cell count (or packed cell volume or haemoglobin) is the most consistently related to growth rate. It has been suggested (Findlay 1950;Walker 1958) that haemoglobin level is specifically relevant to tropical adaptation. Although moderately heritable, it is known to be labile under nutritional and other environmental influences and its moderate correlation with growth rate probably arises from its acting as an index of general physiological status.…”