Age- and sex-related differences in haematological values of captive white-tailed gnu (Connochaetes gnou)

Abstract

During an 8-year period (1980–1989), 199 samples were taken from 52 clinically healthy white-tailed gnu (Connochaetes gnou), 24 males and 28 females, to estimate basic haematological values and to find possible age- and sex-related differences. In nine of the animals under investigation, four males and five females, the effect of sedating agents on blood parameters was studied.

A decrease of red cell counts, haematocrit values and haemoglobin levels were noted during the first 30 min after the administration of the sedating agent LA Immobilon. No changes in other haematological parameters were noted.

No pronounced sex-related differences were found in basic haematological parameters for all age groups under investigation.

Changes of the blood picture during life are pronounced. At birth, high values of erythrocyte counts, haematocrit and haemoglobin content were noted with increasing red cell counts up to the age of 2–3 months, but with decreasing haematocrit and haemoglobin content to age 20–30 days. After that, at the age of 2–3 months, peak values of all basic haematological parameters were reached. From the 6th month, there was a gradual slight fall of these parameters with lowest values in the oldest animals.

The highest leucocyte counts were noted at the age of 20–30 days with lower values at birth and decreasing values during life. The prevalence of neutrophils is maintained for all groups of age.

The results presented in this study are compared and discussed with limited data abstracted from the literature.