Does Kidney Fat Index Determine Body Condition of the Common Hippopotamus (Hippopotamus amphibius) in Luangwa River, Zambia?

Abstract

The body condition of common hippopotamus (Hippopotamus amphibius) in Luangwa River, eastern Zambia was assessed using Kidney Fat Index. Thirty-two (32) hippopotamus carcasses from culled specimens were picked at random to assess body condition. Using a sharp knife, kidneys were extracted from the lumen of each of the 32 hippopotamus carcasses. The whole kidney with surrounding fat was weighed in grammes using a solar powered digital weighing scale. The fat deposited immediately around the kidney (ignoring the fat extending anteriorly and posteriorly in the kidney mesentery), was removed and re-weighed. Kidney Fat Index index of 40 percent was obtained suggesting poor body condition rating of 40.91 percent Left kidneys had 40.20 percent and the right kidneys 41.63 percent Kidney Fat Index varied significantly between seasons (i£ 2 = 55.99, DF= 8, ii= 0.05, P < 0.001), being higher during the first half of the year January - June when pasture was in good condition and lower in the last half of the year July - December, when grass was of poor quality. Quality of pasture per season determined body condition of hippopotamus. More research is required to establish hippopotamus body condition classes during years of good rains and drought.