Abstract
Data were collected from 606 Egyptian water buffalo (340 females and 266 males) ranging in age from birth to almost 16 years. Age (t), live body weight (WT), heart girth (HG), abdomen girth (AG), wither height (WH), abdomen height (AH), body length (L), width from pin to pin (PP), width from hip to hip (HH), and distance from hip to pin (HP), chest depth (CD), abdomen depth (AD), and abdomen width (AW) were simultaneously taken once on each animal. Growth curves were calculated within sex for those measurements, using a non-linear model. Simple correlations were calculated between all traits. Stepwise regression was used to determine the 'best' prediction equation for weight. WH, AH, L, HG, and AD had faster relative growth rates than weight. Males had a faster growth rate than females and were larger at maturity for most traits. There was little difference between the sexes in HH. The PP measurement was greater for females at younger ages, but the males had a greater width at older ages. AH of both sexes was similar up to about 2 years of age; then the growth rate in females reduced rapidly, while the males continued to increase in AH. AG of males increased rapidly but did not reach the size of females at maturity; pregnancy may have influenced this measurement. Adult females weighed approximately 663 kg and were 154 cm tall at the withers, and 148 cm long, whereas adult males weighed 684 kg and were 160 cm at the withers and 146 cm long. The correlation between HG and WT was 0.96 in the females and 0.97 in the males. The correlation between length and weight was 0.95 in females and 0.96 in males. The average HG of adult females was 210 cm, whereas that of adult males was 213 cm. Because of the differences in relative growth rates of HG and WT between the sexes, they were considered as different populations when using HG to predict weight. Prediction equations for females and males were calculated; they tend to overestimate the weight of thin animals, as determined by WT to WH ratio, and underestimate the weight of fat animals.
