Impact of growth hormone receptor gene on measurements of dimen-sions and body weights of local Iraqi sheep

Abstract

This research involved a sample of 50 local Iraqi sheep, consisting of 27 males and 23 females, aged between 5 and 17 months. Data collection occurred during two distinct seasonal periods: October 2022 and January 2023. The primary objective was to investigate the variations in the expression of the growth hormone receptor (GHR) and its influence on the physical attributes of local Iraqi sheep within this age range. The results showed that the GHR gene exhibited a marked increase in expression during the second seasonal timeframe with levels of 23.8 ± 0.2  and 29.7 ±1.4 for first period. This increase in gene expression was paralleled by substantial differences in the sheep's body weights, with values of 33.7376±0.732(kg) for the first seasonal period and 35.77±1.111(kg) for the second seasonal period. Similarly, the dressing percentage showed significant differences, with values of 47.71±0.49 (kg) for the first period and 50.11±0.59 (kg) for the second period. Furthermore, carcass weight demonstrated highly statistically significant variations, measuring 16.037±0.440 (kg) during the first seasonal period and 17.978±0.655 (kg) during the second seasonal period. Gender-based analyses revealed significant disparities, with males exhibiting greater weight measurements (kg) (36.764±1.002) compared to females (32.122±806.0). The same trend was observed in carcass weight (18.362±0.606 for males and 15.242±0.369 for females), dressing percentage (49.8±0.0062 for males and 47.8±0.0047 for females), and viscera weight (1.382±0.029 for males and 1.258±0.032 for females). In addition to these findings, body dimension measurements (cm) showed significant differences in lump height, with measurements of 67.81±0.891 in the first period and 64.88±0.717 in the second period. However, non-significant differences were observed in other body dimension measurements. These findings have implications for understanding the genetic factors affecting the growth and development of sheep which can inform breeding and livestock management practices.