This research was carried out at the Department of Animal Science and Range Management Teaching and Research Farm, Modibbo Adama University of Technology, Yola, Adamawa State, to evaluate the growth performance of ram lamb and ewe lamb raised under natural grazing .The research was conducted by using four ramlambs and four ewelambs which lasted for three months (12 weeks). The data collected was subjected to Mann Whitney test such as Head Length (HL), Vertebral Rump Length (VRL), rump tail (RT), Height at withers (HW) and Girth Circumference (GC).The Mann Whitney testis the non-parametric analogue of the parametric unpaired test, as in non-parametric test, the actual measurement were not employed or used, instead the ratio of measurement were used. The values of the total Head Length (HL) were taken from week one to week twelve (12) and added together and divided by the total number of weeks (12 weeks) and finally obtained the average or mean value of the Head Length (HL), same procedure was followed for the vertebral rump length (VRL), rump tail (RT), height at withers (HT)and girth circumference (GC). The result obtained showed that ram lamb performed better than the ewe lamb under free range system of production. Thus, based on the experimental research, male put more weight compared with female counter part. Generally, it is very difficult to determine the growth performance of ram lamb andewe lamb, raised under natural grazing or production. However, this research find out the effect of extensive system of management on the growth performance of ram lamb and ewe lamb
