Thestudy aims to determine the variability of growth performancein Djallonkedwarf sheep reared on natural pasture in Benin according to the ecotype, sex, season, lambing rank and litter size. Data were then collected on 1061 sheep including 462 ofNorth ecotype and 599 ofSouth ecotype, from November 2014 to December 2015. These data were analyzed with SAS software (2006). The obtained results show that the sheep ecotype had affected (p<0.05) the different age-type weights and Average daily gain excluding the birth weight, weights at 270, 315, 330, 345 and 360 days. Animals of North ecotype were overall heavier than those of South ecotype. Except the birth weight, the sex had influenced the age-type weight of sheep with males heavier than females (p<0.05). The season didn't influence age-type weights excluding the weight at 120 days. However, the average daily gains were affected (p<0.05) by season excluding the values recorded from the age of 120 to 240 days with higher ADG found in animal born during the dry season. The lambing rank had only affected the weight at 225 days, 240 days and255 days (p<0.05) with the lesser growth found in animal born at the first lambing.Except the weights recorded from the birth to the age of 120 days and the live weights at 195, 210 and 225 days, the litter size didn't affected the others growth parameters. Non-genetic factors involved in this study must be taken into account to improve Djallonkesheep production in Benin.

The study aims to determine the variability of testicular morphometric traits in Djallonke sheep reared under traditional system in Benin according to the ecotype and their relationships with their body traits. Data were collected from November 2014 to December 2015 on 21 rams of North ecotype and 24 rams of South ecotype of 12 months old. It appears that chest circumference, back width, pelvis length, paired testes weight, testes length, testes diameter, testes volume, testes density, paired epididymal weight, epididymal length, epididymal volume, and the epididymal density depend on ecotype (P˂0.05). The highest chest circumference (69.24 vs 73.29 cm), back width (15.78 vs 14 cm) and pelvis length (23.03 vs 16.8 cm) were recorded in the animals of North ecotype (P˂0.05). similarly, the highest values (P˂0.05) of paired testes weight, testes length, testes diameter, testes volume, testes density, paired epididymal weight, epididymal length, epididymal volume, and the epididymal density were found in rams of North ecotype (respectively of 300.86g, 6.91 cm, 4.82cm, 146.14 ml, 1.02 g/cm 3 , 27.8 g and 20.1 cm). However, the head length, whither's height, scapulo-ischium length, scrotal length, scrotal circumference, epididymal volume and the epididymal density were similar among ecotypes and was respectively on average 18.21 cm; 54.64 cm; 60.61 cm; 14.09 cm; 22.17cm; 15.35ml and 0.87g/cm 3. In sheep of South ecotype, the live weight was strongly and positively associated with scrotal length, scrotal circumference, paired testes weight, testes length, testes diameter, testes volume, paired epididymal weight, epididymal length and epididymal volume (0.80≤ r ≤0.90; P<0.001); while in sheep of North ecotype, the live weight was proportional to scrotal circumference, paired testes weight, testes length, testes diameter, testes volume, paired epididymal weight, epididymal length and epididymal volume (0.87≤ r ≤0.99; P<0.001). Therefore, improve live weigth will improve the gonads traits as a correlated response.

The study aims to determine morphometric parameters of North and South ecotypes of Djallonke sheep of Benin by age and type of birth. Data were collected from November 2013 to December 2015 on 462 sheeps of North ecotype and 599 of South ecotype. These data were analyzed with SAS software (2006). It appears that all morphometric traits depend on the ecotype of sheep except body length. Indeed, the sheep of North ecotype were heavier (P<0.001) than south ecotype sheep and had recorded the greater wither's height (P<0.001) with the higher values of head length, shoulders width, hip length, tail length and cannon perimeter. Similarly, chest perimeter of sheep of North ecotype was 59.64 cm to 57.9 cm for South ecotype (P<0.05). The values of live weight, head length, body length, hip length, tail length and height at wither increased very significantly with the age of animals (P<0.001). The single born lambs weighed heavier than lambs born from twin, triple and quadruple litter size, and had the highest body length, shoulder width and wither's height (P<0.01). As for correlations, from the cannon perimeter which is slightly and positively associated with live weight (r=0.12; P<0.05), weakly and positively associated with head length (r=0.16; P<0.01), the other measured morphometric parameters were strongly and positively associated with live weight (0.30 ≤ r ≤ 0.85; P<0.001) and head length (0.26≤ r ≤ 0.81; P<0.001). Therefore, selection based on one trait will improve the other traits as a correlated response.