Discussion In this study, live body and testicular and epididymal parameters were evaluated in three goat breeds natives to arid and semiarid agroecologies of Ethiopia. The values of the testicular traits obtained in this study are higher than But the mean value of testicular diameter in this study is lower than The discrepancies in values might be due to breed differences, as it has been reported there exist breed differences in the size of the testicular parameters [ 13 ].
A measurement of scrotal circumference is an integral part of breeding soundness evaluation of animals with a pendulous scrotum, particularly in bulls [ 12 , 13 ].
Furthermore, measurements of the SC are viewed as a cheap, repeatable, and objective way to estimate sperm production [ 32 ]. In this study the overall mean value of scrotal circumference in bucks was Furthermore, the mean values of the scrotal circumference in three breeds in the present study are higher than These differences might be due to the effect of genotype or breed; similar reports of differences among breeds have been reported in goats [ 33 ]. Furthermore, studies suggest that, in addition to breed, season, nutrition, and body weight had an effect on SC of domestic animals [ 35 , 36 ].
Thus, in this study difference in nutritional managements of bucks could also be responsible for the differences in scrotal circumference among breeds. The larger scrotal circumference value for Long-eared Somali breed, as compared to Afar and Woyto-Guji breeds, might be due to differences in size, as large-sized breeds have greater SC [ 20 , 37 ].
SC is reliable measurement of reproductive status and seminal characteristics in goats [ 17 ]. For instance, a decrease in SC is an indication of an increase in morphologically abnormal sperm in an ejaculate [ 38 ]. Body weight and condition influence the reproductive potential of domestic animals and body weight itself is affected by breed, age, and nutritional status of bucks [ 36 ]. In Ethiopia, Long-eared Somali, Woyto-Guji, and Afar breeds of goats are considered as large-, medium-, and small-sized animals, respectively [ 19 , 21 ].
For Long-eared Somali, the mean body weight was Breeding soundness examination of male domestic animals should consider body condition because spermatogenesis tends to be limited in poor body condition; thus, sires should be maintained in moderate condition [ 39 ].
The differences might be due to breed difference, nutritional status, and variations in climatic conditions. Combined with other variables testicular weight can be used to select males for testicular size at puberty since it is a reliable variable for estimating the sperm production capacity [ 40 ] but it varies depending on the breed [ 41 ].
The values recorded in the current study are lower than These differences might be due to differences in breed and nutritional management [ 41 ]. It has been reported that animals with heavier testes produce more spermatozoa than those with smaller testes [ 42 ]. These disparities in the mean testes volume for the different breeds recorded in the current study agree with the report of [ 41 ] in different breeds of goats in Nigeria.
On the other hand, epididymal weight was highest in Long-eared Somali breed followed by Afar breed and Woyto-Guji breed scored the least value. In domestic animals, testes size and sperm production are highly correlated which implies that the larger the testes, the greater the sperm production [ 18 ]. Also, SC is good predictor of testicular size along with strong and positive associations between them [ 18 ].
The correlation coefficients of 0. These differences might be due to the effect of genotype or breed [ 33 ]. Similar reports of BW being significantly correlated with testicular weight were observed in different breeds of goats [ 11 , 44 ]. These high, positive, and significant correlations between body weight and SC with testicular measurements suggest that either of these variables or their combinations could provide a good estimate for predicting testicular and epididymal traits.
Testes weight is known to be very highly correlated with testicular sperm reserves [ 45 ]; thus males with larger testes tend to produce more sperm [ 46 ]. It has been reported that measurement of scrotal circumference, testes length, weight, and width would be a reliable predictor of the sperm producing capacity of bucks and they can be used to select for improved sperm production and breeding males [ 47 ].
In multiple linear regression analysis, simultaneous addition of body condition, scrotal circumference, and body weight were found to increase reliability of predicting testicular parameters in all three breeds.
Body weight and SC were found to be a significant and good estimate of testicular measurements and EW with large standardized beta in Afar, Long-eared Somali, and Woyto-Guji breeds. In conclusion, this study highlighted body weight and reproductive traits in bucks of three breeds native to arid and semiarid agroecologies of Ethiopia.
Breed was found to influence body weight, SC, epididymal weight, and testicular biometry in Afar, Long-eared Somali, and Woyto-Guji breeds. Long-eared Somali breed displayed higher body weight, SC, and testicular measurements. The most suitable live body measurements that can be easily measured on live bucks and could be used to predict epididymal and testicular biometry were found to be SC and BW.
The findings of this study could be used in breeding soundness assessment to select fertile bucks in their natural environments.
Acknowledgments The authors would like to acknowledge administration and staffs of the abattoir for their help and support. Conflicts of Interest The authors declared that there are no conflicts of interest concerning this manuscript. Report on Livestock and Livestock Characteristics in Ethiopia. Effect of water deprivation on dry matter intake, nutrient utilization and metabolic water production in goats under semi-arid zone of India.
Economic significance of sheep and goat. Sheep and Goat Production Handbook for Ethiopia. Participatory analysis of problems limiting goat production at selected districts of East Showa zone, Ethiopia. African Journal of Agricultural Research. Swedish University of Agricultural Sciences; Breeding soundness evaluation of extensively managed bulls in Costa Rica.
Examination of the reproductive tract and evaluation of potential breeding soundness in bucks. Current Therapy in Large Animal Theriogenology 2. Body measurements of red Sokoto bucks in Nigeria and their relationship with testicular biometrics. Iranian Journal of Applied Animal Science. Reproduction in Farm Animals. Clinical reproductive anatomy and physiology of the buck. Current Therapy in Large Animal Theriogenology. Body measurements of bucks of three goat breeds in Ethiopia and their correlation to breed, age and testicular measurements.