Evaluations of Boar Gonad Development, Spermatogenesis with regard to Semen Characteristics, Libido and Serum Testosterone Levels based on large White Duroc × Chinese Erhualian Crossbred Boars

Abstract

Chinese Erhualian pigs are known for prolificacy with distinct reproductive traits compared with Western commercial breeds. In this study, a four-generation intercross resource population was constructed using White Duroc boars and Chinese Erhualian sows as founder animals, and a total of 14 male reproductive traits were recorded in 411 F2/F3 boars including the testis and epididymis weights, the seminiferous tubular diameter and spermatogenesis at 60, 90 and 300 days of age, semen characteristics, serum testosterone concentration and libido level at 300 days of age. The White Duroc-Erhualian boars showed remarkable segregations in the traits measured except for the seminiferous tubular diameter and had high ratio (13.9%) of the abnormality of spermatogenesis, providing a good experimental population for detecting quantitative trait loci affecting these male reproductive traits. Furthermore, the correlations among nine male reproductive traits at 300 days of age indicated that the testis weight and the body weight were strongly correlated with the sperm production, supporting the two traits as important parameters for boar selection to increase sperm production and ultimately improve boar fertility. The libido level in the White Duroc-Erhualian boars that was evaluated by a new and easily recorded scoring system showed a significant correlation with serum testosterone concentration. Yet, both libido and serum testosterone concentration were not correlated with the sperm production. Results of this study provided new information on the male reproductive physiology and genetics in Chinese Erhualian and White Duroc boars.

Effect of active immunization against GnRH on testosterone concentration, libido and sperm quality in mature AI boars

“…These observations agree with results obtained in studies with large White Duroc × Chinese Erhualian Crossbred boars at three developmental stages, where the testosterone concentration correlated with epididymis weight and libido scores, although libido and serum testosterone level were not correlated with sperm production [22]. …”

Production and Quality of Semen in Boars in Insemination Centre

“…With increasing age, the correlation dependence between these parameters grew and in the category of 37 to 48 months it reached the value of 0.65 for CO/NOT and 0.63 for CO/NOC) (p < 0.05). High correlation (0.73) between these parameters reported Ren et al (2009). A very weak negative correlation (-0.13 to -0.19) (p < 0.05) was found between the motility of spermatozoa and the percentage of abnormal spermatozoa throughout the age categories, which is contrary to the conclusions of the Wolf (2010), who found that the correlation coefficient between these parameters was at level -0.57.…”

The influence of boar breed and season on semen parameters

“…In recent years, AI has been widely implemented in the production of pigs. Therefore, the choice of boars is becoming increasingly important and urgent to the pig industry (Ren et al, 2009). Understanding the basic genetic differences between the male reproductive traits of different breeds of boars is necessary to increase the efficiency of sperm production in insemination stations (Safranski, 2008).…”