EVALUATION OF SEMEN COLLECTED FROM ALENTEJANO SWINE BOARS

Abstract

Alentejano swine breed (AL) populations raised under extensive production systems have increased during the last years. Selection and preservation of AL to be exploited under this type of production system will require further development of reproductive technologies to the extent of those used nowadays at modern piggeries. Artificial insemination (AI) with fresh or frozen semen will, in the near future, serve both the targets of genetic improvement and germplasm preservation. The project AGRO 204 “Trial to Test the Usefulness of Reproductive Auxiliary Techniques on Alentejano Swine under Extensive Production System” includes the related goal of: evaluating reproductive parameters of boars from different farms. This paper presents results (i) on the possibility of training alentejano boars for semen collection and (ii) their semen characteristics. During 2003 and 2004, a total of 25 AL young boars (aged 8 to 18 months) from different farms, were taught to jump on a dummy, so that semen could be collected. The following semen analyses were performed: semen rich fraction volume (RFV), solid fraction weight (SFW), % of alive spermatozoa (SPZV), motility (MOT), spermatic concentration (CONC), total number of spermatozoa in the ejaculate (SPZT) and % of abnormal spermatozoa (regarding: heads, tails and acrosomes). Ejaculation times were also registered. After a very variable training period (1 to 15 attempts per animal), regular semen collection was possible from 17 boars (68% of the total number of trained animals). A total of 127 ejaculates were analysed. The ejaculation time (292 ± 22 sec.), the SFW (31.5±2.4 g) and the RFV (78.6±5.3 ml) were found to be independent of the season of the year. However, seasonal influence was observed regarding the following parameters: SPZV (p=0.01); MOT (p<0.05); CONC (p=0.01); SPZT (p<0.01) and acrosome abnormalities (p<0.001). Results reported by other authors are in agreement with the ours provided by this work. The exposition to high temperatures reduces semen quality (% of damaged acrosomes), even in a well-adapted breed such as the Alentejano swine.