Correlation of sperm parameters with fertility in two commercial pig lines.

Background: One of the most important parameters to be considered in the assessment of male fertility or in the evaluation of methods to preserve sperm cells is the study of sperm viability. Considering that semen quality is of great importance for artificial insemination AI) in sows and for the production of an optimal number of piglets, complementary test results can be correlated with the number of piglets born after AI. The present study aimed to characterise the seminal pattern of breeding boars from two commercial lines and to correlate this pattern with the prolificacy of sows. Materials, Methods u0026 Results: The reproductive performance of four boars from two commercial lines (A and B) was determined by evaluating physical and morphological semen parameters and by conducting a complementary analysis of semen. Semen was subjected to the following parameters: total sperm motility, sperm vigor, major sperm defects, minor sperm defects, and total sperm defects, in addition to complementary tests (supravital staining and hypoosmotic swelling tests). The semen was evaluated immediately after collection and every 12 h for up to 72 h of cold storage. A total of 163 breeding sows were inseminated. To evaluate sow prolificacy, the total number of piglets born was recorded. In general, the values obtained for the tests assessing sperm viability (particularly sperm motility and hypoosmotic test) decreased with storage time (P 0.05) to that from sows who received semen stored for 24, 48 and 72 h of storage (14.6, 13.6, and 14.2 piglets, respectively). Discussion: A greater number of piglets born is expected when there is high sperm viability because intact sperm cells show an increased capacity to fertilize the oocytes. Therefore, the results indicate the possibility of selecting breeding boars considering the in vitro test results that evaluate sperm cell viability. Significant correlations were observed between sperm motility and the supravital staining results (r= 0.60) and between sperm motility and the hypoosmotic test results (r= 0.62). These results were somehow expected because sperm cells with intact and biochemically active plasma membranes also exhibited high motility. The hypoosmotic test results were significantly correlated with the supravital staining results (r= 0.43), which was expected because both tests assess sperm cell viability. Although the average values for sperm viability decreased as a function of the increased storage time, this inverse correlation was not observed for the total number of piglets. Therefore, laboratory-based semen evaluations may be useful for identifying breeding animals with increased fertility that could be selected before joining the breeding herd.