Porcine Field Fertility with Two Different Insemination Doses and the Effect of Sperm Morphology

Abstract

In swine artificial insemination, several dose regimens are applied, ranging from 1.5 x 10(9) to 6.0 x 10(9) spermatozoa per intra-cervical insemination dose. A lower sperm dose is more profitable for artificial insemination centres and offers a more effective use of superior boars. To evaluate fertility, 50 boars were used for a total of 10 773 homospermic first inseminations at a dose of 2 billion spermatozoa. In addition, 96 boars were used at a dose of 3 billion spermatozoa for 34 789 homospermic first inseminations. Fertility was determined by a 60-day non-return rate (NR%) of first inseminations. Litter size was registered by total number of piglets born separately in primiparous and multiparous farrowings. On average, a sow was inseminated 1.5 times. A significant decrease was observed in all three fertility parameters (NR%, litter size of both primiparous and multiparous farrowings) with a dose of 2 billion spermatozoa compared with a dose of 3 billion spermatozoa. The NR% was 75.8% and 84.0% (p < 0.001), the mean litter size of primiparous farrowings 10.1 and 10.7 (p < 0.001) and the mean litter size of multiparous farrowings 11.7 and 12.1 (p < 0.001) for 2 and 3 billion spermatozoa/dose, respectively. The proportion of normal spermatozoa in the sperm morphology analysis correlated significantly with NR% in both insemination regimens: p < 0.001, r = 0.604 and p < 0.05, r = 0.223 for 2 and 3 billion spermatozoa/dose, respectively. These results confirm that quantity can at least partly compensate for poor sperm quality. When the boars with <70% normal spermatozoa in the morphology evaluation were excluded from the data there were no correlation between the sperm morphology and NR%. However, the difference between the NR% and litter size remained statistically significant (p < 0.001) in favour for the bigger insemination dose. In conclusion, a decrease in sperm dose from 3 to 2 billion spermatozoa on commercial farms will severely decrease prolificacy at least under field conditions, where a sow is inseminated an average of 1.5 times/heat, and the semen is typically used within 3 days after collection. We recommend that under commercial circumstances the homospermic semen doses contain no <3 billion spermatozoa/dose.

Enhanced fertility prediction of cryopreserved boar spermatozoa using novel sperm function assessment

“…The average litter size produced when using frozen-thawed spermatozoa is below what most of the industry will accept (Ruiz-S anchez et al, 2006). Traditional analyses of boar spermatozoa that include motility, morphology and viability, are only moderately useful for identifying boars of low fertility (Flowers, 1997;Gadea et al, 2004;Gadea, 2005;Alm et al, 2006;Lovercamp et al, 2007;Broekhuijse et al, 2012). Knowledge of the causes of reduced fertility due to cryopreservation is incomplete, although there are reductions in routinely measured sperm traits.…”

“…There are likely additional types of cellular damage due to cryopreservation that are not detected in standard semen analysis, given the low correlation between fertility and traditional microscopic evaluation. Numerous attempts have been made to identify in vitro sperm parameters that that are directly related to fertility (Holt et al, 1997;Tardif et al, 1999;Larsson & Rodrıǵuez-Martıńez, 2000;Waberski et al, 2005;Alm et al, 2006;Broekhuijse et al, 2012;Schulze et al, 2013). However, novel assays that measure sperm interactions within the female reproductive tract and with oocytes may be more predictive of in vivo function as well as useful when identifying reasons for reduced fertility (Fazeli et al, 1997;Braundmeier et al, 2004;Collins et al, 2008).…”

Relationship between sperm plasma membrane integrity and morphology and fertility following artificial insemination

“…However, negative correlations (P >0.05) were observed between conception rate and major sperm defects as well as minor morphological ones. Conversely, boar sperm morphology has been reported to have limited positive predictive value for field fertility (Alm et al, 2006). Although negative correlations were found between fertility and morphological defects, Waberski et al (1990) reported that sperm morphology may assist with boar selection for AI as it provided information about spermatogenesis.…”

Assessment of stallion semen morphology using two different staining methods, microscopic techniques, and sample sizes

“…Sperm morphology assessment consists of determining the percentage of spermatozoa with defective morphological structure and the share of spermatozoa with major or minor defects (25). Male fertility has been shown to depend on the incidence of morphologically defective spermatozoa (1). Even a slight increase in the percentage of spermatozoa with major defects can lower male fertility (7).…”