Measuring Male-to-Male Differences in Fertility or Effects of Semen Treatments

Abstract

Fertility is a convenient but meaningless term unless the outcome measure is stipulated and accounts for dependence of male fertility on the female population. We describe outcome measures and detail the impacts of the physiological status of each female and her external environment, as well as management imposed by humans. We explain the dominant role of the female reproductive tract as a series of hurdles for sperm seeking an ovum. Each spermatozoon in an ejaculate is unique, although usually most are morphologically similar. Semen seemingly contains three subpopulations of sperm, based on fate within a female and role in hampering the success of the ultimate winning spermatozoon; we define these subpopulations. The numerical size of each subpopulation placed into a female determines the shape of the dose-response curve leading to possible live young. Heterospermic artificial insemination provides far greater sensitivity to detect differences, partly because the female environment is identical for each comparison.

Irradiation of semen doses with LED‐based red light in a photo chamber does not improve in vitro quality of thermically stressed boar spermatozoa

“…Equal irradiation of all cells must be ensured, especially with samples of large volumes as in the case of boar semen doses prepared for artificial insemination. The discrepancy between the previously reported positive effects of red LED light on boar spermatozoa in vivo (Balasch & Rodríguez, ; Yeste et al., ) and inefficiency in vitro as shown in this study might reflect the limitation of in vitro measures to predict male fertility (Amann, Saacke, Barbato, & Waberski, ). Future studies testing several hypotheses on the mechanism of LED light effects on spermatozoa as recently proposed by Yeste, Castillo‐Martín, Bonet, and Rodríguez‐Gil () will be helpful to estimate the impact on fertility.…”

Relationship between sperm motility characteristics and ATP concentrations, and association with fertility in two different pig breeds

“…In addition, it has been estimated that a difference of only 0.2 piglets in TNB is of great economic relevance (Roca et al, 2015). In controlled studies for detection in fertility differences, a high degree of standardization is needed with respect to boars, breed, age, semen collection frequency, semen extender used, semen age and basis for exclusion of samples (Amann et al, 2018). In the present study, based on data from a full-scale commercial AI station and its customers, these aspects were considered.…”

Genetic dissection of bull fertility in US Jersey dairy cattle

“…Indeed, the fertility of the bull is critical in determining herd reproductive performance, and hence, it should not be ignored in dairy cattle breeding schemes aimed at improving reproductive efficiency (Amann et al . ; Taylor et al . ).…”