Influence of bull age, ejaculate number, and season of collection on semen production and sperm motility parameters in Holstein Friesian bulls in a commercial artificial insemination centre

Abstract

In the current era of genomic selection, there is an increased demand to collect semen from genomically selected sires at a young age. The objective of this study was to assess the effect of bull age, ejaculate number, and season of collection on semen production (ejaculate volume, sperm concentration, and total sperm number; TSN) and sperm motility (prefreeze and post-thaw total and gross motility) parameters in Holstein Friesian bulls in a commercial artificial insemination (AI) center. The study involved the interrogation of a large dataset collected over a 4-yr period, (n = 8,983 ejaculates; n = 176 Holstein Friesian bulls aged between 9 mo and 8 yr). Bulls aged less than 1 yr had the poorest semen production and sperm motility values for all parameters assessed compared with bulls older than 1 yr (P < 0.01). First ejaculates had greater semen production and greater prefreeze motility values than second consecutive ejaculates (P < 0.01), but despite this, there was no difference in post-thaw motility. When subsequent ejaculates were collected from bulls aged less than 1 yr, semen production and sperm motility did not differ compared with mature bulls. Semen collected in winter was poorest in terms of sperm concentration and TSN, but best in terms of post-thaw motility (P < 0.01). In conclusion, second ejaculates can be collected, particularly from bulls aged less than 1 yr, without a significant decrease in post-thaw sperm motility, thus may be a useful strategy to increase semen availability from young genomically selected AI bulls in high demand.

The effect of age on semen freezability of Swamp Buffalo bull in a commercial artificial insemination center

“…In line with this finding, Ahmed et al (2018) also found that aged buffalo bulls had lower sperms motility post-thawing than the young bulls. In other livestock such as dairy cattle, it was also reported that the bull age had a significant effect on sperms motility post-thawing (Murphy et al, 2018).…”

“…However, the benefit of artificial insemination can only be achieved when supported by good semen quality (Islam et al, 2018). Numerous factors such as age, breed, nutrition, and environmental condition have been well documented, influencing semen quality of bull (Bhakat et al, 2011;Kumar et al, 2017;Murphy et al, 2018). In cattle, the age was recognized as the critical factor affecting semen quality since it determining the reproductive physiology of bull (Snoj et al, 2013;Isnaini et al, 2019a).…”

Role of early life nutrition on the hypothalamic-pituitary-testicular axis of the bull

“…Following the inception of genomically assisted selection, young genetically elite bulls are now being identified within weeks of birth as potential sires for use in artificial insemination programmes. However, these bulls cannot produce ejaculates of sufficient quality for cryopreservation until they are greater than 1 year of age (Murphy et al 2018) and demand for their semen often far exceeds supply. Hastening the onset of puberty and subsequent sexual maturation would therefore benefit the industry and make high-quality semen available at a younger age (Harstine et al 2015).…”

The Number of False Mounting Affects The Quality of Semen in Bulls

“…However, in FM groups, the volume of second ejaculate was able to reach and exceed the first ones. The overall reduction in semen volume seems to be largely related to the short collection interval between consecutive ejaculates [12,21]. In the present study, this interval is prolonged due to FM activity and bulls could have adequate time for sexual preparation.…”

“…In the present study, this interval is prolonged due to FM activity and bulls could have adequate time for sexual preparation. Furthermore it has been stated that, the collection of multiple ejaculates on the same day did not affect the post-thaw motility, but the pre-freeze motility was reduced (P< 0.01) in Holstein bulls [21], whereas no significant difference was observed in Shorthorn-Zebu breed [23]. Although in general, second ejaculates are of less volume and sperm concentration, the collection of sequential ejaculates increases productivity per unit time, as more insemination doses can be obtained on a given day.…”