Skip to main content
ARS Home » Research » Publications at this Location » Publication #62029
Title: COMPARISONS OF SEMINAL QUALITY IN HOLSTEIN BULLS AS YEARLINGS AND AS MATURE SIRES

Author
item GARNER, D - UNIVERSITY OF NEVADA-RENO
item Johnson, Lawrence
item ALLEN, C - ATLANTIC BREEDERS COOP
item PALENCIA, D
item CHAMBERS, C - UNIVERSITY OF NEVADA-RENO

Submitted to: Theriogenology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rapidity and accuracy are critical to the development of reliable in vitro assays of semen for quality. Flow cytometry with appropriate fluorescent stains offers the capability for achieving rapid and accurate evaluation of semen quality. A new DNA sensitive stain, SYBR-14, was tested along with Propidium iodide as a live and dead sperm assay combination. The stain combination was found to be effective for estimating the percentage of living sperm from the semen of bulls tested first when they were yearlings and again at 4.5 years of age. There were no differences in sperm quality between the two ages of the five bulls tested. These results tend to confirm other data that suggests that semen quality, once established for a bull, is reasonably consistent throughout his lifetime except when disease factors are present. These data will be useful in establishing a consistent live/dead sperm staining procedure for measuring sperm quality in bovine cryopreserved sperm.

Technical Abstract: Seminal quality comparisons were made on five Holstein bulls collected as young sires (yearlings) and again after a mean interval of 1,265 days (mature bulls). At both sampling times, semen samples were examined for ejaculate volume, sperm numbers, post-thaw progressive motility and sperm viability. Sperm viability was assessed on cryopreserved samples using SYBR-14 to fluorescently stain living sperm and propidium iodide (PI) to identify dead sperm. The fluorescent populations of stained sperm were quantified by flow cytometry. The percentages of living sperm for the individual bulls, as determined by green fluorescence of the SYBR-14, ranged from 44 +/- 3.1 to 54 +/- 0.3 for yearlings and from 38 +/- 1.5 to 55 +/- 1.0 as mature sires. No differences in sperm viability were found between the samples taken as yearlings and as mature bulls. The percentage of sperm staining with SYBR-14 was negatively correlated (r = -0.97, P=0.0001) with the percentage of dead sperm as indicated by PI staining. Comparisons of identical samples run on two different flow cytometers indicated that either flow instrument could be used to assess sperm viability. The individual bulls differed (P < 0.05) for ejaculate volume and sperm numbers as yearlings, but were not different for these parameters after maturation. The average sperm per ejaculate changed as a result of maturation increasing from 6.2 +/- 1.0 to 10.7 +/- 1.1 x 1,000,000,000. Aging was significantly correlated with ejaculate volume (r = 0.76, P = 0.01), but not with total sperm per ejaculate (r = 0.51, P = 0.13). The maturational changes that occurred in these bulls were minimal with the exception of increased ejaculate volume and sperm per ejaculate.