Abstract

Use of bull semen with high levels of sperm abnormalities, reflecting genital dysfunction, is not recommended for artificial insemination (AI) since it would most likely lead to subfertility. Sperm quality, including sperm morphology, may deteriorate with increasing age of the bull thus becoming a source of concern when using older, progeny-tested AI bull sires. Although a relationship between sperm morphology and fertility after AI in progeny-tested bull sires has been reported, it is yet unclear which sperm abnormalities are most critical. This constituted the core aim of a 22-month long retrospective study in proven (aged 60-84 months at the start of the study) AI sires of the Swedish Red (SR, n = 8) and Swedish Holstein (SLB, n = 4) breeds where their semen (107 freezing batches in total, built by a single ejaculate (n = 3) or pooling two consecutive ejaculates (n = 104) collected at 1-3 months interval), were subjected to detailed morphological examinations on wet- and dry, stained smears. Attention was paid to between- and within-bull variations with regard to presence and level of sperm abnormalities. Sperm morphology differed significantly between sires and ejaculates, with 6/12 sires having ejaculates containing > 10% of morphologically deviating sperm head shapes, a commonly used threshold for young At bulls in Sweden. However, with the exception of pear-shaped or narrow-at-the-base anomalies, the mean values for individual defects were always within the limits expected for a normal bull sire, and were therefore considered acceptable. The percentage of morphologically normal spermatozoa was positively related to fertility, whose output differed significantly among bulls. Among sperm abnormalities, the proportion of morphologically deviating sperm head shapes were negatively correlated with fertility, pear-shaped sperm heads in particular. In conclusion, the relationship between sperm morphology and fertility after AI calls for frequent (2-3 months interval) detailed assessments of sperm morphology in AI stud bull sires. (c) 2008 Elsevier Inc. All rights reserved.

Keywords

sperm abnormalities; non-return rate (NRR); Swedish Red (SR); Swedish Holstein (SLB); bull

Published in

Theriogenology
2008, Volume: 70, number: 4, pages: 682-691
Publisher: ELSEVIER SCIENCE INC

SLU Authors

• Lundeheim, Nils

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

• Rodriguez, Heriberto

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Animal and Dairy Science
Veterinary Science


Publication identifier

DOI: https://doi.org/10.1016/j.theriogenology.2008.04.049

Permanent link to this page (URI)

https://res.slu.se/id/publ/19967