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Research article2004Peer reviewedOpen access

Sperm morphology in Estonian and Tori breed stallions

Kavak A, Lundeheim N, Aidnik M, Einarsson S


The standard procedure for assessing the breeding potential of a stallion includes the parameter total number of spermatozoa classified as morphologically normal. This study investigated sperm morphology of fresh semen in randomly chosen Estonian (E, n=8) and Tori (T, n=7) breed stallions with proven fertility. Two ejaculates were examined from each stallion. An aliquot from each ejaculate was fixed in 1 mL formol-saline immediately after collection and examined with phase-contrast microscope at a magnification 1000x for all types of morphological abnormalities. Furthermore smears were prepared and stained according to Williams (carbolfuchsin-eosin) for a more detailed examination of the sperm heads with light microscope at a magnification 1000x. Analysis of variance was applied to the data, and results are presented as LSmeans (+/-SE). One T stallion that had a disturbance in the spermatogenesis and one 22-year-old E stallion were not included in the analyses. The T stallions had on average 57.5+/-4.1% and the E-stallions 74.4+/-3.8% morphologically normal spermatozoa (p=0.012). In 4 of 7 T stallions and 7 of 8 E stallions both ejaculates had >50% morphologically normal spermatozoa. There was a significant difference between breeds in mean percentage of proximal droplets (17.3+/-2.7% and 2.9+/-2.5% for T and E stallions, respectively; p=0.003)


Sperm morphology; stallion

Published in

Acta Veterinaria Scandinavica
2004, Volume: 45, number: 1-2, pages: 11-18