Sperm production and sperm morphology of Swedish Warmblood stallions.
The present study investigated daily sperm output and sperm morphology of fresh semen in eight Swedish Warmblood stallions aged 5-8 years. They were used for artificial insemination, and their fertility during the breeding season of semen collection exceeded 60% per cycle. One ejaculate of semen was collected daily for 10 consecutive days from each stallion. The gel-free volume was measured, and the sperm concentration was assessed with a Bürker chamber. The volume of gel-free fraction was multiplied by the sperm concentration to give the total number of spermatozoa (TSN). Sperm morphology was examined in ejaculates collected on days 2, 5 and 10. An aliquot from each ejaculate was fixed in 1 ml formol-saline immediately after collection and examined under a phase-contrast microscope (magnification 1000x) to assess morphological abnormalities. Furthermore smears were prepared and stained according to Williams (carbolfuchsin-eosin) for a more detailed examination of the sperm heads under a light microscope (magnification 1000x). Analysis of variance was applied to data. Total spermatozoa number decreased progressively during the first 8 days of collection, and daily sperm output (DSO) was calculated as mean TSN of collections on days 8-10, being 6.4 x 10(9) spermatozoa. The overall percentages of morphologically normal spermatozoa in ejaculates collected on days 2, 5 and 10 were above 70%, being significantly lower in ejaculate 2 (68.6%) compared with ejaculates 5 and 10 (72.9% respectively 75.3%).
Division of Reproduction, Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, CRU, Uppsala, Sweden. stig.einarsson@kv.slu.se
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Einarsson
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Dalin
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Lundeheim
D000818:Animals; D001947:Breeding; D005298:Fertility; D006736:Horses / Q000502:physiology*; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D012621:Seasons; D012661:Semen / Q000166:cytology; D013076:Sperm Count; D013081:Sperm Motility; D013091:Spermatogenesis; D013094:Spermatozoa / Q000002:abnormalities / Q000166:cytology*