Testikelmått och daglig spermieproduktion hos svenska halvblodshingstar
Testicular measurements and daily sperm output (DSO) are important factors affecting reproductive capacity of stallions. In the present study testicular measurements of 10 Swedish half-blood stallions were determined (height, length, width and volume). Ejaculates were collected from each stallion once daily for 10 days to evaluate some important seminal characteristics: gel-free ejaculate volume, sperm concentration, percent progressively motile spermatozoa and total number of spermatozoa (TSN). The gel-free ejaculate volume was measured with a graduated cylinder, the sperm concentration was counted in a Bürker chamber, the sperm motility was estimated in a phase-contrast microscope and TSN was determined by multiplying the gel-free seminal volume by the sperm concentration. Testicular measurements were as follows (left and right testis): height 7,5 cm and 7,8 cm, length 10,6 cm and 10,8 cm, width 6,5 cm and 6,6 cm, volume 278,2 cm3 and 293,8 cm3, scrotal width 12,3 cm and total testicular volume 572,0 cm3 . The gel-free ejaculate volume, sperm concentration and total number of spermatozoa decreased significantly whereas sperm motility slightly improved during the 10 days of sperm collection. TSN of ejaculates collected on days 8-10 were averaged to represent DSO (because the extragonadal sperm reserve was then stabilized). The DSO was calculated to 6,0x10 9. Scrotal width and DSO were correlated (r=0,82 p=0,003) as well as total testicular volume and DSO (r=0,87 p=0,001). These results give us valuable information on Swedish half-blood stallions that can be useful in the future breeding management.