Analysis of seminal plasma biochemical parameters and sperm cryostability in different age groups of stallions

We studied sperm of stallions of different age groups of the Arab breed at the age of 4 to 21 (n=36). The concentrations of total protein (TP), albumin, globulins, glucose, urea, phospholipids, ionized calcium (Ca2+), and enzyme activity of creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), amylase, lactate dehydrogenase (LDH) were determined in seminal plasma. After sperm freezing and thawing the progressive sperm motility and viability at +4 °C were studied. We found that progressive motility and viability of spermatozoa after freezing and thawing in stallions at the age of 6-10 years was statistically significantly higher than that of stallions at the age of 4-5 (p=0.004 and p=0.02), 11-15 (p=0.04 and p=0.04) and 16-21 (p=0.01 and p=0.01, respectively). The concentration of sperm in the ejaculates of older stallions (16-21 years old) is significantly lower than in the ejaculates of stallions aged 4-5 (p=0.04), 6-10 (p=0.003), 11-15 (p=0.04). The level of urea in seminal plasma of older stallions (16-21 years old) was statistically significantly higher than in the group of stallions aged 6-10 (p=0.01). There is a negative correlation between progressive sperm motility after cryopreservation and urea concentration in stallion seminal plasma (r=-0.48; p