The effect of X-radiation upon the quality and fertility of stallion semen
G.C.W. England and M. Keane


Received 18 August 1995; accepted 24 October 1995

Abstract
The exposure that stallion semen might receive during examination using an airport x-ray security screening system was found to be between 0.5 and 1.0 micro Sieverts . Ejaculates from 2 stallions were diluted 1:4 (volume:volume) using a nonfat dried milk-glucose extender. A total of 6 ejaculates from each stallion was collected, and each ejaculate was divided into 3 aliquots and these were then  exposed to x-radiation at a dose of 0, 1.0, or 10.0 . Semen quality was examined immediately post exposure,
and the aliquots were then placed into a water bath at 37°C, after which
sample longevity was evaluated.

In a second trial, 3 groups of 8 pony mares were inseminated with semen that had been exposed to x-radiation at doses of 0, 1.0, or 10.0 . An entire ejaculate was irradiated and inseminated into each mare on one occasion during estrus, based upon ultrasonographic evaluation of the reproductive tract.

After exposure to x-radiation there were no differences among the  3 treatment groups for spermatozoal motility, morphology, or longevity. The 14-d pregnancy rates for the 3 treatment groups were 0  (7 mares),  1.0 (8 mares), and 10.0 (7 mares). One mare (0 ) aborted at 65 d of pregnancy; 21 mares had a pregnancy of normal length, with each delivering a foal at term, although 1 foal died at parturition (1.0 ).

These findings indicate that the exposure of stallion  spermatozoa to x-radiation up to doses of 10 does not have deleterious effects upon spermatozoal motility, morphology, longevity or fertility. The exposure
received during examination using an x-ray security screening system is likely to be lower than this dose.