fifty mares were inseminated on days 2 , 4 , 7 , 11 or 17 of the oestrous cycle with spermatozoa from one of three stallions to observe the distribution of the spermatozoa in various parts of the reproductive tract 12 hr later ( days 3 , 5 , 8 , 12 and 18 ) .
C0025329
oestrous cycle
C0035150
reproductive