Abstract
Adult does were inseminated with a constant number of spermatozoa in different volumes of diluent or with varying numbers of spermatozoa in a constant volume. The number of spermatozoa required for maximum fertility was 1 x 106; 50% of does littered when inseminated with 1 to 2 x 105 cells and inseminations with 2 to 4 x 104 cells were sterile. Even when the number of spermatozoa approached the minimum for fertility, increased dilution rates did not decrease the numbers of does kindling. Some litters were obtained with semen diluted 1 in 10,000 with calcium-free Krebs''-Rtnger phosphate.