Abstract
A comparison of buffer solns. made with 1, 2, 3, 4 and 5% Na3C6H5O7-2H2O showed that the 3% buffer was slightly superior to the 2% buffer and definitely better than the others for bull semen dilution. Freezing point of the 3% citrate buffer was practically the same as that of freshly collected bull semen or egg yolk, indicating that isotonicity is important. Comparisons were made of diluters containing 5, 10, 12.5, 20, 25 and 50% egg yolk mixed with 3% Na citrate soln. Very slight differences were found among diluters containing 20, 25, or 50% egg yolk, and these maintained better sperm motility than diluters with lesser proportions of egg yolk. Satisfactory protection of bull sperm against cold shock was found at all concns. except 5% egg yolk. Sperm were shown to acquire resistance to killing by cold shock after storage at 5[degree]C.