The Effect of Storage Temperatures Upon Certain Characteristics of Bovine Semen

Abstract

Summary Semen samples obtained by means of the artificial vagina from 11 fertile bulls were grouped according to motility, pH values, and concentration, and the effects of storage at 35°, 40°, 50°, and 70° F. were studied. When the semen samples were grouped according to percentage of initial progressive motility, the higher group showed lower initial pH values but no apparent difference was noticeable between the groups during storage. The pH values declined during storage, the lower the temperature the slower the decline. Grouping semen samples according to initial pH values indicated that the lower pH value was associated with higher progressive motility. During storage there was no apparent difference between the groups but there was a decline in percentage of progressive motility and the higher the temperature the faster the decline. Semen samples, when grouped according to concentration of spermatozoa per mm., 3 showed that the higher concentration had the lower pH values. When stored at the various temperatures there was no difference in rate of decline in pH values between the groups. Average semen characteristics for 11 fertile bulls, based upon several hundred samples, together with the number of inseminations and conceptions for both fresh and stored semen are presented. A total of 154 inseminations with fresh semen resulted in 112 conceptions, a conception percentage of 72.7, or 1.375 inseminations per conception. Grouping all stored samples, 28 inseminations resulted in 11 conceptions, a conception percentage of 39.3, or 2.545 inseminations per conception. Fifteen inseminations from samples stored at 50° F. resulted in four conceptions or 26.7 per cent, while 13 inseminations from samples stored at 35° and 40° F. resulted in seven conceptions or 53.8 per cent. A storage temperature of 35° F. was found to be the most advantageous for storing semen, based upon motility and pH values, since at that temperature the least change occurred. The fecundity of semen is best preserved when stored at the lower temperatures.