The Fertility of Bovine Semen Cooled with and without the Addition of Citrate-Sulfanilamide-Yolk Extender

Abstract

Two common procedures for cooling bovine semen used in artificial breeding, (1) cooling semen before adding a buffered yolk extender, and (2) adding extender to the semen before cooling, were compared in terms of fertility. 64 ejaculates of bovine semen were divided equally, and each portion of the ejaculate received one of the treatments. Cooling from 30[degree] to 51oC re-quired 75 min. Based on 60- to 90-day non-returns in 8518 1st- and 2d-service cows, the fertility level of the semen cooled in extender was 59.3% and that of semen cooled without the extender 52.8%. The difference of 6.5% was highly significant statistically (P less than 0.01). The % motile spermatozoa after 3, 24, 48, 72 and 96 hrs. of storage at 5[degree]C were for (1) 63, 56, 51, 47, and 42, and for (2) 48, 41, 34, 30, and 23, respectively. However, covariance analysis indicated that the difference in fertility could not be accounted for by the calculated difference in number of motile spermatozoa per insemination.