Motility of Bovine Spermatozoa Stored at 5° C. when Extended in Mixtures of Yolk-Citrate, Yolk-Glycine, Whole Milk, Skimmilk, and Glycerol

Four semen samples were collected from each of three bulls. Each semen sample was divided into a glycerolated (7.5%) and a nonglycerolated group. Each group was extended 1:24 into ten different extenders at an initial temperature of 32 C. The extenders were egg yolk-citrate (YC), whole milk (WM), skimmilk (SM), and egg yolk-glycine (YG), and their combinations were made up in equal proportions. Progressive motility rated on a 0-10 scale (10=100%) was used to estimate the desirability of the extenders during storage at 5 C. YC, WM, SM, and YG were, on the average, lower in motility after extension at Day 3 and Day 7 of storage (P < 0.01) than their combinations. Both combinations, WMYG and SMYG, showed higher average motility on Day 7 (P < 0.01) than did WMYC, SMYC, WMS:~[, or YCYG. YCYG was superior (P < 0.01) to either YC or YG alone. WM, S~'[, and WMYC had higher motility after extension (P < 0.05) than the same extenders containing glycerol. No other comparisons involving glycerol showed statistically significant differences. Under the conditions of this study, 2.9% glycine enhanced the ability of sperm to maintain progressive motility under storage at 5 C. when used with WM, SM, or YC.