Fertility of bull semen packaged in .25- and .5-milliliter french straws2

Abstract

The fertility of bull semen packaged in .25- and .5-mL french straws was compared. One ejaculate from each of five Holstein bulls was split, extended to 10 x 10(6) spermatozoa/inseminate dose in whole homogenized milk, packaged in .25- and .5-mL french straws, frozen in liquid nitrogen (LN) vapor, and stored in LN. Semen was thawed at 37 degrees C for 30 s. Synchronized heifers (n = 1,360) were inseminated (during a 12-mo period) with semen packaged in either a .25- or .5-mL french straw. Blood was collected on the day of insemination and the serum was assayed for progesterone. Heifers with blood progesterone levels of > 1 ng/mL were eliminated from the data. Blood was collected at 30 to 45 d after insemination and the serum was assayed for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Conception was 63.6 and 62.0% (P = .55) for semen packaged in the .25- and .5-mL french straws, respectively. There was neither a bull x packaging unit interaction (P = .49) nor a day of insemination x packaging unit interaction (P = .87). Conception among bulls ranged from 57.1 to 68.0% (P = .19). No evidence was found that meteorological factors influenced conception. Under the conditions of this experiment, semen packaged in the .25- and .5-mL french straw had similar fertility.

Assessment of the interaction between straw size and thawing rate and its impact on in vitro quality of post-thaw goat semen

“…In addition, bull semen packaged in 0.25 and 0.50 mL straws containing 10 × 10 6 total spermatozoa/straw and thawed at 37 ºC/30 s in both cases, provided similar conception rates (Johnson et al, 1995).…”

“…The 0.25 mL straw has a higher surface-to-volume ratio than the 0.50 mL one, which increases the opportunity for post-thaw temperature changes of the semen within the straw. Such changes can compromise the post-thaw recovery of live spermatozoa and thus decrease fertility (Johnson et al, 1995).…”

Determination of Activable Proacrosin/Acrosin in Bovine Sperm Using an Irreversible Isocoumarin Serine Protease Inhibitor1

“…As shown in Table 2, the average fertility of these samples as determined by pregnancy-specific protein B was 62.8% [18]. Although significant differences (p < 0.05) in the proportion of sperm that had retained acrosin after cryopreservation and thawing were found among these bulls, the activable proacrosin/acrosin levels were not correlated with fertility (Table 2).…”

“…First, samples taken from six bulls were processed in homogenized milk [17] and stored for 24 h at 5C; the samples then were examined for activable proacrosin/acrosin both before and after cryopreservation. A second group of cryopreserved sperm samples from five other bulls for which actual fertility had been determined [18] was examined for activable proacrosin/acrosin. Both sets of semen samples, which had been processed and/or cryopreserved in homogenized milk extender [17], were provided by Atlantic Breeders Cooperative (Lancaster, PA).…”

“…For each straw of semen, three replicates were analyzed by flow cytometry. The samples were thawed at 37C and diluted 1:3 in HE-PES-buffered saline containing 0.1% BSA (HEPES/BSA [18]) to yield a final sperm concentration of approximately 7 x 106 sperm/ml. For each replicate, two different aliquots were examined.…”