Effect of phenylephrine, ergonovine, oxytocin and norepinephrine as an extender ingredient on viability of bovine spermatozoa.

We evaluated effects of three concentrations of phenylephrine, ergonovine, oxytocin and norepinephrine (myometrial stimulants) on viability of spermatozoa when they were included in a seminal extender. Using a split ejaculate technique, ejaculates from each of 10 bulls were extended in egg-yolk citrate to a final concentration of 35 x 10(6) sperm/ml, including 20 mg/ml, 2 mg/ml and .2 mg/ml, of phenylephrine or ergonovine, 20 IU/ml, 2 IU/ml and .2 IU/ml oxytocin or 200 micrograms/ml, 20 micrograms/ml and 2 micrograms/ml norepinephrine prior to freezing. Extended semen without a myometrial stimulant served as the control. Percentage of intact acrosomes was determined prior to freezing for all treatments. Motility and percentage of intact acrosomes were determined immediately after thawing (0 h) and again after 4 h incubation at 37 degrees C. Percentage of intact acrosomes was reduced (P less than .05) prior to freezing by phenylephrine (20 mg/ml) and ergonovine (20 mg/ml) (phenylephrine = 56%; ergonovine = 63%; control = 74%). The same doses of phenylephrine and ergonovine reduced (P less than .05) post-thaw motility and percentage of intact acrosomes at both 0 and 4 h compared with controls. Sperm exposed even to the intermediate concentration (2 mg/ml) of ergonovine had lower (P less than .05) motility 4 h post-thaw. No other compound or concentration of compound or concentration of compound affected percentage of intact acrosome or motility. There were no two or three-way bull x compound and concentration interactions (P greater than .2).(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations of spermatozoa in the vagina of heifers after deposition of semen in the uterine horns, uterine body or cervix.

In Exp. I, virgin Holstein heifers (N = 18) were induced into oestrus with PGF-2 alpha. Animals which stood to be mounted were paired for insemination approximately 8 h later with 56.1 x 10(6) spermatozoa from a single bull. Semen was deposited in the uterine body of one female. Each matched female was inseminated by deposition of one-half of the inseminate into the right uterine horn and one-half into the left uterine horn approximately 7.0 cm anterior to the internal cervical os. In Exp. II, additional heifers (N = 18) were induced into oestrus and inseminated by deposition into the uterine horns or cervix (2.0 cm anterior to the external cervical os). A 1.0 ml aspirate of vaginal mucus was collected at hourly intervals for 8 h after insemination. Concentration of spermatozoa was determined by haemocytometry. In Exp. I, cumulative percentage spermatozoa recovered in an 8 h collection period were similar (P greater than 0.10) for insemination into the uterine horns (17.9 +/- 2.9%) and uterine body (18.5 +/- 4.5%). In Exp. II, cumulative % sperm recovery from the vagina was greater (P less than 0.10) for cervical deposition (59.1 +/- 14.1%) than for that into the uterine horns (30.9 +/- 7.8%). In Exp. II, the insemination treatment x hour of sample interaction was significant (P less than 0.08). Recovery of spermatozoa from the vagina was greatest (P less than 0.05) within 3 h after cervical insemination (31.4 +/- 9.9% compared to 9.4 +/- 2.5% for uterine horn deposition). Percentage recovery of spermatozoa from the remaining hourly collections were similar (P greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)