Type

Journal Article

Authors

M P Boland
J P Hanrahan
A Donovan
P. Duffy
M Wade
P. Lonergan
G P Byrne

Subjects

Veterinary

Topics
random allocation sperm ovum interactions female chemistry pregnancy sperm motility fertility progestins cryopreservation fertilization in vitro male fluorescent dyes centrifugation density gradient semen preservation physiology microscopy fluorescence spermatozoa sheep administration dosage animals organic chemicals veterinary propidium sybr 14 laparoscopy

Effect of freezing rate of ram spermatozoa on subsequent fertility in vivo and in vitro. (2000)

Abstract Ram spermatozoa are most susceptible to damage during freezing between the temperatures of -10 degrees C and -25 degrees C. The objectives of the present study were to examine how freezing rate through this critical temperature zone affected the fertility of spermatozoa as assessed in vivo and in vitro. Semen from six adult rams was frozen at two different rates ("fast": 5 degrees C/min from +5 to -25 degrees C; "slow": 0.5 degrees C/min from +5 to -25 degrees C). In Experiment 1, semen from the fast and slow treatments was used to fertilize ovine oocytes that had been matured in vitro. Semen from the fast treatment yielded a higher cleavage rate (57% vs. 26%; P<0.001) and more blastocysts per oocyte (28% vs. 13%, P<0. 001) than slow-frozen. No correlation was found between fertilizing ability and viability as assessed by fluorescent probes. Experiment 2 was designed to establish the conception rates following both cervical and intrauterine insemination of frozen-thawed semen from the same bank of semen as used in Experiment 1. Ewes were superovulated with FSH and inseminated by laparoscopy with frozen semen. A significant difference was found in the number of fertilized ova following embryo recovery (81.4% vs. 39.3%; P<0.001). In a further study, 119 mature cull ewes were inseminated following a 12-day synchronization treatment with frozen semen by either intrauterine (laparoscopic) or cervical insemination. Insemination with fast-frozen semen resulted in a significantly higher pregnancy rate (P<0.05) irrespective of method of insemination. The data show that freezing rate affects the proportion of spermatozoa that retain their fertilizing ability post-thawing. However, once fertilization has occurred, development to the blastocyst stage is independent of freezing rate.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

M P Boland, J P Hanrahan, A Donovan, P. Duffy, M Wade, P. Lonergan, G P Byrne

Experts in our system

1
M P Boland
University College Dublin
Total Publications: 103
 
2
J P Hanrahan
Teagasc
Total Publications: 58
 
3
P. Duffy
University College Dublin
Total Publications: 42
 
4
P. Lonergan
University College Dublin
Total Publications: 190