Type

Journal Article

Authors

P. Lonergan
A.C.O. Evans
M P Boland
M Wade
D Rizos
S Fair
A Donovan
J P Hanrahan
C M O' Meara

Subjects

Veterinary

Topics
veterinary cervix uteri fertilization in vitro semen male insemination artificial semen preservation sperm count oocytes physiology sheep pregnancy female cryopreservation fertility animals

Relationship between in vitro fertilisation of ewe oocytes and the fertility of ewes following cervical artificial insemination with frozen-thawed ram semen. (2005)

Abstract No laboratory test exists that can reliably predict differences among rams in field fertility after artificial insemination (AI) with frozen-thawed semen. In vitro fertilisation (IVF) has been proposed as a method of predicting these differences. The objectives of this study were to evaluate whether IVF system could discriminate among rams of different fertility in vivo after AI using frozen-thawed semen. Also, to examine effects of lowering sperm concentration on discrimination power between rams used for IVF. The aim of Experiment 1 was to evaluate the effect of altering the sperm concentration from 2 x 10(6) to 0.03125 x 10(6) spermatozoa/mL on subsequent cleavage rate and blastocyst rate in vitro. In Experiment 2, six rams (three High and three Low in vivo fertility; average pregnancy rates of 37.6% and 21.8%, respectively) were compared for their fertilising ability in IVF. Spermatozoa from each of the six rams were added to ewe oocytes using a concentration of either 2 x 10(6) or 0.0625 x 10(6)/mL. There were six replicates with 25 oocytes per well and two wells per ram per replicate. Cleavage rate was monitored at 48 h post-insemination (p.i.) and blastocyst rate determined on Days 6-8 p.i. In Experiment 1, cleavage rate increased with increasing sperm concentration and blastocyst rate was not affected by sperm concentration on any day. When the six rams were tested using 2 x 10(6) spermatozoa/mL, no significant differences were found between High and Low fertility groups for cleavage rate or blastocyst rate on Days 6, 7, or 8 p.i. (P>0.05). When the experiment was repeated using 0.0625 x 10(6) spermatozoa/mL, no differences were found between High and Low group rams for blastocyst rate on any of Days 6, 7 or 8 p.i. (P>0.05). However, there was a significant difference between High and Low fertility rams for percentage of oocytes cleaved (16.4, S.E. 2.02%; P<0.01) and the correlation between fertility in vivo and cleavage rate in vitro was significant (P=0.013). Replicate of IVF was a source of significant variation for both cleavage rate and blastocyst rate and conditions need to be further controlled. However, we suggest that using a low concentration of spermatozoa (0.0625 x 10(6)/mL) for IVF may be a useful method for predicting field fertility of frozen-thawed ram semen.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

P. Lonergan, A.C.O. Evans, M P Boland, M Wade, D Rizos, S Fair, A Donovan, J P Hanrahan, C M O' Meara

Experts in our system

1
P. Lonergan
University College Dublin
Total Publications: 190
 
2
A.C.O. Evans
University College Dublin
Total Publications: 92
 
3
M P Boland
University College Dublin
Total Publications: 103
 
4
D Rizos
University College Dublin
Total Publications: 42
 
5
Seán Fair
University of Limerick
Total Publications: 54
 
6
J P Hanrahan
Teagasc
Total Publications: 58