Type

Journal Article

Authors

A.C.O. Evans
P. Lonergan
C M O' Meara
P. Duffy
A Donovan
J P Hanrahan
S Fair

Subjects

Veterinary

Topics
luteinizing hormone semen veterinary insemination artificial blood crosses genetic physiology ovulation animals female time factors progesterone sheep estradiol fertility genetics

Hormonal relationships during the periovulatory period among ewe breeds known to differ in fertility after cervical artificial insemination with frozen thawed semen. (2005)

Abstract Our previous work indicates that ewe breed differences in fertility following cervical AI with frozen-thawed semen are due to failure of normal sperm transport and/or early embryo development. Here we examined differences in hormone concentrations about the time of ovulation among more (Finnish Landrace and Belclare) and less (Suffolk and Texel) fertile ewes after AI with frozen thawed semen. In Experiment 1, oestradiol concentrations were measured in samples collected frequently from 12h before to 18h after the LH surge and progesterone was measured in samples collected from 9 to 27h after the LH surge in Suffolk (n=24), Texel (n=20) and Finnish Landrace (n=27) ewes. In Experiment 2, oestradiol concentrations were measured in samples collected frequently from 24h before to 6h after the LH surge and progesterone was measured in samples collected from 6h to 6 days after the LH surge in Suffolk (n=35) and Belclare (n=30) ewes. In Experiment 1, there was an effect of breed, time and their interaction (P<0.001) on oestradiol concentrations between -12 and +6h but only breed differences at +12 and +18h (P<0.01). Progesterone concentrations increased over time (P<0.001) and the rate of increase was significantly greater in Finnish Landrace than in the other two breeds. In Experiment 2, oestradiol concentrations were unaffected by breed. There was an interaction between breed and time with the rate of increase of progesterone being greater in Belclare than Suffolk ewes (P<0.001). In conclusion, differences in hormone concentrations in the periovulatory period are not consistent with ewe breed differences in fertility; however, we have showed that progesterone concentrations rise earlier in the more prolific breeds and suggest that this may explain reported ewe breed differences in embryo development.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

A.C.O. Evans, P. Lonergan, C M O' Meara, P. Duffy, A Donovan, J P Hanrahan, S Fair

Experts in our system

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