Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
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16 t h International Congress on Animal <strong>Reproduction</strong><br />
Poster Abstracts 39<br />
P034<br />
Potency of several GnRH agonists (Buserel<strong>in</strong>, Dalmarel<strong>in</strong>,<br />
Gonavet and Gonazon) versus natural GnRH (Cystorel<strong>in</strong>)<br />
<strong>in</strong> an <strong>in</strong> vitro functional assay.<br />
Driancourt, MA 1 *, Fournier, R 2 , Ptasz<strong>in</strong>ska, M 3 , Doornmalen, E 4 , Blomenrohr,<br />
M 4<br />
1<strong>Reproduction</strong>, Intervet Pharma R&D, France; 2 Intervet France, France;<br />
3Intervet International Bv, The Netherlands; 4 Organon Bv, The Netherlands<br />
Natural GnRH and several GnRH analogues are wi<strong>de</strong>ly used to<br />
synchronize oestrus and ovulation, as well as for treatment of<br />
reproductive pathologies (cysts) <strong>in</strong> cattle. However, the relative<br />
potency of each agonist relative to natural GnRH is not known. The<br />
aim of the present study was to use an <strong>in</strong> vitro test (measur<strong>in</strong>g<br />
receptor activation) to compare the potency of natural GnRH (as<br />
Cystorel<strong>in</strong>) versus several GnRH agonists. The agonists <strong>in</strong>clu<strong>de</strong>d<br />
were Depherel<strong>in</strong> (D- Phe6-LHRH) (Gonavet, Veyx Pharma),<br />
Lecirel<strong>in</strong> (D-Tle6, ProNHEt9- LHRH) (Dalmarel<strong>in</strong>, Fatro/Virbac),<br />
Buserel<strong>in</strong> (D-Ser(But)6, Pro9-NEt- LHRH)(Receptal, Intervet) and<br />
Azagly-nafarel<strong>in</strong> (D-Nal(2)6, α-aza-Gly10-LHRH)(Gonazon,<br />
Intervet).The <strong>in</strong> vitro test used a CHO cell l<strong>in</strong>e express<strong>in</strong>g the human<br />
GnRH receptor gene together with a beta lactamase reporter gene. In<br />
this test, cells form β lactamase upon GnRH stimulation. B-lactamase,<br />
<strong>in</strong> turn, cleaves a fluorogenic membrane permeable substrate (CCF4).<br />
Non-responsive cells with low β lactamase appear green, while<br />
responsive cells with high β lactamase appear blue. In the present<br />
experiment, CHO-GnRH-R-β-lactamase bear<strong>in</strong>g cells were plated for<br />
16-20h before be<strong>in</strong>g challenged with GnRH. Cells were then<br />
<strong>in</strong>cubated with a range of concentrations of each test compound. Five<br />
hours later, fluorogenic substrate (CCF4) was ad<strong>de</strong>d to the cells and<br />
the cells were <strong>in</strong>cubated for 2h . The microplate was read with 405nm<br />
excitation and 460 and 530nm emission. The data were plotted as a<br />
ratio of the emissions at 460 (blue) and 530nM (green). Two separate<br />
experiments were run, each dose response curve be<strong>in</strong>g generated by<br />
four replicates. The effects of the different concentrations of GnRH or<br />
GnRH agonists applied were compared us<strong>in</strong>g EC 50 (concentration<br />
of GnRH applied generat<strong>in</strong>g a half maximum response) for each<br />
compound. The sigmoid shapes of the dose-response curves were<br />
similar <strong>in</strong> both experiments. In both assays, the dose-response curves<br />
<strong>de</strong>scrib<strong>in</strong>g receptor activation by the different GnRH could be divi<strong>de</strong>d<br />
<strong>in</strong>to two sub-groups. On one hand, Buserel<strong>in</strong>, Azagly-nafarel<strong>in</strong> and<br />
Depherel<strong>in</strong> displayed similar dose response curves result<strong>in</strong>g <strong>in</strong> similar<br />
EC50-values (0.7 to 1.6ng/ml). On the other hand, Cystorel<strong>in</strong> and<br />
Lecirel<strong>in</strong> (which behaved similarly) displayed higher EC50-values (8<br />
to 15ng/ml). In both assays the slopes of the dose-response curves<br />
proved similar, irrespective of the compound tested. The use of this<br />
cell l<strong>in</strong>e therefore proved to be a potent tool to compare potencies of<br />
different GnRH agonists.<br />
P035<br />
Screen<strong>in</strong>g of parturition time mo<strong>de</strong>ls of Holste<strong>in</strong> breed <strong>in</strong><br />
a dairy herd <strong>in</strong> Karaj suburb<br />
Ebrahimi, A 1 *; Gharaghoozloo, F 2 ; Vojgani, M 2<br />
1Department of Cl<strong>in</strong>ical Science, Faculty of Veter<strong>in</strong>ary Medic<strong>in</strong>e, Islamic Azad<br />
University, Garmsar Branch, 2 University of Tehran, Iran<br />
The <strong>in</strong>fluences of breed<strong>in</strong>g group, age of dam, sex, calv<strong>in</strong>g problems<br />
like dystocia, abortion and some calv<strong>in</strong>g abnormalities, like stillbirth<br />
on the time of day of parturition were studied. Cross-sectional surveys<br />
of 6606 calv<strong>in</strong>g records between 1989 and 2005 were analyzed by the<br />
least-squares and the chi-squared procedures. The cases were divi<strong>de</strong>d<br />
based on the time of parturition with<strong>in</strong> 24 hours <strong>in</strong> four groups of six<br />
hours each, as follows: 0-6, 7-12, 13-18, 19-24 hour with their<br />
belong<strong>in</strong>g calv<strong>in</strong>g numbers of 1762, 1787, 2031 and 1027,<br />
respectively. The distribution with<strong>in</strong> these groups were characterized<br />
with the follow<strong>in</strong>g percentages based on the calv<strong>in</strong>g process: normal<br />
calv<strong>in</strong>g: 86.8, 79.4, 78.7 and 84.8, dystocia (gra<strong>de</strong> one): 2.5, 5.3, 6.6<br />
and 2.2, dystocia (gra<strong>de</strong> two): 10.6, 14.7, 14.3 and 12.6, severe<br />
dystocia (gra<strong>de</strong> three): 0.2, 0.7, 0.4 and 0.4. The cases were divi<strong>de</strong>d <strong>in</strong><br />
four groups accord<strong>in</strong>g to the seasonal distribution of parturitions so<br />
24,4% of all parturitions occurred dur<strong>in</strong>g spr<strong>in</strong>g, 26.2% dur<strong>in</strong>g<br />
summer, 26% dur<strong>in</strong>g autumn and 23.4% dur<strong>in</strong>g w<strong>in</strong>ter. The seasonal<br />
occurrence of stillbirth were 3.9, 4, 3.8 and 5.5%, respectively<br />
(P=0.06). The seasonal occurrence of dystocia were16.8, 14.8, 18.7<br />
and 22.4% with P