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 77<br />
P147<br />
The Effect of an Opioid Antagonist on Blood<br />
Progesterone levels of crossbreed ewes with GnRH<br />
<strong>in</strong>duced short luteal phase dur<strong>in</strong>g the anoestrus season<br />
Fuentes, HV-O. 1 *, Fuentes, CPI. 2 , Moreno, H. 3 , Parra, VM.<br />
1Centro Universitario <strong>de</strong> los Altos, Universidad <strong>de</strong> Guadalajara, Km 7.5<br />
Carretera a Yahualica, Tepatitlan <strong>de</strong> Morelos Jalisco CP47600 (Víctor<br />
Octavio Fuentes Hernán<strong>de</strong>z Ph.D. victoro@servidor.unam.mx;<br />
vfuentes@cualtos.udg.mx); 2 Department of Anesthesiology, Hospital Pemex<br />
Sur Alta Especialidad DF , Mexico; 3 <strong>Facultad</strong> <strong>de</strong> Medic<strong>in</strong>a Veter<strong>in</strong>aria y<br />
Zootecnia, Universidad Michoacana <strong>de</strong> San Nicolas Hgo, Mexico<br />
With the objective of study<strong>in</strong>g the effect of an opioid antagonist on<br />
progesterone levels <strong>in</strong> ewes with <strong>in</strong>duced short luteal phase dur<strong>in</strong>g the<br />
anoestrous season. A group of 20 crossbreed ewes was used. Age<br />
flutuated between 2 and 6 years. Housed <strong>in</strong> oppen paddocks with food<br />
and choped barly hay ad libitum and complemented with 250 g of<br />
concentrated feed. 10 ewes selected at random were implanted with<br />
15 mg naloxone us<strong>in</strong>g cristal<strong>in</strong>e microcelulose as a vehicle. The<br />
rema<strong>in</strong>ig 10 ewes were used as control and were implanted with a<br />
capsule of cristal<strong>in</strong>e microcelulose free of any medicament. Seven<br />
days after implant both groups; treated and control; were <strong>in</strong>jected with<br />
GnRH (250 ng iv at two hour <strong>in</strong>tervals dur<strong>in</strong>g 24 hours) at the end of<br />
treatment 125 µg of GnRH was <strong>in</strong>jected iv. Blood samples were<br />
collected at 12 th hrs <strong>in</strong>tervals s<strong>in</strong>ce the comencement of the<br />
experiment and sampl<strong>in</strong>g cont<strong>in</strong>ued for 15 days after the last <strong>in</strong>jection<br />
of GnRH. It was observed that <strong>in</strong> two of the control ewes<br />
progesterone levels <strong>in</strong>creased 36 hrs after GnRH treatment, reach<strong>in</strong>g a<br />
highest level on day 7, on the 8 rema<strong>in</strong><strong>in</strong>g control ewes short luteal<br />
phases were observed with maximal progesterone concentrations of 1<br />
ng/ml. 3 ewes treated with naloxone showed short luteal phase, while<br />
<strong>in</strong> the rema<strong>in</strong><strong>in</strong>g 7 ewes treated with naloxone, progesterone levels<br />
were similar to those observed <strong>in</strong> control ewes with normal luteal<br />
phase. Dur<strong>in</strong>g the statistical analysis a significant effect fue to<br />
treatment was <strong>de</strong>tected (P