Effect of administration of equine chorionic gonadotrophin after artificial insemination on pregnancy rates in buffalos in Argentina

KONRAD, J.L.; GARRIDO, M.J.; MALDONADO VARGAS, P.; CRUDELI, G.

Cartagena de Indias

Congreso; 11th World Buffalo Congress; 2016

Asociación Colombiana de Criadores de Búfalos

The use of artificial insemination (AI) allow a quick and efficient genetic improvement, in buffaloes the fixed-time artificial insemination (FTAI) is used. High serum Progesterone (P4) concentration during the first three weeks of pregnancies is associated with lower embryonic losses, so use of equine chorionic gonadotrophin (eCG) could benefit the luteal activity because of its luteotropic effect. The aim of this work was to assess the effect of application of 400UI eCG after 14 days of AI on pregnancy rates. FTAI was performed to 645 buffaloes of different categories (138 young buffaloes, 297 buffaloes with calves and 210 dry buffaloes); synchronized by Ovsynch protocol (D0 0,1mg of gonadorelin acetate, D7 0,15mg of D+cloprostenol, D9 0,1mg of gonadorelin acetate); and on D10 insemination was performed. Animals were randomly assigned into one of two treatments (TRT), to receive (TRT1, n=297) or not (TRT2, n=348) 400UI of eCG D14 after FTAI. D14 and D19 after FTAI blood samples were taken by jugular puncture to 120 animals (61 from TRT1 and 59 from TRT2) for P4 plasmatic concentration determination by radioimmunoassay. On D35 after FTAI, pregnancy determination was made by transrectal ultrasonography. Categorical data were analyzed with GENMOD procedure and continuous data with MIXED procedure of SAS. Pregnancy rate was 55,2% (164/297) for TRT1 and 50,3% (175/348) for TRT2, no statistically significant differences were found (p>0,05). TRT1 showed the higher pregnancy rates in all categories evaluated, but the differences were not significant (p>0.05). P4 concentration on D14 after FTAI were 4,48±3,62 and 4,28±3,31 for TRT1 and TRT2 respectively, and on D19 were 3,16±3,22 and 2,66±2,92 for the same TRT, no statistically significant differences were found (p>0,05). Utilization of eCG after AI in buffaloes was not enough to statistically improve the pregnancy, although the results indicate that further studies on this issue is needed.