Resumo

PEROZO MARIN, F.; GOICOCHEA, M.  e  MONTIEL, J.. Progesterone levels during gestation in buffaloes (Bubalus bubalis). Rev. Fac. Agron. [online]. 2002, vol.19, n.1, pp.71-76. ISSN 0378-7818.

In order to characterize and evaluate the progesterone levels (P₄) during gestation in buffaloes, a study was carried out on a commercial farm with a herd of 110 buffaloes in production, located in Mara County, Zulia State, Venezuela. The dependent variable was the progesterone concentration (P₄), the independent variables were pregnancy duration (DG) and sex of calf (SC). 532 observations, (milk samples until week 27 and blood samples up until delivery) were taken from 12 crossbreed female buffaloes with three or more calvings : plasma and fat free milk was obtained by centrifugation and analysed through the Radioimmunoanalysis technique (RIA). The SAS General lineal model process and Pearson correlation study were applied . The mean value for progesterone during the study period was of 2,95 + 0,87 ng/ml, with lowest mean during the last week 1.55 ng/ml + 0.26 and the highest of 4,30 + 1,17 ng/ml during the fifth week. The curve obtained is uniform until week 42 when it starts to fall until delivery. All the values obtained are quantitatively and qualitatively different from other countries reporting. DG had a significant effect (P< 0.001) over the P concentration; it was lower in buffaloes with a DG period between 307 and 313 days : also SC had a significant effect (P< 0.0281). Buffaloes with male calves averaging higher P₄ concentrations. Correlation values between variables were low (r under 0.25) which makes it impossible to predict the behaviour of the variables in relation to the results.

Palavras-chave : Progesterone; buffaloes; pregnancy; plasma.