Fecal Progestins Differentiate Pregnant From Nonpregnant Early Luteal Bitches

Considering the high perimplantation progesterone (P4) secretion that occurs in female domestic dogs, we hypothesize that fecal P4 concentrations distinguishes pregnant from nonpregnant early luteal bitches. The objective of this study was to compare fecal P4 metabolites in early pregnant vs. nonpregnant early luteal bitches. Eighteen 2-6 years of age, 5-15 kg, pure-bred bitches, that were followed up for breeding management, and 2 ovariectomized (OVX) bitches were included in this study. On pregnancy day 18-28, a single fecal sample was collected from each animal. Fecal samples were frozen at -20°C until analysis. Pregnancy diagnosis was carried out by ultrasonography on day 21. Fecal samples were also collected from the 2 OVX bitches. Fecal P4 metabolites were extracted as based on methods described by Brown et al. (2008) and, then, measured by an electrochemiluminescence immunoassay. Eleven bitches were pregnant (PREG) while 7 were non-pregnant (N-PR). Fecal P4 metabolites concentrations were 283.9 ± 60.4 and 102.7 ± 19.1 (ng/g; P < .05) for PREG and N-PR, respectively. Both values were higher than those of the OVX bitches (9.9±1.1; P < .05). This noninvasive technique to measure P4 metabolites in feces appears as a simple and noncostly alternative for early pregnancy diagnosis in the domestic dog. Further large scale studies are necessary before this test could be widely recommended.