A combination of non-invasive endocrine monitoring and predictive models to assess pregnancy status in wild guanacos: a population approach.

MAROZZI, ANTONELA; CANTARELLI, VERÓNICA; GÓMEZ FACUNDO; PANEBIANCO ANTONELLA; GREGORIO PABLO; LEGGIERI, LEONARDO; PONZIO, MARINA; CARMANCHAHI, PABLO.

Pretoria

Conferencia; 7th ISWE Conference; 2019

ISWE

The use of non-invasive methods and predictive models is an opportunity to incorporate pregnancy status information on population studies. Usually, this data is not included due to the limitations of pregnancy detection in free-ranging individuals. With the objective of developing a predictive model to diagnose pregnancy status in free-ranging wild guanacos (Lama guanicoe), we measured fecal progesterone and estrogens metabolite concentrations in pregnant (n=35) and not pregnant (n=34) females used for live shearing management (capture, shear and release). Hormonal data was combined with data on abdominal ballottement as an independent factor of pregnancy diagnosis, to develop a logistic regression model which was then applied to assess pregnancy status in unhandled individuals in La Payunia Reserve (Mendoza, Argentina; n=69 females).To build up the predictive model, dry fecal samples were analyzed to determine pregnanediol glucuronides and conjugated estrogens concentrations by enzimeimmunoassays (PdG R13904 and EC R522-2 respectively, C. Munro). As expected, PdG and EC concentrations were significantly higher in samples obtained from pregnant females (PdG pregnant vs. non-pregnant females: 81.9±58.5 and 45.4±24.4 μg/g respectively, EC pregnant vs. non-pregnant females: 485.6±412.0 and 76.2±47.9 ng/g respectively).The model was applied to hormonal data obtained from free-ranging female guanacos, and predicted the percentage of pregnant females (46% in 2016 and 19% in 2017). Metabolites concentration ± SD were: PdG for pregnant females: 38.1±20.3 μg/g in 2017 and 79.8±66.1μg/g in 2016; PdG for not pregnant females:42.1±15.0 μg/g in 2017 and 39.7 ±16.1 μg/g in 2016; EC for pregnant females: 217.0±162.6 ng/gin 2017and 373.0±321.9 ng/g in 2016; EC for non-pregnant females: 39.6±24.3 ng/g in 2017 and 49.2± 22.3ng/g. These results will be used to incorporate pregnancy status on guanaco population dynamic studies. Moreover, this study approach might be applicable in other wild mammals to monitor pregnancy in large scale studies.