Reproduction in Domestic Animals

Non-invasive Monitoring of Hormones 77Fig. 1. Course of fecal progesteroneand oestrogen metabolites in apregnant (a) and pseudopregnant(b) Eurasian lynx. Samples werecollected over one year beginningwith October (M: mating; P: parturition)significant (n = 310, r 2 = 0.8131, p < 0.0001)correlation between E2 and P4 metabolites wasobtained, when calculated for all females involved inthe study. Altogether, the faecal steroid metaboliteprofiles obtained here are untypical compared to temporalpatterns measured in other felids. In pregnantcheetahs and clouded leopards P4 metabolite concentrationsdropped to baseline coincident with parturitionwhereas the duration of elevated faecal P4 metabolitesduring pseudopregnancy was approximately half thatobserved during pregnancy (Brown et al. 1994). Inaddition, as shown for both female lynxes, a distinctoestrogen peak at mating time was absent.The results from the Eurasian lynx revealed thatfaecal progesterone metabolites are a poor indicator ofreproductive status in this species as they fail to showclear elevations following copulation or during pregnancy.Such unusual endocrine profile conflicts withcourses reported from other felid species (Brown et al.1994, 2001), but is similar to faecal gestagen metaboliteanalysis in the Iberian lynx (Pelican et al. 2006).Faecal oestrogen and gestagen metabolites wereunreliable for oestrus and pregnancy diagnosis inEurasian lynx, wherefore a radiometabolism study wasnecessary to determine whether our enzyme immunoassaywould ‘catch’ the relevant metabolites reflecting thebiological active hormone. In addition a biologicalvalidation of the presumed luteal activity wasdemanded. It includes the characterization of immunoreactivemetabolites during and after pregnancy, thedetermination of blood serum hormones and, finally, anultrasound examination to verify the functional activityof CL outside breeding season.Radiometabolism studyTo identify the relevant progesterone metabolites, whichreflect CL activity in the Eurasian lynx, a radiometabolismstudy was performed. For the development oftechniques for faecal steroid analysis, experiments onthe metabolism of radiolabelled steroids have provided avaluable insight into the metabolism and the excretionof hormone metabolites via faeces and urine. Afterinjection of 3 H (tritiated) labelled hormone, the excretedmetabolites of a particular steroid can be analysed byHPLC.Figure 2a shows the distribution of radiolabelledprogesterone metabolites in a faecal extract of a femaleÓ 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag