Could fecal estrone sulfate be used as a confirmatory pregnancy diagnosis in South American camelids?

Abstract

Pregnancy diagnosis in South American camelids (SAC) is commonly performed in early pregnancy about 30 to 45 days after mating. Due to embryonic mortality, it is advisable to confirm the pregnancy later. A laboratory analysis would be ideal for this confirmative test using samples which can be obtained by the breeders. Sampling of feces from the ground immediately after defecation would be both simple and convenient for the animal and breeder. Estrone sulfate which is synthetized by the placenta indicating pregnancy has been found in feces and used as marker for pregnancy in various animal species (e. g. pigs, primates).The objective of this study was to measure estrone sulfate concentrations in feces of SAC and assess if the fecal estrone sulfate concentrations are suitable for non-invasive pregnancy detection.Eighty-six mares (81 alpacas and 5 llamas) from different herds in Germany and Austria were sampled over a period of one year. The mares were selected by the breeders regardless the age, nutritional status or number of previous pregnancies. Of the 86 mares, 83.72% (72 mares) became pregnant and 16.28% (14 mares) remained non-pregnant despite being mated. All mares were sampled monthly. The fecal samples were analyzed in the laboratory using a commercial Estrone-3-Sulfate (E1S) Competitive Elisa Kit.The estrone sulfate concentrations in feces showed a wide variation over the entire sampling period and between individual animals. There was a significant difference in concentration at the end of pregnancy (14 d before parturition). Additionally, wide variations in estrone sulfate concentrations were also observed in the feces of non-pregnant mares. Consequently, the AUC characterizing the diagnostic value of fecal estrone sulfate concentration to detect pregnancy between days 60 and 150 was very low (0.455).It must be concluded that estrone sulfate analysis in feces as collected post defecation in this study failed to demonstrate any potential as a confirmatory method for pregnancy diagnosis in SAC. The increase at the end of pregnancy is unimportant for practical diagnostic procedures.