Abstract: After 14C-labelled cortisol infusion in ponies and pigs, faecal samples were collected. Extraction of 0.5 g faeces with 5 ml 80–90 % methanol yielded the highest radioactivity in the supernatant. Most of the metabolites were ether soluble. After high performance liquid chromatography (HPLC), the presence of immunoreactive metabolites was demonstrated by measuring each HPLC fraction using enzyme immunoassays for cortisol, corticosterone and 11-oxoaetiocholanolone. Only the assay for 11-oxoaetiocholanolone revealed peaks with co-eluting radioactivity. For biological validation of the test system, adrenocorticotrophic hormone (ACTH) and dexamethasone were injected intravenously successively in both species (n = 6). Cortisol concentration in blood and the 11-oxoaetiocholanolone immunoreactive substances in faeces were determined. In horse faeces, basal values of 2.3–35.2 nmol/kg were measured. After ACTH administration, an increase (more than 200 % above basal values) of these metabolites was seen about 1 day after ACTH administration. After dexamethasone injection the levels decreased, reaching minimum concentrations 2 days after administration. In pigs, an increase in these metabolites was measured in only three animals after ACTH; dexamethasone did not cause a decrease. The stability of the samples after defecation was tested by storing samples from cows, horses and pigs at room temperature. It was shown that there was a significant increase in the concentration of measured cortisol metabolites in bovine, equine and porcine faeces after storage for 1 h, 4 h and 24 h, respectively. In frozen samples this effect was diminished after thawing samples at 40°C; thawing the samples at 95°C prevented an increase in immunoreactive substances.

Abstract: Noninvasive sampling allows genetic studies of free-ranging animals without the need to capture or even observe them, and thus allows questions to be addressed that cannot be answered using conventional methods. Initially, this sampling strategy promised to exploit fully the existing DNA-based technology for studies in ethology, conservation biology and population genetics. However, recent work now indicates the need for a more cautious approach, which includes quantifying the genotyping error rate. Despite this, many of the difficulties of noninvasive sampling will probably be overcome with improved methodology.

Abstract: The concentration of 11,17-dioxoandrostanes (11,17-DOA), a group of cortisol metabolites, was measured using enzyme immunoassay in fecal samples of horses experiencing painful episodes. One group of horses consisted of 10 stallions castrated (samples were collected daily for 10 days); the other group was made up of 29 horses which were brought to an animal hospital because of signs of colic (samples were collected twice daily for six days). Before castration, median concentrations of 10.5 nmol/kg feces were measured. On days 1 and 2 after castration, median 11,17-DOA values increased up to 26.2 and 50.0 nmol/kg feces, respectively, and decreased thereafter to levels lower than at the beginning of the sampling period. High variations were measured between individual cases of colic. In animals with colic, all horses excreted more than 33 nmol 11,17-DOA/kg feces for various periods. The highest concentration measured was 885 nmol/kg feces. One animal out of the 29 colic horses did not show any clinical signs of pain upon arrival in the hospital. The 11,17-DOA values were below 17 nmol/kg feces in all those samples. From this data we conclude, that the concentration of 11,17-DOA in feces is a parameter for painful situations that have occurred one or two days earlier.