Immunoassay of sexual steroids for fertility control in cows, sows and mares. Part 1

The immunological determination of oestrogens in faeces as a method of pregnancy diagnosis in cows, sows and mares, and the stability of oestrogens in faeces was tested. During 8 days storage at -200 to +370C the concentration of oestrogen in faeces was not significantly influenced. During 2 oestrous cycles blood was taken daily of 8 cows and the concentration of progesterone (P4), dehydroepiandrosterone (DHA), androstenedione (AD), epitestosterone (Epi) and testosterone (T) in plasma was determined by radioimmunoassay (RIA). The average concentration of DHA in the blood of cows was 650±71 pg/ml, that of AD 77±8 pg/ml to 122±29 pg/ml (x-bar ± SD). The concentration of Epi and T was from 160 to 243 pg/ml and from 46 to 96 pg/ml plasma. For the pregnancy diagnosis in sows blood and faeces were collected of 6 non-pregnant and 30 pregnant animals day 16 to 30 after mating. In faeces the concentration of oestrogens was determined by means of RIA, in blood that of oestrone sulphate and P4 by EIA on micro titre plates. During the whole period of examination the concentration of P4 remained fairly constant. From day 17 to 23 after mating the concentration in non-pregnant was significantly lower than in pregnant sows. In the blood of non-pregnant sows the oestrone sulphate concentration was 1,3±1,2 ng/ml (x-bar ± SD). Day 24 to 30: >x-bar ± 2SD in pregnant animals. Day 25 and 29 of pregnancy the concentration of oestrogens in faeces was: >x-bar ± 2SD = 20,6 ng/g faeces. Pregnancy diagnosis: 21 non-pregnant cows and heifers, 6 bulls and 83 pregnant cows were examined (10th to 35th week of pregnancy). Faeces samples from 21 non-pregnant mares, 6 stallions and 57 pregnant mares (10th to 35th week) and 18 samples from 3 mares at parturition. 18th week of pregnancy the concentration of oestrogens in faeces of cows and mares was: (>x-bar ± 3SD) in non-pregnant animals; (cows: 21,6 ng/g, mares: 14,3 ng/g ) after parturition. 17 refs. (Author)