INDUCTION OF HYDROMETRA IN GOATS BY MEANS OF ACTIVE IMMUNIZATION AGAINST PROSTAGLANDIN-F2-ALPHA

Hydrometra is a pathological condition of the uterus which is characte rized by accumulation of aseptic fluid in the presence of a persistent corpus luteum, It forms a major cause of subfertility in goats. Activ e immunization against prostaglandin F-2 alpha (PGF(2 alpha)), the lut eolytic hormone in this species, was used to explore the possibility f or artificial induction of this pseudopregnant condition. During the b reeding season, 11 goats (group I) were immunized with 5 mg PGF(2 alph a)-ovalbumin conjugate in Freund's complete adjuvant, 4 goats were con trol-immunized (group CI) and 5 goats remained untreated (group C). Ju gular blood samples were taken twice a week (monday and thursday) for measurements of plasma progesterone and binding of (3)HPGF(2 alpha). I n conjunction with blood sampling, transcutaneous ultrasonographic exa mination of the uterus took place to detect the presence of fluid in t he uterus. Before and immediately after immunization, the mean (+/- SD ) duration of luteal phases (progesterone concentrations greater than or equal to 1 ng ml(-1)) was 16.7 +/- 1.6 (n = 39), 17.8 +/- 1.3 (n = 23) and 16.9 +/- 1.1 (n = 18) days in animals of group I, CI and C res pectively, Ten goats of group I developed an antibody titre. Persisten ce of luteal function (mean duration +/- SD: 150.3 +/- 23.5 days) occu rred in 6 of these animals and in 1 goat of group CI. Accumulation of fluid in the uterus in group I was first observed between day 31 and 3 8 of the prolonged luteal phase. Discharge of uterine fluid occurred a s soon as the plasma progesterone concentration reached a level lower than 0.5 ng ml(-1). It is concluded that immunization against PGF(2 al pha) is an effective method to induce pseudopregnancy in goats, provid ing a model for studies on luteal maintenance and uterine functions in the absence of a conceptus.