Reproductive effects of immunizing heifers against androstenedione and oestradiol-17 beta.

Heifers were treated with saline (Group I, N = 10), keyhole limpet haemocyanin (KLH; Group II, N = 10), androstenedione-KLH antigen (Group III, N = 14), or oestradiol-17 beta-KLH antigen (Group IV, N = 14). Booster injections were given to produce binding of greater than 10% at dilutions of 1:100 to 1:1000 (50% binding = 14 X 4 pg androstenedione and 9 X 5 pg oestradiol). The heifers were mated and killed at approximately 46 days of gestation to establish ovulation rates, calf numbers, blood hormone relationships and ovarian morphology. Ovulation rate in animals immunized against androstenedione (Group III) was significantly greater than in the other groups; 4 of the animals had double ovulations and 3 had twins. No significant differences were found between Groups I, II and IV in relation to ovulation or pregnancy rate and animals immunized against oestradiol-17 beta continued to cycle and become pregnant. Systemic progesterone, androstenedione and oestrogen levels were generally increased in Groups III and IV but the differences were not significant. No differences were detected between treatment groups in relation to CL weights, ovarian weights, follicle sizes or numbers. No binding of [3H]androstenedione or [3H]oestradiol-17 beta was detected in allantoic or amniotic fluids or fetal serum. Maternal antibody binding was correlated with binding of [3H]androstenedione and [3H]oestradiol in the follicular fluid sampled from the two largest follicles in the ovaries of each animal (Group III, r = 0 X 59; Group IV, r = 0 X 60; P less than 0 X 05).(ABSTRACT TRUNCATED AT 250 WORDS)