Abstract: An immunoadjuvant capable of producing secondary antibody responses as great as 50 to 60% of those obtained using Freund's complete adjuvant (FCA) which responses decline at a slow rate while not showing the disadvantages associated with FCA. The immunoadjuvant comprises an immunoadjuvant oil such as a mineral oil, squalene or squalane and a polycationic polyelectrolyte immunoadjuvant such as DEAE-Dextran or polyethyleneimine. The immunoadjuvant preferably comprises an emulsion having the oil in one phase and an aqueous solution of the polycationic polyelectrolyte in the other phases. Such immunoadjuvants are used with antigens, such as conjugates of hormones, e.g. luteinizing hormone releasing hormone, and an immunogenic protein.

Abstract: A method for increasing the fecundity of a flock of female sheep or goats comprising immunizing the animals in the flock against a steroidal androgen, such as 4-androstene-3, 17-dione or testosterone, or a steroidal oestrogen, such as oestrone, as by administering an immunogenic steroid/protein conjugate to the animals, to produce a mean steroid-binding antibody titer in the flock in the range of 1 in 500 to 1 in 3000 at the start of a mating period lasting at least twice the length of the average oestrous cycle for animals in the flock, and to maintain that titer so that it does not fall outside the range 1 in 200 to 1 in 2000 at the conclusion of the mating period, the overall decline in the titer being no more than 75% during the mating period.

Abstract: Novel phosphonothioate compounds of the general formula ##STR1## wherein R.sub.1 is lower alkylR.sub.2 is a steroid residue which is linked to the rest of the molecule through any carbon atom which is not one of the carbon atoms forming a ring junction, or through a side chain carbon atom, andn is 1 to 4,are disclosed as well as the use of these compounds as immunogenic haptens.Immunogenic hapten-protein complexes and conjugates of these phosphonothioate compounds and of steroid phosphates are also disclosed.

Abstract: A method for increasing the fecundity of a flock of female sheep or goats comprising immunizing the animals in the flock against a steroidal androgen, such as 4-androstene-3, 17-dione or testosterone, or a steroidal oestrogen, such as oestrone, as by administering an immunogenic steroid/protein conjugate to the animals, to produce a mean steroid-binding antibody titre in the flock in the range of 1 in 500 to 1 in 3000 at the start of a mating period lasting at least twice the length of the average oestrous cycle for animals in the flock, and to maintain that titre so that it does not fall outside the range 1 in 200 to 1 in 2000 at the conclusion of the mating period, the overall decline in the titre being no more than 75% during the mating period.