4. Unwanted mating and pregnancy termination

What are the indications for terminating unwanted mating and pregnancy in animals?

1. Mismating

2. Too young or old age

3. Dystocia risk

4. Endocrine issues

5. Pregnancy ketosis, etc.

What must be done before terminating a pregnancy?

1. Confirm that pregnancy is present (only 40% unwanted mating end in pregnancy)

2. Determine the number of puppies (using USG or X-ray)

When is the best time to perform an ovariohysterectomy?

In anoestrus, 2.5-5.5 months after the onset of pro-oestrus (3-4 months after bleeding)

What are the risks of performing an ovariohysterectomy during oestrus?

Higher risk of bleeding due to increased uterine vascularisation

What are the risks of performing an ovariohysterectomy during dioestrus?

Can cause lactation/pseudopregnancy due to sudden removal of progesterone

What are the advantages of medical pregnancy termination?

Safe, good efficiency, easy-to-follow protocols, can be applied as soon as unwanted mating occurs

What are the methods of medical pregnancy termination according to time after mating?

1. Early embryonic phase (until day 9-11)

2. Late embryonic phase (days 9-30)

3. Foetal phase (days 30-35 to parturition)

What drug is used for pregnancy termination during the early embryonic phase (until day 9-11)?

Oestrogen (Estradiol benzoate, cypionate, valerate)

How does oestrogen terminate pregnancy in the early embryonic phase?

It causes degeneration of the zygote and is embryotoxic, acting on the uterus

When must oestrogen be administered for effective pregnancy termination in the early embryonic phase?

Before the egg reaches the uterus

What are the severe side effects of oestrogen use for pregnancy termination?

Pyometra and bone marrow suppression

What drug is most commonly used for pregnancy termination during the late embryonic phase (day 9-11 to day 30)?

Aglepristone (Alizin), an antiprogesterone (2 injections 24 hours apart)

How does aglepristone terminate pregnancy?

It competes with progesterone at receptors, blocking its effects on the uterus without decreasing progesterone levels

When can aglepristone be used for pregnancy termination?

Day 0 to day 30

When does resorption occur in a failed pregnancy?

When an embryo fails before day 35

What are examples of drugs used during the foetal stage to terminate pregnancy?

1. Algepristone (AKA Alizin)

2. PGF 2a

3. Anti-prolactin (Cabergoline AKA Galastop)

What clinical signs may occur if aglepristone is used during the foetal phase (day 30-35 until parturition)?

Discharge

How does prostaglandin F2α terminate pregnancy?

It acts on the ovaries: lysis of corpus luteum → decrease P4

How does cabergoline terminate pregnancy?

It stops luteal function, thereby stopping progesterone production.

What is a key difference between Aglepristone and Prostaglandin F2a in how they terminate pregnancy?

Aglepristone blocks progesterone effects, while Prostaglandin F2a lowers progesterone production.