Enzaprost® is indicated for its luteolytic and/or oxytocic effect in cattle and pigs.

The indications for use are:

To more effectively control the time of oestrus in cycling cows.

To treat cows which have a functional corpus luteum, but do not express behavioural oestrus (sub-oestrus or silent heat).

To induce abortion.

To induce parturition.

For treatment of chronic metritis and pyometra.

For controlled breeding (oestrus synchronisation).

Induction of parturition.

To reduce the weaning to oestrus interval (WOI) and the weaning to fertile service interval (WFSI) in sows in herds with reproductive problems.

1. Oestrus control in cycling cattle: Individual cows or heifers treated during dioestrus will normally return to oestrus and ovulate within two to four days after treatment.

This may be employed to advantage as an effective aid towards managing oestrus and breeding in individual animals. (Note: Administration of Enzaprost® to cattle within four days after oestrus is unlikely to result in luteolysis of the corpus luteum.

Administration within 48 hours before the onset of the next oestrus may not influence the timing of the oestrus after treatment).

2. Treatment of sub-oestrus (no visible oestrus) in cattle Individual cattle may have normal cyclical ovarian activity, without detectable behavioural oestrus; this occurs most frequently in the winter months, at peak lactation in high producing dairy cows and in beef suckler cows. If a corpus luteum is present and ovulation has not occurred in the previous four days, administration of Enzaprost® will result in corpus luteum regression followed by return to oestrus and ovulation.

Breeding of cattle treated with Enzaprost® for the above indication may be by natural service, artificial insemination at the usual time in relation to observed oestrus, or by fixed time insemination (78 hours or 72 and 90 hours post-treatment).

3. Induction of abortion: Enzaprost® may be used to terminate pregnancy in cattle through its luteolytic effect during those stages of pregnancy in which the corpus luteum is sensitive to its action and in which maintenance of pregnancy is dependent upon the corpus luteum as the sole source of progesterone.

Stage of gestation in cattle is an important factor influencing response. The percentage of animals responding to a single intramuscular injection decreases as the gestation period increases. Approximate percentages responding are 90% within the first 100 days of gestation, 60% within 101-150 days of gestation and 40% in animals beyond 150 days of gestation. In the early stages of gestation, abortion will usually occur within one week, but as gestation length increases, the period to abortion following injection may also increase.

4. Induction of parturition in cattle and pigs: Cattle: Enzaprost® has been used to induce parturition on or after day 270 of gestation. The interval from administration to parturition is one to eight days (average three days). Induction of parturition in cattle is indicated where there is a risk of oversize calves or where early parturition is desired. In addition, induction is indicated where pregnancies are complicated by miscellaneous conditions such as mummified or macerated foetuses, hydrops amnii, hydroallantois, etc. Enzaprost® is indicated for expulsion of a dead foetus.

Pigs: Enzaprost® may be used to induce parturition in pigs within 3 days of the normal predicted farrowing date. Response to treatment by individual animals varies within a range of 24-36 hours from administration to parturition. This can be advantageously employed to control the time of farrowing in sows and gilts in late gestation. Treatment earlier than 3 days prior to predicted farrowing date may produce weak piglets resulting in reduced survival. It is recommended that treatment be given in the early morning following feeding. A lack of response had been noted in a small proportion of pigs, the specific reason for which has not yet been determined.

5. Treatment of metritis or pyometra in cattle: In the cow chronic metritis frequently occurs as a sequel to an acute or sub-acute endometritis in the first two or three weeks post-partum; typically, there is an intermittent purulent or mucopurulent discharge. Pyometra is characterised by the retention of purulent fluid within the uterus.

Luteal regression through the administration of Enzaprost® is followed by oestrus, during which the uterine environment is relatively unfavourable to the bacteria involved in the infection. Treatment may have to be repeated after 10-12 days where the condition is longstanding.

6. Controlled breeding in cattle: Enzaprost® is indicated for its luteolytic effect in cattle. This luteolytic effect can be utilised to control the timing of oestrus in cycling cattle that have a corpus luteum. For normally-cycling cows, at least 35 days after calving, the identified activity of Enzaprost® permits a wide range of oestrus control programmes.

1. Inject 5 ml Enzaprost® intramuscularly;

2. Repeat the injection in 11 (10 to 12) days; then

3. Inseminate 78 (75 to 80) hours after the second Enzaprost® injection. No oestrus detection or observation is required if animals were cycling normally when injected.

This programme is recommended for most herds with successful A.I. experience where females are known to be cycling.

1. Inject 5 ml Enzaprost® intramuscularly;

2. Repeat the injection in 11 (10 to 12) days; then

3. Inseminate 72 (70 to 74) hours and 90 (88 to 96) hours after the second Enzaprost® injection. No oestrus detection or observation is required if animals were cycling normally when injected.

Double insemination has demonstrated increased pregnancy rates in some herds.

1. Inject 5 ml Enzaprost® intramuscularly;

2. Repeat the injection in 11 (10 to 12) days; then

3. Inseminate upon detected oestrus.

1. Inject 5 ml Enzaprost® intramuscularly;

2. Inseminate upon detected oestrus.

* If it is unknown whether most animals to be treated are cycling, Programmes III and IV calling for oestrus detection should be followed rather than Programmes I and II calling for timed insemination. A follow up bull may be used following any Enzaprost® programme, or the service may be repeated at the next oestrus, one cycle later, in animals that did not conceive at first service.

Practical application of these programmes will vary depending upon many factors, and in many cases these programmes may be altered to meet the requirements of the specific operation. For example, some veterinary surgeons may wish to design their own programmes for specific situations and schedules. The activity of Enzaprost® may be easily adapted for such individualised approach. These changes should be carefully evaluated to ensure that they do not detrimentally affect the success of the breeding programme.

7. To reduce the weaning to oestrus interval (WOI) and the weaning to fertile service interval (WFSI) in sows in herds with reproductive problems: PGF2α has a stimulating effect on uterine contractions, leading to better post-partum evacuation of the uterus. Field clinical trials in herds with reproductive problems confirmed that treatment with Enzaprost® resulted in a more rapid return to oestrus and fertile service after farrowing.