Hormone management (III)-using exogenous progesterone to control the time of estrus in sows

Exogenous progesterone (tetraethylstilbestrol or allyl progesterone) was used to control the time of oestrus in sows.

Hormone management (III)

In our previous article, we have been focusing on how to help sows in estrus. In this article, we will show how to use the "side effects" of progesterone (tetra-diestrone or allyl progesterone) to delay estrus in sows.

In principle, delaying estrus in sows may be absurd, but in some special cases, delaying estrus is useful.

Delay periodic estrus

Through the previous introduction, we know that the presence of corpus luteum in the ovary has a high concentration of progesterone, which will inhibit estrus in sows.

Levels of major hormones in the estrous cycle of sows

At present, there are some synthetic progesterone products on the market, which can inhibit follicular development and ovulation in pigs. Using this method, we can postpone the estrus of sows.

These products need to be used regularly every day, and the more common product is Regumate ®, an oral preparation that is given to pigs by mixing ingredients.

When progesterone products are stopped on pigs, progesterone levels in pigs decrease accordingly.

Exogenous progesterone no longer prevents follicular development, the estrous cycle continues, and sows will return to estrus after 5-6 days.

In the above case, we achieved a 30-day estrous cycle (estrus delayed by 9 days)

Delay postpartum oestrus in sows

We have seen how progesterone can be used to delay synchronous estrus in sows, and the same method can be used in weaned sows.

In this case, suppose the sow is weaned for 24 days, but we want the sow to delay estrus for another week (enter the next week's estrus sequence).

When sows are given allyl progesterone, it is as if they are still pregnant, and high levels of progesterone block ovulation, similar to those in a normal estrous cycle.

As we discussed earlier, the concentration of progesterone decreases after the use of exogenous progesterone products, and follicular development and ovulation resume.

Five to six days after the interruption of exogenous progesterone, the sow will be in estrus, just like weaning.

In this case, the sow was weaned in 24 days, but through our operation, the sow achieved the weaning effect of 31 days in time. Delayed estrus for a week.

Special reminder!

If you want to delay estrus for a week, it is recommended to start the minimum dose on the day before the sow is weaned, rather than on the day of weaning.