Stop Moving Sows and Improve Pigs/Sow/Year

It is well known that moving sows after breeding lowers farrowing rate and the total number of pigs born per litter. Still, it is common on many farms to backfill and move sows during the most critical time of gestation - early pregnancy. The worst possible time to move bred females as far as sow productivity is concerned is between days 5 and 35 post-mating.

Now, with more and more farms using artificial insemination, we no longer run boars and sows to pens for heat checking. Rather, females are heat-checked right in the gestation stall by either tethering or gating a boar in front of four to five females. While the boar is in good nose to nose contact with the females, the breeding technicians can now begin to stimulate her by applying back pressure and watching for signs of standing heat. After heat-checking is completed, identified females can be bred according to each unit’s established mating schedule.

Breeding in the Snake

To save labor and reduce the effects of stress on moving freshly bred females, many farms have now gone a step further. They use a gestation sow flow known as a “breeding snake”. In this flow, the breeding area is no longer in a single designated location, rather it moves through the gestation barn. Weaned sows are placed into the stalls that were occupied by the females most recently moved to farrowing, where they will remain throughout breeding and gestation. This practice is known as “breeding in the snake”.

Weaned sows not in heat by day 7 are either culled, moved to a hot pen, or moved in with the next weaning group. Early weans are usually culled. Just as the boar is used to heat check weaned sows, he is also used to check for sows that become open or recycle. The boar must walk through ALL sow groups EVERY DAY to identify recycles and reduce non-productive days.

Breeding technicians should pay close attention to the 21 and 42 day post-mating sow groups. Keep in mind that these groups will return to heat between days 18 to 25 and days 38 to 46 post-mating respectively. Recycles can be culled, or bred if they are needed to reach the breeding target. If they are needed to reach the breeding target they can be handled in one of two ways. They can either be flowed into a parking or reverse parking system.

Parking

The Parking System designates enough stalls to accommodate 10 to 15 percent of the weekly or group breeding target. Each breeding week or sow group will have females that do not “fit” into the breeding snake. For example, if the weekly breeding target is 50, and the expected farrowing rate is 90%, there are only 45 stalls available in the breeding snake after the previous females have been moved to farrowing. The remaining five females, usually gilts or recycles, are “parked”. The pregnant females in parking are then moved into the snake with their respective group to fill in stalls where open females were pulled out. Do not move these animals until after the 35 day pregnancy check. Usually the remaining pregnant females are moved back into the main breeding snake by 42 days post-mating. It is important to use color coded sow or group cards or computer locations to keep track of these females.

Reverse Parking

In this system, the recycles are not moved until the end of the gestation period, thus the name Reverse Parking. Recycled females are re-mated and left to gestate right where they are. At farrowing time, these recycles will be 3 weeks behind, assuming any later recycles are simply culled. These females are moved into empty stalls as the rest of the group moves to farrowing.

Pregnancy checking should be done between 30 and 35 days post-mating and again between 50 and 55 days post-mating. Open sows are usually culled immediately, but may be heat checked daily and pregnancy checked once more before culling. If using Parking, these sows would be moved to the current weeks' group and a sow from parking moved into her place. If using Reverse Parking, she may be left in place.

Gilts are usually heat checked in pens, but may be stalled when first found in heat, then bred on the next heat. Immediately after the last service, (or before day 5 post-mating), gilts should be moved directly into the current weeks' group or placed into.

This system greatly reduces backfilling and sow movement, and completely eliminates sow movement prior to day 35 of gestation. Used properly, this system will result in more pigs produced per sow, and better overall profitability.