With the arrival of Porcine Epidemic Diarrhea Virus (PEDV) to Eastern Europe, and some finishers in Western Europe, it may be time to start considering “Closing” your herd, and raising your own Replacement Gilts. You will have to dedicate about 12% to 15% of your best sows to becoming your “Temporary Maternal Line”. These will be replaced by their offspring who will have much more “Maternal Blood” in them. From this point forward you will have to maintain this 12% to 15% “Maternal Line Pool” for raising Replacement Gilts. Only Boars and/or Semen will be purchased from outside your farm. Make sure that your supplier is sending you Boars and/or Semen that is free of both PEDV and PRRS!
Raising your own gilts used to be the norm for hog producers, but the Genetic Companies started supplying gilts that had “Super Sow” potential. Also the “Terminal Cross System” provided the simplest system to manage, along with the most profitable system (1). With today’s disease situation, it may be time to reconsider some “Old Practices”, like raising your own Replacement Gilts.
The possibility of losing almost 100% or your farrowed piglets to PEDV for 6 to 8 weeks may be catastrophic to your bottom line? Eventually your sows will get some immunity built up, but “Re-Breaks” of PEDV have occurred to the same farm in some places in the U.S. Raising your own Replacement Gilts cuts your potential disease exposure way down (1).
So how does one “Close” their herd, and start raising their own Replacement Gilts? In the short run you may want to select off of your finishing floors the most feminine gilts you can find that are sound in their feet and legs, have good underlines, and adequate reproductive genitalia. Select as many of these gilts as you had been purchasing in Replacement Gilts. Meanwhile, in your Farrowing Barns, select 12% to 15% of the most maternal sows, and start notching their gilt offspring that have sound legs, and good underlines. In your Breeding Barn, start breeding 12% to 15% of your most maternal sows to Landrace Boars (or Landrace semen). Gilts from these litters will need to be bred to Large White (or Yorkshire) Boars (or Large White or Yorkshire semen). The gilts form your ½ Landrace ½ Market Sow X Large White will be your Sow Replacement Gilts. They will be ½ Large White ¼ Landrace ¼ Market Sow. As stated earlier, you can bring in this Landrace Blood, and Large White Blood, by way of semen.
Managing the “Maternal Line” will take a concentrated effort. All “Maternal Line Females” will be bred to “Maternal Line Boars” (i.e. either Landrace or Large White). Tag gilts out of Large White Boars with one color and bred them back to Landrace Boars. Tag gilts out of Landrace Boars with a different color, and bred them back to Large White Boars. By the fifth mating there will only be 5% of “Market Sow Blood” in your Replacement Gilts! You will bred the bottom 85% to 88% of your “Maternal Line Gilts” to a “Terminal Line Boar “for market pigs! I would like to hear from those who already use this kind of system!
I would also invite your comments on the usefulness of this information to you, and your farm’s, present situation. Any thing we can do to keep PEDV from coming to our farm should be worth our consideration! Best Wishes and God Bless You!
(1) Baas, Tom J. “Purchasing vs. Closed Herd System” Pork Information Gateway Factsheet.
(2) Thompson, Paul Walker Personal Experience Agri-Vest SSP Farm July 1993 to August 1997