Cross-fostering is a common way of maximizing the number of piglets weaned in a sow farrowing operation.
But like all livestock management techniques, there are no hard and fast rules, only guidelines that are based on the resources available to the barn manager, said Dennis Robles, a hog production expert with Swine Health Professionals.
The critical number is not based on the number of sows in the room, but on the number of functional teats that can act as life-support systems for growing piglets.
If a sow has 10 piglets and four appear to be starving, it’s obvious that only six teats are working, said Robles, who gave a “back-to-basics” presentation on sow farrowing intervention at Hog Days.
In a perfect world, there would be 100 piglets for every 10 sows, each with 10 teats, in the nursery.
Unfortunately, litter sizes may vary anywhere from seven to 12 piglets each. The latest in sow genetics may pump out as many as 16 to 20 piglets. But simply dividing up litters is not as simple as matching up one piglet with every visible teat.
“You have to count the number of functional teats in the room. If you do this right the first time, you won’t have problems with starve-outs later on,” said Robles.
Teats should be counted and inspected at farrowing when the sow is laying down. Some may appear normal, but are actually non-functional due to being stepped on, mastitis, underdeveloped, or questionable.
First, leave all the piglets to suckle on their original mothers for the first 24 hours, in order to give them the benefit of “home-cooked meals,” because each sow’s milk contains the right mix of nutrients and antibodies for their own piglets.
Also, try to leave each litter intact with at least 70 per cent original piglets.
Then, look over each piglet with a critical eye to determine which ones are well above the “cut-off” birth weight. Robles admits this may be tough for some, because it is only natural for people to want to see every piglet survive and thrive.
“You have to really decide. Is this pig going to survive?” he said. “Should you keep a little 500-gram pig, just putting energy, electricity, and all the effort to make it survive when it is not going to make it anyway — why do it?”
Some barns set the minimum at one kg, while others are more generous, and aim for 650 to 750 g. To get an idea of the size difference, he held up two drink containers. One, a typical canned soft drink, weighed roughly 500 g, while the other, in a plastic bottle, weighed 750 g.
“To be at the top of our game, we have to have a cut-off birth weight,” said Robles, who added that such guidelines should be included in sow farrowing technician training and in the barn’s S.O.P., or standard operating procedures.
Workers should always be on the lookout for “starve-outs,” or otherwise healthy piglets that for whatever reason are falling behind the rest of the litter. These should be moved onto healthy, nursing sows as soon as possible.
Death reasons should always be carefully recorded and clearly defined so that management can make adjustments based on good information.
Technology is making its way into the livestock industry, he added, but iPhones, iPads and specialized software applications only go so far because “there’s no app” for really good production beyond hard work and consistency.
“Be great at the basics,” he said. “Genuinely care for the pigs, the people, and the industry. There are no magic bullets.”