Blood plasma boosts weaned pig growth, and you’ll likely see it pay off in many situations. The earlier you wean pigs, the more you need an easily digestible, high-quality protein source.

Plasma fills the bill, but it’s not cheap. University and feed company nutritionists keep looking for less expensive and more viable alternatives to get pigs off to a strong start. Several options exist, some of which are outlined here.

But not everyone views the sources as practical. Gary Allee, University of Missouri swine nutritionist, argues you need some plasma protein in that early weaned starter diet. Other protein sources may not duplicate plasma’s effects on the pig’s immune system and intestinal health.

“We need to do the experiments correctly,” Allee says. “Some trials say you can replace half the plasma protein with another protein source, but they don’t try using half the plasma without another protein source to see if they’ll get a similar response.”

The plasma level your pigs need depends on the challenges they face, contends Dean Zimmerman, Iowa State University swine nutritionist. In healthy pigs, Allee says, using 3.5 percent plasma in a corn/soybean meal diet may work nearly as well as 7 percent plasma. And that 3.5 percent plasma may work as well as 3.5 percent plasma combined with some other protein source.

Zimmerman says plasma may be the only source of immunoglobulins. They may improve the pig’s intestinal health and immune system in ways other sources cannot, Allee notes.

If you want a less-expensive diet and feel lower plasma levels alone aren’t the answer, here are some items that have shown promise in trials at various universities.

- Dried skim milk, a carbohydrate, is a good source of protein and of lactose. But it’s often too costly except in a phase I diet for pigs weaned at 10 to 14 days old, Zimmerman says. If you wean at 21 days, dried skim milk usually isn’t as cost-effective.

- Dried whey is the most common milk byproduct found in phase I nursery diets. Allee says its main benefit is a high carbohydrate source ù lactose content is 70 percent ù although the protein it contains is of high quality. It may save you money in some cases.

- Pure lactose may be competitive in cost with dried whey, so watch prices. Use the cheaper of the two.

- Fish meal is a high-protein source, Allee notes. Compare the cost to blood meal and soybean meal. Most research shows high-quality fish meal boosts growth, says Zimmerman. In the Midwest, fish meal can be expensive, so you may want to limit the amount you use.

- Egg protein is getting attention as a protein source. It may hold potential, Allee notes, though more research is needed. Zimmerman is less optimistic about its ability to replace plasma.

- Potato protein is similar to egg protein. Again it may cost less, but it may not fill plasma’s shoes.

- Spray-dried wheat gluten is a relatively new option. Early test results seem positive, Zimmerman notes. But Allee says more research is needed to find how it may work with or without plasma to boost piglet growth.

- Spray-dried red blood cells is a new plasma-free concept, Allee says. Work is under way to see if it fits in starter diets.

- Hydrolyzed pig small intestine is an experimental ingredient made from the pig’s intestine. It’s processed and sprayed on soybean hulls. The result is half HPSI and half soybean hulls.

Zimmerman fed it to pigs weaned at three weeks of age. They ate a diet with 5 percent to 6 percent HPSI for two weeks. After removing the product, pigs posted had increased gains compared to pigs fed a control diet.

Zimmerman speculates HPSI expedites the pig’s digestive tract development, but the mode of action is uncertain. More work is needed to see if the early results hold up.

- Soy isolates may offer potential but aren’t to the point where they can replace plasma, notes Bob Easter, University of Illinois swine nutritionist.

Watch for more research on these items to see which promotes growth best, under which conditions and at what cost.