sealPurdue News

September 2000

If you feed hogs Paylean, feed more lysine, scientists say

WEST LAFAYETTE, Ind. – Hog farmers using Paylean may see little benefit if they do not use the product properly, according to research trials conducted at Purdue University.

"Our research project demonstrated very clearly that you should not feed today's hogs the minimal percentage of crude protein that the Paylean label indicates," says Brian Richert, assistant professor of animal science. "Biologically the product still works the same, and the response to Paylean is still consistent, but the proportions of protein needed have changed since the original research was done."

Richert and Allan Schinckel, professor of animal science, have conducted the nation's first independent nutrient trials on Paylean, a feed additive produced by Elanco, a division of Eli Lilly, Co. of Indianapolis. Paylean is the trade name for ractopamine hydrochloride, a pharmaceutical product that causes the hog's metabolism to shift nutrients from fat to muscle growth. This shift also causes a change in the pigs' nutrient requirements.

The problem, the scientists say, is that previous research trials on Paylean conducted by the manufacturer were done with hogs that weren't as genetically lean as today's hogs. "The original research trials were conducted in late 1980s and early '90s," Schinckel says. "Today we have leaner pigs with lower feed intakes and they have to have a higher percent lysine in their diets."

Richert agrees: "The Paylean label says typically a 16 percent crude protein diet (0.8 percent lysine) is the minimum amount you should feed when using the product, but today's pigs' lean accretion is 15 percent to 20 percent higher than it was when they tested the product," he says. Hog farmers who use Paylean should adjust the amount of lysine based on the genetics of their herd.

"Our research has shown that the lean growth response to Paylean is not constant over the entire 90-pound feeding period," Schinckel says. "The response increases, reaches a plateau, and then declines. If you feed Paylean too long, you can actually end up worse, with less muscle gain than if you hadn't used it."

The research was funded by Purdue and Pig Improvement Co. of Franklin, Ky.

Hog farmers typically "phase feed" hogs before they are sent to market, gradually decreasing the amount of protein in their diets. But the physiological demands of the rapid growth that occurs when hogs are given Paylean means that additional protein, especially lysine, is needed.

"For most farmers, this goes against their logic and against what we've been telling them," Richert says. "Without Paylean we would slowly lower the protein content during phase feeding. But now, when Paylean kicks in, you have to quickly raise the protein back up and then lower it again."

Without Paylean, hog farmers typically feed a finishing diet of 0.65 percent lysine for barrows and 0.8 percent lysine for gilts. But with Paylean, the lysine content needs to be increased to 1 percent to 1.1 percent lysine for barrows and 1.1 percent to 1.2 percent for gilts in order to get the maximum benefits.

"If the hog farmers feed the Paylean with only a 16 percent crude protein diet, which is a standard early finishing diet, they'll get only get 25 percent to 30 percent of the maximum Paylean response," Schinckel says. "And that's because the hogs with current genetics also have higher lysine requirements than pigs did ten years ago."

The timing of adding the extra protein is important, too. "The second and third week is where the Paylean response is the greatest and the predicted lysine response is the highest," Schinckel says. "When you get up to a dose of 20 parts-per-million of Paylean during the second and third weeks, the hogs need a 48 percent increase in the protein. If a pig needed 0.7 percent lysine before, according to our research project it would now need about 1.04 percent lysine during that time period."

Of course, these are general guidelines – specific requirements will vary, because of variations in genetics, facilities and rearing environments.

"In order to use this information, you first have to know what your pigs are eating and your own herd's growth curves, because that's what the Paylean response gets added on to," Schinckel says.

Even if a producer works out the feeding schedule, profits aren't a slam-dunk. "Paylean is priced at $2.50 a gram, so it's not a given that you're going to get enough of a response to pay for the product. It depends on what the packer can pick up," Richert says. "It costs $2.25 per pig to feed Paylean at the intermediate level of nine grams per ton, and we calculate that if you feed at this moderate dose you may see about a $2 per hog increase at the packing plant, plus another 50 to 60 cents cost savings in feed efficiencies. If you feed at the higher dose, it'll cost $4 to $5 per hog, with a feed cost savings of a dollar, but still only $2 to $3 difference at the packing plant.

"In the short term the packer is going to turn out well, because he'll be getting more lean meat than he's paying for."

Schinckel agrees that packers will like Paylean even more than farmers. "Even the most accurate equations and measurements will only detect 50 percent of the increased lean growth of the Paylean-fed pigs," he says. "And packers just can't pull a number and say we'll pay you three bucks per head more for pigs on Paylean, because the response is variable, depending on duration, level and dietary lysine levels fed."

Schinckel and Richert say that although the benefits of Paylean can be dramatic, it isn't for everyone. Here's who shouldn't be using Paylean:

• Farmers who don't know the feeding curves of their herd or who aren't interested in the extra management time required: "One problem is that if you feed it too long – that is, more than six weeks – the pigs don't grow as well at the end of the finishing period as non-Paylean fed pigs, negating some of the benefits," Richert says.

• Farmers who have very low feed costs: The main benefit to Paylean is that it improves feed efficiency, so less feed is needed. But farmers have to balance that against the extra price of the additive. "As diet costs go up – if corn and bean prices go up – the improvement that you can see will be dramatic," Richert says. "An 18 percent improvement in feed efficiency when feed costs are high makes a product pay a lot better. But right now with grain prices low, it's harder to get the value out of the product."

• Farmers who have problems with diseases on the farm: "Currently, you cannot feed antibiotics with Paylean. You can use injectable water-soluble antibiotics, but that's not always feasible. So that's a major concern with farms that have a history of having ileitis outbreaks or respiratory disease problems," Richert says.

Complete details of how hog farmers can best use Paylean can be found on the Purdue Pork Pages web site.

Sources: Brian Richert, (765) 494-4837;

Allan Schinckel, (765) 494-4836;

Writer: Steve Tally, (765) 494-9809;

Related Web sites:
National Hog Farmer magazine article on Paylean

Freedom of Information summary of FDA approval of Paylean

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