Add ionophores to rations for improved feed efficiency

URBANA, Ill. — Adding ionophores to sheep rations helps to capture more energy from the feed.

“Anything that helps feed efficiency and feed conversion is going to be a good thing when we have expensive feed,” said Josh McCann, assistant professor of animal sciences at the University of Illinois.

Ionophores have been fed to animals since the 1970s.

“Monensin works really well against coccidia in chickens and then they figured out it worked for cattle and ruminants too,” said McCann during a presentation at the Illinois Lamb and Wool Producers Sheep Day. “Ionophores are an antibiotic, but they are a really good antibiotic because we don’t use it in human medicine.”

It is important to remember, McCann said, that not all antibiotics are the same.

“We can put ionophores in feed and we don’t have resistance develop,” McCann said.

“When you feed your sheep, they don’t get the first cut of the nutrients. The bacteria in the rumen are what you’re feeding first,” he said. “The bacteria transform everything to allow your sheep to get the nutrients.”

About 70% of the corn kernel is starch and hay has a lot of hemicellulose and cellulose.

“Carbs are broken down in the rumen by bacteria to get glucose,” McCann said. “Then they get fermented into volatile fatty acids.”

Volatile fatty acids normally have acetate, propionate and butyrate.

“Propionate has a unique quality because it can be turned into glucose by the animal to help the animal grow faster,” McCann said. “Acetate gets turned into fat and we like to have a lot of acetate in a lactation diet.”

Ionophores will improve energy metabolism by increasing the proportions of propionate by 50% to 75% depending on the type of diet.

“So, the diet may be just as digestible, but the animal will capture more efficient energy which is really positive,” McCann said. “They also make a little less methane and every time they pump out methane, they’re losing carbon.”

Adding ionophores to the ration can help improve the energy absorbed as starch by sheep.

“Animals have to get some absorption in the small intestine and if we push a little more to the small intestine, that will be helpful,” McCann said.

“Protein is the most expensive macro nutrient,” he said.

“Some of the protein that is fed gets digested and some of it doesn’t,” he added. “Bacteria use the protein that gets digested and we like to capture as much of that protein as we can.”

Ionophores impact the organisms that digest the protein a little too fast.

“That will get more amino acids in the small intestine so they’ll lose less nitrogen as ammonia and they make the nitrogen more digestible,” McCann said.

McCann talked about a study that evaluated the impact of feeding ionophores on nitrogen metabolism.

“Nitrogen digestibility at 65% is pretty normal and when we fed monensin, it was bumped up to 68%, a 4% increase,” he said. “Feeding lasalocid bumped it up to 70%, a 5% increase and when feed is expensive, every little bit counts.”

Ionophores can reduce digestive disorders and coccidia.

“Ionophores help animals eat a little smaller meal and that makes it less likely an animal will get acidosis,” McCann said.

“Ionophores can’t make coccidia go away, but they are one of our best tools to manage it,” he said. “Coccidia doesn’t really bother the ewes because they have a pretty robust immune system, but lambs are really susceptible to it especially right after weaning because stress at weaning gives coccidia a chance to flourish.”

At one feed mill, McCann said, a sheep 34% crude protein pellet included 150 grams per ton of lasalocid.

“By feeding one pound of pellet, that would be 75 milligrams per day of lasalocid at a cost of 37 cents per pound,” he said.

McCann advises shepherds to make plans now to extend the fall grazing period due to the higher corn and grain prices.

“Maximize every bit of pasture you have because when grain gets more expensive, grass becomes more valuable to you,” McCann said.

“If you’re making hay, make it as good of quality as you can,” he said. “Higher quality has more digestibility and that can reduce the need for grain.”

Typically corn is the cheapest source of energy, McCann said, but that may not be true in 2022.

“Compare different feedstuffs by taking the price per ton and divide that number by the total digestible nutrients,” McCann said.

“Soyhulls don’t have as much energy as corn, but they are cheaper today,” he said. “So, soyhulls are cheaper on an energy basis than corn and it’s not normally like that.”

For corn gluten feed at $260 per ton, McCann said, it is more expensive that corn or soyhulls.

“The TDN value on grass hay can be really variable so testing your hay is always a good thing,” he said.