Adding flaxseed and flaxseed oil to feedlot cattle rations can help improve health and carcass quality in those animals, but a big added payoff is a resulting spike of “good fats” in the beef produced.
So says Jim Drouillard, a Kansas State University professor of beef cattle nutrition and management, who has studied flax feeding for the past five years. He's collaborated with North Dakota State University's Plant Sciences Department in the work, with funding provided by the North Dakota Oilseed Council.
Drouillard says their early studies looked at controlling the inflammation that occurs with bovine respiratory disease (BRD) in cattle. Its price tag is estimated to cost the beef industry as much as $1 billion annually.
That first study was a spin-off of earlier research that looked at ways to reduce stress and enhance immune response of newly arrived feedlot calves. The study involved feeding fried onion residue from an onion-ring processing plant.
The researchers found cattle eating the by-product stayed healthier than those on traditional feeds. Further research concluded it was actually the oil used to fry the onions that was beneficial. In particular, it was a fatty acid called alpha-linolenic acid (ALA, an omega-3 fatty acid), an essential fatty acid that must be supplied in cattle's diet.
That finding led Drouillard to look at flaxseed, which is high in ALA, as a cattle diet additive. His literature search turned up the fact that the exaggerated inflammatory response of some diseases is due in part to the types of fats the animals consume.
“Some fats metabolize to ultimately form compounds that are pro-inflammatory (inducing inflammation). Others actually produce anti-inflammatory compounds,” Drouillard says.
The latter compounds work to reduce the harmful effects of endotoxins in the body, he explains. Gram-negative bacteria are often the most damaging pathogens in respiratory disease because they create endotoxins that produce a great deal of inflammation and can quickly damage and shut down many body systems and organs.
Drouillard says the team learned that when animals consume a diet containing omega-3 fatty acids — in this case, flaxseed — inflammation was reduced. A variety of follow-up studies that included challenge-type experiments and larger-scale studies of 300-400 animals were performed to monitor the impact on animal health, he says.
In their animal health experiments, the researchers used long-haul, 400- to 500-lb., weaned feeder calves that had been commingled at sale barns. The researchers found that the inflammation that normally occurred with BRD was partially suppressed when flaxseed was fed. The flax diet seemed to slow the production of a certain inflammatory substance (tumor necrosis factor alpha) usually produced in excess during many inflammatory diseases.
“We also learned that adding flax to the diet resulted in a large increase in feed intake,” Drouillard says. “This was unusual because when fat is usually added to the diet, energy density is increased and feed intake is depressed. The animal just doesn't have to eat as much to get the same amount of energy. But flax increased the intake well beyond what happens with no fat in the diet.”
When fed flax, calves ate and gained more. But, it wasn't necessarily a matter of efficiency as feed efficiency remained about the same, he adds.
Another interesting finding was that when animals were fed flax, death loss was reduced. However, there was no change in first-time incidence of respiratory disease.
“Animals appeared to respond more favorably, however, to antibiotic therapy,” Drouillard points out. Calves recovered better and there were fewer re-treatments, while fewer antibiotics were used overall.
“At some point we want to come back to this work, refine it and elaborate on it, but I feel there is benefit from flax in improving response to antibiotic therapy,” he says.
Flax And Carcass Quality
Flax was fed to stressed feeder calves the first five to six weeks of the feeding period. Researchers then followed the animals through finishing to monitor feeding and carcass performance. They found animals receiving flaxseed or flaxseed oil had better carcass quality.
About 180-220 days after flax was included in the ration, calves demonstrated a large residual effect on marbling and quality grade. Starting with a baseline of 33% Choice or better, Drouillard says flax may have boosted the figure to 44%.
“In another case, we started with a base line of 67% [on cattle fed tallow or no fat, with comparable levels of quality grade]. After feeding flax, it jumped to 82%,” he says.
“When fed flax oil, it jumped to 94% Choice or better, with 39.8% Prime. The oil greatly impacted quality grade. It appears the oil is the active component,” he explains.
Unfortunately, the oil isn't readily available, and the one available source is very expensive, Drouillard adds.
“Linseed meal [the protein meal remaining after extraction of oil from flax seed] generally isn't a good source due to the very low level of oil left in it. So we buy commodity flaxseed, grind it and add it to feed. The material is about 40% fat, and we typically add 5-15% fat to the diet this way. Most of our work with flax has been at about 10% of the diet,” he says.
One project compared feeding flax vs. tallow, as well as no fat. Quality grade improved in the flax-fed cattle.
“In this experiment, flax was fed to yearling steers the last 80 days before slaughter. We did some analysis of blood, and found a high concentration of ALA,” Drouillard says. “We analyzed muscle tissue and also found high concentrations of ALA. This was exciting, because ALA is among the omega-3 class of fatty acids and there are a number of human health benefits linked to these.”
Enhancing The Good Fats
Drouillard says their flax work of the past two years has concentrated on the finishing animal for two reasons — carcass quality effects and the potential for enrichment of carcasses with omega-3 fats. He's found feeding flax to cattle for 70-120 days before slaughter can mean a tenfold increase in omega-3 fats deposited in muscle tissue.
“Most of that increase comes in the form of ALA. But, we do get some increase in ecosapentanoic acid, which is part of the omega-3 family and one of the fatty acids associated with certain types of fish that are supposedly good for human health due to the long chain, omega-3 oils,” he explains.
Early in the finishing work, Drouillard says researchers discovered an off-flavor — a mild degree of rancidity — that seemed to be created along with the increase in ALA in the muscle.
“Because ALA is more easily oxidized than other fatty acids, we had to resolve this problem or there would be little point to feeding flax. We added vitamin E to the ration as an anti-oxidant and completely eliminated the off-flavor problems. Plus, it appears the flax increased absorption of vitamin E,” he says.
That's probably true with any fat added to diet, since vitamin E is a fat-soluble vitamin, he says. “Subsequently, in all our flax work, we've added about 1,000 units or more of vitamin E per day in each animal's diet.”
Since that time, Drouillard says a number of flax studies have found a corresponding increase in quality grade, with only a couple of exceptions. In one instance, when flax was fed to yearlings at a rate of 10% of the diet, the cattle graded 65-67% Choice.
“We didn't see an improvement in quality grade, but saw marked reduction in yield grade. It was a large impact. So there still seemed to be some repartitioning of the fat to where we maintained marbling but greatly reduced the subcutaneous fat, kidney/pelvic fat, etc.” Drouillard says.
In cattle not fed flax, there were 12-14% Yield Grade (YG) 4s. In the group of cattle fed 10% ground flaxseed, there were virtually no YG 4s and there were more YG 1s and 2s.
“We don't understand why it happens, but we've seen it a couple of times where the flax is administered later in the feeding period. It's normally manifested, however, as an increase in quality grade. On occasion, it's made no change in quality grade but a significant improvement in yield grade,” he says.
Drouillard says the outcome depends on what the Choice/Select spread is, and what kind of discount on YG 4s and 5s is in force. But, in many cases, he adds, the researchers have seen an increase in value ranging from $10 to more than $20/head.
“We're currently doing a couple of different projects. Since many feedlots aren't equipped with hammermills or rollermills, we felt it was important to determine if it would be possible to derive these benefits by feeding flax in unprocessed form,” Drouillard says.
He explains that flax is a very small seed. They had assumed it needed grinding or breaking to facilitate digestion.
“We need to know if we can feed flax in unprocessed form and still derive some benefit. We've started a pilot project on that, and know of some other work around the country looking at similar questions,” Drouillard says.
They're also engaged in larger-scale, feedlot studies, trying to understand more about the timing of flax feeding in order to derive the greatest benefit in terms of carcass quality and carcass enrichment with the omega-3 fats. Current studies, however, are more focused on carcass traits than on health benefits for the calves.
“These studies have really opened our eyes, Drouillard says. “For years we thought fat was fat. We've discovered that fats are not all the same. It's not just a source of energy; there are some biologically important properties of fats that we historically failed to consider. We're learning that flax and some of the other fats may have some important repartitioning effects.”
Heather Smith Thomas is a rancher, book author and a freelance writer based in Salmon, ID.
A Little Flax Reaps Big Benefits
Flax grows best in cool climates like that in North Dakota, and Manitoba and Saskatchewan, Canada. Shipping flaxseed to major cattle feeding states likes Kansas, Nebraska and Texas, however, may not be much more expensive than feeding a ration with similar fat and protein contents using a tallow and soybean meal mix.
One advantage in its use for fed cattle is that flaxseed needn't be fed for a long period. Even short-term diet exposure to flax in feedlot cattle can have major long-term effects on marbling and carcass quality.
Short-term feeding of flax (even just the first 35 days after entering the feedlot) can also increase carcass weight.
For instance, in a study on different fat sources in calf diets during the first 35 days in a feedyard, the control group's average carcass weight was 663 lbs. Meanwhile, cattle fed tallow had carcass weights averaging 668 lbs. Cattle fed flaxseed averaged 670 lbs. and those fed flaxseed oil averaged 680 lbs. Meanwhile, carcass weights of cattle fed tallow and linseed meal (minus the oil) averaged less than 656 lbs.
About 69% of the control group graded Choice or Prime, reports Kansas State University researcher Jim Drouillard, but only 67.4% of the cattle fed tallow for the first 35 days graded that well. Almost 83% of the cattle fed flax graded Choice or Prime, compared to more than 93% of those fed flaxseed oil.