Research attempts to enhance CLA in confinement meat and milk products fall far short of direct grazing

Staff report

Dr. Tilak Dhiman of Utah State University, a leading researcher into CLA, found that efforts to raise the CLA content in confinement raised beef and dairy products through the feeding of high fat grain oils, synthetic CLA and green-chop pasture had fallen far short of matching the CLA level naturally produced in direct-grazed animals.

He said that direct-grazed milk had 500 percent more CLA than enhanced confinement milk and grass-finished beef had 300 percent more CLA than enhanced feedlot beef.

He said the big research push into trying to increase the CLA percentage was being driven by the knowledge that for typical North American beef and dairy products to be able to claim a cancer-fighting benefit from CLA, the consumption level must increase by 400 to 500 percent over today's levels or the percentage of CLA must increase by the same amount.

Interestingly, he said, this level of increase in CLA is almost exactly the level of CLA that Dhiman's research found naturally occurs in direct-grazed meat and milk products. He said that one glass of whole milk from a grazed cow plus one serving of grass fed beef or lamb per day would meet the CLA percentage required to provide effective cancer prevention.

DAIRY COWS SHOW FAST CLA RESPONSE TO PASTURE

With dairy cows, his research showed that confinement cow's milk recovered the cancer- fighting percentage needed after only five days of being on direct-grazed pasture with no grain. Similarly, the cow's milk lost its CLA percentage just as quickly when taken off fresh pasture and put on a diet of stored forages and grain.

He said the knowledge that there was a significant difference in the milk between cows on pasture and those fed in a barn was first discovered at the University of Wisconsin in 1935.

In 1946, the University of Wisconsin discovered that butter made from the milk of pastured cows made young rats grow faster compared to confinement cows.

In 1967, an Australian researcher first discovered CLA.

Dhiman, a former researcher at the University of Wisconsin, said CLA - conjugated linoleic acid - is created by fiber digesting microbes. As a result, it is only found in ruminants (and turkeys which can digest fiber in their lower intestine). It has not been found in pork, chicken or fish.

"CLA is the only compound of animal origin that has shown in research trials all over the world to inhibit cancer," he said.

While most trials in the USA have been on animals, there have been significant human studies overseas that have shown equally positive results. Also, Dhiman said, researchers have traditionally found a good correlation between animal response and humans in cancer causes and prevention.

"You can definitely feel confident in promoting your grassfed products as a cancer preventer," Dhiman told the grassfed producers.

He said some recent research has indicated that CLA is also effective in stopping the growth of cancer tumors in those who already have it and in preventing heart attacks.

SUPERMARKET MILK HAS ONE-FIFTH THE CLA OF PASTURED COWS

He said analysis of current supermarket dairy products found a CLA percentage of 4.5 mg/g in milk, 3.6 mg/g in ice cream, and only 4.8 mg/g in cheese. He said these were one-fifth the amount of dairy products made from the milk of direct-grazed cows.

He said research at the University of Wisconsin found that there was 500 percent more CLA in cows direct-grazed with no grain and no TMR supplementation over those fed a normal confinement diet. As the level of stored forages and grain is increased in the diet of the dairy cow the level of CLA in the milk declines in linear proportion.

In that research trial, the control cows fed a typical grain/TMR diet had a CLA percentage of only 5.5 mg/g of fat.

Those fed fresh pasture with no grain had 23 mg/g of fat.

Those fed hay with no grain had 14 mg/g fat.

"The secret to high levels of CLA is fresh pasture. If you allow the forage to wilt, such as with hay or (wilted) silage, it drops the CLA percentage in the milk by one-third."

He said they have found that normal milk processing does not change the CLA percentage in a dairy product. In fact, pasteurizing actually increases the CLA percentage slightly as does cooking.

DIRECT GRAZED MILK SAID WORTH AT LEAST $27 CWT

Dhiman said he is currently doing research into how much of a premium a 100 percent grassfed milk should bring in the marketplace. He said if you priced the CLA in the milk at the same price as the synthetic CLA in the pills that are now available it should sell for at least $27 cwt. (Commodity cheese milk in Wisconsin was selling for as low as $8.50 cwt in November 2000 when Dhiman talked about this research.)

"However that does not take into account that the natural CLA in milk is six times more efficient than synthetic CLA," he said. "I would say you have an extremely valuable product."

While milk shows a very fast CLA increase when the cows are returned to pasture, Dhiman's research has found this is not the case with beef.

GRAIN FEEDING IN WINTER LOWERS CLA IN SUMMER PASTURED BEEVES

Unlike dairy products which have only one kind of CLA, beef has two. The Type 1 CLA is the cancer preventer found in both beef and dairy products. Type 2 CLA is only found in ruminant meat products. This is the form of CLA that prevents obesity. (Unfortunately, it does not make you lose weight if you are already fat.)

In feeding trials with high fat grain oils, it was found that Type 1 CLA could be increased very slightly but that Type 2 only increased with access to fresh pasture.

Initially it was believed that a grain-on-grass approach or the mechanical harvesting of grass and the feeding of it to feedlot animals might increase the CLA percentage in meat. However, this was not found to be the case.

Steers that were given 25 percent of their diet as fresh grass showed no increase in CLA.

Steers that were given 50 percent of their diet as fresh grass showed no increase in CLA.

Steers who were fed 100 percent on grass cut in the morning and fed in the feedlot that afternoon showed no increase in CLA.

"The only thing we have found that significantly increases the CLA level in beef is to direct graze fresh pasture," he said.

Unfortunately, grain feeding an animal during the winter appears to have a negative impact on the CLA percentage even long after it has been put back on a 100 percent diet of fresh-grazed grass.

In Dhiman's research, steers that were fed a typical feedlot backgrounding diet of 60 percent wilted forage and 40 percent grain for five months and then finished on a high grain ration had a CLA percentage of only 3.4 mg/g.

Steers that were fed a typical feedlot backgrounding diet for five months and then returned to pasture for five months before slaughter had a CLA percentage of 8.5 g/mg.

This compared to grass-finished steers who had never been fed grain of 15 g/mg.

"It is very significant that steers that had been fed significant amounts of grain during the winter never recovered their CLA percentage even after five months on pasture with no grain. It may be that for beef to meet our minimum level of CLA (for cancer prevention) we may have to go to a 100 percent forage production model."

Dhiman said to remember that the CLA was found in the fat of ruminant animals. Therefore it was higher in dairy breeds such as Jersey with high-fat milk and in beef that had been well-fattened on pasture.

"We need to rethink our prejudices against animal fats. They are very good for us when they come from direct grazed cows."

© by The Stockman Grass Farmer

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