Beyond energy to improve bottom line
By Ron Goble
TULARE – Clemson University dairy animal nutritionist, Dr. Tom Jenkins, shared some of his research findings with Dairy Profit Seminar attendees recently at World Ag Expo in Tulare. He was joined by James Tully of Pine Creek Nutrition Service, who added some practical evaluation tools to the panel presentation.
The overall presentation, “The Skinny on Fatty Acids: Beyond energy to improve bottom line,” was sponsored by Virtus Nutrition.
Jenkins told the group of dairy farmers, “we need to determine what we are trying to accomplish when we are putting fat supplements or fats from other sources in the dairy ration. We’ve been misled in the past by thinking too narrowly on the subject; thinking there is only one benefit that comes out of it – energy.
“Fat obviously supplies a lot of energy that can be used to help with the milk income check. And while we don’t want to forget that, we want to think what are some alternative uses of fat supplements,” he said.
Debunking three lipid myths
In pursuing these alternatives, Jenkins set out to debunk three lipid myths:
• Myth No. 1 – Cattle don’t have any significant fat in their feed unless you add high fat supplements.
“That’s not true. Every feed ingredient you put in front of a cow has fat in it, with the exception of maybe water and a mineral pack,” Jenkins declared. “When you consider the huge amounts of grain and forages cows eat each day, that’s a pretty good load of lipid going into the rumen environment. The first place it goes is to the rumen microbial population and they don’t like high amounts of lipid; especially unsaturated fats.”
Fatty Acids in Hay and Grain
Ether Extract % – 4.23
Fatty Acids % – 4.03
Ether Extract % – 2.64
Fatty Acids %– 2.01
Ether Extract % – 3.19
Fatty Acids % – 2.21
Ether Extract % – 3.50
Fatty Acids % – 2.28
Pasture Fatty Acids:
Higher than hay –
6.8% annual ryegrass (Freeman et al., 09)
11.6% perennial ryegrass (CPM v 3.0.8)
What is the upper limit of fat that should be in a dairy cow ration? “Some of the guidelines have been 7 to 9% total. Sometimes it’s like having cows on a high fat diet when they are out on these pastures,” Jenkins said. “Don’t count on your hay analysis to reflect what the cows are eating out there on pasture.”
Five forages Jenkins analyzed at Clemson included: red clover and alfalfa at 3% total fatty acid; crimson clover at nearly 4%; wheat and ryegrass at slightly more than 6%.
The thing about byproducts is the inconsistency and their unpredictability. If you try to go by book values alone, you can get burned. They could be way too high or way too low. A notorious example of that is distillers grains. Jenkins data went from a minimum of 5% to a high of 13%. So there are several places where fats can come in besides your fat supplements. Jenkins has a formula he uses to help monitor this variation. He calls it his Rumen Unsaturated Fatty Acid Load, or “RUFAL.”
The three major unsaturated fatty acids were, 18:1 = oleic acid; 18:2 = linoleic acid; and 18:3 = linolenic acid.
“The most abundant one dairymen are feeding their cows is usually linoleic acid. If you let that number get too high, it will interfere with the microbial population in the rumen and bad things are going to happen. The same is true if it gets too low,” Jenkins said.
There’s fat in them TMRs
In five studies, Jenkins reported that typical RUFAL values in a TMR with no added fats totalled 473 grams of unsaturated fat consumed per day.
“Look at the spread on that from 220 grams to 973 grams, all in a control diets with no added fat. So there were differences in the feed ingredients that was dumping a lot more unsaturated fat in one study than in another, even though they proclaimed they were all control diets,” said Jenkins. “So, in your animals, how much unsaturated fat is coming in? If I leave it up to your judgment, to decide what has fat in it and what doesn’t, it is easy to overlook some things.”
Jenkins’ RUFAL calculation is a simple way to make sure you don’t leave anything out, and sometimes the results can be surprising, he said.
“By contrast, a TMR with fat added shows a RUFAL number of 696 grams per day. I’ve seen dairy herds go over 1,000 grams of unsaturated fat per day and do perfectly fine with it. Others crash at 600 or 700. We are still trying to figure out the rules that guide where some work and some don’t.
“Hopefully, I’ve convinced you that there is fat in almost everything you put in front of a cow. It all adds up and the rumen micro-organism in there don’t care where it’s coming from, if it gets too high bad things will happen,” Jenkins said, as he moved on to the next myth.
• Myth No. 2 – Fat serves only a single purpose of supplying energy for milk production.
“We don’t want to discount the energy. Comparing it to corn the way we’ve done in the past, corn has 85% TDN and vegetable oil has 184% TDN.
“On a digestible energy (DE) basis, the amount of energy absorbed for digesting, corn has 8 Mcal DE/lb and oil 17 Mcal DE/lb. So if you want to supply the cow with an equal amount of energy from fat, it would take a much smaller amount of fat to supply the same amount of energy than corn would supply. That means you have space in your diet and could put other things in there. Maybe you could add more forage to take up that space.
Don’t compromise forages
“Fat has been a way to supply more energy, maintain our high energy for our cows, but not compromise forages too far. So that’s energy and it’s important, but fat does other things. It carries vitamins through the animal. It makes sure they get mixed into the digestive tract well and absorbed. And those are fat-soluble vitamins A, D, E, and K,” Jenkins explained. “Also, fat is absolutely critical and a necessary component of every cell in the body. If you don’t have fat, those cells are not going to function.” Jenkins explained there are dozens of different fatty acids in the cells. A lot are nonessential fatty acids that the body will manufacture for the cows. You don’t have to have them in the diet. However, there are two essential fatty acids (EFA) that the body can’t make that nutritionists must provide in the diet for things to work right.
The final lipid function is synthesis of cell regulators. These are made from EFA and includes prostaglandins and various omega3 fatty acids that are made from these two essentials. These EFA play a role in regulating cell growth, reproduction and immune response. “So if you don’t have the right amount of EFA,” said Jenkins, “what do you think is going to be compromised? Reproduction? Disease resistance? just to name two.”
Forage, grains rich in EFA
Jenkins also pointed out that “forage and grain lipids are rich in these two essential fatty acids, and cows need a lot of them. You have to supply them, but there is a lot of them in typical TMRs. The problem is, most of the EFA in the diet are destroyed by the microbial population in the rumen during biohydrogenation. Microbes don’t like unsaturated fats so they protect themselves by destroying the two EFAs. The EFA are converted to a group of compounds called CLAs, and then to trans fatty acids and then to saturated fatty acids.”
• Myth No. 3 – Varying fat levels in cattle diets has little impact on animal health and production.
Jenkins took a look at this from both ends – too little fat and too much fat.
Too little fat may mean a shortage of EFA that might compromise reproduction and immune function.
“Once the animal consumes the EFA it has to use it for either body condition or making milk. If there is too little of it, you may be compromising these two functions.
Losing EFA in the milk
Studies by Jenkins have shown that in most cases the cows are losing more EFA in the milk than they are digesting. So slowly, day-by-day they are depleting the plasma membrane (two fat layers) that holds the cell together.
“Reproduction is an example where we’ve seen responses from adding back these essential fatty acids,” said Jenkins. “Studies have shown an increase in the diameter of the corpus ludium, increased synthesis of series 3 prostaglandins and increased pregnancy rates, which has shown increased first and second service conception; increased early embryo survival; and 15 more pregnant cows for every 100 confirmed pregnant.”
In a research study, cited by Jenkins, of “cows pregnant over time” in a 100-cow pen, cows were given two diets – a control diet versus one that had omega3 fatty acids in it. The percent of cows pregnant 60-days post-insemination was 25% on the control diet and 30% pregnant when fed omega3 fatty acids after first service. After second service it went from 44% to 58% pregnant.
Citing two other studies from University of Florida, Jenkins pointed out that pregnancy loss was 5% and 3% for the cows that received omega3 fatty acids from fish oil, compared to losses of 13% and 12% for the control, which received a saturated fat source.
Too much fat, however, results in reduced DMI, negative effects on ruminal fermentation and digestion, reduced milk yield and milk fat components, and milk fat depression.
How about milk fat depression
Jenkins said he has helped numerous nutritionists battle milk fat depression. He found that increasing distillers grain in the diet resulted in a steady drop in milk fat percent. “It doesn’t always work that way. A lot of people feed distillers grains and don’t have the milk fat depression problem. But when you get too many risk factors in your diet, all piling up on each other, things work against you,” he said. “We know a lot more today than we did 10 years ago, about milk fat depression.
What are the causes of biohydrogenation shift? Jenkins cited: low rumen pH, antimicrobials (antibiotics, monensin), forage-source and amount, and too much fat.
Fat risks for CLA shift go from a high level with restaurant greases, bakery wastes and spoiled fats from prolonged storage to a moderate risk from vegetable oils, and low risks for oilseeds and Ca salts, saturated fats.
Jenkins concluded making the following key points:
~Animal tissues REQUIRE fatty acids:
• Plasma membrane of all cells.
• Synthesis of cell regulators.
• Body makes all fatty acids except EFA.
~Fatty acids in all feed ingredients including EFA.
~Rumen bacteria destroy EFA and may compromise tissue function.
~Too much fat may cause problems.
Evaluation of products
James Tully of Pine Creek Nutrition, brought some practical perspective to the presentation. He said his firm will focus on dairy nutrition and management, and he provided a step-by-step process for the chore of evaluating products on the dairy.
Tully said he always asks a series of questions when evaluating the validity and effectiveness of variious products presented to the dairy producer:
1) Does the product make sense? All products make a wide range of claims about what they will do for your bottom line. “You’re going to get a 20:1 return; feed this and you will get 8 lbs. of milk. “Outside of BST, I don’t know anything that will get you 8 lbs. of milk. Do this and all the cows get pregnant! Yeah, right!” said Tully. “If we follow these steps, most products that are presented to a dairy or feed company are going to be eliminated. If it sounds too good to be true, it probably is.
2) Is it research supported? “Are there biological reasons why this additive, or product, or a specific fatty acid are going to do the result? If you can’t find a physiological pathway to get from point A to point B, probably eliminate that additive or product as well. But, if the chemistry is right and the story makes sense, then we like to focus on the research and proceed to what the researcher is going to tell us.
“Dr. Jenkins talks about the university research that he is conducting. Is there a database behind the research,” Tully asks. “Some companies fund research; some don’t. Without the solid science behind a product, we get a little skeptical about it. Were the studies done with true controls? Combining that with actual on-farm results is very hard to accomplish, he said.
Tully said he didn’t like using testimonials. “Everything changes every day on a dairy, so a testimonial is probably not going to cut it. We prefer the unbiased, well controlled study,” he said. “So if the product makes sense; if there is research behind it; then you proceed to determine whether you can actually apply it.”
3) Is there a practical application? So, if you have to add 2 lbs. to a 30,000 lb. TMR to get it to the specific animals, it probably isn’t going to fit your equipment. The product that you want to get to 20 cows in a particular group, your equipment might not be able to get it done.
“Sometimes the whole thing has nothing to do with products, but is management based. The key to everything on a dairy is management. Dr. Jenkins mentioned variation being a big thing, and that is what we are trying to manage or control on a dairy…is the variation. It is up to good management to find the application for any of the products,” said Tully. “If the management is so-so, we probably need to focus on that first, before the product is going to make any improvement.”
4) Can you measure the response promised? “We look at bulk tank milk as just that; milk that is leaving. It’s probably not a very good reflection of daily milk production. If you’re trying to get a 1 lb. response, and the product does 1 lb. that’s normal variation. it better happen very consistently if they are going to pay you with 1 lb. Another example is a product that is supposed to help your feed efficiency. That’s critical because feed is expensive. But if you’re not tracking DMI very well, or having equipment that is unable to give you very accurate milk production figures, I’m not sure a product that is going to improve FE is really the way to go. You won’t be able to measure it. If you can’t measure it, the response on your operation probably doesn’t have application,” Tully concluded.
However, if you can get those things done, then proceed. We focus on measuring key performance indicators that are correct for your operation. Every dairy is different as to what their key performance indicators are that they can actually measure.