Feed Additives for Dairy Cows

Published on Thu, 01/19/2023 - 11:08am

Feed Additives for Dairy Cows.

 By Heather Smith Thomas.

 There are a number of feed additives commonly used in dairies.  Dr. Peter Erickson, Extension Dairy Specialist, University of New Hampshire, says the first important thing about feed additives is that they have to be cost effective.  “We have to be able to turn a profit with these; we can’t afford to feed them and not see any benefit.”

Dr. Mike Hutjens, Professor of Animal Science Emeritus (Department of Animal Sciences at the University of Illinois Urbana) does many webinars for dairy producers and often discusses feed and feed additives and says the definition of a feed additive is something that is put into a feeding program that doesn’t play an active nutritional role.  “An example might be a yeast culture or yeast product; it influences rumen fermentation and microbial makeup and VFA (volatile fatty acid) production in the rumen.  We don’t add yeast culture as a source of protein.  You could, but it would be very expensive to use that much,” he says.  Yeast is mainly utilized to help the rumen create building blocks for important nutrients and energy production.

Other additives include buffers like sodium bicarbonate.  “Sodium is a nutrient and therefore not a true additive, but the reason it is added to feed is as a buffer to keep the rumen pH at 6.25,” he explains.

 Sodium bicarbonate is one of the most common feed additives for lactating dairy cows since it helps maintain rumen pH and optimum environment for important microbes to survive.  “The sodium in the sodium bicarbonate also helps drive water intake,” says Erickson.  This helps speed the rate of passage of feed in the gut.  “As water intake increases, the more quickly the ingesta goes through the gut.  The cow can eat more, and ultimately absorb more nutrients and produce more milk,” he explains.

“Buffers include sodium bicarbonate and sodium sesquicarbonate.  You don’t want to feed sodium bicarbonate to a dry cow, however, or a pre-fresh cow, because it can set them up for hypocalcemia,” Erickson says.

Other common feed additives include direct-fed microbial products like yeast and yeast cultures.  “These can aid digestibility of feed.  They also appear to be beneficial in heat stress situations.  There is some use for these in lactating cows.  Direct-fed microbials, yeast, yeast cultures, enzymes, prebiotics, probiotics, etc. all tend to benefit gut health,” Erickson says.

The use of feed additives in dairies, based on a 2021 market survey, showed rumen buffers as most popular, followed by yeast and yeast cultures, rumensin, niacin, probiotics, mycotoxin binders, anionic products, Omnigen and feed bunk stabilizers.  “Mycotoxin binders have increased in popularity, probably because producers don’t want to take chances with mycotoxins impacting animal health, immunity and milk production,” says Hutjens.  Mycotoxin binders are common in the poultry industry because a small amount of mycotoxin can upset feed efficiency and feed conversion.

Erickson recommends that every dairy in North America should feed a mycotoxin binder because often there are challenges with forages and risk for molds.  “You will potentially run into problems at some point and mycotoxin binders are a good insurance policy and could save a lot of grief,” he says.

Anionic products are minerals that improve blood calcium levels at calving.  “Anionic salts are often fed to pre-partum cows,” says Erickson. “You need to work with a nutritionist on this, but there is a new product on the market that is a zeolite which actually binds calcium and seems to be effective in reducing milk fever.  This is a new thing coming down the pike and there are some herds in the upper Midwest and some here in the Northeast that are now feeding these products.  There are several variations of it—zeolite, zeolite clinoptilolite, etc.” he says.

Feed bunk stabilizers are added to prevent secondary heating in feed bunks and these are typically propionic and acetic acid products that acidify.  

OmniGen is a branded company name for specialty products formulated to provide immune support in dairy cattle to help prevent mastitis, heat stress, reproductive challenges and even fatal diseases like hemorrhagic bowel syndrome.

“Many dairies use chelates, replacing some of the standard minerals in a mineral mix,” says Erickson.  “Chelates aid in absorption of some of the specific minerals and there is good data on that.  People often use zinc methionine, for instance.”

There is also extra use of some vitamins.  “We’ve been doing some work with niacin and from our data we’ve seen that the nicotinic acid form of niacin improves colostrum quality and increases some of the components in colostrum that affect gut development in the calf.  This research has been published in the Journal of Dairy Science and we have other studies we are continuing with.  There is also some data showing that niacin may help reduce heat stress,” says Erickson.

Originally a lot of the niacin research was done with lactating cows and there were mixed results.  “Our data with dry cows and pre-partum cows indicates that it does have some positive effects in improving the colostrum quality when they calve.”

Biotin is another one that some dairies utilize.  “It has been shown to improve hoof health, and is well worth using,” says Erickson.  

Ionophores are useful and the old standby is monensin (rumensin) which is approved in the U.S. for improved feed efficiency.  “I tend to like the Canadian reason for approval better, which is for reduction in ketosis.  There is a lot of good data on that, because of how ionophores function in the rumen.  Ionophores also work against coccidia in calves and heifers,” he says.

Silage inoculants are commonly used, but technically they are a silage additive rather than a feed additive, since these products are added when ensiling the forage rather than adding to the feed.  “They modify the forage to make it more beneficial,” Erickson explains.

“We have done a lot of research work with sodium butyrate, which is commonly used in Europe because it’s been effective in heifer diets for growth response, similar to rumensin.  Our data shows this and we see some benefits from it, even though most people in the U.S. don’t feed it.  A person would have to price it out to see if it would be beneficial for them.  Our data shows that it gives a response but I haven’t done any economic analyses on this,” says Erickson.

About 7% of dairies surveyed don’t use any feed additives mainly because of cost.  Feed costs are high and feed additives tend to be one place dairies try to cut costs.  “The farmer is trying to cut down the feed bill but can’t cut out protein or energy and decides to cut out feed additives.  This is like saving a nickel and losing a quarter because we get more benefit from the feed if we do use certain additives,” says Hutjens.

Expectations When Using Additives
“When talking about additives I focus on what I call the four R’s which are response, returns, research and results,” says Hutjetns.  “For instance, when using a silage inoculant, what do I expect it to do?  It will speed the fermentation process, reduce the amount of heat damage, save on nutrients and increase performance in my cows, supported by research.”  Other responses from a feed additive could include improved rumen digestion, better milk yield or test, reduced stress, improved health and growth or greater feed intake.

“The second R is return; what do I expect to get back when I buy an additive for my dairy operation?  We need a 2-to-1 or greater benefit-to-cost ratio which means that if I spend 6 cents on a rumen buffer I want 12 cents back in terms of increased milk production and milk components.  I also want to see what I call non-saleable returns.  An example would be biotin which can improve hoof health.  We don’t sell hooves but we know that hoof health reduces lameness and improves cow longevity, and fertility.  We can’t sell that in the bulk truck but it still makes a difference,” says Hutjens.

“In terms of benefit-cost ratio when milk prices go down, it takes more milk to cover that cost.  When milk prices are high, a feed additive becomes a better bargain, but when all costs are high it get squeezed hard.  Once a feed additive costs more than 10 cents per cow a day, you’d better have solid research and expectations that you will get your money back.  Some farmers will say, ‘If it will cost me 2 or 3 cents per cow per day I might try it for a month and see what my cows tell me.’  But once something costs more than a dime it becomes significant dollars in a large dairy and they may be more reluctant to try it,” he explains.

“The next R is research.  I use a chart showing a pyramid.  At the top is the gold standard which is peer-reviewed research, but this probably costs $40,000 or more for a large cow study at a land grant university; it’s very expensive to do.  Many companies struggle with that cost if they don’t have large budgets for research, but some will do controlled research studies or uncontrolled studies.  Next down the line is on-farm research—trying something on your own farm to see if it seems to work.  In some cases, however, farmers simply utilize anecdotal evidence.  ‘Joe used it and it worked in his herd so I will try it,’ the farmer might say,” Hutjens says.

The fourth R is results.  “Can you measure it on your farm?  If an additive is supposed to increase milk production by 2 pounds, can you actually measure that?”  The problem is that these things are hard to measure because there are other factors that influence milk production.  Maybe it rains, or there is heat stress or a change in feed or conditions.  There are so many variables; cows freshen, cows dry up or get sold.  

“Yet it is important to know if something is actually working on your farm.  Most research deals in probability.  If the probability is less than 5% this means there is a 95% chance that it should work on your farm but there is always some risk factor,” he says.

Evaluating Additives
“We often use 6 or more research studies that have been journal published.  It’s not a guarantee; there is always a risk, but that risk is actually pretty small when using a feed additive with a favorable response based on controlled research,” says Hutjens.

“We can also do meta analysis.  This means we take all the research that has been published on a certain topic and summarize it.  This allows us to look at all the studies rather than just a few.  This allows us to have more statistical power with the results and a better expectation of how the product is going to work,” he says.

The classic meta analysis is one from University of Guelf in Canada, looking at using the ionophore Rumensin (monensin).  “This gives us a good idea about responses you could expect to see on your farm.  These are the two best tools we have for evaluating feed additives.  Another one is going to conferences, listening to researchers present their data and talking to people like nutritionists and veterinarians and getting their input.  These are powerful tools because they are based on controlled research results on farms,” says Hutjens.

“In evaluating feed additives, I use 6 points which are function, level, cost, benefit-to-cost, strategy and status.  Function: how does it work.  Level: how much to feed.  If you use a rumen buffer it typically needs to be around 200 to 250 grams per cow or .75% of the ration dry matter.  Strategy would be when we’d want to use it, and the status might be that it is recommended or that it is still experimental and we’re not quite sure if we are ready to recommend it broadly.  Evaluative status means you are on your own for a certain additive, as it may work under some situations but not others.”  Some additives may not be recommended because there has not yet been enough research or not enough response to justify cost.

Some additives might be fed as needed.  “If you have moldy feeds you should use a mycotoxin binder,” says Hutjens.  “If you have fat dry cows you could feed a rumen-protective niacin product.  If you have cows with ketosis you would feed propylene glycol, glycerol or calcium propionate.  It all depends on your situation on the farm.  The herd manager or the person in charge of nutrition could determine the things to add as needed,” he explains.

Hutjens also has what he calls a “watch list” of products that are still being researched.  “This list includes essential oils and direct-fed microbes (probiotics) and feed enzymes,” he says.

“There are some additives that I am not convinced are helpful,” says Erickson.  “These include the essential oils.  There is a lot of data regarding the benefits of essential oils in the lab, but we are not seeing much potential response in live animals.  I am hesitant to recommend essential oils at this stage.  I have done some work with them with heifers and haven’t seen much positive effect, yet the in-vitro data is very good.  There seems to be some disconnect, so the jury is still out on using those in dairy cows.”

There are also some products that he is hesitant to use because he doesn’t know what they are made of.  “Some companies have products with claims that they work for certain things but when you ask what’s in them you don’t get an answer.  It’s their proprietary secret and I don’t like not knowing what’s in them,” says Erickson.

Ranking In Order Of Importance
The additives most commonly recommended for dairy cows are rumen buffers, yeast culture and yeast products, monensin, silage inoculants, biotin (which has an effect on metabolism) and organic trace minerals.  Hutjens says that when people ask him to rank them in order of importance, the first one is Rumensin (monensin), second is silage inoculants, third is organic trace minerals, fourth is yeast culture/yeast product, fifth is buffer and biotin is sixth.  “Buffers are very important, but I list it 5th on this list because I can actually feed my way out of a buffer situation by feeding more forage in a total mixed ration.  I could feed less corn or barley and correct the acid imbalance,” he explains.

“Rumensin, by contrast, is an antibiotic that selects certain feed organisms in the rumen to shift rumen volatile fatty acids and there is no other way I can do that right now at 3 cents per cow per day.  I could use essential oils but that could cost me at least 6 to 8 cents per day to get that accomplished,” he says.

Lactating Versus Dry Cows
Certain additives may be more specifically used for fresh cows or for close-up dry cows, according to Hutjens.  “For the close-up dry cows there might be some additional things you’d consider adding to the basic list, such as anionic products like dietary cations to balance and improve blood calcium levels in cows.  Another one is rumen protective choline.  No buffers are fed to close-up dry cows because sodium bicarbonate works against DCAD balance and would be wrong for the drying-up cow,” says Hutjens.

“Another list would be for fresh cows and it changes slightly; buffers are back on the list, along with calcium supplementation. Rumen-protective choline’s best response is when fed to the close-up dry cows and the fresh cows, which means you’d only be feeding it for 42 days, which makes it less costly,” he says.

Feed Additives For Dairy Calves
There is some indication that adding yeast and yeast cultures to calf diets can promote production of immunoglobulin A in the small intestine, which will help fight pathogenic bacteria in those calves.  Ionophores are also given to calves in their feed, to help prevent coccidiosis.