The role of phosphorus is summer mineral programs

Jun 17, 2019

Do you know the difference between macrominerals and microminerals? Jon Albro breaks down the difference and explains why phosphorus is so important for beef cattle production.


Tom:      I’m Tom Martin, and I’m talking with Jon Albro, a nutritionist with CRYSTALYX Brand Supplements.

               Welcome, Jon.

Jon:        Thank you.

Tom:      Jon, summer is upon us and now is the time that many cattle producers are thinking about their summer mineral programs. Today, we’re specifically talking about the role of phosphorus in summer grazing. Why is phosphorus — as a mineral element — important for beef cattle production?

Jon:        The minerals phosphorus, calcium, magnesium, potassium…all of these minerals are referred to as macrominerals. Sometimes you hear about macrominerals and microminerals, or trace minerals. Macrominerals — the ones I mentioned — are required in the body at higher levels, whereas, the microminerals or trace minerals, such as zinc, copper, manganese and cobalt — some of those are required in smaller amounts. We often refer to them being required in milligrams per day, whereas the macrominerals like phosphorus are required in grams per day, so, that’s kind of the difference between the macros and micros.

Related: CRYSTALYX options for your summer mineral program

               Phosphorus is a very important macromineral to a lot of bodily functions and a lot of metabolic functions. It’s not only important for proper skeletal development and maintenance of the skeletal system; it’s involved in just about every other metabolic function — everything from acid-base balance to synthesis of protein and fat in the body, to glucose metabolism. One area where phosphorus plays a very important role is in energy metabolism because it’s a component of ATP, which is adenosine triphosphate; this is basically the fuel for every cell in the body. So, if you’ve ever studied biochemistry or energy metabolism, you’ve definitely read about ATP.

               Deficiencies of phosphorus have really been associated — in beef cattle nutrition anyhow — with both poor reproductive and poor overall performance, as well as growth. If you have a phosphorus deficiency, it’s going to interrupt some of these basic metabolic functions which are all going to be important for growth, feed efficiency and reproduction.

               So, sometimes with a phosphorus deficiency, in respect to reproduction, we might see poor conception rates, weak or silent heats or anestrus interrupting the estrus cycle in the cow, causing reproductive problems there.

So, again, real severe deficiencies probably aren’t as common as maybe they once were in the past, but you hear about conditions like pica which is basically cattle eating different things in the pasture that they normally wouldn’t, like wood or even bones from an old carcass that might be out there that’s fully decomposed. You don’t really see that, maybe like you used to, or don’t hear about it a lot, but that’s probably not a problem that would be a normal behavioral issue with animals. If they did have a true phosphorus deficiency they might eat different things that you wouldn’t normally see them eat.

Tom:      Jon — for just a little bit of historical perspective — have producers have been supplementing phosphorus for a while now?

Jon:        Yes. It’s probably one of the minerals that first got some attention because, if you go back several decades, we didn’t know a lot about the trace mineral nutrition like we do today. It seems like today, if you get into a discussion or if you read an article about mineral nutrition in beef cattle, chances are it’s going to focus more on the trace minerals, like zinc, copper, manganese, and cobalt. Our industry has really come a long way in the last 20 to 30 years with recognizing the value of those minerals and selenium as well, even though selenium deficiency has been studied and explored for probably 40 or 50 years, or even longer.

               The trace minerals get more attention today than phosphorus, however, it’s always been supplemented in a lot of our standard mineral formulas. And, if you go back several decades, it was the more understood mineral that got more attention; the dairy and swine industries understood this probably more so, and a lot of the nutrition — in feed companies and in the mineral companies that develop supplements — kind of evolved out of more focus on those other species.

               So, phosphorus was focused more on because that’s what we knew the best and the benefits to supplementation were being demonstrated.

Tom:      So, would you say we’ve changed the way we think about supplemental phosphorus in the last three to four decades?

Jon:        I would say most definitely. I really recall that even in my time — and I don’t want to date myself too much — but in my time in college and in graduate school, when you picked up a paper and you would read something about a research diet, when they talked about or referred to a mineral that was being supplemented, it was pretty basic. They would feed a 2:1 mixture of dicalcium phosphorus and trace mineral salt. And dicalcium phosphorus is a very standard ingredient used to supplement not only phosphorus, but calcium as well.

               And so, I think, again, a lot of the emphasis back then was on phosphorus; a lot of sales strategy and product differentiation focused on the phosphorus source and the level in the supplement. It was often thought that a mineral that was higher in phosphorus was simply better, and some people differentiated themselves by saying, well, so and so’s phosphorus in their supplement is 10 percent, ours is 12, plus we have one that’s 14, 16 or 18 percent. There were some very high phosphorus minerals that were sold and fed — free-choice even — in the past and we rarely see that type of formula today. You do maybe see it in some beef premixes, but not in free-choice supplements. We don’t see those high levels of phosphorus-containing supplements like we used to.

               And, another reason for that is not just because of better understanding or better nutrition or the realization that maybe we were overfeeding phosphorus, but the cost. It was relatively cheap —cheaper back in those days several decades ago — than it is today. If you look at phosphorus history and the price of it — from the rock phosphate industry to some of the mining industries and the phosphate in fertilizer industries — if you look at the prices over the years, there was a real sharp increase in the cost in the latter half of the last decade, around 2007 or 2008.

And, some of the prices went up so much — the raw rock phosphate products went up severalfold — and we had minerals at that time that probably went up as much as $300 per ton and that would have been for a phosphorus-containing product that was in the 8 to 10 percent range.

               So, that happened in a very short period of time, and that really got the attention of the consumer. All of a sudden their mineral prices started to skyrocket and so, nutritionists and producers and the industry as a whole really kind of look at this a little closer and that’s when we probably decided, okay, well, we know that we don’t really need this much, let’s just go ahead and make the decision to formulate. So, we had a lot of lower phosphorus minerals being offered at that time and, looking back, it was probably the right thing to do.

Tom:      So, what is the right or the correct level of phosphorus in your typical mineral supplement?

Jon:        If you look at our CRYSTALYX® mineral supplements, we have some that are less than two percent, but we have quite a few that we like to focus on at the two percent phosphorus level, and these would be for a product like BGF-30™, which is a very popular product that we feed in the fall and wintertime on low-quality roughages; it supplies protein as well. And, it’s going to be typically consumed at three quarters of a pound, give or take, and that will get you about six to eight grams of phosphorus, depending on the intake.

A lot of our other minerals that are specifically mineral formulas that don’t contain any protein — products like Crystal-Phos® or our latest product the 6% Blueprint® phosphorus supplement — they’re going to be in that six to eight percent range, We have some mineral products that are four to five percent, but, they again — at a quarter pound intake — are going to get us into six to seven or eight  grams per head per day of supplemental phosphorus.

               So, that’s usually going to be adequate. A mature cow around 1200 lbs. is going to need — peak lactation is where her highest phosphorus demand is going to be — somewhere around 25 grams of total phosphorus. Those numbers can be a little bit debatable, depending on the size of the animal and if you’re looking at absorption and how well that phosphorus is utilized. But, for the most part, if we’re supplementing or if we’re delivering around 20 or 25 grams in their diet, with about six to eight of that coming from a supplement, we really ought to be in pretty good shape.

               The grasses will vary in their phosphorus content, but most of our forages are going to be in that 0.2 range; some of them are going to be quite a bit lower than that, as there are some forages with as low as 0.1% phosphorus. But, most of our summertime forages are going to have a fair amount of phosphorus as the quality of the forage declines through the summertime and through maturity, and in low-quality forages. For example, in fall and winter grazing situations the phosphorus content in the grasses will be depleted and, so, some supplement is going to be needed.

               But, the bottom line is, if we’re feeding a phosphorus-containing mineral of around six to 10 percent and if it’s being managed correctly, we should be getting the correct levels, if not maybe even a little bit higher than what we need in a lot of cases, so we should be in good shape.

Tom:      Okay. Jon, I was going to ask you which feed sources are high and low in phosphorus; I think you just covered that, but do you want to elaborate a bit more?

Jon:        Yes, I will. On the grasses, again, forages that are good quality usually have a fairly adequate level of phosphorus, however as they mature, they will be depleted in phosphorus and need some additional supplementation.

               We oftentimes think of forages as adequate to maybe low in the phosphorus content, depending on the maturity of them. And, grains on the other hand — like corn, for example — they are going to have a lot higher phosphorus level. And so, grain and grain byproducts are usually going to be adequate to high in their phosphorus level.

               So, the key here is a lot of diets typically — we’ve always understood this to be true and it is true — but there’s a little bit of wiggle room there; a lot of diets were said to have been adequate in calcium and phosphorus levels if they are in a ratio of 2:1 — two parts calcium, one part phosphorus — and that rule is also true for ruminants on forage-based diets. However, if we satisfy the phosphorus requirement first in the diet, that ratio is not quite as important. We oftentimes have ratios that are much, much higher than that.

For example, if we’re feeding a lot of alfalfa — alfalfa is relatively high in calcium and also adequate in phosphorus but it has a much higher level of calcium. And we might have some ratios in some diets out there that are as high as 6:1, and a lot of commercial mineral supplements are even at a 2:1 level, or sometimes even higher.

               So, in terms of satisfying the phosphorus requirement, that ratio is not quite as important in ruminants, and that’s what we see more so today.

Tom:      Well, in terms of phosphorus needs, what benefits do ruminants have — or what advantage do they have — over other livestock species such as swine and poultry?

Jon:        That’s a good question and I might answer this several different ways, Tom. The availability of phosphorus has been a concern in other feedstuffs. The variation is pretty great. In forages it’s probably a little bit more available than it would be in grain, especially to ruminant animals. But, in grains the availability can be somewhat low; only half of the phosphorus that’s in the grain may actually be available to the animal. This is truer with monogastric diets, like swine, for example. And I think — getting back to the history — I think that may have been why we had a lot of high phosphorus minerals being sold or being incorporated into diets, just to overcome this.

               Now, you fast forward from three or four decades ago to today and we’ve come a long way in animal nutrition when it comes to phosphorus — especially in these other species — by using different types of enzymes. Phytase, for example, helps make phosphorus more available and we’ve done a much better job [with it]. And, part of the reason has just been, you know: #1: better nutrition, #2. we don’t need to be feeding so much phosphorus because it becomes more expensive, plus there’s an environmental concern. A lot of this excess phosphorus that is not utilized or absorbed or that is overfed winds up in the environment; it winds up in manure and that becomes an issue in manure or nutrient management, because a lot of this manure gets put back on crop land, so, more attention has been placed on that.

               In ruminant diets, the phosphorus is a little more available to the animal in forages, and ruminants themselves have some ability to break down some of the unavailable phosphorus or extract more of it out of the diet because some of the rumen bacteria and the rumen population has some phytase enzymes in it that are natural. I kind of learned this recently from a discussion with another nutrition colleague of mine in Canada that did a lot of work in feedlot diets and had that knowledge.

               So, there is an advantage. Ruminants have an advantage in a lot of areas, obviously, including breaking down fiber and forages and extracting energy there, but also in obtaining certain minerals.

Tom:      Jon, what specific CRYSTALYX products would you recommend for producers who are looking to supplement phosphorus this summer?

Jon:        Well, a lot of it is right in the name of the product. We have one of our first mineral-type supplements that we introduced on the market many years ago, called Crystal-Phos®. It has that eight percent level, however, we did add another product about 10 years ago when the price of phosphate was going up awfully high, known as Crystal-Phos® 4. So, we have one with the four percent phosphorous and one with eight percent. Some of our older mineral formulas, like Mineral-lyx®, have four percent phosphorus and some of our newer ones are more in the middle, like our new Blueprint® 6% Phos mineral. We also have some fly control minerals that all contain around five percent phosphorus, depending on which fly control measure you want to use and which compound. We have Rabon®, Altosid®, and ClariFly®.

               So, we do have several available, and they all will work very well if managed correctly and provided at adequate levels.

Tom:      We’ve been talking with Jon Albro, a nutritionist with CRYSTALYX Brand Supplements.

               Thanks so much, Jon.

Jon.        Thank you.


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