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Mike Howell (00:08):
The Dirt with me, Mike Howell, an eKonomics podcast where I present the down and dirty agronomic science to help grow crops and bottom lines. Inspired by ekonomics.com, farming’s go-to informational resource, I’m here to break down the latest crop nutrition research, news, and issues helping farmers make better business decisions through actionable insights. Let’s dig in.
(00:38):
Well, hello again everyone. Welcome back to The Dirt. I’ve got another episode for you today. I’m not really going to focus on soil fertility or agronomy, but we’re still going to talk about nutrients today. I thought today we would talk a little bit about nutrition as far as it’s related to livestock. And to help us do that, I’ve got Dr. Daniel Rivera with us. I met Daniel, oh, it’s probably been 15 years ago now. Daniel, it doesn’t seem like quite that long until you start thinking about it, but it’s been a while. Daniel and I both worked at Mississippi State years ago, and when I was the peanut specialist here, Daniel was our livestock specialist. Daniel, welcome to The Dirt and if you will, tell us a little bit about yourself and what you’re doing now.
Dr. Daniel Rivera (01:15):
Thanks a lot, Mike. I appreciate the opportunity to visit with you guys today. I was at Mississippi State until about two and a half years ago. I was a research scientist at one of the outlying experiment stations, and so shifted gears a little bit and came over to Arkansas where I’m the director of the Southwest Research and Extension Center, as well as having a 50% research appointments, so get to wear the multiple hats and it’s been good. I was trained as a ruminant nutritionist and so a lot of the work that I did at Mississippi State was looking at pasture cattle, specifically stocker cattle, but with my background, we’ve done studies with feed lawn animals and cow calves, grazing animals throughout my career. It’s good to be able to visit with you guys today regarding some of the needs that we see with our beef cattle.
Mike Howell (01:59):
Well, Daniel, we’re glad to have you. And we usually talk about soil fertility and nutrient management, that type of issues. And when we’re talking about plants, we know there’s 17 essential nutrients and we’ve touched on each one of these in past episodes and talked about the importance of those for plant growth and development. But when we start talking about cattle specifically, we know that there’s about 14 essential minerals that these cattle are going to need, and when you start comparing those, about 10 of them are the exact same nutrients. Those are going to be things like calcium and copper, iron, manganese, magnesium, molybdenum, phosphorus, potassium, sulfur, and zinc. So Daniel, if you would, talk a little bit about some of those nutrients and why they’re important, why the cattle need those nutrients in their diet.
Dr. Daniel Rivera (02:43):
If you really want the textbook answer, most of these are going to be used as co-factors, but in reality, they all play a pretty integral role in everything from structure, muscle development, muscle function, as well as immune response, reproductive health, all these things are affected by these minerals, so these minerals are extremely important. Unfortunately, you really don’t see any of these problems until after the fact. If there’s a deficiency, you really don’t realize it until the animal doesn’t breed back or you’re having really high incidences of respiratory disease, things of that nature. So just to rattle them off, the big ones that we typically will worry about primarily when we’re formulating rations or when we’re worried about supplementation will be calcium and phosphorus. And in livestock, calcium and phosphorus have to be balanced at a two to one ratio. So two parts calcium, one part phosphorus, and that’s typically the ratio that we like to see when we’re putting together any type of supplement program or rations.
(03:37):
So calcium, bone structure, obviously it’s going to be used for muscle function. The way our muscles work is dependent upon calcium. Phosphorus again works with calcium as far as building those bone matrices. Additionally, it’s used for reproduction. Some work out of Texas has shown that when cattle are in a deficient phosphorus state, reproduction can be affected. Reproduction is important with phosphorus as well as the other co-factor it has with calcium. Copper, zinc, primarily going to be used in immune response. We see a lot of effects of zinc and copper deficiencies as it relates to poor immune response, higher incidences of respiratory disease, things of that nature. Manganese can also function as muscle contraction and as well as magnesium. So both of those minerals are important. That way, sulfur, amino acid development, potassium, again, is also used for some muscle function and molybdenum is again used for muscle function.
(04:32):
A lot of these things primarily deal with bone, muscle, as well as some reproduction and immune response effects. Those are probably the minerals that I would worry about the most as far as when we’re putting together any type of supplement program or a mineral to feed to the animals.
Mike Howell (04:47):
Now, Daniel, you mentioned that it’s almost impossible to tell if these animals are deficient or not until it’s too late. Does that mean that we need to just make sure that these animals are given a good balanced mineral or supplement added to them to ensure that we don’t have any deficiencies?
Dr. Daniel Rivera (05:01):
That was the way I would like to approach it because prior to going to Mississippi State, I worked as a nutritionist for a feed company and I couldn’t tell you how many times somebody would tell us that they decided to save money and not feed mineral and then have a high incidence of respiratory disease when they weaned their calves, or the breed back percentage was a lot lower this year on my heifers when I pulled the mineral out. So unfortunately, a lot of these problems don’t manifest themselves until it’s too late when it’s already starting to affect the producers’ bottom line. So the way I like to do it when we visit with producers or whomever is I try and do it in a preemptive manner where we look at what’s available in the pasture and we try and match what we can match, make up any deficiencies with our mineral program.
(05:45):
And a lot of times unfortunately, unless you’re buying a lot of mineral, it’s hard to get a custom mineral made, specifically tailor-made for your operation or what your grass is looking like. What we always recommend is just a high quality type beef mineral and just make sure it’s out year round, the animals have access to it so that we can see that they are getting these nutrients that they need.
Mike Howell (06:06):
Now, Daniel, you mentioned if it’s not in the grass, and that’s something we’ve spent a little time talking about is sampling our plants and making sure the nutrients are there that we need to be there to optimize their growth. And that kind of leads me to another point that I was going to bring out today is, is it better for these cattle to take it up in the plants straight out of the pasture or is it better to get it to them in the form of some kind of supplement, or does it matter?
Dr. Daniel Rivera (06:33):
The only issue I would see with the plants, and I would say that yeah, ideally in the perfect world they should be able to take up everything from the plant, but in a lot of situations those nutrients are missing in our forages. If you look at a lot of our range land or our pasture land here, especially in the southeast, a lot of times it’s on marginal type soils, and even though you can grow grass, there’s still going to be some deficiencies as it relates to certain nutrients. I know Mississippi selenium deficiency was an issue. We also had some issues that we saw with copper and zinc too on a study that we did down there where we were looking at stocker cattle responses to mineral.
(07:03):
Some of those things, even though the grass is actively growing and is lush and just providing sufficient protein and energy, some of those nutrients may be deficient and you really don’t realize it until it’s too late. I would say a good mix of knowing that your pasture’s probably not going to provide everything you need, so make sure you have that safety net of a complete mineral.
Mike Howell (07:24):
That’s exactly right, Daniel. We can do some testing on our forages, we can do plant samples, we can do soil samples and find out what’s there and what may be lacking and take corrective measures, but we have to be able to spend that money on fertilizer to make sure that those nutrients are getting to the plants and then getting into the livestock.
(07:44):
Daniel, another thing we talk about is nutrient availability. Just because we have nutrients that show up in our soil tests doesn’t necessarily mean it’s available for the plants, and I’m assuming we can make the same comparison when we’re talking about livestock. Just because it’s there, is it necessarily available or does it have to be in a certain form to be available?
Dr. Daniel Rivera (08:03):
That’s a great question, Mike. And typically what we look at when we’re looking at our nutrient availability or mineral availability when we’re looking at mineral mixes, those mineral sources can come from either oxide, sulfates, or they can be chelated. I don’t know if you guys have talked about chelated minerals, but that’s when a mineral is down to an organic atom, whether it’s a protein or an amino acid, or something along those lines. It’s down to an organic molecule. So in terms of availability, our oxides are going to be the least available, and when you read a mineral tag that’ll give you the nutrient breakdown, the percentage of each mineral that’s available by law, so those have to adhere to those nutrient tags if they’re selling them. But then following that, it’s going to break it down in terms of what specific ingredients are in there.
(08:45):
If you see a lot of zinc oxides, copper oxides, that’s a red flag, that those probably are not going to be as available as a sulfate would be. So typically we look at the oxides are the least available followed by the sulfate. So zinc sulfate, copper sulfate are more readily available to the animal with the chelates being the most available, but chelates are expensive, so buying a chelate in mineral’s extremely expensive. One method that we’ve talked to with producers, and this really worked when I was doing nutrition work as a consultant, was to feed the chelated minerals prior to a stress event. So prior to weaning, start feeding some chelated minerals maybe 45 days prior to weaning to allow those stores to build up in those animals prior to that stress event. So that way they’ve got the stores there to help them overcome these stresses of weaning prior to calving, maybe feed the chelated mineral, and the rest of the time you could probably get by with the sulfate, but the data is out there.
(09:41):
A lot of the times we can’t see some of these effects with the cow calf operation or cow calf data, but when you look at a feedlot operation where they’re really putting the nutrients to those animals and maximizing growth and things of that nature, just shows that those chelated minerals are a lot better and they’re more readily used than what we would see with our sulfates.
Mike Howell (10:00):
Daniel, listening to you go through that scenario, that’s really about the same situation we face in fertilizing row crops or pasture. No, we haven’t talked a lot about chelated nutrients. That is something we have scheduled to do coming up in season three. People can tune in and find out more about the chelates next season if that’s something you’re interested in.
(10:22):
Daniel, another nutrient that cattle need is selenium, and you kind of mentioned that earlier. And I’m really getting outside my comfort zone when we start talking about this, but I remember, it’s probably been 30 or 35 years ago, there was a big study going on at Mississippi State in fescue. It had to do with the fungus free fescue or the endophyte-free fescue, and the cattle were either getting too much or not enough selenium, and I don’t remember which way it was, but talk a little bit about selenium and that situation if you can.
Dr. Daniel Rivera (10:49):
Well, that’s a good one because I would venture to see … I tried to find that study and I couldn’t seem to find it when you talked to me about it earlier. But selenium that we saw, especially down there in the southern part of the state, was virtually non-existent. We pulled four samples on the study we did down there and the selenium levels were almost nil, so selenium was a deficiency down there. Now selenium affects your … well, again, like a lot of the other things, it can affect reproduction, it can affect immune response, it can affect muscle development, so selenium deficiency is a major concern. There was also a producer that had some issues when he shipped his calves off to the feedlot, and even though he had done a good job background in these animals and vaccinating these animals, they still had respiratory issues and health issues, and turned out the culprit was selenium. So selenium’s a big problem, and the crazy thing is is there’s an easy fix. Just go feed a complete mineral. Selenium levels in those minerals can usually make up for those deficiencies.
Mike Howell (11:45):
Daniel, we’ve talked a lot about the minerals and what the cattle need. How should a grower go about selecting a good mineral? You mentioned the sulfates versus the oxides. What else do they need to look for?
Dr. Daniel Rivera (11:55):
This is the extension guy in me coming out that go get one of the agents out there to go pull a forage sample. 50 bucks can get you a pretty comprehensive nutrient profile of what those forages look like. But a lot of times what I would like to recommend is plot out what we call a nutrient map. So if you have various pastures and various soil types, go pull samples from each of those different types, submit them. You only have to do them maybe three times a year just during the different phases of growth so you can get an idea of what your minerals look like and what your deficiencies are, and then you can make plans accordingly. And when you go to select a mineral, and I’m not going to refer to any specific name brand, but most of them are all getting … their ingredients are all coming out of the same place.
(12:35):
There’s only certain sources of copper sulfate. Just because brand A says they’re better than brand B, if they’re both copper sulfate, more than likely it’s coming from the same source. Again, look at your nutrient profile, what you need. Calcium is an issue, which it probably isn’t, but phosphorus may be an issue. Make sure you have a mineral that may be higher in phosphorus or where that phosphorus level is a little bit higher than others, because depending on the mineral, most minerals will be anywhere from 10 to 20% calcium, four to 10% phosphorus, so phosphorus is an issue. Maybe lean towards that higher level of phosphorus. If copper, zinc are issues, maybe make sure that you’ve got higher levels of those as well as making sure that they’re either sulfates or the chelated versions. A lot of minerals, they’ll blend the two. They’ll have a zinc amino acid as well as the zinc sulfate, and they do that to increase the bioavailability of the zinc as well as try it and make it more budget friendly for producers.
(13:32):
One of those things that a producer will go look at a bag of mineral and they’ll be shocked at the sticker shock of the actual bag of mineral, but if you look at the actual intake on a per head basis, it’s pretty cheap and it’s really cheap insurance in my opinion to ensure that you have a well-functioning immune system and a well-functioning reproductive system, especially when those are the two things in the cow herd that will really help your bottom line. You want that female to breed back and have a viable healthy calf that’ll live to wean him.
Mike Howell (13:59):
If that female is not able to produce a calf on a consistent basis, you’re going to be losing a lot of money in a hurry.
Dr. Daniel Rivera (14:04):
The numbers we run here, Mike, anywhere from 700 to 900 bucks a year to just carry a cow. She has to have a viable weaned calf to pay for her way, otherwise you have to spent a thousand dollars on a cow that’s just hanging out in the pasture looking pretty.
Mike Howell (14:19):
Lawn ornaments.
Dr. Daniel Rivera (14:20):
Yeah, lawn ornaments.
Mike Howell (14:21):
Lawn ornaments get expensive enough.
Dr. Daniel Rivera (14:23):
Yeah, they do.
Mike Howell (14:24):
Daniel, another nutrient that we haven’t talked about, and it’s not really necessary for cattle, but we spend a lot of time talking about it on The Dirt, and that’s nitrogen. And we’ve talked about how nitrogen and sulfur work together to form proteins and amino acids, and we know that that’s something the cattle are going need as well. So talk a little bit about nitrogen and converting that to protein and how the cattle are going to need that protein source.
Dr. Daniel Rivera (14:46):
Nitrogen is an extremely important nutrient, especially as it relates to protein for the animal, and with cattle it gets a little bit more complex because you’re talking about more than just one type of protein. You’re looking at the degradable protein and the undegradable protein. So there’s two fractions of protein, and usually what’s degraded in the room and right away is going to get broken down and used for those microbes in that rumen. If you look at a cow, it’s essentially two living organisms in one. You’ve got the cow that we see that we get our stakes from and everything else, but within that cow, inside her rumen is a fully functioning ecosystem. So you’ve got a whole population of rumen microbes that sit there and they break down forage, they digest the grass, they allow that animal to utilize those crops that we as humans cannot utilize as monogastric.
(15:35):
Ruminants are really unique in that they can utilize energy source or forage source feed source that most monogastrics can’t. So those rumen microbes, like any type of living creature, they need energy, they need protein, they need their nutrients to survive. The degradable protein would be used to supply those rumen microbes with their amino acids so that they can grow and maintain that healthy ecosystem in that rumen. The undegradable portion as well as some of the microbial protein gets passed out of the rumen and is absorbed by the cow and utilized as protein for that cow to grow. So the undegradable protein, which survives that rumen breakdown, make it out of the rumen and gets absorbed in the small intestine. Additionally, if you think about that rumen, it’s a big washing bat, and when you haul buckets of water in the back of the RTV or the truck, that’s going to slosh around.
(16:24):
Same thing with that cow. So some of the action in that room and some of those microbes are going to slosh out and go into small intestine and get utilized by that animal. You have those two different sources of protein that are going into that animal. Yeah, nitrogen is extremely important, especially as it relates to growth of these animals. A growing animal’s going to have a greater protein requirement than a mature cow, but at the same time, once she starts lactating, when she has that calf, then her protein requirements go up significantly. So yeah, protein is a major, and probably one of the big ones that we look at when we start trying to formulate supplements or make sure that we’re meeting requirements for that female.
Mike Howell (17:01):
And Daniel, we also know that nitrogen can be a problem if it’s in the wrong form within a cow. I was up in your area a few weeks ago, and I know y’all have gotten a good bit more rain this summer than we have, but here in Poplarville, Mississippi, we’re about 30 inches below normal on rainfall this year. Pastures are dead. The row crops are really struggling, and some guys are even talking about bailing up some of this corn for hay, and some have done that, but we can get into a problem with that and even with things like Johnson grass and these drought situations with nitrate toxicity. Talk a little bit about that problem and what growers need to be aware of on that.
Dr. Daniel Rivera (17:36):
Nitrate toxicity. So you bring up a very challenging topic. This is a topic that we’ve seen that seems to come up time and time again. We haven’t had the deficiencies you have, Mike. We have had some deficiencies and it seems to come at inopportune times. So last year we had some of those issues with our forage crops as well. Nitrates can be toxic to livestock. The kicker is, and then this is where a lot of the data gets very gray, at what level? So the recommendations that we typically use is that if it’s 10,000 parts per million, we really start to worry. That part is when we start to think about maybe having to either blend it with something else to make sure that we’re diluting the nitrates. But if you look at some of the data out in Nebraska, it looks like you can push those levels a little bit more. So what constitutes a problem? That’s where I think we seem to always have the big challenge.
(18:29):
I would recommend anytime that you’re in a drought stress situation and you’re bailing up like corn stalks or sorghum-sudangrass or Johnson grass, things like that, you run that risk for that nitrate toxicity. What’ll happen is you’ll start to see these animals will just become very uncoordinated and nitrate toxicity happens quick. They’ll go down, they’ll be thrashing around, and then they’ll die. One way you can tell really quickly if you have access to a syringe or something, just pull a blood sample, if that blood comes back in almost like the color of ink, then you know you’ve run into some issues there with nitrate toxicity. So any type of plant that can accumulate nitrate, so be wary of feeding weeds. I’ve seen instances where people were chopping down a bunch of weeds and decided to feed it to the cows and voila, something falls over dead. If you are concerned, if you have any types of suspicions that you might have it, I would get it tested.
(19:22):
And again, if you’re at that really high threshold, maybe look at doing something that you can dilute the feed with or the forage with to allow those animals to better utilize that nitrate or not be affected by the toxicity.
Mike Howell (19:36):
Well, Daniel, we sure appreciate you taking time to visit with us today. I know we’ve covered a lot of subjects here in just a short time. So do you have any closing comments you want to leave our listeners with?
Dr. Daniel Rivera (19:46):
Well, just the typical ones that we will at this time of year. Most of the time as people are going into the winter, our hay has already been bailed. We’ve got what we’ve got, whether we managed it correctly or not, that remains to be seen. I would recommend before you go into the winter, get hay samples, get your local extension agents to help you pull hay samples or someone to help you pull hay samples, get those things analyzed for your nutrient levels and make sure your supplements fit what you have accordingly. A lot of times we see people overfeeding simply because they never looked at what their nutrients were in their hay and they just end up feeding this feed because it was available when in some instances they may not have needed to feed it. So that 25, $30 hay test can bring back dividends if you use the information correctly. So again, just keep that in mind for any livestock producers. Just make sure you get your forages tested before you go into the winter so you can make your supplementation plans.
Mike Howell (20:39):
Great advice, Daniel. Thanks again for being with us today. Now, listeners, you know it’s time now for our second segment where we talk about somebody famous in agriculture. And today I wanted to talk about Dr. Emil Von Wolff. Dr. Wolff was a German scientist that proposed a feeding standard based on digestible protein, digestible carbohydrates, and digestible fats contained within the feeding stuffs. His standards for dairy cows weighing a thousand pounds was 24 and a half pounds of dry matter containing two and a half pounds of digestible carbohydrates, and four tenths of a pound of digestible fats. This standard was an improvement over previous models, and it did not consider the quantity or the quality of milk produced, and the maintenance of production requirements were not considered separately. Keeping these shortcomings in mind, other published information on feeding standards of the era were based on this work.
(21:34):
Wolf’s standards were published annually without fundamental change until about 1897 when they were modified by another German scientist named Lehmann, and they became the Wolff-Lehmann standards for various classes of animals. One fun fact about this research was the idea that spinach was full of iron, and it goes back to a lot of this research that Dr. Wolff conducted. His figures showed that it had an astronomically high amount present. In fact, that ended up being a mistake that was determined years later. He had actually put the decimal point in the wrong place in his calculations, so the result was not actually 10 times as high as they thought it was, but nonetheless, spinach was still full of vitamins and nutrients and still a good food to eat, but not quite as good as they thought it was back at the time. We want to thank Dr. Wolff for his contributions to the world of animal nutrition.
(22:23):
Listeners, if you need any more information on this or any other topics that we discuss here on the show, you can check out our website, that’s nutrien-ekonomics.com. Until next time, this has been Mike Howell with The Dirt.
