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Winter Mineral Intake Beef Cattle

3 May

Minerals for beef cattle are a topic that is difficult to discuss, while there are libraries of data regarding minerals and their role in beef cattle production, surprisingly we know very little.  One topic of great interest is mineral intake, and when the topic of minerals come up at Extension meetings, the topic of intake comes up.  Intake is a measurement that is “felt” by beef producers, thus it is hard to quantify.  Producers know when they are putting out beef minerals, but are they consistent in putting out minerals?  The one theme that is discussed time and time again is the role that forage quality plays in mineral intake, with the consensus being that as forage quality declines mineral intake increases.  I would disagree with that thought.  The thought behind that idea is sound, since forage quality is decreased, the animal “knows” it needs more minerals, therefore it eats more minerals.  In summarizing data from an implant study we had conducted over a two year period, we had forage quality data on a rough 28 d schedule, as well as mineral issue and weighback information, mostly to see if an implant effect existed with mineral intake (which there was no effect), and I was putting that data together, I realized something.  While not related to implant status, I had mineral intake data as well as forage quality data for a 110-150 d period, I could analyze the data and see if mineral intake was related to forage quality.  If conventional wisdom was correct intake should increase as the growing season progressed and the forage lost quality.  In general terms, we had 6 sampling periods, from January to late May, we looked at forage quality parameters (Crude Protein, Acid detergent fiber, and Dry Matter) and how they related to mineral intake.

intake x cp

This plot is the relationship between Crude Protein and intake.  When analyzed, the relationship was not significant (P = 0.35) with an r = 0.07.  The high P value signifies that the relationship was weak, therefore we conclude that CP level has no effect on mineral intake.

Acid detergent Fiber

Acid detergent Fiber

This plot is the relationship between ADF and intake, here we see more of a relationship (P = 0.05) with an r value of -0.13.  Going back to our basic Feeds and Feeding, as ADF increases forage quality decreases, so it was somewhat of a surprise that the relationship (r = -0.13) was negative!  That means that as forage quality expressed as ADF decreases so does mineral intake, which is the exact opposite of the conventional thought.

DM = intake

This last graph is the one that surprised me the most.  Forage Dry matter as it relates to intake, and surprisingly, it had the greatest relationship!  P = 0.001, r = -0.38. As dry matter increases (as forage matures), mineral intake decreases, again disagreeing with conventional wisdom!

In general I have always thought that mineral intake is driven by salt and the animals need for salt.  My theory on this project is that early in the growing season, forage is high in moisture, feces in the cattle are very loose.  Perhaps there is greater loss of electrolytes due to the excessive water loss in feces and urine which make the animals crave the salt in the mineral.  As dry matter increases (less moisture as plants become more mature), the need for salt decreases.

Forage allowance and ryegrass cattle

13 Apr

We weighed a group of steers and heifers off of ryegrass the other day, and many ranged from 770-850 lbs.  That made me think about an old rule of thumb I was once told regarding growing cattle on wheat pasture.  The cowboy logic I was told “once they hit 800 lbs, they’re done”, and as a nutritionist, I see the logic in that.  Assuming that maintenance requirements are driven by metabolic body weight (emphasis on the word body weight), as that animal gets bigger, more and more of its diet is going to simply maintain weight.  In a feedlot, dry matter intake is fairly easy to measure, however, it is quite the opposite in a pasture scenario, and there is not a good method to measure DMI.  Nonetheless, this concept has been further examined by researchers at Arkansas who compiled data of cattle on wheat pasture and determined that to maintain their rate of gain, a range of 3.7 to 7 lbs of forage is required per pound of body weight in the animal.    Based upon their review, these researchers felt that 5 lbs of forage (dry matter basis) per pound of body weight is required for weight gain.  While we cannot reliably measure DMI in cattle grazing pastures, we can effectively measure forage allowance.  Using the time honed tools of the trade, grazing stick, rising plate meter (the homemade one works well too), or simply cutting weighing and calculating (for those who really want a good estimate).  Similar to wheat, ryegrass pastures are highly digestible and high in CP, so the logic would seem to fit in ryegrass cattle scenarios as well.  Additionally, like wheat, the overall nutrient content of ryegrass throughout the grazing season (based upon samples collected at White Sand Unit) is fairly high, and based upon calculations from NRC (2000), it should support 1.75 lb ADG in an 850 lb yearling even at its lowest level.  However, if we use the figures compiled by Arkansas, that 850 lb steer will need at least 4,250 lbs of forage to meet those gains.  Examining the data from MSU Forage Variety data, Poplarville is the only location that has all varieties with an average yield that high on a per acre basis.  In fact, based upon that data in South MS we could in theory keep cattle gaining up to 1,100 lbs (stocked at one animal per acre).  However, we must keep in mind that those are averages for yield, calculated over a growing season, which means that yield data will differ within a season.  Additionally, those numbers generated by our forage colleagues are based upon small plot harvest data, continuously grazed pastures might have different averages.  Moreover, fertilization regimen and other management scenarios might offer different yields.  The question of economics then plays into the scenario.  Using NRC equations, and our forage allowance assumptions, we can determine how many cattle we can effectively stock per acre, and still maintain good weight gain.  Rather than worry about individual animal gain, the area that should be focused on is gain per acre.  Examining the scenario presented in Example 1, will give you an idea why that old saying about the 800 lb steer being done comes about.  

Example 1.  Two management scenarios for grazing beef cattle on ryegrass for 28 d

Two Stocking Scenarios

                                                      850 lb animal                                               425 lb animal

Pounds of forage available            9800 in 2 acres                                                  9800 in two acres

Stocking rate @ 5 lbs/lb of BW     2 animals total                                             4 animals total

Calculated ADG (NRC, 2000)      1.75 lb/d                                                          1.40 lb/d

Total gain                                             98 lbs                                                           156.8 lbs

The above scenario shows that while more cattle per acre might yield less individual gain, the overall gain was greater on that pasture.  Oftentimes, the individual ADG is the factor that is most talked about, however, when our expensive inputs (NPK) are applied on a pasture level, pasture gain is more important than individual ADG.  Unfortunately, to most optimally manage stocker cattle grazing pastures, requires a lot of flexibility and resources to be able to move heavier cattle off, and bring in light weight cattle.  

In conclusion, knowing how much forage is available can help determine forage allowance and stocking rate.  Additionally, there comes a time when the heavier cattle are not as efficiently using resources as well as a lighter animal, and the decision needs to be made whether that heavy animal is “done”.  

Hay Quality and the Power of Brand Awareness

27 Mar

Recently I had two conversations about three weeks apart, with two distinct individuals who wouldn’t know each other if they were sitting together on a plane, but the conversations were eerily similar. The conversations revolved around hay quality. Quality hay is often thought of as an oxymoron, similar to” efficient bureaucracy”, and it dawned on me that we as Extension personnel still have a long hard road ahead of us in terms of teaching about quality. Human beings compartmentalize, we put things in nice categories, “the good side of town,” the “kid-friendly restaurant,” those “mean people,” and so on. We do the same with hay and our forages. Ryegrass hay is GOING to be good hay simply because its ryegrass, right? When I think of ryegrass I think of 2.5-3 lb average daily gain in growing cattle, (nothing to scoff at), others think of lush green fields, early spring, cattle fat, happy with their backsides covered in green. Most of the variety tests (I am not speaking to any specific variety here) and our ryegrass pasture samples show a forage product that is high in total digestible nutrients (TDN, mid 60%) and high in crude protein (CP,18-24%); in short, a very good feed for ruminants. I suspect most of us have all those thoughts in our heads when we hear about ryegrass hay. Being stewards of the land, and understanding the limitations of production agriculture (timing, weather, equipment), we KNOW that we are not going to have hay that is as high in quality as the forage in pasture, but how bad can it be? I was fortunate enough to work with Dr. Lemus on a small project looking at hay quality among samples sent in from MS to the LSU Ag Center Forage Lab. We found that on average ryegrass hay samples were 10% CP and 56% TDN, which is a far cry from what we have sampled in pasture!  When confronted with a cattle nutrient requirement question, my Standard Extension Questionnaire that I start with is “What are they eating?” “Ryegrass hay” is the response. “Did you test it”, I ask. “No” is the reply, “however, its ryegrass so it has to be good, besides I tested some a few years back and it was really good.” I think most of us rank hay/forages in our minds, saying to ourselves that ryegrass better than bermudagrass, which is better than bahiagrass, which is better than ____(Fill in the blank)_____. This is what the marketing people would term “brand awareness.” The “Ryegrass” brand is equated with quality; hence ryegrass hay is quality hay. In a practical setting all forage varieties have their strengths, and fit into individual production scenarios and locations. Data from the White Sand Branch Station have demonstrated similar performance with cattle grazing bahiagrass or common bermudagrass pastures, as well as both pastures being similar in forage quality. Bahiagrass is often associated to be of lower value, but ask any producer and they will tell you about the mismanagement and poor fertility bahiagrass can tolerate; is that not a strength in itself?

In my opinion, I feel the Extension specialists have done an excellent job in showcasing and helping producers understand the various varieties out there, and they should be commended. However, I think that too many of us automatically assume that forage type equals quality. In the scenarios I discussed at the opening, cattle were in a nutrient deficient state, and the producers were at a loss because they thought they had “good” hay, simply because it was ryegrass! When we think of hay production, we know there are many factors that influence quality: 1) Forage variety, 2) stage of maturity, 3) nutrient management, 4) environmental conditions and 5) storage conditions. Is it fair to accurately judge the quality of hay based solely upon one of the four factors? One might even argue that stage of maturity would have a greater impact on quality than variety. All too often yield trumps quality, simply because it makes us feel better to say “I put up # tons of hay off of 10 acres last week”.  Talking with our friends, we NEVER want to be the one who caught the smallest fish! As our input prices increase, we must strive to become more sustainable (after writing grants, it pains me to use that word!), and ensure that every dollar we spend results in increased production. Rather than worry about the size of fish we caught, and rather than assume what we have is quality because of its name, we must begin to judge hay more critically, and in looking at the factors that affect hay quality, we can assume that certain varieties have the POTENTIAL to be higher in quality, but that alone does not make them higher quality. Additionally, if we are needing our hay to be high quality, we must test, test, and test it to ensure that it meets our standards, rather than assume it does simply due to the variety it is. The danger exists when everyone involved in the decision making and problem solving (producer, vet, Extension person, etc.) assumes that because a hay was a certain variety it was high quality, and the real problem is never addressed. In both cases, producers were dumbfounded that they hay (or lack of quality hay) was the big part of their issues. In another instance, a producer was astonished that his ryegrass hay was lower quality than his bahiagrass; he could not wrap his mind around that fact (a testament to the power of brand awareness).

In summary, the surest and best way to truly know the hay quality is to simply test it. Hay sampling equipment is available in most county Extension offices, and most Extension personnel will be happy to sample it with you or show you how to sample your hay. I would also challenge everyone (myself included) to begin thinking of hay in a different manner, and rather than compartmentalize hay into these pre-conceived categories based upon forage type, we compartmentalize hay into quality ranges based upon hay test results.

Please direct all questions and correspondence to Dr. Daniel Rivera,; 601-403-8777.


Note: Much appreciation is expressed to Dr. R. W. Lemus for his input and review of this article.

Research updates

31 May

It has been a while since I have posted last, and had I not met with some friends today it probably would have been a while longer!  Anyway, I was telling my friend about what all we’ve had going on at the station, and he replied “no need to do that I read your blog/newsletter, I’m up to date”.  This guy is famous for his sarcasm, so I took that as a kind request to Post Something! I think I lack a “creative” gene in my DNA, and I find coming up with topics very difficult at times, so I take the easy way out and find other things to do.   I have started to do a better job updating our Facebook page (White Sand Branch Beef Unit; shameless plug), and I promise, my loyal readers to do a better job with this.

We have had a busy winter/spring.   We had an implant study going on with ryegrass cattle, did an encapsulated fertilizer study, then we were fortunate enough to work on a contract project with a private company, which allowed us to almost triple our research capacity at the Experiment Station.  We now have 38 replicated  pastures (which the crew essentially built from the ground up -water troughs, gates, etc., in a span of 5 wks) , which for the types of studies we do, means we have 38 experimental units, which allows us to increase the number of studies, and can increase the turnaround on projects as well.  For example, a “rough” number of replicates needed to find a difference is around 4 or 5.  If we have four  treatments, then we need anywhere from  16-20 units (four x 4 or 5 = 16 or 20).  Studies can eat up space really quick!  I hope to discuss this further in greater detail in a later blog, so stay tuned…

Before I get out of topic, let me share what we’ve been doing the last few months at the experiment station:

Long term implant study.  We looked at a 200 d versus a 70 day implant (given twice) on performance of beef cattle grazing ryegrass pastures.  As expected we had an implant effect compared to controls, the cattle were shipped to Iowa where our friends at Iowa State will be getting them fed out.  This is the second and final year of this study.  Last year’s data will be presented at the ASAS national meeting in Indianapolis this summer. There was an implant effect during grazing, but at the feedlot, there were no carry over effects noted.  Many times our producers are under the assumption that by implanting cattle while they graze they somehow hurt carcass quality.  We did see a slight dip in % Choice, but the carcasses were much heavier thereby more than making up for that loss.  That was something I learned at Texas Tech, while working there, with the cattle we shipped to slaughter and reviewing the close outs.  A heavier carcass  has greater benefit despite the loss from losing a bit of quality grade.  Anyway it will be interesting to see if the cattle do similarly this year…

encapsulated urea.  We have done some work looking at an encapsulated urea product compared to other commercial fertilizers on ryegrass production.  This product has a coating around it that releases ammonia when soil temperature and moisture levels are correct.  We have not completed the total analyses yet, but as of the March harvest, the encapsulated product alone or mixed with urea (50:50) had better response on the small plots compared to conventional fertilizer types.  We have begun a hay study looking at the product’s effects on hay production.

Hay injection systems.  We tested a commercially available product that is designed to be injected into round bales to increase quality.  Injection (at label directions) did not improve quality. Injected bales were put into pastures randomly with non injected bales to see if there was animal selection preference, and none was noted as well.  We hope to do some follow up work looking at increasing the level of product applied.

So in a nutshell those were the three major studies that we worked on this spring.  We have sorghum sudangrass in the ground and are making preparations for our final year of our N-source study.

Remember to “Like us” on Facebook and keep up to date with what we have going on.  2013-02-22 07.59.41sampling 2013-05-07 09.19.29

Rainfall totals South MS Branch Exp. Station

18 Jan
Rainfall dec_jan

Here is weather data from what we have captured at White Sand Unit from December thru January. Pretty soggy!


Sugar Cane Feed

19 Sep

Hello Everyone,

I have joined the world of the on-line bloggers, although to many, my blogs won’t be that interesting, unless you like cattle and what they eat!

One of the first things I wanted to do was share this information with everyone.  It seems that a company has recently began to market a feed composed of sugar cane bagasse and some distillers grains.  The bagasse is the fibrous residue that is remaining following the syrup manufacutre.  We first became aware of this a little over a week ago, and have been keeping our eye on it.  Right now this product is available for sale @ $120/ton fob New Orleans.  We have analyzed a sample of this product and the analysis is listed below.  We (myself and Rhonda Vann at Brown Loam) are currently making plans to do a small type of study with this product to get a better handle on what we might exptect this feed to do.

Here are a couple of things you and your producers should be aware of:

Right now they only handle semi-loads, the option for supersacks may not be there, and they are in the process of “developing” the feed more, so the formulation may change

Sulfur is rather high (due to the DDGS in it, and the bagasse itself).  From a NRC perspective this feed fed alone with nothing else is at a level to be considered toxic.  Therefore you might want to ensure that this is fed in conjunction with something eles (pasture or other hay)

Phosphorus is high as well, and the Ca:P ratio is non-existant almost, therefore a good beef mineral with high level of Ca should be fed if you are going to use this product.

Here is the analysis, all values except dry matter are on a dry matter basis

  • Dry Matter                      67.87%
  • Crude Protein                 23.7%
  • ADF                                  55.6%
  • TDN                                  48.5%
  • Sulfur                                 0.56%
  • Calcium                             0.09%
  • Phosphorus                      0.73%

My final thoughts are that while this product might make a good protein source, I would be wary of using it as the SOLE source of feed in your operation.  If you are using it to extend pasture or  hay (much like you would a supplement), it may work for that, just be aware that right now as its blended it is low in energy.  Also if you are mixing feed, this product may work great for added protein and some roughage.  Just be aware of the mineral issue.

Should any of you have any questions I will be happy to answer them.  601-403-8777 office, email