Albrecht's Animals

Sweat and "Excess" Potassium

I don't keep up with the latest research on IR and EMS, so maybe someone has already made this specific connection.  If so, comments welcome to "flesh out" my thoughts.

Anyone who is involved in the production of grassfed meat and dairy can tell you that grazers and grass co-evolved.  They keep each other healthy.  However, they are usually referring to ruminants, not horses.  These same grassfed gurus generally know squat about grazing horses, especially idle, non-breeding horses.

Having become keenly interested in restoring a piece of deteriorating high desert land with the  assistance of my horses, my interest in the actual role that horses play in grassland environments has grown.  The first realization is that with correct management, the wild horses under the care of the BLM, might actually be managed on the range to restore the broken water cycle.  (See Allan Savory's "Holistic Management" before you scream that overgrazing is the cause of desertification.)

These ideas begin to take root and to branch out in many directions.  Because I am so convinced that "excess" potassium in grass is at the base of many equine metabolic diseases, I can only ask, "WHY" is grass such a luxury consumer of potassium, if that very habit makes it toxic to horses?

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With winter bearing down rapidly, my driving mare, Spunky has grown a thick coat.  My determination to work with her through the winter, so she is fit for long pleasure drives next year has forced me to consider partially clipping her.  The reason for this is because she sweats heavily under the heavy coat, and our cold, wet weather prevents her from drying properly.  Even the neighbors are taking notice.  Her long hair tends to curl when it gets damp, and they all think I've been flogging her to death when in reality, I keep close watch on her expenditure of energy so as not to overface her. So horse sweat is suddenly a topic of keen interest.

I like to nose around in equine conditioning books, and I began recalling some things I read about electrolyte loss in working horses.

According to Sarah Pilliner, Getting Horses Fit, horse sweat is ten times richer in electrolytes (potassium, sodium and chloride) than human sweat.  Horse sweat contains 130-190 grams of sodium per litre, 20-50 grams of potassium and 160-190 grams of chloride.  A teaspoon is roughly 5 grams, so a litre of horse sweat contains up to 5 teaspoons of potassium.   A horse can lose 15 litres (about 3 gallons!) of sweat in an hour of hard work in hot conditions.  She goes on to say that while human athletes are more concerned with hydration, horses are deeply concerned with electrolyte loss.  It takes something like three days for a horse to replenish its electrolytes after hard work in hot weather.

So...perhaps the grass DID evolve to serve the horse.  Horses are meant to travel as much as 30 miles per day for food and water.  That probably entails a lot of sweating.

I have been looking at +3% potassium in grass as "poison" for at risk horses.  Of course it is, when it is not balanced with adequate salt, calcium and magnesium.  But the problem once again reverts back to human management, or mismanagement.  Our horses were designed to be constantly on the move, and require constant replenishment of electrolytes.  Because of confinement and forced idleness (who has to "force" a horse to stand around, doing nothing?) the electrolytes are still being constantly replenished, but we have eliminated movement, and consequently sweating, which may be the natural healing agent we seek for our horses.  That, and plenty of salt, calcium and magnesium.  I still believe that all that potassium passing through the horse's system is responsible for disruption of Ca and Mg metabolism, which is one of its indirect routes to IR and EMS. Perhaps it is NOT the potassium that is the killer - perhaps it is the removal or restriction of the horse's natural requirement for heavy exercise that is killing them.  Just like the desertifying rangelands of the west, perhaps nothing is "broke" with our horses except human intervention in the natural way of things.

As Pogo said, "I have seen the enemy, and he is us!"

Spunky got a "trace clip" yesterday.  I'm looking forward to seeing how she dries after a drive today!

 

 

Letter to Soil Consultant 11/13/2011

Enclosing two samples for your analysis this year.  These two samples were taken 150 miles apart.

Sample #2 is taken from a piece of property that we own in the Oregon High Desert.  We’re starting a small native grassland restoration program there and want to know what we have to start with.  Soil is subject to extreme erosion and 10” rain per year.

Sample #1 is from our hay field.  The field is naturalized grass and legumes.  We are no longer grazing sheep, but instead have shifted our focus to growing nutrient-specific hay for our pleasure horses.  Here are some specifics that we are trying to achieve:

As the soil has become more fertile through remineralization, vetch and clover are threatening to choke out the grass.  We wish to discourage the growth of the legumes, and encourage the growth of the grasses. 

It is not that the legumes are undesirable nutritionally.  The vetch has become so rampant that it is almost impossible for the disc mower to cut through it, and because of our increasingly wet and cold springs, it is nearly impossible to cure, making the hay musty.

We also lost our hay crop this year, partially on account of the vetch.  It grew so long and heavy that it forced the grass to the ground in June rains, where it began to rot.  We were forced to mow the field and let the hay lie on the ground, which leads me to the next subject.

Our organic matter content seems to be on the rise again.  Last year it was 11% (OM, not necessarily humus).  This year, because there is a MASSIVE amount of OM from the ruined hay, I am wondering if we are going to need a more liberal dose of nitrogen to help digest it all.  This leads me to the next issue.

Despite applications of copper sulphate to apparently adequate soil levels, our copper uptake in the grass continues to fall while the molybdenum continues to rise.  The Cu level in the last hay crop was 3ppm, and the moly was 4ppm.  The ratio of Cu:Mo needs to be as much as 10:1 for animal health.  Obviously we need to unlock the Cu somehow, to get it into the grass.  I am also hoping that better Cu uptake will help the grass resist lodging. I am guessing the OM is trapping the Cu and making it unavailable.  This ongoing low copper issue has been fatal to some of my stock.  I am very wary of adding any more Cu to the soil – prefer to see if managing the OM will correct the problem.

Potassium is a subject of extreme concern, as most grass hay has far too much potassium in it for idle/light work horses.  An idle horse needs only .8% K in the diet, and most grass hays run far higher than that.  Our last hay crop was 1.7%, which is quite a good level, but we have starved the K down in the soil quite a bit, which hasn’t had the least effect on yield.  So we prefer to try keeping the K in the low-to-mid range of base saturation requirements.  On the other hand, we  also request that you examine the Na to make a recommendation for salt application.  We applied Redmond salt at 150 lb/acre one year, and that brought the animal nutrient level of Na up to .25%, which is the bottom of the NRC requirement.  I know that K and Na have to be in the right proportions.  The Na level in the fall fresh forage that year had dropped to negligible levels, so I’m sure the Na can use topping up again, especially with our excessive rainfall.

Another real problem we have is pushing the Mg up into the grass.  The hay is more or less meeting minimum NRC requirements, but it is constantly suppressed in comparison to Ca and especially K.  I strongly believe that this is a function of the cold spring/early summer soil, and wondering if you can recommend a biostimulant that might help us push more Mg into the plants.

Just as an aside, regarding Ca, Mg and K uptake, we used to have lamb livers analyzed when we were raising sheep.  The livers were chronically low in Ca in particular, and Mg tended to be borderline, while K was always off the charts.  These lambs were always harvested at the end of June, at the peak of the grass growth. These numbers are particularly damaging to metabolism.  It doesn't show so much in young livestock, but eventually produces metabolic disease in longer lived animals such as horses.

The other mineral that the hay is chronically low in is zinc.  We have not applied any to the soil, and I believe it’s probably time.

I am enclosing a copy of a blog article I wrote, comparing some Eastern Oregon (rained on) commercially grown orchard grass hay, with our home grown stuff, which hopefully shows the type of nutrition we are trying to coax out of the grass.

Looking forward to receiving your advice!

 

 

 

Barb Lee

 

Our 2011 Horse Hay Debacle

September 23, 2011 

PLEASE NOTE:  The formula I have posted for converting %Crude Protein into % Nitrogen has been called into question.  I have checked my resources and CONFIRM that in order to convert the %Crude Protein Number into %Nitrogen, DIVIDE the Crude Protein Number by 6.25%.  If you wish to convert a %Nitrogen value to Crude Protein, MULTIPLY the % Nitrogen by 6.25% .  Here is a quotation from Rose Scientific Ltd. regarding the Kjeldahl method of determining nitrogen content:

"Calculation

"After all this chemistry it is now time to calculate the amount of nitrogen present in the sample.  This calcualtion can either be performed as percent nitrogen or percent protein.  For percent nitrogen:

% N - 14.01 x (ml titrant - ml blank) - (N of titrant ) x 100

Sample Wt. (grams) x 1000

It has been shown that protein is 16% nitrogen.  (Wheat and dairy products are some exceptions.) By dividing 100 by 16, we get the conversion factor for nitrogen to protein of 6.25.  Hence, the percent protein is calculated as follows:

% Protein = 6.25 x % N"

It follows then, that in order to find the %N in the Crude Protein analysis, that

% N = CP DIVIDED by 6.25

Just as stated below. 

IF YOU FEEL THIS IS INCORRECT, or anything else on this blog, PLEASE SAY SO and give me the opportunity to either correct or justify any statement I have made.  This blog is for the benefit of everyone.  It needs to be accurate!  Thank you!

_____________________________________________

 

I guess in this year of deep droughts in certain parts of the country, I should be grateful for any hay at all.  But what I got this year, and the amount I paid for it, is a crushing blow for someone who has worked so hard to get horse hay “right.”

Our horses are both “insulin resistant.”  For the non-horse owner, that means they have a sort of type II diabetes which has been brought about by excessive sugars in their diet.  These sugars are largely to be blamed on deranged soil mineral balances, either by the natural absence of minerals in the soil, or by excessive applications of certain minerals by the grower.

As Wm. Albrecht said, the pedigree of the plant is worthless if it is grown in unbalanced soil.  So we have made no effort to plant supposedly low sugar grasses.  Our hay ground is populated with naturalized species.

We have worked for several years to balance our soil mineral content to produce hay that is nutritionally balanced for our horses.  Millions of years of excessive rainfall have leached much of the mineral fertility out of the soil.  This has produced forage that was deadly deficient in almost every category.  Our efforts to return mineral fertility to our soil have been expensive, and more successful than I realized.  But for various, valid reasons, I tossed it out the window this year and purchased hay from another source.

One of the results of our fertility program has been an explosion of legumes, notably vetch.  This would be a fine thing for grazing ruminants, but for making horse hay, it was definitely not what we had in mind.  Clovers for instance, can give horses “the slobbers.”  Too many legumes can bring the protein levels up to excessive amounts for mature horses, which only require about 8-9% protein.

For the last two years, the vetch has run rampant.  Vetch is a spindly, viney legume that clamors up the grasses toward the light.  In 2010, it was so heavy that it gummed up the haying equipment.  Our hay guys were very impressed, thinking that was about some of the finest local hay (standing) they’d seen!

In 2009, the hay got cut in June, as I recall, before the vetch really got crazy, and before it had all gone to seed and shattered.  That year we produced quite a fine, low carbohydrate hay that was very fit for our at-risk horses.  Some of the mineral were in short supply, but it would be hard to get everything exactly perfect.

In 2010, our roughly 6 acres of hay ground produced 20 tons of hay, despite being grazed almost right up to haying by sheep.  At that time, we had numerous livestock animals besides the two horses, and we needed those 20 tons. This was stuff that was loaded with vetch.  Overall, the numbers were within reason for insulin resistant horses, although the nonstructural carbohydrate number had crept up to about 11%.  We want to keep it below 10%.  The biggest problem we had was that the baled hay was over 20% moisture, where it should probably have had no more than 10%, so much of it got musty/moldy.  This was not the fault of the hay balers or anything really, except perhaps that the ground was still moist from a terribly wet spring.  The weather was just not conducive to drying broad-leaved legumes.  It hardly ever is in this part of the country.   As it was, the hay was baled in mid-July, when the vetch had shattered and was mostly dead.  Certainly past its prime.

Another strike against growing legumes for insulin resistant horse hay.  Our hay ground is also now positively loaded with clover and black medic, a relative of alfalfa.

We were our own greatest liability.  I was 59 in 2010 and Bob was 70.  Despite having purchased and refurbished an old Henry bale loader, the work of picking up 20 tons of hay and putting it in the hay loft nearly killed us.  It took us a week to bring it in out of the field, and about two weeks to recover!

At that time, we had numerous livestock animals besides the two horses, and we needed those 20 tons.

At some point during the fall/winter, we decided that our sheep operation was not gratifying enough to continue the backbreaking work, so we eliminated all the ruminants.  Two horses remained…two horses on strict diets.  We no longer needed all that hay, and so stupidly, we sold half of it.  We anticipated having to put up another crop in 2011, and we needed the storage space.

The 2011 winter and spring rains drove on relentlessly, and it was obvious we were in for another late haying.  It nearly killed us physically to put up the last crop, and we dreaded the work ahead of us. But worst of all, three rains in June permanently lodged much of the crop.  The vetch growing up the grass mashed it over and it never stood again.  Much of it began to ferment/rot underneath.

That was the death knell for the 2011 crop.  It was something we could do nothing about, so the decision was made not to harvest.  Even after we had spent about $1800 on soil minerals the previous fall.

It was rumored that the local hay broker was now selling “low carb” hay.  We paid a visit to the broker and found that he had about 7 tons of 2010 low carb hay left over and no real prospects for finding any more.  So I put my name on the year old “low carb” hay and paid $255 per ton, plus delivery.  This hay is monoculture orchard grass hay, commercially grown in Central Oregon.  The soil there is basically volcanic ash/sand, irrigated desert.

Now, you must know that desperate horse owners have been paying top dollar for rained-on central Oregon orchard grass hay, because supposedly the rain washes out the sugar.

This was what I had just bought:  Year old, rained on central Oregon orchard grass hay, for $255 per ton.

While the hay was still on the truck, I took my sample and sent it in to Holmes Lab for analysis.  The results are an absolutely crushing blow, but have once again given tongue to my passion for soil mineralization.

What I am about to share with you is a comparison of the purchased hay versus the home grown hay, and any supporting documentation that I can find to help you understand the profoundness of the differences.

Please note, that because of our constant leaching due to heavy rainfall, and considerable crop uptake, we make heavy applications of certain minerals each year, according to consultant recommendations.  The cost of the homegrown hay is very near the cost of the purchased hay.  In our circumstance, concern for animal health must play into our decision to shoulder the work and expense of growing hay ourselves versus buying it and letting others do the work.

Another consideration at this point, is the convenience of Oregon’s shipping ports to the Orient.  Asia is buying Oregon hay at record levels which are only likely to increase.  Trying to grow our own is hopefully a hedge against rising prices and scarcity.

The Comparison

References to horse nutritional requirements are extracted from:  Nutritional Management for Horses, AS-429, Purdue University Cooperative Extension Service http://www.ces.purdue.edu/extmedia/AS/AS-429.html

CRUDE PROTEIN

Nutritional Requirement (mature horses):  8-10%

Purchased hay: 10.30%

Homegrown hay:  11.19%

Discussion:  The first thing that you need to understand without question is that “crude protein” only refers to the amount of nitrogen in the hay.  The CP number absolutely does NOT reflect the amount of “true” protein contained in the hay.  Thus the CP may actually reflect an excessive amount of nitrogen that was used to produce a bumper crop as opposed to true nutrition.  How do we know? And what are the consequences of excessive non-protein nitrogen?

Most proteins contain about 16% nitrogen, so a mathematical equation was devised to estimate true protein in our hay.  In order to estimate how much nitrogen is in your Crude Protein value, divide the CP by 6.25%.

According to Jerry Brunetti, holistic livestock nutritionist, the only real tool we have to evaluate the CP value on a hay analysis is the sulphur value on the analysis.  Sulphur is required to help turn some of that nitrogen into protein.  Here is his formula:  A healthy ratio of nitrogen to sulphur is 10:1, that is, 10 parts nitrogen to one part sulphur.  To get a feel for how much “true” versus “funny” (nitrogen) protein is REALLY in your hay, divide the nitrogen by the sulphur value to determine your N:S ratio.

(BE SURE to order sulphur analysis when you send in your hay sample to the lab.  Many labs don’t offer it automatically)

To determine how much sulphur the hay needs to achieve a 10:1 N:S ratio, first determine your nitrogen content.  For the commercial hay, we have 10.30% CP.  10:30 CP ÷ 6.25 = 1.648 x .10 = .1648.  The amount of sulphur required in this hay to help insure true protein versus excess non-protein nitrogen is .1648.  The hay contains .15% sulphur.

The horse’s requirement for sulphur is .15% with a maximum tolerable level of 1.25%.  Keep in mind that NRC requirements are generally expressed as the lowest amount required to prevent clinical disease.  This hay is not adequate in sulphur to produce such essential amino acids as sulphur-bearing methionine.

The homegrown hay is produced on sulphur-enriched soil.  However, sulphur is susceptible to leaching, so even though we apply it, some leaching occurs during winter rains.

The CP of the homegrown hay is 11.19%.  11.19÷6.25 = 1.79% x .10 = .179% sulphur required to balance the nitrogen.  The homegrown hay contains .19%.  There is adequate sulphur available to help convert the nitrogen into essential amino acids, along with meeting the horses’ nutritional requirement for sulphur.

Reference:  Jerry Brunetti, True Protein vs. ‘Funny Protein’ www.acresuse.com/toolbox/reprints/Brunetti_Protein.pdf

NON-STRUCTURAL/WATER SOLUBLE CARBOHYDRATES (SUGAR AND STARCH)

For insulin-resistant horses, I would like to see the NSC below 12%.  10% or lower would be better.

Purchased Hay:  5.82%

Homegrown Hay:  10.89%

I put the homegrown hay in red because even though it is just barely within boundaries, the rained on hay beats the homegrown hay hands down for low sugar and starch.  Breaking the numbers down further:

Sugar, Purchased Hay: 5.18%

Sugar, Homegrown Hay: 7.53%

Starch, Purchased Hay: .64%

Starch, Homegrown Hay: 3.36%

Huge difference in the starch content.  It’s too bad we don’t have a pre-rain and post-rain evaluation on the purchased hay.   And I wish there was a way to determine what other vitamins and other soluble nutrients were washed out of the hay along with the sugar.  I know it didn’t make a bit of difference to the potassium content in the rained on hay, as it is excessively high.  This I believe brands the rained on hay even more dangerous than the homegrown hay as you continue to read through the comparison until you get to the grass tetany ratio.

CALCIUM

Nutritional Requirement: .25 -.30%

Purchased Hay:  .20

Homegrown Hay: .50

Many of us believe that the nutritional requirements assigned by the National Research Council are the bare minimums to prevent clinical disease.  As long as everything is in balance, perhaps 150% of the NRC requirements would be more healthful.

Right off the bat, we see that the commercially grown hay is deficient in calcium.  But it gets worse…much worse, as you will see.

The homegrown hay is certainly adequate at 200% of the basic need.  Yet again, there are factors involved that may prevent the metabolism of the calcium.  I will share an anecdote later.

 

 

 

PHOSPHORUS

Nutritional Requirement: .20-.25%

Purchased Hay: .29

Homegrown Hay: .18

Here the mineralization program on our hay field is not yet up to full speed, despite annual applications of phosphorus.  It is a work in progress.

Phosphorus must be available in a specific ratio with calcium.  That ratio is between 1:1 and 3:1.  With a deficiency of calcium or an imbalance of the two elements, the horse’s bones will become soft and weak or simply won’t develop properly.

Ca:P RATIO

Nutritional requirement:  1:1 – 3:1 Calcium to Phosphorus

Purchased Hay: 0.69:1

Homegrown Hay: 2.8:1

Despite the deficiency of phosphorus in the homegrown hay, the Ca:P ratio is still within bounds.    The commercial hay loses pretty badly.

MAGNESIUM

Nutritional Requirement: .1 - .15

Purchased Hay: .13

Homegrown Hay: .18

Magnesium is known to be one of the key minerals for metabolic health.  In our neck of the woods, magnesium (Mg) is rarely recommended as a fertility element because it does not increase yield.  Livestock owners with cattle and sheep are expected to deal with grass tetany problems by setting out magnesium blocks at times of the year when magnesium is known to be in short supply in the grass.  From what I have gathered over the years, I believe strongly that deficient magnesium may be strongly suspect in metabolic diseases such as inexplicable winter laminitis attacks.  I will elaborate when I get down to potassium.

Although the homegrown hay is adequate for Mg, it could be better.  It is not for failing to add magnesium to the soil.  It is more a matter of difficulty moving it into the grass plants in cold spring soil, when microbial activity is low.  It may be necessary to provide a stimulant to the microbes in the spring, to improve the magnesium value. 

As with Calcium and Phosphorus, so is there a correct ratio between Calcium and Magnesium.  That ratio is 2:1. 

Ca:Mg RATIO

Nutritional Requirement: 2:1 Calcium to Magnesium

Purchased Hay: 1.5:1

Homegrown Hay: 2.7:1

So even though the individual numbers in the homegrown hay are better than in the purchased hay, we could stand to add more Mg to bring it into balance with calcium.  This is especially true for our insulin resistant horses.

POTASSIUM

Nutritional Requirement: 0.8%

Purchased Hay: 3.06

Homegrown Hay: 1.4

Excess Potassium – The Silent Killer.  Why?  Before going any further, please read this article by animal nutritionist Woody Lane – Too Little, Too Much, Early Spring http://veterinarycalendar.dvm360.com/avhc/article/articleDetail.jsp?id=571062&sk=&date=&pageID=3

This article, being devoted to evaluating forage for its risk for producing grass tetany may not seem to be related to horses and their metabolic diseases, but read carefully, about the impact that excessive potassium has on blocking the absorption of calcium and magnesium from the intestinal wall.

In another matter, excessive potassium will fool the body into thinking it has no need for sodium.  Sodium intake and thirst are directly linked.  Too much potassium intake means too little sodium intake, which means inadequate thirst and water intake.  Now contemplate whether your horse simply needs warm water in winter to hydrate itself, or do you need to sprinkle his hay with salt water?

Aside from the Ca:Mg:K ratio predicting metabolic problems, how much K (Potassium) is actually too much?  Some writers say that excessive Potassium passes harmlessly through the system and most of it will be urinated out.  In light of its impact on Calcium and Magnesium metabolism this obviously is not true.    Mr. Lane feels over 3% in the diet is dangerous.  I tend to start worrying when the hay goes above 1.5%. 

Achieving that low a Potassium level in grass hay is no accident.  Mr. Lane partially explains why grass goes so high in K when the plant does not need it. The soil chemistry can be manipulated to suppress “luxury consumption” of K by the grass, but you do have to have a plan.

 

Grass Tetany Ratio – Ca:Mg:K (Calcium:Magnesium:Potassium)

Tetany Ratio: (potassium% x 256) divided by the sum of (calcium % x 499) plus (magnesium % x 823)

Results greater than 2.2 represent an estimation of increased risk.

Purchased Hay:  Potassium - 3.06 x 256 = 783.36

                             Calcium - .20 x 499 = 99.8

                             Magnesium - .13 x 823 = 106.99

                             99.8 + 106.99 = 206.79

                             783.36 ÷ 206.79 = 3.79

Homegrown Hay:  Potassium – 1.40 x 256 = 358.4

                             Calcium - .50 x 499 = 249.5        

                             Magnesium - .18 x 823 = 148.14

                             249.5 + 148.14 = 397.64

                             358.4 ÷ 397.64 = 0.90    

Since I am now stuck with seven tons of the purchased hay, I am going to have to devise a serious strategy for managing not only the sugar risk, but almost more importantly, the POTASSIUM risk!

SULPHUR

Nutritional Requirement: .15 (Maximum tolerable 1.25%)

Purchased Hay: .15

Homegrown Hay: .19

Sulphur is needed by plants to help convert nitrogen into protein, notably the essential sulphur-bearing amino acid, methionine.  Refer back to Crude Protein, and the Jerry Brunetti article on crude protein to review the equation that helps determine whether your forage contains enough sulphur (10:1 nitrogen to sulphur) to assure that the crude protein is really high quality protein, and not non-protein nitrogen. 

THE N:S (NITROGEN:SULPHUR) RATIO

Purchased Hay: 10.30% CP ÷ 6.25 = 1.65 x .1 = .165% Sulphur to help assure quality protein

              This hay contains .15% Sulphur

Homegrown Hay: 11.19% CP ÷ 6.25 = 1.79 x .1 = .179% Sulphur to help assure quality protein

              This hay contains .19% Sulphur

Even though the purchased hay contains enough Sulphur to theoretically meet the horse’s nutritional requirement, it falls short of being in the correct ratio with nitrogen for proper protein production.

SODIUM

Nutritional Requirement: .10 - .30%

Purchased Hay: .071

Homegrown Hay: .128

See the article Don’t Short Salt by T.W. Swerczek, DVM, Ph.D

http://beefmagazine.com/mag/beef_dont_short_salt/

Even though the homegrown hay is “adequate” for sodium, it could be much better.  Why?  Because sodium (salt) is protective against excess potassium.  The sodium in the homegrown hay is no accident.  It was actually applied to the soil as a fertilizer.  This practice, when done properly, also has the advantage of offering the grass plants something to take up in spring besides potassium.  Although the plant does not need the salt, it will store some salt without damage in compartments called vacuoles.  Hay with adequate sodium for animal health is said to be very palatable to the horses. 

Rarely will a hay grower add salt to his fertility program, which means that hays grown on sodium deficient ground will almost surely need DELIBERATE supplementation.  Because free choice salt is not always interesting to animals (especially those full of excessive potassium), the only way to make sure they are getting enough (roughly 2 oz. per day) is to FEED it to them.  My horses quite like slightly salty water sprinkled on their hay.  NEVER add salt to drinking water!

CHLORIDE

Nutritional Requirement: .3 - .4%, maximum tolerable level 5%

Purchased Hay:  .61

Homegrown Hay: .53

Both hays are slightly above the necessary range, but neither is anywhere near being toxic.

Chloride is the last mineral to be added to the list of known essential minerals, in about 1954.  Naturally, chloride comes with salt.  Chloride also comes with potassium fertilizer known as Muriate of Potash, which is Potassium Chloride. 

Excess chloride will hitch hike along with Potassium in Muriate of Potash (Potassium Chloride) .  The grower of the purchased hay could have used Potassium Sulphate instead and brought his sulphur level up a bit.  But Potassium Sulphate is more expensive, and that would affect his bottom line.  Besides, he doesn’t know that too much chloride is said to be toxic to soil life.

COPPER

Nutritional Requirement: 5-8 ppm (parts per million)

Purchased Hay: 1 ppm

Homegrown Hay: 3 ppm

Copper has proven to be the slipperiest of all the minerals to get into our grass plants.  Over the years we have added enough copper to be good for “general cropping “ (Neal Kinsey, Hands On Agronomy). However there are things going on in the soil that perpetually tie it up.  My strongest guess is excessive organic matter in our soil (Neal Kinsey, Hands On Agronomy). On other soils in this area, it seems that copper deficiency is a prevalent, but unacknowledged threat to livestock.  Our strategy is to attempt to reduce the organic matter to about 8%, to attempt to release the bound-up copper.

MOLYBDENUM

Nutritional Requirement:  No requirement established by the National Research Council.

Purchased Hay: 1.7ppm

Homegrown Hay: 3.0ppm

I've marked both in red because of the desperately incorrect ratio of copper to molybdenum in both hays.  Both hays are dangerously low in copper.  I have found this for EVERY SINGLE HAY ANALYSIS I've read from different parts of the state of Oregon.

I have always had a great fear of molybdenum in excess of a ratio of 10 parts copper to 1 part molybdenum, because of sheep losses due to copper deficiency in the past.  Molybdenum is an antagonist of copper.

However, my reading for this article suggests that horses are not nearly as severely affected by moly as ruminants are.

MANGANESE

Nutritional Requirement: 40ppm, Maximum tolerable level, 1000ppm

Purchased Hay: 19ppm

Homegrown Hay: 114ppm

Manganese deficiency can result in defects in lipid and carbohydrate metabolism.

ZINC

Nutritional Requirement:  40ppm, Maximum tolerable level, 500ppm

Purchased Hay: 14ppm

Homegrown Hay: 22ppm

We have not yet added zinc to our fertility program.

BORON

Nutritional Requirement:  None Established      

Purchased Hay: 1.43ppm

Homegrown Hay: 11.71ppm

Although there is no established daily requirement for boron, virtually all animals on earth are known to require boron.  It is active in calcium and hormone metabolism, notably insulin.  Therefore, I feel it is very important to know the content of a given hay.  Penn State University (I think that’s right!) says that  healthy grasses contain around 11ppm boron, on up to 30ppm for legumes.  Since there is little to go by, I consider that what is healthy for the plant is healthy for the horse.  I consider 11.71ppm boron in the homegrown hay to be adequate, and 1.43ppm in the purchased hay seriously deficient.

Boron is involved in sugar transport within the plant.  We are all told that hay cut in the morning will be lower in sugar than hay cut in the afternoon.  If you know how to use a Brix refractometer, you can tell yourself.  If grass sampled in the morning has the same Brix reading (for sugar) as grass sampled in the afternoon, there is a strong possibility that the grass is boron deficient and that the sugar transport from the leaf to other parts of the plant (roots) is inoperable. 

DIGESTIBLE ENERGY

Nutritional Requirement:  Varies.  The DE Mcal/lb. value will be used to judge how much hay the horse gets in its ration each day. 

Purchased Hay:  .90 Mcal/lb.

Homegrown Hay: 1.03 Mcal/lb.

The higher digestible energy is probably due to the higher sugar in the homegrown hay.

LIGNIN

Lignin is the indigestible fiber in the plant.  Excessive lignin will reduce availability of nutrients, making the hay less digestible.

Purchased Hay: 5.72%

Homegrown Hay: 3.11%

The homegrown hay appears to be somewhat more digestible.

RELATIVE FEED VALUE

Relative Feed Value (RFV) is an index that combines digestibility estimates of Acid Detergent Fiber and intake estimates of Non Detergent Fiber.  The reference value of 100 is based on full-bloom alfalfa.  Theoretically, hay with 110 RFV would have 10% more energy than full bloom alfalfa.

http://www.wa-hay.org/business/newsletters/march02.pdf

Purchased Hay:  95

Homegrown Hay: 105

TOTAL DIGESTIBLE NUTRIENTS

An estimate of the digestibility of the forage.

Purchased Hay: 45.12

Homegrown Hay: 51.64

CONCLUSION:

There are still many things that I have to learn about extracting useful information out of a forage analysis.  There are still numerous ratios between the major and minor minerals to memorize and apply. I do not know them all.

While neither of the hays is perfect, it appears that the only real saving grace of the purchased hay is that I may be able to feed more of it, especially in light of the fact that I am going to have to soak it to remove excess potassium. (Update:  Rather than soak the purchased hay, we are combining it with the much lower potassium homegrown.)

It looks as though we don’t get “something for nothing” after all, in terms of outlay of effort.

Our cost for fertility elements and contracted haying services are pretty much equal, whether we buy or bale.  When we grow our own we are also tasked with picking the hay up out of the field and stacking it in the barn.  We are out in the rain during fall and spring, liming and fertilizing.  We are running back and forth to the fertilizer dealer some 25 miles away.

But the cost of the commercially grown hay only begins with the $255 per ton.  I am going to have to soak this stuff, and try to figure out how to balance nutrients.  I have to face the knowledge that because the hay is deficient in so many areas, complete nutrition in the form of vitamins, enzymes, immune substances, pigments, and a whole host of phytonutrients are lost, because the growing orchard grass was not provided with the necessary minerals to catalyze them into existence.

The main worry I have is the potential aggravation of the horses’ metabolic problems.  My older horse has recently been guardedly diagnosed with potential cancer (we are not going looking for it.)  His resistance will be down.

I couldn’t save our hay crop this year.  It was pounded to the ground by late rains until it began to rot. That was a blow, and made me turn away from my involvement with producing our own hay.  The life of a farmer is too uncertain.

But the life of letting someone else take care of things for me is far more uncertain.  This coming year, I will have a different strategy, and a healthier respect for what we have managed to achieve in our effort to manipulate soil chemistry to produce the healthiest possible hay.

UPDATE:  Since I originally wrote this, I have gained a new understanding of potassium’s role in horses at heavy exercise.  Please see the post, “Sweat and “Excess” Potassium.  I will be elaborating on this aspect of potassium and perhaps the impact of exercise in moderating its effect on calcium and magnesium metabolism.

 

 

 

 

 

 

                            

                            

 

 

 

 

 

 

 

Thoughts on Grazing

Finally, I feel I have the tools to allow my horses some grazing.  It's been truly enjoyable to witness the sheer joy they derive from the simple act of harvesting their own food.  This picture was taken on 11/14/11.  Yes, it was foggy out!

From my days of raising grassfed lamb, I have learned a bit about rotational grazing, and have a lot of equipment for it.  In this picture the horses are in an acre paddock behind the barn.  We have been gradually restoring the soil with applications of balanced minerals.  Thanks to near perfect conditions this fall, the grass is just gorgeous, about 8" tall.

Before commencing to graze the horses, I made a rough guess at sugar content with a Brix refractometer.  The sap from the green grass read roughly 2.5 on the Brix scale.  I calculate this to be roughly 7% NSC, based on a fresh fall forage sample I had analyzed this year.  I Brix the grass weekly, and expect the number to go down as winter deepens.

I am going to take numerous samples this winter of varying degrees of Brix, and try to determine the cut-off point at which I will no longer allow access to fresh grass.  My rule of thumb has been 3, but I will do a more studied estimate when I have more information.

From my sheep grazing days, I know that the fall (naturalized) forage does not produce near as much sugar as spring.  Reduced daylight hours, types of perennial grasses, etc. are not high enough in sugars to properly "finish" a butcher lamb.  So even though it might be slightly harder on the wet soil, I think a studied course of rotational grazing with the horses will minimize "pugging" of the soil.

The trouble with the fall forage is not the sugar, it is once again, the high potassium and suppressed uptake of calcium and magnesium.  The microbes in the soil that are responsible for pushing the heavier minerals into the plants have gone to Florida for the winter. Referring back to the Grass Tetany Ratio, the sugar in the grass has little to do, I believe, with the potential for winter laminitis.  I can't do anything about the Ca:Mg:K ratio in the fall grass, so I go on the defensive with added SALT (to minimize potassium's impact, as well as to assure the horses crave water, thereby reducing the risk for winter impactions), calcium and magnesium (in the form of dolomite).  I should be topping up the phosphorus as well.

The grass is at least 80% water.  In Oregon, the grass will stay green pretty much all winter, and the fact that it contains 80% water is probably responsible for what the local vets call "Clackamas County Disease."  (I live in Clackamas County.)  Basically, it just means starving animals fed nothing but lush green grass.  Grazers such as ruminants will graze for a certain number of hours each day, beyond which they will not try to satisfy their hunger with more grazing.  If they cannot eat enough dry matter in the alloted grazing time, they go hungry.

I limit the horses to about two hours' grazing.  In that amount of time, I doubt that they nip five pounds of grass, so I haven't even adjusted their feed program.  Five pounds of grass would equal about a pound of dry matter. 

The horses have a positively uncanny ability to know which blades of grass they have already nipped.  When confined to a certain area, they uniformly nip about 50% of the top of the grass off, if not allowed to regraze that same area.  They may wander around where they have been, but they will quickly lose interest and go back to the new area, so I have not found it necessary to use a back fence.  Interestingly, I brixed the already-nipped grass and found that it, too, had a Brix reading of 2.5.  So it is not just the sweetness of the grass that they are starving for.  They want those green tips. Their round hooves don't cut up the ground as much as cattle/sheep hooves, as long as they are not capering around.

You can see two electric wires in the picture, side by side.  The one nearest the horses limits the amount of fresh grass they are allowed to nip.  The second wire is simply set up for the next day's ration.  I will take down the first wire and leap frog it over the second wire, and allow the horses another two foot strip of grazing for the following day.  These strips are about 150 ft long, and seem to be just about right for my two horses to remain interested in for the two hours they are on pasture.

In the mean time, the grass has been nipped down to a very healthful (for the grass) level, leaving a substantial "residual" to allow for regrowth.  The grass plants will shed a few roots, adding to the organic content of the soil.  The grazed area will not be re-grazed until the grass has regrown to the 8" level.  That may be next spring, and if that's the case, sorry ponies, no more grazing if the Brix is over 3! We have ten acres of this grass to rotate the horses through.

This has been a wonderful experience for all three of us!  The horses GLADLY come in after their grass feed.  Their hunger is anything but satisfied from the watery grass, and they are always ready for hay.  (They get turned out after their morning feed of hay.)  They are not frustrated by grazing halters.  They are taking care of the most fundamental partnership in nature, grass and grazer, and they are doing it in a magnificent way!  It just requires some knowledge of the this partnership to be able to mimic nature as closely as possible.  This means we must first and foremost understand what's good for the grass, as well as the horse!  The two are inseparable.

Adventures in Grazing Fresh Fall Forage

 

After all these years of information gathering, I have decided that I have enough information to help me calculate the risk of allowing my horses a bit of fall grazing.  The experiment begins in November, 2011.

My primary concerns are:

Making sure the horses receive adequate salt:  I know that in our area, spring and fall grass will contain an excess of potassium.  This I believe to be equal to, or greater than, the danger of excess sugar.  While I can’t buffer the effect of excessive sugar, I believe I can offset the risk of the excessive potassium by making absolutely CERTAIN that the horses ingest adequate salt, calcium and magnesium.

It goes without saying that in our high-rainfall area, the sodium in the grass will be dismally low.  And I do not trust the horses to ingest enough salt voluntarily to meet their daily needs.  This is particularly dangerous in fall and spring when the K (potassium) level is going to be high in the grass.

Excess potassium can fool the horse into believing it actually has enough sodium.  This will limit sodium intake and a cascade of evils follow.  One of those is disinterest in drinking sufficient water.  What a setup for a winter impaction colic!  Excessive K disrupts calcium and magnesium metabolism as well.

I try to assure that the horses are receiving adequate salt – about one ounce per day – by sprinkling salted water on their hay.  They seem to like the slightly salty hay just fine.

Making sure the horses receive adequate calcium and magnesium:

In the cold weather, it is hard for the grass to take up adequate amounts of these two “heavy” minerals.  I have been surprised by my fresh forage analyses that the calcium content of the grass tends to be quite good even in colder weather.  Magnesium (Mg) is enough to meet NRC requirements but never quite enough to match the Ca (calcium).  We top up calcium and magnesium on the pasture every year but this situation tends to repeat itself, so this year I will be looking for ways to boost the magnesium uptake.

At any rate, based on analysis of their foundation hay, more magnesium wouldn’t hurt a thing, especially when it comes to allowing fall grazing.  I top their ration up each day with roughly a tablespoon of dolomite, which contains both calcium and magnesium. 

Checking sugar content in the grass with a Brix Refractometer:

This is a Brix refractometer.  It is a small, hand held device that is used to measure the amount of sucrose in a liquid.  A drop or two of liquid is put on the prism (left end) and the plastic cover is lowered onto the sample.  Then the prism is held up to the light to obtain a reading.

 

 

 

The reading looks something like this.  We are only interested in the scale on the left, the Brix % 

You’ll note that where the blue and white come together, the number on the left hand scale is roughly 17.  This suggests that the percent of sugar in the liquid is 17%.  That might be the sweetness of a nice, juicy apricot.

To further put this into perspective, I added one teaspoon of table sugar to one cup of distilled water (this is all very unscientific, kitchen chemistry).  The Brix reading of the liquid was 2.5%.  However, things aren’t so cut and dried, as I was soon to discover.

I added a teaspoon of Morton Lite Salt, which has a high percentage of potassium, to the brew.

The new brix reading was 5%. So it IS true that a Brix refractometer reads other compounds besides sucrose in plant sap.

My first reaction was, well, that is a GOOD thing, because it means the sugar in the grass sap would be LOWER if the refractometer is reading the other minerals.  Once again, things were not so cut and dried.

I have in the past, regarded a Brix reading of 3 to be the maximum that I would allow for limited fresh grazing.  However, I never quite understood why my inclined-to-be-fat mare gained weight readily on grass of such a low brix reading.  The answer became clear as I rummaged through more data.

Fresh Forage Analysis

Here is the fresh forage analysis:

Download 11-11 Fresh Forage Brix 1.5 - 2.0

In order to see if I could correlate the Brix reading to the actual sugar content of the grass, I gathered a sample and sent it in for a quick analysis.  Before I sent the sample, I took several Brix readings of the grass sap and came out with an average of 1.5-2%. 

In my mathematically challenged brain, I was assuming that a simple sugar content of 1.5-2% Brix meant a super-safe grazing level, right?  Wrong again.

Looking at the AS SAMPLED column, I discovered, much to my delight, that the simple sugar value was 1.9%, right in line with my brix reading of 1.5-2%! 

But the sugar in the DRY MATTER column was 14%!

How could this possibly be?!  I thought long and hard about this, and then thought, hey wait!  I was sampling grass sap, not dry hay.  Maybe that had something to do with the low-Brix, high DM sugar analysis (high meaning over 10% for at risk horses).

Now my confusion became acute.  I had sent in a sample at almost the exact same time last year, so I consulted it.  I knew it was of roughly the same Brix reading. 

Upon consulting the 2010 report, I discovered that the As Sampled sugar content was 1.42%,  and the Dry Matter sugar content was a mere 7.53%.  How could the Dry Matter sugar content have DOUBLED when there was such a minor difference in the As Sampled sugar content between the two reports?

You have probably already guessed the answer.  The difference is not so much in the SUGAR content of the As Sampled column; it is the amount of DRY MATTER in each sample that made the difference.

The 2011 sample contained 13.7% Dry Matter.  The 2010 sample contained 18.87% Dry Matter.  That is a difference of 5.17%, apparently enough to send the actual amount of sugar the horse is eating in each bite soaring in the LOWER dry matter sample, the 2011 sample.

By now my brain is a shredded mess, as I try to figure out the correlation, based on the as-sampled values. I am still trying to salvage my Brix reading.

Then, realizing that the lab isn’t testing the wet grass, but the dried grass, it suddenly occurred to me that they are determining the percent sugar in the DRY MATTER CONTENT first, then doing the simple math to get the AS SAMPLED number.  What threw me off is that the As Sampled column always comes first.

So, you can run it out on the above analysis:

% Dry Matter Sugar x % Dry Matter = % As Sampled Sugar

.14 x 13.7 = 1.9

It worked on the 2010 test as well, plus the other values that are reported on the tests.  Whew, I thought I’d lose my marbles before I figured that out!

Having the as-sampled value first (the Brix %) does us no good without knowing what the dry matter content of the fresh forage is, and knowing the percentage of the sugar in the plant sap does us no good whatever in determining the safety of grazing fresh grass.  However, I think I’ll continue to use the refractometer as a tool for checking sugar content, but I think I’ll lower my maximum tolerable Brix to 2%.

GRAZING

After crunching the numbers on the fresh forage analysis against analysis of the hay that forms the foundation of the horses’ ration, I realized that a bit of grazing on the 14% sugar DM grass wasn’t going to add a significant amount of sugar to the horses’ diet.

What worried me more was the high potassium content of the grass.  3.31% is quite high!  So I ran the Calcium:Magnesium:Potassium numbers through the Grass Tetany equation and discovered that the grass is still well below the threat threshold, particularly if I assure the sodium, calcium and magnesium values are topped up in their diet.  I decide to risk it.  The main thing is managing their intake.  How, with a grazing muzzle?  No, I’m going to try something different – “Management Intensive Grazing,” or perhaps more accurately, “Strip Grazing.”

During my years as a grassfed lamb producer, I read reams of information about Management-Intensive Grazing (MIG).  Although I never became proficient at it (I never had enough sheep), I have a good working knowledge of rotational grazing.  Plus, I have a considerable amount of idle equipment for rotational grazing with the horses. 

I’ve spent a lot of time researching to be able to estimate how much grass a horse will eat in an hour, and the answer as always is, it depends.  The averages of how much grass they will eat, and how many hours of grazing it would take to get full nutrition from grazing alone, range from variable to ridiculous to dangerous.  We’ve seen that a difference in sap concentration of sugar has no correlation whatever to how much sugar a horse ingests at any given stage of the grass’ life cycle.

So, I had to come up with my own estimate, and decided that I could risk allowing them to graze for 1 ½ hours per day (after accustoming them slowly) on this 2% Brix grass, based on an estimate of 4 pounds of grass eaten per hour.  I cannot even begin to fathom the relative good they receive from the grazing, in terms of both nutrition and happiness.

Their foundation hay is very low in sugar (but unfortunately high in K) and four pounds of grass penciled out to be roughly ½ pound of additional dry matter.  So I subtracted a pound of hay from their daily ration, and cranked up the salt, calcium and magnesium in their diet.  Now the interesting part begins.

In the grazing literature, it seems that cows have a perfectly uncanny instinct for the best grass.  Needless to say, that is the un-bitten, un-trampled, un-pooped on grass.

If you give a cow a strip of fresh grass each day, it is unlikely she will need a fence behind her until all the fresh grass along the new strip has been eaten.

Oh my, do we underestimate our horses’ instinct for fresh, virgin grass!

Day after day, as I parcel out a narrow strip of fresh new grass to the horses, they do not leave that strip until the upper 50% or so of the grass has all been nipped!

If I wait too long, they will have wandered back into the already-bitten grass.  This is absolutely what we DON’T want.  Every time that fresh grass has been bitten ONCE, it needs to be rested until it re-grows.  The amount of time it takes for the grass to recover depends of course, on the time of year.  In the fall, our grass is growing very slowly, so the horses may never return to the original strip of grass I have given them before the new growing season arrives!  If they were allowed to graze in summer, they might return to the original spot in as few as seven days!

One grass plant, one bite.  That is the Law of the First Bite, as the graziers call it.

The horses are presently strip-grazing a one-acre paddock, and the grass is about 6-8” tall.  I move the fence roughly two feet each day, giving them a new strip of grass about 2 feet wide and 150 feet long. They are uniformly biting off about 4” of the top – the ice cream – then moving on along the fence.  If they have gone back to the already-bitten grass, they are starting to eat the cardboard box that the ice cream came in.  This we DO NOT want.  One reason is because more of the villainous fructan is concentrated in the lower parts of the plant.  The other reason is that we want the grass to have enough leaf surface to continue photosynthesizing, so it can strengthen itself and recover.

In addition, keeping adequate cover on the ground helps the water cycle and prevents erosion.

Just because there is grass left, does NOT mean you still have grazing!

The grass should never be bitten lower than about a 3 – 4” “residual.”

So, what I have become quite confident in, is that my two small horses, will “cream” a strip of grass that is roughly 6-8” high, 2 feet wide and about 150 feet long, in about an hour to an hour and a half.  Absolutely reliably.  If I go out and find them nibbling around in the previously grazed area, I’ll know that I either need to shorten their grazing time or widen their strip.  No frustrating grazing muzzles.  Just pure joy for an hour and a half a day.  How many of us humans enjoy that much happiness!

Interestingly, after having a breakfast of hay before turnout, they seem to be famished after an hour and a half on the watery grass and come in at a gallop for a carrot and a little more dry matter.

Time will tell if I have made a mistake in allowing grazing on the watery fall grass.  Like any of us, all I can do is hope I’ve covered all the bases.