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.

Comments

[Nancy Taylor Rojo]

Horses and grass look good! Thanks for the update. Nancy Rojo