Managing grass for lower sugar content
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These plots were duplicated in Utah by USDA researchers. The grasses at the Colorado site with colder climate had consistently higher levels of NSC. The amount of solar radiation was also a significant factor in NSC content.
Perennial ryegrass is the highest in NSC (sugar and starch), followed by tall fescue, timothy, crested wheatgrass, orchard, redtop, Garrison meadow foxtail, Kentucky bluegrass, meadow brome. Native warm-season species were lowest in NSC.
While native species are lower in sugar, they will die if overgrazed. They store food reserves in the roots. Repeated grazing depletes root reserves. They survive only when migrating herds eat them once or twice per season. Not many horse owners have large enough pastures for effective migration. Instead, we have to rotate pastures. Not many people are set up to do this.
Photosynthesis makes sugar in grass. On a cloudy day, less sugar will be made. A week of cloudy weather will make a bigger impact. Two weeks of cloudy weather can make grass significantly lower in sugar.
If hay is cut after a period of cloudy weather it will be lower in sugar. Let your hay grower or broker know that you need lower sugar hay and get them to test and set aside those lots that are grown under conditions conducive to lower sugar content.
If the nighttime temperature is above 40F (5C) sugars made the day before will be used for growth. This makes the morning after the best time to graze horses that need less sugar in their diet. Here the amount of grass is limited by strip grazing, and the grass has had the high NSC seed heads removed.
If you don’t have a dry lot, make one now. Some horses can only have a couple of hours of pasture per day. When conditions cause grass sugar to increase, you must keep them off of pasture completely. A sacrifice area is also essential when pastures are muddy or drought-stressed.
Many times I have seen dry lots fail because the ponies can reach grass and weeds outside the fence. You must clear everything outside the fence within reach of your most determined pony.
A grazing muzzle can be useful for limiting the amount of grass per mouthful. There are many models to fit different sized horses. You may need to add padding to prevent rubs. Make sure it’s on a breakaway halter.
In cloudy climates, they have to grow grass species that are more efficient in producing sugar, like ryegrass. But if you have a stretch of sunny days, watch out! These grasses will turn into candy!
Find a place in your pasture that is shaded for part of the day. Since photosynthesis can only make sugar when the sun shines, this area of the pasture will be lower in sugar. Fence it off for your easy keepers. They might not be able to stay out there all day, but they should be able to handle more than if it were in full sun.
Pastures with a lot of trees to decrease sunshine on the grass will be lower in sugar than the same grass out in an open field. Make a cross fence to keep those that need a lower sugar diet in the shady areas.
When you wake at crack of dawn, graze your pony on your lawn.
Sugars raise in afternoon, to foundered ponies this spells doom.
Your sugar sensitive horses might be able to graze for a couple of hours starting at dawn. My fondest memories are of watching my horses graze while having my first cup of coffee. This might even fit into your schedule if you work away from home.
If you have the time, you can hand-cut grass in the early morning, put it in the shade, and it will stay as low in sugar as it was when it was cut. A tasty evening treat for a fussy eater.
While Teff is a good choice for testing, some growing conditions can cause it to be too high for sugar sensitive horses. It’s soft and sort of fluffy, but many horses eat it just fine.
Lots of science to back this up. When essential nutrients are missing, grass can’t grow. It just sits in the sun and makes sugar. Plenty of people have foundered horses on overgrazed, neglected pasture, especially when they are large.
When essential nutrients are limiting, grass won’t grow and just sits in the sun and makes sugar. Adding nitrogen makes more grass, but it is lower in sugar concentration. This is good when pasture access it limited or when making hay.
The microclimate surrounding a blade of grass makes a huge difference. Thick grass makes its own shade. Thin spindly grass has nearly all leaves in the sun all day. This is a big reason why fertilized grass ( or hay made from it) is lower in sugar per bite, even if there may be more sugar per acre since there is a lot more grass.
When night temperatures are near or below freezing, growth stops and the sugar made the previous day cannot be used. In spring, stop grazing sensitive horses until good growing conditions return. If this is in fall, don’t graze until the pastures are completely dead.
Even before the heads emerge from the stem, the developing seed head is a collecting sugar. This is a stage of growth where clever horses often just eat this top sweet portion of grass plants. They can also be observed just eating the emerged seed heads. That’s why grass that is in early heading stage is not suitable for grazing sugar sensitive horses.
Cool nights in a high mountain valley, plus cloudless skies are perfect conditions for high sugar hay. It’s much harder to find low sugar hay in these regions. I ended up shipping hay in from out of state.
When grass needs nitrogen, growth slows, sugars accumulate, and weeds take over the pasture. Weeds can be higher in sugar than grass. This poor pasture management can lead to laminitis.
When pastures are deficient in nitrogen, clover has a competitive advantage because it makes its own nitrogen. Clover can be very high in sugar and starch and is not a good forage for horses with EMS. Thick, properly fertilized grass will keep clover from taking over.
Sugar is not green. Even brown hay can be very high in sugar. The color of hay is more about how long it laid out and what happened to it before being baled. Don’t be fooled by thinking that color has anything to do with sugar content.