About NSC's in pasture

Clarissa · About NSC's in pasture

We have a vet in Australia who has done a lot of research on pastures & supplements for horses. He is Dr John Kohnke. Some of us Aussies have written about him here in other threads.

He puts out a newsletter periodically which is available online :-

http://kohnkesown.com/newsletters.php

& it also turns up at feed merchants.

The latest one has some intersting info about sugars in fresh or stressed pastures. Here below I have pasted some excerps from this latest newsletter. There is also a great article about feding "good doers". I just wish I HAD some good doers/easy keepers!

Stressed Pastures Can Increase the Risk of Laminitis in Grazing Horses

Although many horse owners have a ‘Jenny Craig’ paddock set aside for the pony during winter and spring, low pasture with short, stressed grass can actually be high in sugars and increase the risk of laminitis, even with limited grazing. Studies have shown that short dominant grass tufts exposed to frost and/or a sudden dry spell, actually contain higher levels of soluble non-structural sugars (NSCs) and carbohydrates as the plant tries to maintain its viability. Ponies and other horses are attracted to the ‘sweet’ tufts and many that are bordering on laminitis and Equine Metabolic Syndrome (overweight, Insulin Resistance and abnormal fat distribution) can go ‘over the knife-edge” and develop laminitis within 24-48 hours. Avoid grazing stressed pastures 24/7 particularly after a heavy frost.
Allow susceptible horses and ponies only limited day time grazing for 1-2 hours, and confine them to a yard overnight with bulk provided by soaked hay to reduce the NSC content and lower the GI of the diet.

Low GI Feeds

Low GI feeds include sugar beet fibre, soaked lucerne hay (provides fibre and protein), lupin and soyabean hulls and limited non-starch grains, such as lupins, soyabean meal and sunflower seeds for protein and oils, as well
as soaked copra meal. Feed carrots as a treat rather than apples. Avoid molasses as an appetiser. Do not feed cereal by-products such as wheat and rice bran, pollard and millrun to EMS and Insulin Resistant horses and ponies. Early spring grown grass hay, especially ryegrass and fescue hay, as well as oaten hay and Rhodes grass hay cut before milk seed stage, are likely to have a high NSC content and should be soaked in double the hay biscuit volume of luke-warm fresh water for 60 minutes to leach out soluble sugars and NSC before being air dried and fed to these horses. Wheaten hay, usually cut as a mature crop, has lower NSC content, but it must be dampened prior to feeding to avoid impaction colic, especially in
ponies and miniatures.
In Australia hay can be tested for NSC content by Feed Test Laboratories of Victorian Government at Hamilton, Victoria.

Did you know that…….

Grass species which have developed drought tolerance and ability to grow
under cool temperatures are likely to have the highest GI and NSC content. All grasses contain some sugar. The accumulation of NSC’s is related to growing temperature, moisture and day length. Generally, when night temperatures fall below 10°C, NSC’s accumulate due to cold or dry weather conditions, rather than direct seasonal influences. Stressed grasses have a higher NSC content.

When grass is growing under late spring and midsummer warmth, NSCconcentration is lowest. However, during these conditions of rapid increase in pasture even with a lower NSC content, grazing horses, especially ‘good doers’, have an opportunity to overeat and can take in large amounts of NSC’s, sugars and carbohydrates, often triggering laminitis due to insulin resistance, especially in EMS affected overweight horses and ponies.

Horse owners often overgraze and neglect pastures – moisture stressed
and sparse grass can have less NSC per hectare, but each mouthful of grass consumed can have a higher NSC content. Weeds which thrive when grass is stressed by dry conditions, poor competiveness and cold early spring conditions may have a higher NSC‘s. For example, capeweed and dandelion growing under these conditions have a very high fructan sugar and NSC content and may taste ‘sweet’ to horses.

If horses are forced to graze these preferentially because there is very little else to eat, long limbed horses, such as Thoroughbreds, Warmbloods and Draft horse breeds, can develop Stringhalt, especially when these plants grow faster from tap-root reserves than grass which has to germinate from seed after rain following a summer dry spell.

Pasture grasses growing under warm cloudy conditions or growing under the shade of trees and grass protected from frost, have a lower NSC content. Unstressed re-growth after mowing or intensive grazing also has a lower NSC level.

That is a very intersting fact about stringhalt. I was asked recently what I knew about this condition & if I thought it could be fixed. All I knew was that horses (mostly TB's & X's) that grazed weeds tended to get it so I suggested they remove the horse from the weedy pasture or feed it some fresh grass hay. In a round about way I was right!! Amazing

Scouring when Grazing Lush Green Pastures

Green pastures in early spring can contain a high NSC content as well as water. Horses hungry for a ‘green’ pick may consume large volumes of ‘laxative’, high moisture grass which can lead to hind gut acidosis and bowel irritation causing diarrhoea and runny droppings. Restricting grazing time on highly succulent green grass reduces NSC intake as well as excess moisture, and feeding dampened hay as roughage often helps to ‘firm up’ the droppings. Large amounts of lucerne hay can cause soft manure and anal dribble of green fluid after the droppings are passed – reduce lucerne to half a biscuit per 150 kg body weight and feed grass hay – but soak it to remove fructan sugars and NSCs for overweight and EMS horses and ponies.

Theory of the ‘Thrifty Gene’

In order to explain why some horses become obese more easily than others, researchers believe that certain breeds, such as Morgans, Saddlebreds, Paso Finos and some Warmblood and Pony breeds, have a ‘thrifty’ gene. This enables them to metabolise their feed more efficiently and expend less energy (as compared to Thoroughbreds and
Arabians for example) on a lower ‘calorie’ intake.

There is also a wide belief that some horses inherit ‘obese–prone’ genes. It is possible that these horses have a higher number of fat ‘storage’ cells in their abdominal cavity and subcutaneous tissues and are more likely to accumulate more regional fat storage deposits when fed a high energy diet in excess of their daily needs.

When brought into small paddocks, yards and stables and fed on processed feeds, grain by-products and good quality hay or pasture, without regular or adequate work, the ‘thrifty’ genes facilitate the storage of fat in abnormal places – behind the shoulders, tail-butt and ‘crest’ of the neck. This particular fat storage has its own large blood supply, perhaps producing its own hormones (many ‘anabolic’ hormones are synthesized from fatty acids), which trigger more fat to be stored, leading to a vicious cycle of ‘food to fat’.