After addressing worms, teeth and health, the most important feeding step when you want a horse to gain weight is to provide as much pasture or grass/meadow hay as the horse can eat. You can do this by either giving your horse 24 hour access to pasture or by feeding just enough hay that a little is left over each day.
The best ways to promote healthy weight gain in horses are:
1 lb) per 100 kg BW per day, being sure to split it into as many feeds as practical during the day. You might also consider starting to add some high fat feeds like rice bran or straight vegetable oils to the diet for extra energy to help with body condition.
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Feed for a weight gain of 0.5 to 0.75 pounds daily. Three to four pounds of an additional grain product can meet this gain if the horse’s body weight is stable. Use the table below as a guideline. Horses take about three weeks to adapt to a high fat diet.
The best feed for an underweight horse is good quality hay or pasture grass. 1 Give him free choice hay unless there is some medical reason (such as metabolic syndrome, founder (also known as laminitis) or Cushing’s disease) not to.
Oats have been traditionally considered a low starch choice in grains; however, this grain is really only low starch when compared with corn. Oats typically contain between 32 and 43 percent starch. … A diet of oats alone would not be sufficient for any horse, and as a weight gain supplement oats are definitely lacking.
To add or develop muscle you must evaluate your horse’s current dietary protein levels and sources before increasing intake or changing protein sources. Mueller says he might opt to add a higher-protein feed or supplements or make a change in hay. “Alfalfa is one of my protein levers,” he says.
Beet pulp can be used to help underweight horses gain weight, as it provides approximately 1,000 kcals per pound (one quart of dry beet pulp shreds weighs approximately 0.5-0.6 pounds).
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