Question
My 11-year-old Miniature Horse mare weighs about 225 lb (102 kg) in moderate body condition. She spends about a third of her time in a drylot. She’s fed 2.5 lb (1.13 kg) of orchardgrass/timothy hay daily as well as 175 g of concentrate (a mixture of two types), 20 g wheat bran, and 35 g ground flax. She’s fed a pre/probiotic and a liquid vitamin/mineral supplement. She has a salt block in her stall and paddock. She's not a big drinker, and this concerns me. Her feed is mixed with 2.5-3 cups (600-700 mL) water and half an apple. She won’t tolerate more water. I would like her to be on a simpler diet. She is prone to mild colic. After the most recent bout in mid-December, my vet and I agreed to have a gastroscopy performed. The mare is currently sound and otherwise healthy.
Answer
A simplified forage-based diet supplemented with a high-quality protein, vitamin, and mineral supplement is often ideal for Miniature Horses that maintain their weight easily. Because pasture is not available, I would maximize the intake of hay to 1.5-1.8% of ideal body weight to support digestive health as well as to extend the time spent eating. This would be 3.75-4.5 lb (1.7-2 kg) per day of grass hay for a 225-lb (102-kg) horse. To supplement the forage program, I recommend offering a ration balancer (typically 100-150 g per 100 kg BW) to replace the concentrate, bran and vitamin/mineral supplement, as this will provide essential nutrients in a low-intake, low-calorie form.
As you increase the amount of hay, you should monitor her regularly for any increases in weight. If weight gain occurs, sourcing a lower calorie (more mature) hay would be necessary to allow for the increase in hay while controlling total calorie intake.
To encourage water intake, offering soaked feed is great, as is providing salt or electrolytes. Offering more long-stem hay should also increase water intake as studies have shown water intake to be closely related to feed intake. Adding a highly digestible fiber source such as beet pulp or a high-fiber feed can also be fed to make a mash.
Kentucky Equine Research has developed digestive health supplements that would be suitable for your mare. If the gastroscopy showed signs of ulcers or gastric irritation, I would suggest using RiteTrac, a total digestive tract buffer that provides both gastric and hindgut support. If the scope was clean—meaning no ulcers were detected—then I recommend the time-released buffer EquiShure to provide targeted hindgut support.
When pasture grazing is limited or prohibited, a bioavailable source of supplemental vitamin E, such as Nano-E, should be offered to support health and wellness.
