Question
Vanna is my five-year-old event mare that needs to gain weight (BCS 4). She’s turned out in lush fields 12 hours each day, and gets first-cut orchardgrass (6 lb or 2.7 kg) in a haynet when she’s stalled. Each day she’s also fed senior feed (4 lb or 1.8 kg), alfalfa pellets (a few handfuls), canola oil (3 cups or 750 mL), and a natural-source vitamin E supplement. Vanna is prone to ulcers and, though not confirmed, I suspect she might have PSSM2. My boarding barn has a one-feed, one-amount policy, so that complicates feeding. Because she has a difficult time putting on weight and muscle, I think a low-starch diet is best. I would like to eliminate the oil as it is messy, and it is hard to get her to eat all of her grain with the oil in it. Can you provide some help, please?
Answer
You may consider a different approach, one that is based on high-quality forage that would also include a ration balancer to supply essential nutrients. The key with this type of diet is selecting highly digestible forage or fiber sources that provide enough calories to support weight in an amount your mare will readily consume.
Leafy alfalfa hay is a great option for horses with higher nutritional needs and is generally low in starch and sugar, which makes it more suitable for metabolic horses. If you can source high-quality alfalfa hay, I would recommend adding this to the orchardgrass hay offered when your mare is stalled. If alfalfa hay is not available, you can feed more alfalfa pellets. Supplementing with alfalfa should allow you to reduce the amount of oil being fed.
If your mare responds well to the higher forage intakes, then you could try to reduce the amount of senior feed offered and replace it with a ration balancer or lower intake performance feed formulated to be fed at 4-6 lb (1.8-2.7 kg) per day. The amount of senior feed fed to Vanna currently does not supply optimal nutrient intakes for the level of work she performs. Switching to a feed that is lower in calories and molasses should help to reduce nervous or anxious behavior. Amino acid supplementation can be beneficial for horses with PSSM2, so look for a ration balancer or supplement that provides essential amino acids, including branched-chain amino acids.
A grazing muzzle can be used to allow turnout and access to grazing but in a controlled manner. This seems counterproductive for weight gain, but it may help to restrict grazing especially during lush growth periods. This can help reduce the amount of rich, highly fermentable fiber reaching the hindgut, which can lead to digestive upset and reduce feed value of the diet.
A digestive product to consider to support both stomach and hindgut is RiteTrac, as it contains an antacid blend to support gastric health and the time-released hindgut buffer EquiShure. EquiShure is recommended for horses grazing lush pasture to promote hindgut health and reduce the risk of subclinical acidosis.
