Question
My broodmare is a very easy keeper. She does not receive any feed, only forages and supplements. She has access to coastal hay 24/7 and gets one flake of timothy-alfalfa mixed hay in the morning and at night. My vet recommended she lose some weight before getting pregnant, and I want to make sure I am not feeding anything that could harm the foal. Her current diet, in addition to the hay, consists of fiber-added complete feed, alfalfa pellets, ground flaxseed, and several supplements (MSM, electrolytes, stomach support, and an herbal mix).
Answer
You are wise to evaluate your mare’s body condition and diet prior to breeding, as both can affect reproductive efficiency.
First, I suggest evaluating the total amount of hay and other forages your mare receives daily. Weight loss for your mare will likely require forage restriction, which means free-choice hay is not ideal at this time. If possible, limit her to a few hay meals throughout the day to decrease her intake to about 1.5-1.75% of her body weight. The alfalfa pellets are not necessary if she is already receiving high-quality hay. Cutting alfalfa pellets from the diet will help to reduce caloric intake.
As an easy-keeper, she is probably not getting the amount of feed necessary to meet nutrient requirements. The fiber-included complete feed you mention can be offered up to 25 lb (11.5 kg) per day; the high feeding rate takes into account the product’s forage-replacement feature. However, at least 6-8 lb (2.7-3.6 kg) must be consumed per day in order to obtain the nutrients outlined on the guaranteed analysis.
Because your mare doesn’t need the calories found in the complete feed, a vitamin and mineral supplement makes more sense. Micro-Max is a concentrated micronutrient pellet designed to fill in the missing vitamins and minerals in an easy keeper’s diet. (In Australia, look for Gold Pellet.) For example, feeding approximately 15-17 lb (6.8-7.7 kg) of hay and 1 lb (0.45 kg) of complete feed top-dressed with 120 g of Micro-Max will meet your mare’s requirements and should help reduce calorie intake. Alternatively, replacing the complete feed with a low-calorie ration balancer pellet such as All-Phase will fulfill protein, vitamin, and mineral requirements in just 1-2 lb (0.45-0.9 kg) daily. Balancer pellets are appropriate for broodmares that maintain weight easily. You may even find you can keep her on a balancer pellet well into her pregnancy before she requires more calories to maintain weight.
None of the supplements you list should be problematic to her foal during pregnancy, but it would be prudent to investigate the herbal mix more closely as there is little research on the use of herbs in horse nutrition.
Kentucky Equine Research recommends the supplementation of omega-3 fatty acids, particularly DHA and EPA, and antioxidants to boost reproductive efficiency. Mares supplemented with marine-derived DHA and EPA have enhanced passive transfer of antibodies to foals, leading to stronger immune systems. Omega-3s have also been shown to improve fertility and lower risk of uterine inflammation. Marine-derived DHA and EPA offer greater benefits than plant-derived sources of omega-3s because they do not require conversion for use within the body, like flaxseed does. EO-3, a product developed by Kentucky Equine Research, contains DHA and EPA from fish oil, not plants.
Antioxidant support with natural-source vitamin E has also been useful in improving fertility in mares and boosting the immunity of their foals. Nano-E is a natural-source liquid vitamin E that offers superior bioavailability and effectiveness.
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