Vitamins in horse nutrition

What do we know about vitamins in the horse? When is it necessary to supplement them in the diet? If they are already present in the basic feed, can we avoid complementary feeds that contain them? Vitamins, along with minerals that we will discuss later, are called micronutrients because they make up only a small part of the horse's diet, but their importance is indirectly proportional to weight. We answer most of the questions that may arise for those who own, breed or train a horse.

What vitamins does the horse need?

Each vitamin plays a significant role in the health of the horse and no micronutrient is more important than another is, as they all have a function: muscular, bone, hormonal, digestive and more.

Horses synthesise certain vitamins in the intestine, through the microorganisms that colonise the large intestine. These include the group B vitamins, vitamin K, biotin and folates. These micronutrients are therefore considered non-essential for the horse, but individuals who do not consume enough good quality forage or those under stress, with heavy workloads, do require supplementation with complementary feed like Megavit for example.

Vitamins A and E are not produced within the horse's body and must be introduced into the diet. For endogenous production of vitamins, it is necessary to maintain good intestinal function, which can be promoted using complementary feeds containing yeasts such as Equigest.

Vitamins and functions:

VITAMIN	FUNCTION	SOURCE FOR THE HORSE	RECOMMENDED DAILY INTAKE FOR A 500 KG HORSE
VITAMIN E	ANTIOXIDANT	FRESH FODDER (fresh and green grass)	500 IU in maintenance 1000 IU in hard training
VITAMIN A	SIGHT SKIN IMMUNE RESPONSE REPRODUCTION MUSCLE GROWTH BONE DEVELOPMENT	FRESH FODDER	15.000 UI in maintenance
VITAMIN D	BONE DEVELOPMENT AND MAINTENANCE	FRESH FODDER	800 UI for growth, pregnancy, lactation 300 IU in maintenance
VITAMIN K	COAGULATION FACTOR ACTIVATOR	FRESH FODDER	10.000 mg in allenamento
VITAMIN C	ANTIOXIDANT BONES AND TEETH USE OF VITAMINS B	HEPATIC PRODUCTION	6.000-10.000 mg in maintenance 20.000 mg after the age of 20
VITAMIN B1	NERVOUS STIMULATION AND TRANSMISSION	FRESH FODDER YEAST	1.000 mg
VITAMIN B2	ENERGETIC METABOLISM	FRESH FODDER YEAST	30 mg
NIACIN (nicotinic acid)	ENERGETIC METABOLISM	FRESH FODDER YEAST	35 mg
Pantothenic acid	ENERGETIC METABOLISM	ALMOST ALL PLANTS	130 mg
VITAMIN B6	AMINO-ACID METABOLISM	INTESTINAL PRODUCTION	10 mg
VITAMIN B12	RED BLOOD CELL PRODUCTION	INTESTINAL PRODUCTION	5000 mg

How do vitamin deficiencies manifest themselves in horses?

The most serious vitamin deficiencies can cause dramatic signs: skeletal deformations, delays in growth, but also invisible problems. In fact, milder deficiencies may not be apparent at first, but cause complications, such as improper bone development leading to gait alterations and/or reduced performance.

Can vitamin excesses occur in the horse?

Like deficiencies, excesses of vitamins in the horse's diet are also dangerous for the animal, but they are less frequent. If complementary feeds, formulated by experts in equine nutrition, are used, no mistakes can be made, as there are established contents for certain micronutrients, and being feeds defined as "complementary" it is considered that already from the basic feed there is a vitamin supply from hay and feed.

This is not guaranteed by injectable formulations, which can create plasma vitamin peaks but do not guarantee durability and can create metabolic changes. In addition, B vitamins and vitamin C are water-soluble, which means that any excess not quickly used by the body tends to be eliminated rather than stored.

When to use vitamins in horse nutrition?

Horses on diets with low forage and high cereal content
Horses that eat poor quality hay or are over 12 months old (a loss of 9.5% of vitamin A activity in hay occurs every month)
Horses subjected to treatments that have reduced immune and intestinal function
Horses subjected to stress, intense training, transport

Is your feed already supplemented with vitamins?

Vitamins can decompose when exposed to sunlight, heat, air. Losses during long-term feed storage are greatest for vitamins A, D, K and Vitamin B1. Particular attention must be paid to Vitamin A, which is the most important of these since it comes entirely from the diet.

It has been shown that diets based on hay and supplemented feed can only meet 90% of the nutrient requirements of a sport horse. This percentage drops dramatically if the hay is of poor quality and the feed consists only of a cereal mix

The advice is to rely on a person experienced in horse nutrition and get advice on the right complementary feed to avoid deficiencies of micronutrients that are essential for the horse in the different phases of growth, breeding and training.

Bibliography

Nutrition and equine performance. H F Hintz, J Nutr 1994

Pharmacokinetics of inorganic cobalt and a vitamin B 12 supplement in the Thoroughbred horse: Differentiating cobalt abuse from supplementation. L L Hillyer, 2018

https://ker.com/equinews/chelated-minerals-enhance-nutrient-bioavailability/

Vitamin Requirements In The Horse, K Crandell, 2000