Vitamins are essential for growth, health, reproduction and survival of all classes of livestock.
Vitamins, just like almost every other nutrient in a mineral, can go from being far in excess of animal requirements to well below. Especially in grazing cattle conditions where vitamins are often overlooked in the basal forage supply.
In the cattle industry, there's a belief that more vitamins are always better, but that's not necessarily true. Too many vitamins in a mineral and they're wasted through urine or feces. Not enough and it can put cattle at risk of vitamin deficiencies.
In this article, expert ruminant nutritionists clarify how you can determine the vital vitamins your herd requires during different stages of their lives.
What vitamins do cattle need?
Beef cattle mostly require vitamins A, D and E. Cattle are unique in the fact that the bacteria in their rumen can produce vitamins K and B vitamins in sufficient quantities to meet animal requirements without needing supplementation.
How much vitamin A do cattle need?
Vitamin A is found only in animals, but its precursor form comes from plants. To make the vitamin, animals convert carotene (a pigment in green and yellow plants) into vitamin A.
Vitamin A is essential for the maintenance of tissues, eyesight, kidney function and normal development of teeth and bones.
Deficiencies of vitamin A are most common in cattle that are confined in a feedlot where green and yellow plants are not most of their diet. However, deficiencies can also occur in grazing situations where forage has extended periods of brownout during a drought or in situations with long-stored hay. It is also recommended to watch vitamin A levels with forages with higher nitrate levels after fertilizer applications.
One of the tell-tale signs of vitamin A deficiency is usually night blindness. If you’re looking for a way to check for deficiency, watch cattle around twilight and see if they easily stumble over obstacles without moving around them. Other symptoms to watch for include rough hair coats, staggering gaits, watery eyes, lameness or stiffness. In grazing cattle, breeding efficiency will also be significantly impacted. Cows will have higher rates of abortions and weak calves. Additionally, cows will be easily excited.
To determine the proper amount of vitamin A needed for your herd, several factors must be assessed like feed source, level of carotene, dry matter intake, storage of vitamin A in the liver, age, stage of reproduction, etc. This chart from Missouri State Extension offers a general vitamin A requirement for beef cattle based on a basic understanding of these factors.
Vitamin A requirements of beef cattle
Growing Steers and Heifers
Stressed Steers and Heifers
Vitamin A, IU per day
Chart source: Missouri Sate Extension
How much vitamin D do cattle need?
Most know that vitamin D is obtained from sunlight. Mechanisms in the skin convert vitamin D into a form that’s usable by the body. In most grazing conditions, cattle receive enough vitamin D from direct sunlight or sun-cured forages. However, calves and younger growing animals have a higher requirement for vitamin D.
Vitamin D is necessary for the formation of strong bones and teeth but also the metabolic use of minerals like calcium and phosphorus. Most common in younger animals, vitamin D is often injected to prevent rickets or in some cases with mature animals to prevent softening of the bones.
A deficiency of vitamin D is often seen with poor bone structure or an unstable gait. Animals will show signs of decreased growth, swollen joints, arching, easily broken bones or deformed calves in pregnant cows.
To prevent poor bone structure, research shows that growing calves require about 300 IU of vitamin D per 100 pounds of body weight in their mineral.
How much vitamin E do cattle need?
The role of vitamin E in cattle is unclear, but many researchers believe its primary function is as an antioxidant to protect soft tissues from oxidative stress and other vitamins in the digestive tract.
The most common vitamin E is deficiency is shown in calves with white-muscle disease. Injectable vitamin E and selenium have been shown to help cure and prevent white-muscle disease from occurring.
The need for vitamin E in beef cattle rations has not been clearly identified. Until more is known, experts recommend that cattle be supplied with a minimum of 50 IUs of vitamin E a day.
While cattle obtain most vitamin E from forages, and it isn’t needed in most grazing conditions, it should be supplemented between 50 and 100 IU/day to cattle-fed grains or low-quality hay for extended periods of time.
Let us help you build a custom mineral program specific to your herds' vitamin and mineral requirements. Get started today by directly contacting Ralco’s ruminant nutritionist, Dr. Jeff Hill, by calling 507-337-6916 or emailing RuminantHelp@RalcoAgriculture.com.