The Importance of Vitamin A Supplementation During the Winter Months

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As fall begins to give way to winter, pasture grasses go dormant, pulling their nutrients into the roots for the long, cold months ahead. Stored hay starts to lose its nutritional potency as it ages. What is left behind, while still holding some nutrition, can lack greatly in an essential nutrient – Vitamin A.

Where vitamin A comes from

Vitamin A is found in abundance in lush, green grasses. It is converted from beta-carotene, a nutrient that is present in most leafy green plants. Plants and grasses that are not sufficient in chlorophyll (the green pigment found in plant life) will, in general, also be lacking in vitamin A.

Hay may contain high levels of vitamin A shortly after cutting, but these levels will begin to drop the longer hay is stored. The two biggest factors in the degradation of vitamin A in hay are temperature and light exposure.

The importance of vitamin A in the bovine diet

Much has been learned about the role vitamin A plays in the diets of bovines. As with humans, every system in the body depends on this nutrient at least to some extent. The liver stores vitamin A as retinyl ester; this converts to the active form retinol that is then easily accessed by the body as vitamin A. Unfortunately, these stores only last so long, necessitating consumption of forage and feed that contains vitamin A to address immediate nutritional needs and replenish reserves.

Digestion, growth and development, immunity, respiratory function, and reproductive function are all dependent on adequate availability of vitamin A.


In calves, vitamin A is vital for growth and development. It contributes to the normal ossification of bones and teeth, ensuring that the animal’s skeleton will mature properly. Ruminal development is dependent on adequate levels of vitamin A. In addition, the growth and function of nervous tissue requires optimal levels of vitamin A.

Breeding Animals

For cattle in their reproductive years, Vitamin A is essential to keeping soft tissue linings including those found in the reproductive tract supple. A vitamin A deficiency in cows can cause thickening of the uterine tissues, making implantation more difficult and can even lead to fetal resorption or abortion.

Bulls that do not receive enough vitamin A in their diets may encounter problems with spermatogenesis (the development of sperm in the seminiferous tubules of the testicles), decreasing sperm count and quality.

All cattle

The overall effects of vitamin A deficiency in cattle can be disastrous for animals of all ages. As with the lining of the uterus in cows, the epithelial lining of the rumen is dependent on vitamin A to maintain pliability. Pliability in the rumen allows it to properly absorb nutrients. If it becomes thickened and rigid, the papillae start to shrink and reduced surface area for absorption occurs. An unhealthy ruminal lining is also more difficult for colonies of microbes to populate, leading to other issues such as poor feed conversion and sub-acute ruminal acidosis (SARA).

The respiratory tract can also become more brittle in the absence of adequate vitamin A. This makes animals more susceptible to infections such as BRD and can decrease the lungs’ ability to absorb oxygen.

The eyes are especially susceptible to vitamin A deficiencies. A prolonged vitamin A deficiency will result in night blindness; corneal ulcers can develop, causing lasting damage, even if the deficiency is corrected.

Symptoms of vitamin A deficiency

Cattle will display a wide range of symptoms in the presence of a vitamin A deficiency. Calves may grow more slowly and be sicklier than those that are receiving enough vitamin A. They may also have difficulty transitioning from milk to forage.

In general, cattle of all ages often present with inappetence, poor gains, decreased feed conversion and low energy levels. Physically, swelling of the legs may be present, in addition to a rough hair coat and dull eyes.

Supplementing vitamin A

Luckily, vitamin A is incredibly easy for producers to supplement. Before adding vitamin A to the diet, however, it is important to find out how much vitamin A forage and other feeds may be providing. Cut hay, as mentioned above, can begin to lose its potency as it ages. It should be assumed that dormant winter pasture will not provide adequate levels of vitamin A.

Depending on the size and type of cattle operation, different methods to supply this nutrient can be used. In the feedlot setting, vitamin A can be mixed into the TMR or offered in blocks or lick tubs. Many commercial TMRs will already contain certain levels of vitamin A. Consulting with the facility’s veterinarian or nutritionist will help determine if there are gaps that need to be filled.

Cattle on dormant winter pasture do well with uninterrupted access to lick tubs that contain adequate levels of vitamin A. Loose vitamin and mineral supplements and blocks can also be used but may not be as compelling to animals as lick tubs.

Vitamin A deficiency can have detrimental consequences on the health of a herd, but it doesn’t have to. With proper supplementation throughout the winter months, cattle can thrive and continue to perform at their best.

5 Reasons You Should Consider Lick Tubs

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There’s no disputing that horses and cattle that receive a well-rounded, complete diet with proper levels of essential nutrients perform better, live longer, and have stronger immune systems. In an ideal world, all of their nutrition would come from the forage or concentrated feeds they are given. This, however, is rarely the case, as forage or grazing quality can vary wildly. There is also the factor that each animal will have different nutritional needs throughout their lives. Filling in the gaps in the regular diet is essential to ensure that they thrive.

Luckily, with the advent of lick tubs, fulfilling these nutritional needs is easier than ever. Here are five reasons you should consider adding lick tubs to your feeding regimen.

  1. Tubs deliver balanced nutrition in small quantities of product. Most tubs are formulated to be consumed at a rate of anywhere from 1/2 lb to 2 lbs per day, depending on brand and formulation. This makes them an economical choice for the smallest farm to the largest cow-calf operation or horse farm. Multiple tub sizes make it possible to ensure that your animals are receiving a product that is consumed in a timely manner.
  2. Tubs allow animals to self-moderate consumption. Good tubs will have a limiter built into them to prevent overeating — particularly molasses-based tubs, where the sweet flavor can be irresistible. That being said, most animals will eat only what their bodies require to sustain a proper energy balance. For instance, you may have noticed that your horse will visit the mineral block more frequently after a strenuous workout. This is because his body is telling him he needs to replenish the minerals and electrolytes lost through exercise. Tubs allow your animals to regulate what they consume when they need it, taking the guesswork out of top-dressing and mixing supplements into rations.
  3. Weather-resistant formulas ensure product quality. A good tub will not be affected by rain, snow, wind or sun, assuring that the nutritional integrity will be preserved. Pelleted and granular feeds can be ruined by any of these weather factors, leading to feed waste and lost money.
  4. Multiple formulations for different regions and life stages. The variety of tubs available allows the specific needs of individuals or groups of animals to be met. For instance, cattle grazing on lower-quality pasture may need extra protein, while nursing cows often need a boost in calcium and fat.
  5. Economical and easy to store. Because tubs have a long shelf life and take up relatively little space, they can become an economical way to supplement horses and cattle. Often times, money can be saved by ordering a larger quantity of tubs and storing them until they’re needed. This also allows for rotation throughout the year, should nutrient requirements change (for example, high energy tubs for colder months and more mineral-dense for hotter months).

As you can see, tubs are a beneficial addition to your feeding regimens. The versatility and ease of use make them a great option for both the large or small livestock operation.

If you’d like to explore adding tubs to your feeding regimen, please don’t hesitate to contact us!

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