Extension Agent: Drought and Vitamin A

Dec. 6, 2011 at 6:06 a.m.

By Joe Janak

The drought is unrelenting. Even this past week, with rain forecast for more than three days, most got a trace or a few sprinkles when we need 3 to 6 inches. Besides basic supplementation of hay, energy and protein, one thing that comes into play during drought for livestock producers - usually not a problem - is vitamin A deficiency. Cattle can store from two- to four-month's supply of vitamin A in the liver on diets exceeding vitamin A requirements, basically a little something green. With the drought limiting green forage and recent freezes burning back what was green, that supply probably is exhausted.

How do you supply supplemental vitamin A? Dr. Ted McCollum, extension beef cattle specialist at the Texas AgriLife Center in Amarillo, recently provided this as a recommendation for supplementation of vitamin A.

First, if supplementing with fortified range/breeder cubes fed at 1 to 11/2 pounds per day for dry cows, or 11/2 to 2 pounds per day for lactating cows, most cubes should provide adequate levels of vitamin A. Also, mineral supplements that are used and fortified with 200,000 units vitamin A per pound would provide adequate levels when consumed at rates of 2 to 4 ounces per day. The key is, are your cattle eating minerals at that rate? Also, the stability of vitamin A in supplements can be affected by the composition of the supplement, source of vitamin A, and length and conditions of storage. So, old sources of feed supplements and improper storage may minimize the effectiveness.

Lastly, and one that probably should be on every cattlemen's agenda, now is injectable vitamin A. It can be administered in an intramuscular shot and used to provide from about one to three months of vitamin A reserve, depending on the cow's stage of production and the concentration and dose of the product. That should carry her through the winter, and by spring, hopefully, the drought has broken some and green grass is plentiful.

Supplementation of vitamin A is relatively inexpensive and should be an integral part of drought management. For more information on drought management, go to VictoriaAdvocate.com and click on the link provided.

Colostrum for newborn calves

Research has shown that a calf's consumption within 24 hours after birth of the first milk from the cow, which is rich in colostrum, is important for good health. This is usually accomplished by normal nursing during this period. However, for various reasons, this may not occur. The current calving seasons are after an extended drought. The winters may be especially cold. All this means calves may be weaker, not be as energetic or have the stamina to withstand the cold and nurse immediately when born.

As backup, some producers, usually dairies, maintain a supply of frozen colostrum. But supplies may sometimes be exhausted or colostrum might be contaminated with disease-causing organisms. Commercially available bovine serum-based colostrum replacements and supplements have been obtainable for years now, and a recent study proved their effectiveness.

A study was conducted in Wisconsin using 287 dairy heifer calves from eight dairies. Half received fresh colostrum either in one or in two feedings, between two and 12 hours after birth. The other half received a commercial colostrum replacement the same times. Results? There was no difference between the two groups in percentage of calves that had an adequate level of passive transfer of immunity.

It was concluded that sequential feeding of bovine serum-based colostrum replacements and colostrum supplements is an alternative to feeding colostrum for achieving immunity in newborn calves that can't get it from the cow. So, if you have a newborn calf that hasn't gotten up, and you can't get it to nurse the cow, providing it with some commercial colostrum will help get the calf up and going.

Joe Janak is a Victoria County extension agent.



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