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Virginia Cooperative Extension -
 Knowledge for the CommonWealth

Beef Management Tips

Livestock Update, April 2000

John B. Hall, Extension Animal Scientist, Beef, Virginia Tech

April Beef Management Calendar

Spring Calving Herds

Fall calving herds

Grass Tetany Time Again The spring flush of grass is great to see after a winter of tight feed supplies, but this new growth is high in nitrogen and low in magnesium. High nitrogen levels reduce absorption of what little magnesium is in the grass. As a result, cows are deficient in magnesium. Cows come down with grass tetnay when magnesium deficiency is combined with a stress like high milk production or bad weather. Cattle go into convulsions that include bellowing, blind running and falling down and paddling their legs. Cattle usually die within a few hours of the first signs.

Thin cows are susceptible as well, but often exhibit signs of stiffness or over reaction to sound or touch for a few days before convulsions begin. In thin cows, these signs can occur after only a brief stress. Prevention of grass tetany by feeding minerals that contain high levels of magnesium (12-14% Mg) is the key. Most producers can supply enough magnesium by feed a high magnesium complete mineral mix. However, producers that are feeding poultry litter need to top dress the litter-mix with 2 ounces magnesium oxide (MgO) per cow per day. Treatment is difficult because it must be administered so rapidly that we normally don't have time to treat the animal before it dies.

Careful Early Castration is Important We are not doing as good a job castrating calves as we should. Several recent experiences have brought this point home. At several recent management workshops and herd visits, I have been involved in helping "fix" castrating mistakes. These included leaving 1 or both testicles inside "steers" due to improper banding. Another common mistake is leaving part of the testicle or epididymus when "pinching calves".

Improper castration has a large impact on the marketability of Virginia calves. When we visited feedlots in Pennsylvania recently, their number one complaint was improperly castrated calves that resulted in stags or bulls. The packer heavily discounts stags and bulls, so they cause a problem for our feeder customers. The problem is common enough that in feeder cattle selection section of "Blueprint for Success for Feeding Cattle in Pennsylvania" it says all "males castrated with a knife at less than four months of age."

The best way to castrate calves is surgically between birth and 3 months of age. If you are banding calves it should be done early and you need to ensure that both testicles are below the band. Contact your extension agent, veterinarian or experienced producer if you need a refresher on proper castration technique.

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