Monday, May 9, 2016

Summer Annuals



It’s the first part of May, and so far (at least in the past week or so) we’ve had rain to make us think we’re going to have plenty of grazing in the summer.  However, we probably all know that the rain will shut off before long.  So, now is the time to think about what your horses are going to eat during the summer.

A lot of pastures have a base of fescue, which is a cool season perennial.  That means it comes back from year to year and grows best in the cooler times of year – spring and fall.  It doesn’t do a lot of growing in the summer because of the temperatures.  So, planting something that grows well in the hot, and most likely dry, summer is an idea you should consider.  This will allow you to provide your horses with grazing during this time when the fescue growth slumps off, and can potentially decrease overgrazing in those perennial pastures.  Also, a lot of summer annuals can be higher in nutritional value than fescue or bermudagrass.

Summer annuals typically grow quickly which means that you can potentially graze them within one or two months after planting.  With adequate moisture, they will grow back so that you can graze them multiple times throughout the growing season.  Frost kills summer annuals and they will not grow back next year.

Nitrate poisoning can be a problem with summer annuals.  When heavily fertilized with nitrogen, these plants can develop toxic nitrate levels if they are slow-growing and drought stressed.  Take home message – do not graze summer annuals that have had significant nitrogen and are drought stressed.  Plants can be tested for nitrate levels.  Check with your local extension office about sending samples off to be tested.  

Pearl Millet is a popular summer annual for horse pastures.  It should be planted in May and will provide grazing from June to September.  Begin grazing with the millet is 16-20 inches tall and remove the horse when the stubble is 6-10 inches tall.  This leaves adequate energy stores so that they plant can regrow.  Pearl Millet does not produce prussic acid.

Crabgrass is often thought of as a weed, but it can provide high-quality summer grazing for horses.  Typically, it is higher in nutrition that many warm season perennial grasses.  It can produce forage from June to September and can grow from 12-24 inches tall.  Just like most summer annuals, it responds well to nitrogen fertilization and small amounts of rainfall with is typical in our summers.  Proper management of crabgrass may allow for some reseeding to take place.

Teff is a summer annual grass that originated in Ethiopia.  The seed is tiny but is an aggressive competitor once it is established.  It can be ready to harvest 45-55 days after planting. It can do well in both drought-stressed situations and water-logged soil conditions.  

There are some summer annuals that are NOT recommended for grazing by horses.  These include sudangrass, sorghum, sorghum-sudangrass hybrids, and foxtail millet. Sudangrass, sorghum, and sorghum-sudangrass hybrids can accumulate prussic acid, especially after frost. When drought-stressed plants are grazed, they may cause cyanide poisoning, cystitis, incoordination, and sometimes fatal kidney disease. Since prussic acid volatilizes during curing, properly made and stored hay produced from these grasses may be safely fed to horses. Foxtail or German millet has been reported to have a diuretic effect in horses that may lead to kidney and joint problems. The coarse, fuzzy heads may also lodge in the tissues of the mouth and gums and create sores.

Below are some additional resources you may find helpful.




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