Wednesday, September 22, 2010

Graze Pasture Residual or Use a Sacrifice Lot?

By: Rory Lewandowski, Extension Educator Athens County and Buckeye Hills EERA

I recently received an email inquiry from a livestock owner who practices rotational grazing. His question is one that many graziers may be facing with dry fall conditions. Copied below is his email question and my response to his question.

It’s very dry.
Have saved residual 3 to 5” forage in most paddocks. I don’t expect any more growth this fall due to lack of rain. I have penned up the cattle and have been feeding hay. I think I have read that it may do no harm to next years growth to graze very dormant forage to the ground. I would prefer to bale feed on pasture rather than in a sacrifice area. This would mean letting the cattle graze the remaining forage to the ground. Will this damage the pasture for the future? By bale feeding on pasture rather than penned in a sacrifice area I would save the work of dealing with manure, and reduce loss of nutrients by having the bales waste and manure deposited on the pasture.

What do you suggest?

You have done well to save a 3-5 inch residual in pasture paddocks, good management!
I understand your reasoning about feeding hay in a sacrifice area vs. out in a pasture paddock, and you are right, you would have the nutrients deposited in the areas you feed in. You are also right that grass growth will be limited (if we get rain and cooler temps) or non-existent (if it stays dry and hot). However, I advise against grazing down your forage residual if that is what it takes to feed bales. This would be un-doing all of your good management up to this point.
Even though the grass is not growing those leaves can still photosynthesize and help that plant build up carbohydrate reserves that are necessary to overwinter the plant and provide for spring green-up and root growth. Even in a fall with better rainfall, grass growth rates fall off much more than photosynthetic rates. That is why it is so important not to overgraze in the fall of the year and to maintain adequate leaf area for photosynthesis.
Once we get to the point where soil temperature drops to around 40 degrees F, then grass growth and root development is truly done for the year, and the leaf residual can be grazed down close to soil level if necessary. Grazing off forage residual now will stress plants and will open up the sod base to invasion by weeds, especially some of the winter annuals. Pasture will green up slower next spring and next season’s overall production potential can be decreased. So, at this point in the year, I still advise that the sacrifice lot is used.