A couple of weeks ago I talked about the possibility of harvesting alfalfa earlier than normal. Selling that high quality hay and buying back lower quality hay that more closely matches the nutrient requirements of your cows.
Harvesting earlier, for higher quality hay works for grass hay, just like it does alfalfa. Rick Rasby, our Extension Beef Specialist that there are three items that determine forage quality: maturity at harvest, maturity at harvest, and maturity at harvest. I might throw forage species in there. Legumes are higher quality than grasses, and not all grasses are the same. But since we aren’t going to change the species of grasses we have in our meadows, it’s safe to say that stage of maturity is the main thing that affect forage quality.
As plants mature forage quality declines. As the plant matures, a larger portion of the plant is stem as compared to leaves. Also, as the plant matures the fiber components of the plant increase, causing a decline in quality and in digestibility. Not only do the fiber components in general increase, but so does the lignin content specifically. Lignin is a cell wall component of the plant that is not digested by ruminants.
It would be easy if quality was the only thing to worry about, but quality and yield are on opposite ends of a teeter-totter. As the plant matures, more plant material is produced and what is there is taller and more accessible to harvest. So, as plants mature, forage yield goes up. Hay producers have to balance the teeter-totter. If the producer maximizes quality, then forage yield is minimized. If yield is maximized, then quality suffers.
One place to start as you try to find the right balance is with the nutrient requirements of your cows. With protein supplement becoming more expensive, you might want to consider harvesting a little earlier. That way you would have hay that didn’t need supplemented in order to meet the needs of your cowherd.
You should be asking, wait a minute, you just said that yield will go down if I harvest early. How much yield will I lose? Unfortunately I don’t know the exact answer. James Nichols, who was at the UNL Research Station in North Platte in the early ‘90’s conducted a sequential harvest study looking at the trade off between yield and protein content. It wouldn’t be useful if I just rattled off a bunch of numbers over the radio. So I’ll just give you a quick summary. In the Sandhills warm season grass meadows where he conducted the study, Dr. Nichols found that hay yield increased by 1 ton per acre between June 1 and July 1 and Crude Protein content fell from about 12% to 8% over that time span. Yields continued to increase by about ½ ton per acre from July 1 to August 1, but crude protein levels had fallen to less than 7% by July 15.
They also studied the yield and quality of the meadow regrowth. The earlier the hay harvest the more regrowth there was available for fall grazing.
I have a nice chart at the Extension Office that shows the tradeoff between yield and quality as well as between harvest date and amount of regrowth. Contact the extension office at 376-1850.
