As wet weather continues to delay the alfalfa harvest in some areas, Purdue Extension specialists say the crop's nutritional value for livestock feed is on the decline.
"The greatest concern is that with each passing day, the crops that should have been harvested lose quality," says Keith Johnson, Purdue Extension forage specialist. "As alfalfa and other forage crops mature, the cell wall content increases, leading to lower digestibility, palatability and dry matter intake for livestock."
The percent neutral detergent fiber, or NDF, is a quality factor that can be used to predict how much of the forage an animal will eat. For high quality alfalfa hay, the NDF is approximately 40 percent. Johnson predicts the NDF for most Indiana alfalfa hay is likely closer to 50 percent. With a higher NDF value, less forage will be consumed.
For example, an NDF value of 60 would result in an unexpected dry matter intake of 2 percent of body weight, while an NDF value of 40 would be about 3 percent. Thus, a 1,200 pound cow would eat 24 versus 36 pounds of dry matter per day.
He recommends hay growers send in samples to have their hay quality analyzed.
"Producers need to get real numbers," Johnson says. "They may find out it's of inferior quality, but they also might find out it is still in a very acceptable range. Having hay analyzed puts farmers in a position to use best management practices and provides buyers with analytical data in addition to visual information."
Experts agree that forage growers should take advantage of warm, dry weather if they have the labor available. When farmers make hay, effective harvest management practices that get the cut crop off the field without rain damage can reduce the possible transmission of a disease to re-growth.
Johnson urges farmers to reduce field traffic by making a few key lanes for driving, especially if the soil is still wet. Excessive driving through the field can cause more soil compaction and damage the plants' crowns, which allows for the possible entry of disease organisms.
Find out more about quality analysis from the National Forage Testing Association at: http://www.foragetesting.org
Source: Purdue University