In the last issue of Land and Livestock Post, byproducts for winter supplementation were discussed. In this article, various types of forage for winter feed are explored. Primarily, the options are stockpiled standing forage, hay and haylage.
Stockpiled standing forage
“One of the oldest pasture-rangeland management strategies is stockpiling warm-season perennial grasses,” said Monte Rouquette of Texas A&M AgriLife Research. “Forage is stockpiled by deferment of grazing during late summer-early fall for use by cattle after frost occurs. Stockpiled grass does not have active dry matter (DM) production and its quality does not improve with time. A good investment is to take forage samples for quality analysis to determine if supplementation is required. If supplementation is required, the analysis will show whether the supplement need is energy-based or protein-based.”
“Stockpiled forage utilization and stocking strategies may range from continuous access to an entire pasture or controlled rotational access to a portion of the pasture. For any stockpiled grass, the bottom third of the plant is always lower in nutritive value than the top third of the plant,” Rouquette said.
“In many instances of controlled rotational grazing, animals forced to consume the bottom third of the plant may not maintain weight due to less nutrients and restricted DM intake. Depending on the lactation or pregnancy stage of cows, rotational stocking is usually better for animal performance if maximum utilization efficiency is not the primary objective.”
Hay is a significant component of livestock feed with more produced in Texas than any other state. In 2016, Texas produced nearly 12.5 million tons of hay followed by California at approximately 6.6 million tons; Kansas, 6.2 million tons; and Missouri, 6 million tons.
Several varieties of hay are harvested in Texas with some of the most popular being bermudagrass, Sudan, Sudan hybrids, bahiagrass and native prairie grass. Most producers in Texas grow hay for their own use, but a significant number raise it for sale.
“Nutritive value of hay depends primarily on plant variety, soil fertility, environmental conditions and time of harvest. As forage plants mature, each bite provides less nutrition because crude protein content decreases with maturity. Fiber components in the forage also become less degradable,” said Vanessa Corriher-Olson of Texas A&M AgriLife Extension. “Mature plants contain more lignin than growing forage, which is either an indigestible or slowly digestible compound that provides no energy to the animal.”
Optimum nutritive value of a forage plant depends on the target animal. Capturing the desired nutritive value requires careful attention to maturity of the various forage species. For optimizing both nutritive value and yield, it is commonly recommended to harvest forages such as bermudagrass every three to five weeks.
“Many hay crops are harvested when dry matter yield is the highest,” Corriher-Olson said. “Since the nutritive value at this stage is generally lower, animals will usually need supplementation during winter or drought. It is usually more economical to fertilize appropriately and harvest at the correct stage of maturity than it is to purchase supplement. The goal is to harvest hay when yield and nutritive value are balanced for the target animal species and class.”
Hay mowers mainly fall in two classes: sickle-bar cutters and disk mowers. Sickle-bar mowers have long cutting heads with reciprocating teeth. Disk mowers have cutting heads with several small rotating cutters. In the past, it was difficult to adjust cutting height and most mowers left a stubble height of 2 inches or less. Cutters today are more adjustable and a higher cut leaves some leaf material to support photosynthesis and encourage a more rapid recovery from harvest.
“After cutting, hay should remain in the field to dry or field cure,” said Larry Redmon of Texas A&M AgriLife Extension. “Dried or cured forage is raked into windrows that are the width of the take-up header on the baler. Sometimes a heavy dew, high relative humidity or rain will cause the windrow to remain dry on top, but wet underneath. When this happens, producers can use a tedder to turn the windrow over to facilitate drying of the forage.”
Most forages contain about 70 to 80 percent moisture when cut. Field curing (drying) forage as quickly as possible helps preserve its nutritive value, especially energy. Drying time of forage depends on humidity, temperature, wind speed and solar radiation. Hay cures quickly on hot, sunny, windy days with low relative humidity. It cures more slowly when weather conditions are cool, cloudy or humid.
“As long as forage moisture content is above 40 percent, hay will continue to respire and burn up carbohydrates. Respiration reduces the amount of energy for animals that ultimately consume the hay,” said Redmon. “Harvested forage, that is rained on, may exceed 40 percent moisture content for an extended time and lose substantial energy content due to leaching of nonstructural carbohydrates. Rain can also shatter leaves off harvested forage and reduce both crude protein and energy levels. It is better to wait for good curing conditions than take a chance that rain will fall on mowed hay.”
At baling, moisture content of hay for large round bales should not exceed 18%, and for small square bales it should not exceed 20%. Although experienced producers can estimate moisture content by touch, a moisture meter provides a more accurate reading. One way to obtain consistent readings with a moisture meter is to use an 18-inch diameter PVC pipe with a threaded cap on one end. Pack the harvested forage into the PVC pipe, then insert the moisture meter into the hay to obtain a reading. It is important to pack the tube to the same density each time. When finished, unscrew the cap and push the hay out with a wooden dowel. Then replace the cap and sample other parts of the field.
“Temperature of baled hay will increase during the first few weeks after baling,” continued Redmon. “This heat increase is called sweating or going through a sweat. Sweating is mainly caused by microbial activity, though it can include some final plant respiration. As hay dries, it loses roughly 1% dry matter for each percent of moisture loss.”
At moisture content of greater than 20 percent up to 35 percent, mold production becomes a great concern because it consumes nutrients in the hay. Mold also creates heat from respiration and produces toxins that make the hay less palatable. While mold-related heat up to about 120 degrees F does not damage hay nutrient value, higher temperatures can. Protein degradation begins at temperatures above 120 degrees F and browning begins at about 140 degrees F. This browning reaction (caramelization) can further increase temperature and take forage nearly to the point of combustion. These high temperatures also bind up much of the protein in forage, making it unavailable to the animal.
Under certain circumstances, it may become necessary to harvest hay at higher than recommended moisture content. There are three ways to handle high-moisture hay: inhibitors, drying agents or haylage.
“Haylage involves cutting forage with 45 to 55% moisture content, then putting it into airtight plastic sleeves. Haylage is typically wrapped in plastic to exclude air,” Corriher-Olson said. “Aerobic bacteria consume the oxygen remaining inside the hay within a few hours. Under these conditions, anaerobic bacteria reduce the forage pH and preserve it in a slightly pickled state. Low pH inhibits mold and respiration losses that typically occur in high-moisture bales. Haylage does not, however, attain as low pH as silage, so it won’t store as long. While haylage reduces leaf shatter loss and allows preservation of high-moisture forage, it is typically fed on-farm because of difficulty in moving large tubes.”
The three described forage options allow flexibility in meeting animal nutrient requirements. Regardless of the forage type, always sample for quality analysis to determine if additional protein and/or energy supplement is needed.
Article based on “Hay Production in Texas.” 2011, by Vanessa Corriher-Olson, Tony Provin and Larry Redmon. Texas A&M AgriLife Extension Publication. E-273. agrilife.org/foragefax/files/2013/05/viewpdf_2853_94340.pdf.
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