Grain and roughages have varying shelf lives, depending on how they were harvested, processed and stored.
“Becoming familiar with how certain processes affect livestock feeds will enable producers to retain quality and palatability from these feeds,” says Susan Markus, an Alberta Agriculture beef specialist.
Grain and oilseeds vary in fat content, which affects storage life. If higher-fat-containing oilseeds such as canola, flax and sunflower seeds are cracked or rolled, they may go rancid if left too long, she said.
Barley, peas and wheat have a relatively low fat level of 1.5 percent compared to oats, which is 3.5 percent, giving them a longer storage life.
High-fat processed grain such as oats can be stored for up to three weeks in warmer temperatures before going rancid and up to four months when it is cooler.
Processed low-fat grain such as barley, wheat and peas can be stored for up to three months in the summer and up to six months in the fall and winter. Nutrient quality loss is not significant with the longer storage, but the feed becomes less palatable so livestock may eat less.
Markus added that the way the feed was processed significantly affects shelf life.
“Rolled or cracked grains have a decreased storage life compared to whole grains. As more surface area is exposed to the elements and changes in temperature and humidity, storage life decreases.”
Heat-treated feeds, such as pelleted grain or other byproducts, store longer because the heat kills some of the bacteria. Expect at least three months and up to six months of storage from heated pellets. When feed is pelleted, it is broken into smaller pieces and mixed with other ingredients. This dilution effect can help increase storage life by up to double that of a comparable single type of rolled grain.
Tempering or steam rolling, which is the addition of water or steam, aids in the processing of grain of different sizes and reduces dust. However, since the process increases the moisture content by four to eight percent, storage times must be less than one to two days to minimize heating and spoilage.
If the moisture content of a mixture of tub-ground feed exceeds 15 percent, it should be fed within a few days to avoid heating and digestive upsets, Markus said. High-moisture grain and silage must be fed within a day or two.
Treating roughage with anhydrous ammonia kills bacteria and mould.
It increases feed quality and lengthens the storage life of these high-moisture bales by up to six months.
“Large round hay bales can lose a significant portion of dry matter within the first year. Uncovered forage stacks can lose up to 30 percent dry matter whereas covered stacks may lose between five and 15 percent dry matter,” Markus said.
“How bales are harvested, handled and the amount of rain or moisture they receive can affect optimum storage life. In the case of forage, quality losses in protein and energy content do occur over time. Vitamins in cut hay can be viable up to 60 days post-harvest, but little remains after that period. This situation is different from silages, where the ensiling process renders vitamins inefficient.”
Round bale silage should be fed within six months to a year of being harvested. Properly packed and sealed pit silage can be stored for two to three years with minimal quality losses. However, initial quality and moisture content at harvest will affect length of storage.
Adding minerals, vitamins and medicine to feed also affects storage time. The efficiency of most vitamins and some minerals will be reduced if feed is stored longer than three months. Markus recommended that producers consult with the manufacturer for storage times on medications that are added to feed.
“When it comes to byproducts, handling and storage requires special consideration. Feed byproducts vary in their handling characteristics, feed-out rate and type of storage facility required,” Markus said.
“Many byproducts can be obtained in either high-moisture, loose or pelleted forms. Handling characteristics to consider are moisture content and bulk density. Wet byproducts, such as wet corn gluten feed, have a shorter shelf life than dry gluten. Shrink or loss of product over time must also be considered when evaluating high-moisture byproduct usage.”
As well, Markus said liquid byproducts stored in bulk tanks for long periods of time should be mixed on a regular basis to ensure a consistent product.
Nutrient analysis is the only way to know for sure what your feed quality is.
“Understanding and interpreting moisture level, protein, energy and some macro minerals will enable you to develop a suitable ration for your livestock,” she said.
“Feed test in the fall and keep these tips on storage times in mind, so adjustments to the feeding program can be made if necessary.”