Source: Saskatchewan Agriculture and Food
When winter-feeding cattle, not every portion of feed gets consumed.
Instead of referring to the material as "wasted feed", Glenn Barclay, forage development specialist with Saskatchewan Agriculture and Food (SAF) in North Battleford believes we should think of it as a soil enhancer.
"It seems a more appropriate description," he says. "Plus, in addition to the leftover feed, the cow produces manure, which also enhances the soil."
Barclay explains that Dr. Dan Buskirk and his associates at Michigan State University studied feed losses from various designs of cattle feeders. They found losses ranging from 3.5 to 14.6 per cent.
When hay is fed with no access restrictions, animals will trample, over-consume, foul and use hay for bedding. Bell and Martz at the University of Missouri found waste levels could even reach 25 to 45 per cent in unrestricted feeding areas. This material will eventually wind up back in the land, as nutrients.
"Straw and hay," Barclay explains, "are slow to break down, so the impact of the nutrients will start showing up in later years. Nutrient content in hay and straw can vary a great deal."
An SAF study in 1998 found the following average levels of nutrients in wheat straw: nitrogen, 0.4 per cent; phosphate (P2O5), 0.1 per cent; potassium (K2O), 1.4 per cent; and sulphur, 0.1 per cent.
"These levels are quite low and, because they aren't as available in the first year as commercial fertilizer, they do not produce immediate results," says Barclay. "However, the release of nutrients, the increase in the water-holding capacity of the soil, and the build-up of organic matter will occur in the future."
In addition to the hay or straw that is not consumed, cattle also supply manure. Cattle manure is diluted and variable in nutrient content. A 1,200 lb. cow that is seven months pregnant and fed a 50:50 hay/straw ration could produce about 13 lb. of dry matter per day of manure. Just before calving, the same cow, getting fed a hay ration with only three to four pounds of straw, might produce 11.5 lb. of dry matter per day of manure. The same cow, being fed hay and six pounds of grain per day when it is lactating, might produce 11.3 lb. of dry matter per day of manure.
"As the digestibility of the feed increases, the amount of manure dry matter decreases. Normally, better quality feed has higher levels of digestibility," he says. "If you assume manure is about 50 per cent water—although this varies—a reasonable estimate of 20 to 25 lb. of wet manure per average day per 1,200 lb. cow could be assumed in a winter feeding program."
Barclay advises that, when feeding bales, "keep in mind where you want to increase the production and soil organic matter of a hay field or pasture." A knoll, for example, could benefit from being a feeding area. Feeding in a low-lying area, on the other hand, could result in some of the nutrient benefits being lost through leaching and denitrification because of the water that tends to accumulate there. Small areas of pasture can be rejuvenated by making them feeding areas and scattering some forage seed on the soil surface. The cattle's hooves will incorporate the seed with the soil, and the leftover nutrients plus the topdressing of manure will assist germination.
Barclay has one more tip for cattle producers:
"If you are using a four-year reinvigoration plan for a field, you can feed cattle in one corner one year, another corner the next, and so on until the entire field has been covered. Cattle can adapt to snow as their water source, so this can be attempted even on fields far away from a water source."
As a final word of advice, Barclay encourages producers to monitor their fields to ensure excess nutrients aren't being applied.
"When feeding cattle this winter," says Barclay, "keep our land enhancement plan in mind."