Taking Another Look at Winter Grazing

Source: Saskatchewan Agriculture and Food
Long thought to be a practice that entailed more disadvantages than benefits, more producers today are wintering their beef cows extensively on fields and pastures with swath grazing, crop residue grazing, and bale feeding. 

Lorne Klein, a Forage Development Specialist at Saskatchewan Agriculture and Food, sought to acquire a clearer picture of what the advantages truly were. He approached the Western Beef Development Centre (WBDC) in Lanigan to find out more.

“In past decades, it was common practice to feed and bed beef cows intensively in confined areas during winter, usually close to where the feed and straw supply was assembled,” explains Klein. “During the following summer, the manure pack was hauled out and spread onto the land. 

Our search for other solutions raised a few questions about the environmental impact of extensive wintering because, when it occurs, the manure and urine is being spread during winter, which contradicts current recommendations encouraging producers not to spread manure during winter months.
The WBDC began a trial in the fall of 2003 to compare the environmental and economic implications of intensive and extensive wintering systems. The study site was an old pasture of Russian wildrye. Four treatments were applied. 

In the intensive system, cows were fed in a corral and the manure pack was spread onto the pasture.
Two of the treatments involved spreading composted manure from a previous year, and spreading raw manure from the current year. 

In the extensive system, cows were fed on pasture. 

The other two treatments involved bale grazing and bale processing in rows. All of the four treatments were applied at a rate of 832 cow days per acre, which is the normal manure application rate.
The trial found significant environmental and economic advantages to feeding extensively on pasture during winter. 

“Researchers found that bale grazing and bale processing captured a higher level of nitrogen in the soil, when compared to manure spreading. On average, these two practices captured about 100 pounds per acre more nitrogen than the manure spreading treatments,” Klein says. 

Using a nitrogen price of 50 cents per pound, and an estimated volatilization loss of 20 per cent during broadcast application, this is equal to introducing approximately $2.25 worth of nitrogen into the soil for each month that a cow is fed on the land. 

“The increased nitrogen in the soil resulted in greater forage yield and quality,” Klein points out. “After the first growing season, the bale grazing and bale feeding treatments produced on average about 1,500 pounds per acre more forage than the manure spreading treatments. And it appears this effect will last for another three to four years afterwards,” Klein says. 

“Using assumptions and average numbers, this translates into the following basic formula: for each month a cow is fed extensively on pasture, you will get four to five days of extra grazing over the next four years. This is extra production over and above the yield advantage that manure spreading will produce.”
When asked why this is occurring, Klein has this answer.

“At this point, it is believed the nitrogen from the urine is lost in a confined situation. About half of the nitrogen excreted from a cow is in the urine; the other half is in the manure.”

One added benefit of extensive wintering is reduced or eliminated manure hauling. Most producers are equipped to haul feed, but have to pay for hauling manure,” adds Klein. 

So is it advantageous to winter extensively? The answer is yes, no, and maybe, according to Klein.
“Each producer has a unique set of circumstances and will have different costs associated with different systems. The figures above are a starting point for discussion and calculations. Hats off to WBDC for doing the research and getting us the numbers!”
For more information, contact:
Lorne Klein
Forage Development Specialist
Saskatchewan Agriculture and Food
(306) 848-2382

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