NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

November 12, 1998

Proper Supplementation is Key to Winter Grazing

Winter range can be an inexpensive forage resource, but producers need to carefully manage their cows' nutritional needs to ensure successful calving and rebreeding, according to a North Dakota State University beef specialist.

"You don't want to have to improve the condition of thin cows on native winter range, but for cows in good condition grazing winter range is an economical option," says Chip Poland of NDSU's Dickinson Research Extension Center.

That means cows moving on to winter range in late fall and early winter should already be in good condition. "At pregnancy checking time, you may want to sort off any cows that are especially thin for a more intensive feeding program," he says.

Cows that are turned onto range are going to need feed supplements to make up for nutritional deficiencies in plants they'll be grazing. Producers will probably need to provide some supplemental vitamins and minerals to their cows while winter grazing. Vitamin A and phosphorus are particularly low in dormant grasses. Protein, however, is the nutrient most likely to be limiting performance of beef cows grazing native range in the late fall and early winter.

"Proteins vary in their ability to supply nitrogen and amino acids to the cow and these differences need to be taken into account when designing feed supplements," Poland notes. "The supplement formulation you use is going to be different if you provide supplement every day as opposed to once each week or some other schedule."

Proteins can be broken into three broad categories:

• Degradable protein is readily available for use in the rumen. This protein maintains the rumen microbes that break down the fibrous plant material. Because it is degraded fairly rapidly in the rumen, protein supplements that contain high levels of degradable protein should be provided at least three times a week. Good sources of degradable protein include field pea and sunflower, canola, crambe and safflower oil meals.
• Bypass or undegraded protein is not degraded in the rumen but moved further into the digestive tract where it can be used directly by the cow. Commercially available forms of undegraded protein tend to be more expensive than those listed above, but offer some benefit in terms of nitrogen recycling thus providing an option for producers that choose to provide supplement twice a week or even less frequently.
• Non-protein nitrogen is nitrogen that's almost immediately available to rumen microbes. Examples are urea and biuret. These supplements must be consumed daily to avoid excessive nitrogen losses in the rumen.

"What it comes down to is your management system and what is economical to use as a supplement on your ranch," Poland says.

He cautions that nutritional needs for the beef cow become more intense as calving approaches. Cows require their highest levels of nutrition just after calving when they're supporting both themselves and the nursing calf.

"When using winter range it's important to start with cows in good condition and to maintain that condition right through calving," Poland says. "If the cow's needs aren't met and cow condition slips before calving, we're likely to see health problems and difficulty rebreeding next spring."

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Source: Chip Poland (701) 227-2078

Editor: Tom Jirik (701) 231-9629