December 4, 2003

 

Feed Thin Cows Now to Avoid Problems Later, Specialist Advises

With drought-stressed pastures and hayfields, keeping cows fed has been a challenge for ranchers across the region. But if cows are thin now, they’re likely to face severe challenges as calving approaches, says a North Dakota State University livestock specialist.

"There are a lot of cows out grazing crop stubble late in the season as producers try to conserve forage," notes Karl Hoppe of the NDSU Carrington Research Extension Center. "But in most cases, that low-quality stubble is not going to provide the energy those cows need."

That means cows will be drawing on body fat and losing body condition as the worst months of winter loom. "Even though those cows look full, there’s not enough nutrient value in what they’re eating to maintain them," Hoppe says.

He says cows are in danger once they reach a body condition score of four or lower. At that score, the backbone becomes prominent, two or more ribs can be counted on each side and there is little fat evident in the brisket.

Those cows are more prone to stress. They have no body fat to insulate them from the cold. They’re more likely to experience difficulty calving and have breeding trouble after calving. Calves born to thin cows will suffer more health problems and have reduced weaning weights and poor performance.

Hoppe advises producers to take action now to prevent those consequences.

As a general rule, to make a one-number improvement in body condition score requires a body weight gain of about 90 pounds. "The closer we get to calving, the more difficult it becomes to improve condition," Hoppe notes. "As the calf grows, the cow simply doesn’t have room for more feed. She can’t consume as much." Also, later in pregnancy, an improvement in nutrition may be directed by the cow’s body toward the calf. The result is an increase in calving difficulty because the calf grows larger.

Cows in the second and last trimesters of pregnancy need crude protein at a rate of about 8 to 10 percent of their diet to maintain body condition. Crop stubble may only contain 4 to 6 percent crude protein. "Once the protein needs of those cows are met, producers may want to look at adding carbohydrates in the diet. That’s an approach that will maintain or improve cow condition without reducing calving ease," Hoppe says.

For cows in the second trimester of pregnancy, it’s easier to improve condition. For cows to gain a pound a day, the diet should be about a third grain and two-thirds good quality hay. For more rapid gain of two pounds per day, the ration should be half grain and half good quality hay. "That’s a diet similar to what you might use to background calves," Hoppe says.

Most cattle producers wouldn’t feed that much grain to a pregnant cow. However, it takes a lot of grain to make dramatic changes in body condition in a short perod of time. Instead, Hoppe encourages feeding grain at 1/2 of 1 percent of body weight plus free-choice good quality hay to improve body condition. "Don’t confuse gut fill with improved body condition. Full cows may look better, but they can still be thin," Hoppe warns.

Hoppe says crop processing co-products like wheat midds, barley malt sprout pellets, corn gluten feed and distillers dried grains are excellent sources of protein that can be used to maintain and improve cow condition. Crops such as barley, corn and field peas can also be used in the ration.

Management also plays a role. "It’s unlikely to see an entire herd of thin cows. Typically it’s individuals within the herd – the yearlings and younger cows." Hoppe says. "To give those individuals what they need and make the best use of feed resources, producers may need to sort them out into separate pens and feed them specifically to improve condition. Once they’re separate from the rest of the herd, they’ll have less stress from crowding and competition with older more dominant cows."

Hoppe says cows with a body condition score of six to seven are more likely to weather stresses from cold temperatures, disease, feeding interruptions and other factors. "Obese cows are a waste of money, but cows at a body condition score of four to five have no cushion for those kinds of problems. The less condition your cows have on them, the more you have to pay attention to the details of managing them."

###

Source: Karl Hoppe, (701) 652-2951, khoppe@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu