Aiming for the midrange: Body condition scoring for beef cows

Though beef cattle producers constantly assess the condition of their cows and heifers, agriculture nutrition specialists say applying a more scientific approach, called body condition scoring, can help producers assess their nutritional program and make better informed business decisions about production.

Research has proven that body condition, or how much body fat a beef cow or heifer has, directly affects the health of its calf through amount and quality of colostrum production and determines how soon the cow cycles for re-breeding after calving, along with affecting the general health of the cow.

"It's a simple method to evaluate the nutritional status of cows," said Jennifer Thorson, beef cattle nutritional reproduction researcher at Northern Agricultural Research Center south of Havre. And the scoring can be done without equipment or moving the cows, she added.

More specifically, body condition scoring, or BCS, is a system for analyzing and describing the relative fatness of cows with a nine-point scale, helping producers to understand and affect breeding outcomes, calving success, losses and weaning weight, said University of Nebraska-Lincoln's Rick Rasby, associate dean of extension agriculture programming.

One point on the BCS scale is equivalent to about 75 pounds, he said.

What BCS Is

BCS focuses on body condition in six different areas - brisket, spine, hips or "hooks," pins, tail head and ribs. These points give consistent measurement of body fat across age and breed differences in cows, Thorson said.

The thinner that cows are the more evident the ribs, hips, pins and back bones are, Rasby said. Thin cows score BCS 1 to 3. The fatter that cows are the more difficult it is to see or feel these bony areas. BCS 4 to 6 is a good range, but 7 to 9 is too heavy.

With little muscling in the six assessment points, especially the bony areas, the majority of fullness will be attributable to fat.

"You aren't evaluating muscle - and hair can get in the way. You want to make sure you're evaluating condition," he said. "Sometimes what that means is that you might have to kind of train your eyes with hand feel, so you might have to practice when you run cows through a chute."

BCS 5 is a good average to shoot for, he said. That means a herd will likely have some 4s and some 6s, but those are within the healthy range. At the extremes, cows scored at a 1 have no evident fat or muscle and are likely near death, and at a 9 their bone structure cannot be seen or easily felt. The heavy cows will likely have trouble moving around and calving, their longevity is compromised through weight-related lameness issues and the excess fat represents money and resources wasted on feed.

At a 5, "the 12th and 13th ribs are slightly visible to the eye. The transverse spinous processes can only be felt with firm pressure and feel rounded but are not noticeable to the eye. Spaces between the processes are not visible and are only distinguishable with firm pressure. Areas on each side of the tail head and the fore-rib, behind the shoulder are starting to fill," Rasby's BCS description on the UNL website http://www.unl.edu says.

First-calf heifers are the only game-changer for desired BCS, Rasby said.

"The system doesn't change, but your target condition will change. Your target condition for mature cows would be 5 at calving, for spring calving cows. Your target condition for first-time heifers will be condition score 6," he said.

Heifers have more demands on them after calving, he added. It's their first time lactating and first time recovering from calving, and the heifers are still growing themselves, so they need the stored energy.

The score is not just about having healthy cows, it is about production and making sound business decisions.

Importance at Breeding

"The ideal body condition score ranges from about a 4 to a 6 - that way the animal isn't too thin ... (and) not in a really good state, where they can't support themselves let alone a calf," Thorson said, adding that a too-low score "will actually trigger the body to inhibit reproduction."

Another key point about having a healthy BCS is the affect body fat has on the length of time a cow takes to cycle for breeding after calving.

Rasby wrote that to maintain a 365-day calving interval a cow has to rebreed within about 82 days after calving. At a BCS 3 the postpartum interval is likely 89 days. At a 4 that changes to 70 days average, which is just under the deadline. But if the BCS is increased to 5 or 6, the postpartum interval decreases to 52 to 59 days, substantially bettering the odds that a cow will get rebred within the calving interval.

"Although cows that calve in a BCS of 7 have a short postpartum interval" of about 31 days, he wrote, "it is not economical to feed cows to a condition score of 7."

Importance at Calving

Research has shown that cows that are thin at calving "produce less colostrum, give birth to less vigorous calves that are slower to stand and these calves have lower immunoglobulin levels, thus impairing their ability to overcome early calf-hood disease challenges," Rasby wrote.

Studies of antibodies in calves 24 hours after birthing show that calves from BCS 2 cows have only 75 percent of the antibodies of calves born to BCS 6 cows, and calves from BCS 3 cows have more antibodies, but at 83 percent it's still significantly lower, a UNL report says.

By biological design, nutritional energy put into cows and heifers after birthing goes toward milk production, Rasby said, so it's almost impossible, and economically unfeasible, to put weight on cows and heifers after they calve. That means producers are unlikely to improve their postpartum interval with spring feeding.

And for first-calf heifers, which are at about 85 percent of their mature size when that first calf drops, being underweight at calving can be detrimental to their long-term growth and health.

When to Score

Rasby wrote that he recommends scoring six times a year - late summer/early fall, weaning time, 45 days after weaning, 90 days before calving, calving time and beginning of breeding season.

At late summer/early fall and weaning time producers might want to consider weaning calves early if cows and heifers are thin and if pasture is compromised, especially from drought. This is particularly important for first-calf heifers, he said.

A body condition assessment 45 days after weaning will give producers an idea of how quickly the cows are recovering after weaning and the number of thin cows will indicate if cow type matches the producer's available resources, he said.

An assessment at calving time will show if the producers pre-calving feed program needs changes, though it's too late to improve the cows' condition economically, he said. And if the number of thin cows increases by the beginning of breeding season, he added, then producer's might want to consider changing their calving to later in the season.

A careful assessment at the point 90 days before calving is the most crucial for success in the coming year, Rasby said, largely because changing a herd's condition takes time, and this during the period of high energy demand from fetus development.

That 90 days before calving, when the unborn calf does the most growing, demand the most energy in utero, and it's the last opportunity to get thin cows and heifers up to weight, Thorson said.

"It would pretty unrealistic to think that once a cow has calved that you are going to be able to increase her weight and do it in a profitable way, so you'd be having to put a lot of input into her that you probably wouldn't get back," she said.

"During those last three months of pregnancy is when you have an exponential growth in fetal size, so the more they're growing the more nutrients they're requiring," she said. "So if you get on those cows and get them increasing before the calf starts increasing exponentially then you get ahead of the curve."

This can be especially important with Montana winter and spring weather, she added.

Learning the Scale

"This is an excellent tool, but if you call a cow a 5 and she's really a 3, that's a problem," Rasby said. "... But it's easy to overcome."

UNL has developed a training app for smart phones, but the university's website also has training modules, with photos of cows at each BCS score as well as descriptions, he said. And an internet search will provide more information, photos, videos and tutorials, he added.

Ranch owners or managers can get all their employees on the same page with some practical experience, Rasby added, by having everyone score a herd or selection of cows independently then together for a discussion.

It can help to separate cows into thin, moderate and fat groups before trying to assess a numerical score, he said.

Decisions About Production

Body condition scores should be recorded, Raasby said. Over time, the information could reveal needed management changes, he said, and that may mean a change in calving time, a change in feed sources or a more significant change in the herd.

"If you have cows that are continually thin at weaning time and they don't bounce back after you get done weaning the calves, then you got to really take a hard look at your breeding program," he said. "... If they're always thin at weaning time and you have to feed (them up) to get condition back on them before they calve the next time, what's going on there?

"You may be just a little bit out of whack in regards to cow size and milk production for your resources," he added, "and you always hate to get yourself into corrective mating situations, but that may be what you have to do."

Links

http://ianr.unl.edu/nu-beef-bcs-app

http://beef.unl.edu/modules-apps-webinars

http://beef.unl.edu/learningmodules.shtml

http://beef.unl.edu/learning/condition1a.shtml

http://newsroom.unl.edu/announce/beef/1922/12076

http://beef.unl.edu/learning/condition1b.shtml

http://beef.unl.edu/learning/condition3c.shtml1

http://aces.nmsu.edu/pubs/_circulars/CR-575/welcome.html