by: Heather Smith Thomas

Body condition of cows determines whether they give birth to strong, healthy calves, and rebreed on schedule. Keeping track of body condition can help a rancher determine the nutritional needs of cows through winter and spring until they are safely rebred.

Body condition score is rated 1 to 9, with 1 denoting emaciation and 9 obese. Most stockmen try to keep cows at body score 5 to 6, for best health and fertility. Some cows (and some breeds) need more flesh than others to cycle and breed successfully. Some crossbred cows, because of their hybrid vigor and increased fertility, will breed successfully at body score 4.

Cows that give a lot of milk may be thinner at weaning time than cows who give less milk. A heavy milking cow may go into winter carrying less flesh than the poorer milking cow and needs a higher level of winter nutrition to get ready for her next calving. In dry years it may be hard for cows to milk very well and raise a good calf without losing weight.

According to Shannon Williams, Lemhi County Extension Agent (Salmon, Idaho), the thing that producers really need to remember is that during the 60 days following calving, they are asking the cow to produce milk, repair her uterus and breed back again. “This requires an extreme amount of energy and nutrients,” she says.

If a cow is in poor body condition when she calves, she doesn't have a very good chance to prepare for rebreeding while she's producing milk for her new calf. She may continue to lose weight, even if you increase her nutrient levels, and fail to cycle on time. This is a crucial phase in her production cycle, and if she is a young cow (still growing), her needs for energy and protein will be even greater than that of an older cow.

“Because of these factors, producers should feed 2 and 3 year olds different from the way they feed the main herd. You also need to pay attention to body condition score, especially in these young cows,” says Williams. The young cows should be separated from the herd and fed differently, preferably before they've lost too much weight.

“If an older cow is losing weight, she should also be pulled out of the herd and fed differently. Some producers put their old, thin cows with the young cows—whatever works for their own operation,” she says. Protein requirements for pregnant cows increases during later stages of gestation, and is even higher for young cows. If you are keeping the young cows (coming first and second calvers) separate, they can be supplemented with protein, if necessary, without having to supplement the whole herd.

It's always a good practice to sort out the young ones, such as yearlings, first and second calvers, to feed separately from the older cows. If cows are on hay or being given a supplement, this will ensure the young ones get their share. When the whole herd is together the young cows do not get enough, since they eat more slowly and are more timid. The older cows may dominate them and keep them away from the feed. It is not cost efficient to feed the whole herd to meet the needs of young and thin ones; most cows don't need the extra feed or supplement.

Keep first and second calvers separate after calving also; this is when they need pampering the most, in order to milk, keep growing and breed back. They need better hay or extra protein that mature cows can get by without. The same goes for older thin cows. You don't want to perpetuate genetics of cows that need a lot of expensive feed, but it does pay to pamper thinner older cows you will be selling. Then they can hold their flesh and do justice to their last calf--and be sold more advantageously the coming fall.

Closely monitor condition of all cows; then if some start to lose weight there's time to correct it by feeding hay to augment dwindling, dried up or snowed under pastures, or to increase the hay if weather turns cold. A cow needs more roughage in cold weather. Digestion of cellulose creates heat. If she doesn't have enough roughage, her weight will melt off as she robs body fat to create energy to keep warm.

Nutrition during the first 90 days after calving determines whether the cow will start cycling and rebreed. It's hard to get cows to gain weight after they calve; energy requirements increase 17 to 50 percent depending on how much milk they produce. Inadequate feed may lower the weaning weights of calves 20 to 50 pounds and reduce conception rates of cows as much as 25 percent. A really thin cow (body score 3 or less) nursing a calf may not start cycling at all. A study in South Dakota showed cows with higher body condition scores return to heat earlier in the season and are more likely to settle.      

The two most critical periods are 30-50 days before calving when the fetus is growing fastest, and 60-100 days after calving--until the cow is rebred. Make sure cows go through winter in adequate flesh without losing weight before calving.

Even if the cows came through pregnancy in good body condition, you don't want them to lose ground after calving. “They can always rob a little from their backfat if they were in good flesh at calving, but you may pay for this later if you don't catch the weight loss soon enough,” says Williams. Don't just turn them out to grass and stop feeding them if the grass isn't quite ready yet. They may lose too much weight and not breed back quickly.

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