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Brood Cow Rules of Thumb For Mid- And Late-Gestation

We are approaching the time of year when cow-calf producers are breathing a sigh of relief. They are weaning their
calves, getting ready for harvest, and can let the cows make their own living for a few months.

While this is true to some degree, NOW is the time to put a little condition on the cows if they need it before we get
to the cold days of winter. One body condition score added while the weather is still warm can be worth its weight in
gold when the snow starts flying.

Rather than get into a bunch of specific rations and feeding scenarios, I will put forward some general energy
requirements based on cow weight and stage of gestation.

In general, 1 mcal of NE maintenance per 100-lb body weight will maintain a brood cow in mid-gestation. Decent
quality hay has 0.5 mcal of NEm and grain products have 1.0 mcal of NEm per pound of dry matter. So you can see
that 2% of a cow’s body weight fed as decent hay or 1% of her weight as a grain product will maintain her. Obviously,
we are not going to feed strictly a grain source, but a combination of that will do. If you have access to co-products,
that works very well, since they help stick the ration together and are not contributing a bunch of starch to the diet.

We also need to qualify what “decent” forage is. Good-quality grass hay or alfalfa/grass mix is a good source. Corn
stalks can be used to fill the cows up, but they probably have about half the energy of good hay. This can depend
on how many small ears and grain kernels get caught up in the baling process. A good “barnyard” mix of 1 part
co-product; 1 part good hay; and 1 part stalks has worked for many producers in the past. At that point, you need to
determine the cow’s weight and estimate how many as-fed pounds of product to feed. The mix outlined above will
probably be around 65-70% dry matter. So if you have a 1400-lb cow, she needs approximately 28 lb DM or about 43
lb as fed. This is for normal winter weather with dry hair coats and a light amount of wind.

Once you get into late-gestation, the energy requirement goes up about 20-25%. Since she is also filling up with
calf, you may not be able to simply feed more ration, but may have to step up the hay quality or increase the energy
density of the diet.

My general guideline is to use 60 NEm for mid-gestation, 65 NEm for late-gestation and 70 NEm for lactation. These
are guidelines and must be adjusted for BCS and weather.

Always use Framework ADE Mineral at 4 oz/head or if using co-products, the Beef Cow Co-Product Mineral works
very well. Protein always helps ruminants digest poor quality forage better so providing a 20-32% EnergiLass tub is
good insurance for low intake older cows or second-calf heifers.

The suggestions given here are just that, suggestions. But, it at least gives you a place to start. Remember, when
using corn silage, it is half forage and half grain on a dry-matter basis. So normal corn silage fed at 30 lb/head is
providing about 5 lb hay and 5 lb corn. Keep this in mind when a producer thinks he is overfeeding cows with 30-40
lb of silage. While that looks like a lot of feed, when you do the math, it really is not.

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