Supplemental Energy for Beef Cattle
With colder temperatures, cattle and other livestock can experience cold stress. This cold stress causes them to burn energy stores(fat) to maintain normal body temperature.
Normally, the stress begins at the Lower Critical Temperature,( or LCT), which for our area , is generally 30ºF. When the average daily temps fall below 30ºF, cows must either consume extra energy to keep warm, or burn energy reserves to do so. This energy shortage is increased when cattle become wet. The LCT then becomes higher, generally between 45ºF-50ºF, making energy even more critical on cold rainy days.
Cows generally require an extra 1% Total Digestible Nutrients(or TDN), for every 1ºF below the lower critical temperature in addition to the maintenance diet. When wet, cows require 20%-40% increase in total energy, than when they are dry.
Best management practices should have cows in late gestation on a daily ration of 54.6%TDN, and around 8.6% crude protein. Lactating cows need a diet of 59.2%TDN, and around 10.5% protein, with gestating heifers, treated likewise. Lactating first calf heifers have the highest energy requirements of all classes, and should be receiving 62%-64%TDN and around 12-14% protein. Any energy supplementation should be in addition to these daily recommendations. Corn Gluten Feed or CGF has increased in popularity and is a good energy source for winter supplementation. It is best combined with other alternative feeds for cattle, such as a tri- blend of CGF, soy hull pellets and wheat mids to counter some of the problems from the CGF. This mix would have around 75 to 83 % TDN where corn grain would be 88% TDN, so it would substitute for corn at almost the same rate.
Winter Feeding Rules of Thumb
- 1lb of corn for each 5ºF below LCT for gestating cows
- 5 lbs of corn for each 5ºF below LCT for lactating cows and gestational heifers
- 7 lbs of corn for each 5ºF below LCT for lactating 1st calf heifers
Remember to test forages in order to accurately supplement hay ration based on nutrient content of your hay.