Recently, Steve Boyles, OSU Extension beef specialist wrote an extensive article on winter-feeding of beef cows for the OSU Extension Beef Cattle Letter. Due to space limitations, I am excerpting some highlights from that article, available in its entirety at http://u.osu.edu/beef/2019/01/30/winter-feeding-beef-cows/#more-6357.
“The period from approximately 60 to 90 days prior to calving affects the calf subsequent reproductive performance. Fetal growth is at its maximum. Nutrition during this period affects the quality of colostrum. Underfeeding during this time period results in:
- Lighter calf birth weights (although calving difficulty won’t be reduced).
- Lower calf survival.
- Lower milk production and calf growth.
- A longer period for cattle coming back into heat.
Cold Temperatures: The only adjustment in cow rations necessitated by weather is to increase maintenance energy. Protein, mineral and vitamin requirements are not changed by weather stress. The general rule of thumb is to increase winter ration energy 1 percent for each degree (F) below the lower critical temperature. While cold weather generally increases intake, windy or wet weather will reduce grazing time and intake. The cows would rather find shelter out of wind than eat.
Forage Quality and Intake: As forage quality decreases, forage intake also decreases. Beef cattle selectively graze, eating the better-quality forage first. Providing protein supplementation to lower quality diets can increase the number of ruminal microorganisms to digest forage. Protein supplementation of poor quality forages will increase forage intake. Increased forage intake meets the cow additional energy intake. Thus, to maximize profitability, it is essential to optimize protein.
Protein Requirements in last 1/3 of pregnancy: Gestation has little effect on the cow’s protein requirement until about the seventh month of pregnancy. About two-thirds of the fetal growth occurs during this last one-third of pregnancy. Increase the protein intake of the cow during the last one-third of pregnancy to ensure the cow will be in good condition at the time of calving. The cow is programmed to take care of the fetus at the expense of her own body, and losses of body condition can occur in late pregnancy when protein or energy are not increased to match the needs of the pregnant cow. Adequate protein during this period also is essential for the cow to produce abundant, high-quality colostrum. Colostrum quantity and quality influences the newborn’s immune system.
Energy Supplementation with Grain: When the protein content of the forage is high (> 10% crude protein), grains or low protein supplements (< 20% CP) can be used.
Digestible Fibers as Energy Sources: Studies with readily degradable fiber sources as energy supplements for grazing and forage-fed ruminants have yielded different responses than research with grains. Soybean hulls result in only a small decrease in forage intake. Other sources of readily degraded fiber such as wheat midds, beet pulp, and corn gluten feed have generally not decreased forage intake as much as grain-based supplements.”
Rory Lewandowski is an OSU Extension Agriculture & Natural Resources Educator and may be reached at 330-264-8722.
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