In fall and winter, most pastures are lower in protein than other times of year. Producers often like to continue grazing as long as possible. One of the most effective ways of improving the utilization of the forage is to feed additional protein to meet the animal’s requirement.
Adequate protein content is crucial for optimal microbial growth and animal performance. Rumen microbial growth is reduced in diets that are low in protein. With protein supplementation on dormant pasture, the rumen microbial population will have a higher growth rate, improving the energy available to the animal and increasing the intake of low-quality forages. In other words, protein provided through supplements such as liquid feed, cubes, blocks or tubs improves digestion of low-quality forages.
The key number is 9% crude protein. That’s the average protein requirement for cows, even for mid-gestation dry cows whose calves are weaned. The rumen microbes can make a living on a slightly lower protein content, so if we meet the cow’s requirement, we should cover the rumen needs.
If protein level in forage falls below 7%, it limits microbial fermentation in the rumen. The animal can’t grow a large enough population of microbes to get the job done. Digestion slows, forage moves more slowly through the tract and the cow can’t eat as much because fiber digestion is reduced.
To ensure adequate nutrition during fall and winter grazing, you need to know the protein level in the forage. Cattle are selective grazers. If you clip a sample of forage, it may be poorer in protein content than what they are actually eating. You’ll come closer to an accurate estimate by observing what they are eating and hand-plucking a sample of similar plants. Many native cool-season grasses can be good fall and winter pasture without a protein supplement. They have more nutrients in their mature, dormant state than many tame grasses do. Many stockpiled fescue samples are adequate, often with greater than 10% protein content.
Watch cow body condition and ensure they stay in good flesh. Evaluate the viscosity of manure. Beef cattle manure in the spring or on any lush green feed is very loose, almost liquid. This is a sign of excess protein. The material is digested quickly, traveling through the digestive tract too fast with waste of some nutrients. Often performance is good. On the other hand, if the manure is hard and makes a pile that stacks up, this can be a sign of protein deficiency. There’s not enough to digest forage efficiently and keep things moving through at a proper pace. Ideally, manure should be moist and loose but not liquid. It would stack maybe 1.5 inches high. This is how it would generally be when forage is green and protein level is in the low teens, about where it should be.
It is interesting to observe how well cattle do when you first put them into a new, ungrazed dormant pasture. They select a diet higher in protein and energy than in the average forage. The longer they stay in that pasture, the less protein they’re getting, because they are eating the higher-quality material first.
Young animals need more protein because they have a growth requirement, whereas the mature dry cow just needs maintenance. Replacements or stockers can’t hold as much feed as older animals, and they have less ability to ferment large enough amounts of low-quality forages. This can be partially addressed with grazing management. Forward graze the young animals. Let them graze a pasture first and get the best material to meet their higher requirements. Then let the cows clean up after them. The cows may need a protein supplement because the forage that would have allowed them to meet requirements of the rumen microbes has probably already been eaten.
There are many kinds of supplements and nitrogen sources. The question comes down to what is economical and available and how much needs to be fed. The next point is to determine what is going to be used and how it will be fed. The supplement might be 2 pounds per day of hand-fed Ricochet Breeder Cubes, a self-feeder full of Cadence or half a percent of bodyweight of MFA Trendsetter three times a week. How we provide the feed may depend on how far over the fence the truck can deliver or how many sacks we can get on the four-wheeler.
Some feed additives need to be fed very uniformly, such as melengestrol acetate—also known as MGA. Urea is better fed frequently, particularly when fed at higher rates. For ionophores or all-natural protein supplements, the reduction in utility is small if they’re fed every other day rather than every day. Feeding a supplement such as MFA Breeder Cubes can be done three times a week with acceptable results on mid-gestation beef cows in good flesh. Check with your livestock specialist about the right supplements for your operation.
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