Grazing CRP by Mike Mehren Ph.D.

Grazing CRP
BY MIKE MEHREN

Apparently the government will allow CRP grazing beginning in July and ending in November due to the extreme shortage of feed. This practice was allowed several years ago, and we wound up with quite a few wrecks. In many parts of the Northwest, CRP ground has dried up and the plants have gone to seed during the period allowed for grazing. There is very little green feed available to the animals. I have seen cows literally starving to death in a field where feed was up to their brisket!

Here are some feed samples that I took during the last CRP grazing period. These samples came from fields around Northeastern Oregon and Southeastern Washington. Some of the samples came from fields about 800 ft elevation, while others were 2000 ft elevation. Please understand that field sampling is pretty inaccurate. Man cannot choose the same plants or parts of plants that cows will. Cows will select a variety of plants that will have more nutrients than the average that I collected. However, even if the cows were able to eat plants that had twice as much protein as my sample, there was only one that would meet the needs of a dry cow. Don’t even think of running cows and calves on CRP ground. They will lose weight in a hurry. The most we can hope for is to maintain a dry cow if a protein supplement is fed. Mature bulls would be another good candidate for CRP.

Sample ID	Crude Protein %	TDN %	Calcium %	Phosphrus%
	...all values are 100% dry matter basis
1.	3.4	38	.15	.05
2.	2.1	37	.11	.06
3.	5.5	40	.20	.03
4.	3.9	37	.14	.08

Many years ago Randy Mills and co-workers, OSU Extension, did a study on forage production on CRP ground. Their results are summarized here:

ELEVATION
	750-1000 FT	1000-2600 FT	2500-2800 FT
	.....LBS OF FORAGE DRY MATTER/ACRE...
AVERAGE	1227	1255	1510
HIGH	1599	1661	1884
LOW	767	948	1320

These two tables give us an idea how much forage there would be and that the nutrients were BELOW the needs of the animals. All animals grazing fields similar to those shown would lose weight without additional protein, TDN, and phosphorus.

There is no way to predict what the feed will have for nutrients ahead of time. Taking a sample in June and having it tested will not tell us what the feed will be like in July. If we continue to get summer rains in June and July we may have reasonable feed quality.

If you believe that the feed would maintain a dry cow, then that means that the calves will have to be weaned early in most cases. There are many options available for the early-weaned calf. They don’t all involve putting them on high quality grass. They can be brought into a dry lot and fed hay alone to gain about 1 lb/day. They might also be fed hay and grain (or a grain substitute) and gain anywhere from 2 to 3 lb/day. These calves can go onto the finishing lot and do very well. Research has shown that these calves will go onto feed very well, have minimal health problems, perform and convert feed very efficiently and a high percent are able to grade choice.

If you try to graze yearling cattle, and can live with gains of 0.5 lb/day or less then the CRP might work. The cattle would still need to be fed a protein supplement. If not they will LOSE weight. It might be possible to feed 3 to 5 lb/hd/day of a supplement with digestible fiber and extra protein. Wheat millrun and middlings are products that we have available that provide energy from digestible fiber and enough protein to compliment the low protein grasses. Products such as soy hulls or beet pulp provide the digestible fiber, but would need to be mixed with a source of protein such as cull peas, canola meal, cull beans, the wheat by-products mentioned above or other vegetable protein. Feeding these types of products in this situation would require some means of self-limiting or daily feeding. These products should not be fed once or twice a week. Even with all that expense and effort, gains will probably be around 1 lb daily.

If you decide to feed a protein supplement, make certain that you feed enough. Studies by Hart and co-workers from Colorado State found that cattle lost weight when they were fed 0.21 lb of actual protein daily, but managed to hold their own or gain a little weight when fed 0.5 lb of protein while grazing. Let’s convert this to pounds of a protein supplement needed to provide 0.5 lb of protein.

	PRODUCT POUNDS NEEDED TO PROVIDE 0.5 LB PROTEIN PER DAY.
12% Protein	4.2
20% Protein	2.5
24% Protein	2.1
30% Protein	1.7
36% Protein	1.4

This list covers the range for most sources of protein. Commercially manufactured supplements having the protein shown on the left usually have a feed intake range of 1 to
2 lb/head/day. So any protein supplement with less than 24% protein will require excessive intake to provide enough protein to meet the needs of the animals. Alfalfa, at 18% protein, would require 2.8 lb daily. When choosing a supplement, look very carefully at two things.

You can make these calculations for any source of protein. If you used alfalfa or some other forage to provide the protein, then add about $.08/head/day to cover the cost of a vitamin-mineral supplement. All commercially prepared protein supplements have added amounts of vitamins, phosphorus, and trace minerals. That calculation for alfalfa, other source of protein such as peas, or canola meal would be:
18% Alfalfa Hay cost $240/ton. You need to feed 2.8 lb/day. That costs $.34/cow/day. ($240÷2000=$.12/lb. 2.8 lbx$.12/lb = $.34 + $.08 for vitamin mineral = $.42.

This is the first time in my memory when alfalfa hay wasn’t the most economical source of protein available.

These calculations also show the huge difference in cost between a protein supplement and a vitamin-mineral supplement. Make certain which one you need. There are huge dollars involved. Grazing CRP successfully will require extra management. Don’t just turn cattle in and think they’ll do fine, because they won’t.

Michael J. Mehren, Ph.D. is a livestock nutritionist seeking shade during the heat of the day. He can be contacted by Email at mehrens@eotnet.net.