feed Quality and Health by Mike Mehren Ph.D.

A factor I consider important is the quality of feed the cattle were on prior to being shipped. Cattle that are not gaining and possibly losing weight have a much higher incidence of sickness and death. If you leave cattle out on range that has matured there are consequences. When the protein in the feed has gone below 6%, there is no chance that calves or yearlings can gain weight. This happens at different times of the year due to lack of moisture, species of plants, elevation, and weather. This is true for both the calf suckling the cow or the yearling. Let’s say that you normally wean the calves in October, but this year we are experiencing one of our frequent droughts, and the feed dries up in August. That means that the cattle have been on poor quality forage for two months before any action is taken to move them to better feed. The cows continue to milk and lose weight because they have to draw on body reserves to produce milk. The calves are depending on forage for most of their nutrition because the cow is not producing enough milk to sustain them. Yearlings held to a shipping date also stop gaining when forage quality is low. Whether calf or yearling, weight gain during the dry feed period will be minimal at best. Weight loss is also possible. Recent research has found that the amount of marbling is determined during a narrow window in the animal’s life. It appears to be determined between 4 and 8 months of age. If this is true, feed quality during this time must have a bearing on future marbling.

Poor quality feed at 4 to 8 months is a potential weak link in the chain of life from birth to death. Those that retain ownership suffer the consequences. Animals that are sold lose their identity through the system and the person that owned the animal at birth never hears much about how good or bad things might have gone. However, if ownership is retained, you get the good or bad news when the check arrives from the packer. Feedlots and packers recognize cattle from sources that provide exceptionally good cattle or those that don’t work. As we move toward individual I.D., the poorer animals will be rejected long before they reach a finishing feedlot. They will be heavily discounted at best. The discounting may be due to poor carcass, poor performance, or poor health.

We often use 12% protein as a guideline for forage quality. In other words, forage that has less than 12% protein may be satisfactory for maintaining a cow, however it will not support gain for a young animal. The table following illustrates what happens to plants when they mature.

PLANT I.D	% PROTEIN	% TDN
	….100% dry matter…
Cheatgrass , immature	16	68
Cheatgrass, mature	4	47
Fescue, immature	15	64
Fescue, mature	7	51
Meadow grass immature	14	62
Meadow grass mature	6	50
Crested Wheatgrass, immature	12	62
Crested Wheatgrass, mature	6	51

No matter what plants make up your range, the same scenario occurs. As the plants mature, their ‘grazable’ nutrients decrease and animal performance will decrease.

Spring and summer are the times of year that the least amount of supplement is needed or provided. In most cases, the cattle are provided with some kind of salt. Block is probably the most convenient, so they are offered plain white salt blocks, trace mineral salt blocks, sulfur salt blocks, or selenium salt blocks. Sometimes cattle aren’t provided a supplement because the ‘elk eat it’, or we share public range and don’t want to supply salt to the other permittees who feed nothing. The time out on range is when cattle gain rapidly and cost of gain is the least for any period during their life. Most normally their health is excellent during this period. We have remedies for flies and worms if they are a problem. Both of these parasites can be treated without handling the cattle. An additive can be added to a mineral or other supplement. Some ranchers use technology during this period to improve rate of gain and efficiency of gain. Examples are Bovatec, Gain-Pro, or Rumensin. Another means of improvement is by implanting. Both types of product return many times more than they cost.

Another means of improving performance is to have a mineral designed to compliment your range. Most ranchers don’t hesitate to do this in the fall and winter, but few take this step during spring and summer. Yet, this offers every bit as much benefit as the other sources of improvement. In fact, animals deficient in minerals such as copper, zinc, and selenium don’t perform as well, even when using a feed additive or implant, as those animals on a well-balanced diet. They are more likely to be affected by stress and disease.

Now off my soapbox and back to the issue at hand. Feeding a mineral during the spring and summer is just as important as any other time of year. If decent quality graze runs out, consider weaning early. This can give the calves an opportunity to gain weight in the late summer and fall. It also allows the cows a chance to gain weight and go into winter in good condition. I believe that nutritional deficiencies in the late summer and early fall are at least partially responsible for some of the health issues that calves have after weaning and in the feedlot. . This is one of the reasons for ‘preconditioning’ calves. We not only vaccinate them, we train them to eat feed from a bunk, and drink water from a trough. Rations fed at that time are designed to replenish the calf’s store of nutrients. They are heavily fortified with vitamins A, D, and E. Many have chelated minerals and organic selenium added. Research has found that animals respond to vaccines much better when on a good plane of nutrition than when deficient in nutrients. This period of preconditioning is designed to get the calf past the stress of weaning and ready for life on its own.

Since yearlings aren’t preconditioned, they must survive the stress of gathering, shipping, change of surroundings, pen-mates, and diet on whatever they have in their body. The trace minerals are not stored in the body for future use. If they aren’t present, then whatever function they perform in the body won’t work properly. What if that function is immune response? When yearlings are moved into the feedlot they don’t receive the special calf receiving ration that helps calves adapt. They are moved onto the finish ration as fast as possible.

Whether you run yearlings or are a cow-calf producer, paying attention to your late season forage and managing to promote gain during that time will pay huge dividends in the performance and health of your cattle.

Michael J. Mehren, Ph.D. is a livestock nutritionist from Hermiston, Oregon that is patiently waiting for his ‘bail out’ check. In the meantime, he can be contacted by Email at mehrens@eotnet.net.

FEED QUALITY AND HEALTH