The rumen and use of feed additives |

The rumen and use of feed additives

Professor Emeritus, University of Nebraska
Ivan G. Rush |

As I write this article the thermometer reads 19 below and it tempts me to write about cold stress in cows but we all know it just takes more feed, either grazed or fed to keep cow condition, so will wish you the best in getting through this cold spell. I am glad they are meeting in Copenhagen now discussing global warming as my water sources could sure use some help now.

I recently attended the Range Beef Cow Symposium in Casper, WY and I am excited and enjoyed hearing of many new technologies, especially about the opportunities to identify cattle that excel in feed efficiency. This has tremendous potential to have a positive impact on the cattle industry as we know feed costs are by far the largest expense we have and we know we have tremendous differences within cattle in each herd. Even though individual gene testing is not practical for the commercial producer at this time we know its accuracy and application will improve in the future. It is also exciting to learn that some leading seedstock producers have already put considerable emphasis on finding the more efficient cattle and are making them available to their customers. It is exciting to think that in the future the accuracy of EPDs can be increased considerably in yearling bulls plus down the road perhaps some accurate predictions can be made on some important economical traits very early in the calf’s life.

A highlight of all the Range Beef Cow Symposium has always been to hear from producers in the intermountain high plains area and this year was no exception. It is always interesting to hear of how different successful producers think and manage their operation and further emphasizes how we can use different resources, genetics and management and still be very successful in achieving ones goals. The symposium is always great to attend as you have the chance to interact with a group of forward thinking and optimistic producers. It is also good to see many of the innovative products and concepts that exhibitors bring to the meeting.

I had the pleasure of speaking at the symposium this year with a title of “Rumen Physiology for the Rancher.” The purpose of this topic was to assist in a better understanding how the rumen functions and hopefully allowing us to make better nutrition decisions. For example supplementing cows consuming low quality winter range that is low in protein will respond very well to relative high protein supplements but high energy, low protein feeds such as corn or barley will have little if any benefit to the cow and may be slightly detrimental. Understanding how protein stimulates microbial levels and activity in the rumen explains why this occurs. It should be of little surprise that ionophores such as Rumensin and Bovatec, will improve cattle performance if fed with moderate or greater energy rations as it can be explained how these products alters fermentation in the rumen.

Understanding rumen function also helps one screen some of the feed additives offered, especially those that have limited research under your situation. Many feed additives such as ionophores, antibiotics, and direct fed microbials such as yeast, bacterial products or enzymes has limited research with beef cows in the short grass native prairie regions. The interest in the natural occurring direct fed microbials has increased recently, especially in feedlots, as more companies have invested considerable dollars in research and sales. This is due to the increase in interest in producing “all natural” cattle where the benefits found with antibiotics and growth implants cannot be utilized. The good news is that many of the leading companies have continued to improve the strain or blends of microbials and often some benefit can be observed. It is more difficult to always find an economical advantage especially in a normal full functioning rumen. When you consider that one ounce of rumen fluid contains over a trillion (about as big as the national debt) microorganisms it may explain that the amount fed may be overwhelmed by the organisms already present. It appears an economical response may be greater if the rumen is or has been under some stress such as weaned calves or a heavy lactating dairy cow. Some of the enzyme products do appear to aid in forage digestion, however as with any products, the costs and benefits must be weighed. As I stated earlier this is an area that is currently receiving considerable attention and research support. I am confident that some of these products will be more economical in the future especially where other technologies are not utilized.

In general, every effort needs to be made to feed the cattle so the microbes in the rumen can be maintained at a very high and balanced population. The choice of feeding feed additives should be based on controlled research conducted under conditions that you have at your operation.

Hope the water stays open and the cows get some relief from the cold soon.