No one can dispute the fact that the rapid development of technology has touched everyone in the beef industry. I think this was hammered home to me the first time I saw a cowboy sitting on his horse, talking on a cell phone. When he got back to the headquarters, he walked into the office and entered all the calving and doctoring information he had just collected on his laptop computer. I've wondered when saddles would start coming equipped with laptops or GPS's (Global positioning systems)? Over the next few weeks we are going to explore some of the emerging technologies which are at some stage of development in the beef industry, first in feeding and nutrition and then in management (systems and equipment). This will not be an all-inclusive list by any means but we'll work on identifying those which may hold the most long-term promise.
Feeding Technology – a Movement to “Natural Feeding” Systems
An area in cattle feeding that is showing increased interest is that of feeding DFMs – direct fed microbials. Essentially this is a practice of feeding one or more bacterial strains to cattle with the intent of improving performance and/or health. As the industry succumbs to increased pressure to reduce the use of antibiotics and hormonal implants, the use of products such as these will increase.
The following text was taken from a very good paper by McDonald, et al (2005) which discussed many facts and facets of DFM feeding.
Direct-fed microbial (DFM) products containing lactic acid-producing or lactic acid-utilizing bacteria are fed to improve performance of cattle. While largely focused on feedyard animals, growing and developing cattle on the ranch as well as breeding animals can likewise realize the benefit. In general, research data show substantial benefits in rate and efficiency of growth in a wide variety of production situations. Recent analyses of population data have confirmed performance benefits of DFMs in practice, as originally shown in research. Population data can also be used to increase our understanding of DFM effects. While controlled research studies are the ideal means to assess performance response, population data are ideal for looking at ancillary benefits such as improved health. Future analysis of these additional benefits will examine effects on feed intake variation, digestive death loss and response to rescue treatments.
As mentioned, one way we can assess the effectiveness of DFM's is by reviewing and analyzing the population data through the use of the VetLife Company's Benchmark Performance Program. The Benchmark program can be used to compare results of feedyards that used DFM products to results from yards that did not. In this case Benchmark member feedyards were surveyed regarding DFM use. Of the 267 feedyards that responded to the survey, 118 used DFM products, and 149 did not. Analysis was conducted on records from cattle closed in these feedyards between Jan. 1, 2003, and May 31, 2004. Records on 73,870 lots containing 10,900,504 cattle were classified as yes or no based on DFM use and subsequent effects were extracted. This is obviously a substantial data base.
Effects of DFM on feedlot performance.
Cattle in feedyards that used DFM products had 1.9 and 1.4% higher average daily gains (ADG) for steers and heifers, respectively. These feedyards also had 1.9 and 3.9 percent lower (favorable) feed conversion ratios (feed:gain) for steers and heifers, respectively, than cattle in feedyards that did not feed DFMs. Further investigation of population data strengthens the case that DFM products are resulting in improved performance. The ADG data from cattle of different weight classes were sorted by DFM use or non-use. For both steers and heifers in all weight classes, cattle fed DFMs had numerically higher ADG. The consistency of this advantage across different weight groups, as well as the fact that DFM results were numerically favorable in each weight comparison, provides strong support for the advantage shown in mean ADG and feed:gain in both steers and heifers.
Performance advantages (ADG and feed:gain) are the primary reason cattle feeders choose to use DFM products. However, population data can be evaluated to determine if there are other benefits to DFM products that are difficult or impossible to assess in traditional research settings. These are called ancillary benefits because they are not the primary reason to use the product and may not be included in economic analyses, but they accompany the performance benefits the producer does expect to receive.
Two potential ancillary benefits of DFMs as noted above are improved health or response to treatment and fewer digestive disorders or digestion-related deaths.
The collected data show clear, positive trends for health-related variables. Improved health could manifest itself as reduced death loss or increased performance in the face of health stress. This may be especially true in lots with cattle that have substantial health challenges. As we relate the data on health and performance we see some interesting trends develop. In DFM fed steers and heifers in the Central Plains or High Plains in 2003-04 with only data from lots of cattle that had less than $20 per head of processing and treatment charges (relatively low health challenges), ADG advantages were 4.5 and 3.1 percent in steers and heifers, respectively, with feed:gain advantages of between 1 and 2 percent. In cattle with more than $20 per head of processing and treatment charges (moderate health challenges) the advantages to DFM use were much greater.
If DFM products allow cattle to extract more energy from feed or if they encourage greater feed consumption or more rapid recovery from nutritional or health challenges, that could explain much of what these feedyards observed during these periods.
DFMs also appear to reduce death loss in heavier (700 lb. or greater) cattle. Death loss in these cattle was lower for lots of cattle fed DFMs than for those without DFMs (0.85 and 1.01%, respectively; P < 0.01). The percentage reduction is similar between weight groups and is fairly consistent across the regions of the country. This conclusion is made stronger by the repeatability of the result. In 22 of the 24 comparisons, the DFM death loss is numerically lower.
Mechanism of DFM Action in the Animal
DFMs achieve positive performance and health benefits in all species through several mechanisms, including:
* Alteration of intestinal microorganisms;
* Prevention of pathogen adherence or activation;
* Improved gut permeability (greater nutrient absorption)
* Modulated (improved) immune function.
In addition, the unique aspects of ruminant fermentation allow DFMs to work in other ways in feedlot cattle. Ruminal microorganisms convert feed to volatile fatty acids (VFA), which enter the bloodstream and are used by the animal for energy. VFA's are the primary metabolic source of energy in the ruminant. Bacterial populations also are a direct source of protein and energy to the animal, as a portion of them are constantly washed into the lower gut and digested. DFMs can alter species composition of the ruminant bacterial population, resulting in changes in fermentation that could be beneficial to the animal.
An inherent risk in feeding high-energy (high grain) diets to cattle stems from the rapid conversion of starch to acids by microbes in the rumen. Rumen pH is lowered as acid accumulates. If acid accumulates faster than the animal can absorb it, rumen health is compromised, and rumen function could be impaired, resulting in acidosis, bloat or other disorders. If too much acid enters the bloodstream, the health of the animal can be compromised, even to the point of death. These acid overload situations are most likely if the animal overeats or if the rumen bacterial population is unprepared to deal with high-starch feedstuffs.
Role of DFMs
Newly received feeder cattle typically have ruminal bacterial populations geared for digesting forage but not starch. As cattle are "stepped-up" from high-forage diets to high-grain diets, the rumen population shifts toward species that can handle starch. The transition is toward the most beneficial (efficient) species and away from those that are less efficient or most likely to produce lactic acid. DFMs can be involved in this process in two ways. As cattle are placed on feed and stepped up to a high-grain finishing diet, lactate-producing bacteria could be beneficial. Feeding lactate-producing bacteria such as Lactobacillus
Acidophilus could help prevent acidosis at a later stage by allowing ruminal microorganisms to adapt to the controlled presence of lactic acid in the rumen, boosting the number of lactate-utilizing organisms. When the bacterial population has shifted to one capable of fermenting high-starch diets, there seems to be further benefit in using DFMs to shift the population toward the most efficient, consistent and safest fermentation end products. Feeding lactate-utilizing bacteria such as Propionobacterium can result in increased propionic and diminished lactic acid production. Propionic acid is preferred to other VFAs because it provides the most energy to the animal.
Avoiding lactic acid is desired because it is a stronger acid than propionic acid, it is used less efficiently by the animal and its accumulation seems to set up a negative cycle that often culminates in what has traditionally been termed lactic acidosis. An increase in recovery of dietary energy as a result of feeding DFMs can result in increased ADG and improved feed:gain with DFMs.
One thing to understand in DFM feeding is that not all organisms are the same and that different strains produce different results. The data collected demonstrate the ability of Propionbacterium to favorably influence rumen fermentation in the face of an acid overload challenge. In this work, Propionbacterium
freudenreichii (strain P63) was fed for five days. Cattle then fasted for 24 hours and were then reintroduced to a 90 percent concentrate diet designed to make acidosis likely. When animals overate after the fast (not uncommon), rumen pH dropped significantly (increased acid), but the pH drop in cattle fed P63 was not as severe as controls, and the return toward normal pH was more rapid in P63 - fed cattle. The P63 organism also shifted rumen fermentation in a more efficient direction. Propionic acid production (favorable) increased after the high-concentrate diet was fed, and the increase was greater with P63. In addition, lactic acid production (unfavorable) also increased as a result of high-concentrate feeding after a fast, but the increase was reduced with feeding of the P63 strain. Further, the cattle that did not receive P63 did not return to feed after the lactic acid began to build up, whereas those fed P63 returned to feed during the study.
Among the Propionobacterium species, P63 appears to be among the most favorable in feedlot diets. The P63 organism was selected from among 44 strains representing four species of Propionobacterium. The bacterial strains were evaluated based on growth rate and ability to utilize lactate at a pH of 5.0 or 7.0. Effectiveness at a pH of 5.0 was required because this mimics rumen conditions during acidosis, and P63 was the most efficacious of all strains at pH 5.0.
DFMs improve performance and health of feedlot cattle. Extensive research and reviews of published literature by researchers found that, in typical research settings, DFMs result in a 2.5-5.0 percent increase in ADG and a 2 percent average improvement in feed:gain. This matches performance results from population data fairly well and would result in a $10-15 economic benefit per head.
In addition, the population data demonstrate that there are ancillary benefits to feeding DFMs, including increased response to health stress and lower death loss. The response in death loss is presumably due to a lower incidence of digestive deaths, resulting from reduced frequency of subacute acidosis and/or an improved ability to recover from acute lactic acidosis. In
vitro and in vivo mechanism of action data support these roles for Propionbacterium P63, as indicated by favorable rumen pH, lactate utilization and propionate production.
We see the benefits here of DFM use in cattle diets. These products are only one of an assortment of product types that will become prominent as we move toward a different stage of technology applications in the beef industry. In the next issue we'll continue this exploration of tools and technologies.
Dr. Steve Blezinger is and nutritional and management consultant with an office in Sulphur Springs Texas. He can be reached at 667 CR 4711 Sulphur Springs, TX 75482, by phone at (903) 885-7992 or by e-mail at firstname.lastname@example.org. Also, visit BLN's web page at www.blnconsult.com.