A way to gain insights about microorganisms.

Metagenomics is a field of molecular microbiology where the presence of a microbe is determined by identifying its DNA in a sample rather than trying to grow the organism in culture . . .

Studying individual microbial genus or species in the rumen only provides part of the story, Osterstock said. In fact, the rumen is a complex microbial system comprised of bacteria, protozoa and fungi where the impact of a specific microbial species is dependent upon the activity of other microbes in the system.

Metagenomics is an ideal approach to studying these microbial communities because less than 10 percent of rumen microbes can be grown in culture using routine anaerobic methods, Osterstock said.

The team's current work has focused on bacterial populations in the rumen using sequencing methods and bioinformatics to classify which bacterial genera are present under different dietary conditions.

The bloat team recently completed the first genomics-based characterization of bacterial populations from steers associated with changing from a warm-season grass hay diet to a cool-season grazed forage diet. Their study included 14 steers sampled at two time points, the largest study of its kind to date, the scientists said.

During their research, the scientists found that the distribution of bacterial genera changes dramatically when stocker cattle transition from Bermuda grass hay to winter wheat forage diets, Pinchak said. In addition, analyses determined that bacterial communities were clearly different in the fiber, liquid and whole rumen fractions within the rumen, he said.

Overall, more groups of different bacteria occurred on Bermuda grass hay than wheat forage diets, which is consistent with the increased rumen retention time of the less digestible Bermuda grass hay, Pinchak said.

During the study, they found that specific bacterial groups would increase, decrease, appear or disappear from one diet to the other, highlighting the complexity, plasticity and specificity of rumen bacterial populations, he said. . .

The Bloat Research Project team recently formed a consortium with scientists at the Borlaug Institute at Texas A&M University; the J. Craig Venter Institute, a leader in genomic research in Rockville, Md.; and the University of Illinois.

Pinchak said metagenomics also can be used to study how cattle adapt to diets containing bioenergy co-products, discover novel enzymes for biofuel production, or to help understand how microbial community dynamics affect food safety pathogen prevalence, feed efficiency and greenhouse gas emissions.

Cattlemen, especially dairymen, have a rough and ready grasp of the issues and are careful about dietary changes. Well, the good ones are careful but there are also a lot of dolts in the business. The general rule is to make changes slowly, allowing time to adjust. I wonder if a time will come when you can feed cattle a bolus of microorganisms tailored to a selected ration and avoid problems?