To jump right to the end of the story, researchers have found when 15% of the diet of steers in pasture was a supplement of red clover hay/ with about 3 pounds of dried distillers grain, they gained more weight than those on pasture alone – 2.45 pounds a day compared to 1.94. That’s interesting and helpful information, but it leaves out information that tells us why we care and what we can do with it. So let’s go deeper.
Why Red Clover?
To answer this question, we need to know a little more about the rumen and how it functions. Ruminant digestion is a process that relies on billions of bacteria and microorganisms. While beneficial bacteria break down fiber and turn forage into nutrients, there are some that “steal” protein and turn it into methane excreted as gas, or ammonia excreted in urine. One way to prevent this theft is feeding low-levels of antibiotics. Antibiotics suppress these “Hyper Ammonia-producing Bacteria” (HABs) so that the animal can absorb nutrients that otherwise would have been lost and can gain weight more rapidly.
In 2012, the U.S. Food and Drug Administration asked feedlots and producers to phase out the use of antibiotics as feed supplements over concerns that it could lead to more antibiotic resistant bacteria. The hunt for a replacement ramped up, and Red Clover was explored as one option
Red Clover contains an isoflavone called biochanin A. In lab tests biochanin A prevented HAB from growing. It also promoted cellulolytic bacteria. Those are the bacteria that break down all the cellulose in the grasses and other forages ruminants eat, converting them into usable sugars. Knowing this about biochanin A, the next step was to test it in actual feeding trials. Researchers found that animals fed biochanin A while grazing on pasture gained more weight than those without: 2 pounds a day compared to 1.5 pounds a day.
How Do We Convert This to the Pasture?
Feeding pure biochanin A is too expensive to use commercially on pasture, plus it ignores the potential synergistic activity of other chemicals in Red clover. To eliminate these short-comings, in their next trial, researchers used red clover hay as a supplement with an eye toward how results could be translated into simply grazing pastures interseeded with red clover.
Over two spring grazing seasons, Angus cross steers were supplemented with two levels of red clover hay on endophyte-free cool season grass pasture. One group was fed 30% red clover and the other 15%. A rumen-fistulated Holstein steer was included in each treatment as a microbiological tester to see what was happening in the rumen. Researcher’s hypotheses were that red clover hay supplementation would
1) increase average daily gain and that more red clover would be better than small amounts,
2) suppress HAB;
3) promote cellulolytic bacteria and fiber degradation.
More is Not Better
Of course, I already told you the punchline. The steers gained the most weight on the 15% red clover diet.
This is important to keep in mind in case you were thinking of adding lots of red clover to your pastures. Biochanin A is a phytoestrogen, meaning that it is chemically similar to estrogen, and has the potential to impact fertility. Sheep are the most vulnerable with amounts of 25% or more in their diet reducing ewe fertility rates and lambing. Results on beef cattle are inconclusive and the the Forage-Animal Production Research team will be running experiments with ram lambs and market cows in the future. It seems the best idea at this point is not to go overboard with red clover.
One more thing in the list of “Why Red Clover is a Great Forage” is that biochanin A also helps prevent fescue toxicosis. You can read more here:
And…if you want to know more about planting red clover, we’ve got that for you too!