Recent research at our USDA-ARS unit in Lexington has shown that Red clover is probably the best vasodilator there is for cattle on toxic fescue (it contains high levels of the isoflavone Biochanin A which cause the the vessels to enlarge). They’ve proven this from several research studies. The limitation is that it’s hard to keep a consistent level of red clover in a pasture. Most vasodilators added to mineral are not as proven. Biochanin A is present in white clover but at lower levels. Any clover though helps to improve nutrition and dilute toxic fescue.
So if you have a good stand of KY-31 tall fescue, especially if it’s on sloping ground prone to erosion then I would leave it and add clover. Maybe even frost seeding red clover every other year. and using rotation grazing to help keep the red clover in the stand. Use an improved variety of red clover. Add a good ladino white clover makes sense too, but at a low rate since it can sometimes overtake a stand.
On land that you are considering or planning to redo completely (a lot of weeds, poor grass stands, fescue toxicity is noticeable, land that lays well, etc…), then I definitely recommend a novel endophyte variety of tall fescue. Sure it costs more, but novels definitely have a longer term stand. We have seen many farm pastures with novel varieties surviving 10 plus years in Georgia, North Carolina, Virginia, Tennessee and Kentucky, as well as other states. They showed good survival as long as the fertility was maintained and they weren’t overgrazed. Not a complex grazing system, just not grazing into the ground (leave approx. 3 inches of stubble), and providing rest periods.
In our Lexington variety test we can get 4-6 year survival from endophyte free tall fescue. But our soils are ideal, naturally high in phosphorus, well drained etc… and our test plots are rigorously maintained. In short, the conditions in most “real farm” situations in KY make it be harder for endophyte free varieties to survive than at our variety testing location in central KY. Click here for the tall fescue variety report.
The novel endophyte varieties are identified in the table. Look at the summary table to see all the novel endophyte varieties. The only one I don’t recommend for most beef producers is Tower Protek. It is soft leaved and very palatable and can tend to be grazed out because they graze so low. ~ Ray Smith