Dairy cows produced more milk when grazing endophyte-free or novel (non-toxic)-endophyte tall fescue varieties instead of conventional fescue in a study by researchers at Ohio State University and the University of Kentucky. But the financial benefits of the improved fescues were less clear.

Forage yield and milk production from the three fescue types were measured over a two-year period on several farms. Novel-endophyte and endophyte-free varieties were established at a cost of $320 and $280/acre, respectively, while the conventional fescue was already established. In general, the two improved types brought similar milk production, but cows grazing conventional fescue on one farm produced 4.9 lbs/cow/day less milk.

Net-present-value analysis was used to determine if the improved fescues offered financial benefits. Variables accounted for included establishment costs, chance for stand failure, stand life, decay rate of stand and the interest rate. In addition, a production model was used to measure the advantages of novel-endophyte or endophyte-free fescue in a stocker cattle operation. It accounted for differences in grazing days, reduction in dry matter intake due to the toxic endophyte, and the resulting impact on average daily gain.

The advantages of improved varieties over conventional fescue were mixed, say the researchers. In general, they add, the benefits were greater for dairy cattle than for beef cattle. They saw few financial advantages from using novel-endophyte instead of endophyte-free fescue, except where endophyte-free pastures had a high likelihood of endophyte reinfestation that would require replanting.