Fall-planted cool-season annual forages make economical winter feed for beef cows, say University of Missouri agronomists.

They say several annual forages, including annual ryegrass, wheat, cereal rye, turnips and rape, can be fall-seeded for grazing in late fall, winter and early spring. Using a computer model, they compared the cost of those forages with that of stockpiled tall fescue, tall fescue hay and alfalfa hay.

The annual forages were considered separately and in a limited number of combinations. A spring-calving herd was fed from Dec. 1 to April 1.

They found that growing and grazing winter annuals is significantly less costly than stockpiled tall fescue or hay. If stockpiled fescue is assigned a relative cost of 100, annual ryegrass would have a relative cost of 68. The most economical crop was turnips, with a relative cost of 51.

However, the researchers say that annual ryegrass and cereal rye last longer and cost only slightly more than turnips. And turnips should be consumed before Jan. 1 in Missouri to avoid palatability problems.

The relative costs of tall fescue hay and alfalfa hay were 130 and 192, respectively.