Grazing Evaluation of Cool-Season Grasses with and without Legumes

Abstract

Reducing the length of time that cattle must be sustained on stored forages during the winter by extending the grazing season is a growing interest of cattle producers in the Southeast. This project was conducted to evaluate several of the predominant cool-season forages and forage mixtures for their capability to extend the grazing season. Six cool-season forage treatments were assigned to 0.8-ha paddocks in an incomplete block design with two replications and continuously grazed at a fixed stocking rate of 4 steers/paddock. The treatments were as follows: ‘Texoma’ MaxQ II novel endophyte tall fescue grown in combination with ‘Durana’ white clover (TF+WC) or treated with 50.5 kg N/ha (TF), ‘Nelson’ annual ryegrass grown in combination with ‘Dixie’ crimson clover (RG+CC) or treated with 50.5 kg N/ha (RG), and a mixture of ‘Graze King 90’ cereal rye and ‘Nelson’ annual ryegrass grown in combination with ‘Dixie’ crimson clover (RG+R+CC) or treated with 50.5 kg N/ha (RG+R). Steers were put on treatment when forages emerged from winter dormancy and available forage DM was estimated to be greater than 2000 kg/ha. Steers were taken off treatment when steer average daily gains (ADG) fell below 0.45 kg/d or forage DM availability fell below 1120 kg DM/ha. In year one treatments containing tall fescue furnished 75 days of grazing while all other treatments furnished 68 days. In year two treatments containing tall fescue provided 84 days, RG+R and RG+R+CC 57 days, and RG and RG+CC provided 85 days of grazing. In year one steer ADGs were greatest on RG+CC and RG+N but did not differ significantly from TF+WC, which was similar to all treatments. In year two steer ADGs were greatest on the annual treatments, which did not differ. With the exception of TF and TF+WC in year one, clover inclusion or N treatment had no effect on ADG or G/ha in either year within grass and small grain-grass treatments. Legume inclusion increased total forage DM yields of annual ryegrass and novel endophyte tall fescue in year two only. Results indicate that crimson clover can replace N fertilizer for spring grazing on annual ryegrass and annual ryegrass-cereal rye pastures.