This Is AuburnElectronic Theses and Dissertations

Grazing Evaluation of Cool-Season Grasses with and without Legumes




McKee, Robert

Type of Degree

Master's Thesis


Agronomy and Soils


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.