102 Effects of Cattle Removal Date on Forage Production and Steer Performance in Grazed Cover Crops

Abstract

Abstract Grazing of cool-season cover crops has been shown to be a viable tool in extending the grazing season while mitigating environmental risks associated with row crop farming systems. Grazing cover crops is not novel, but most information available on this practice focuses on soil health as opposed to forage production and animal performance. The objective was to evaluate the effects of cattle removal date on steer performance, forage yield, and forage quality. Twelve 1.2-ha pastures were established in a forage mix consisting of ‘Cosaque’ oats (Avena strigose), ‘FL401’ cereal rye (Secale cereale), ‘AU Sunrise’ crimson clover (Trifolium incarnatum), and ‘T-raptor’ brassica (Brassica napus ×B. rapa) and randomly allocated to be grazed through either mid-February (FEB), mid-March (MAR), or mid-April (APR) with an un-grazed control (CON). Three tester steers were randomly placed in each paddock with the exception of CON and allowed ad libitum grazing. Animals were weighed every 30 d for determination of average daily gain (ADG). Forage was harvested bi-weekly and analyzed for average yield, NDF, ADF, and CP. All data were analyzed using MIXED procedure of SAS version 9.4 (SAS Inst., Cary, NC). The following data represents the first three years of a four-year project. Differences in yield were detected between CON and FEB (3,913 vs. 2,398 kg/ha; P < 0.001), CON and MAR (3,913 vs. 1,908 kg/ha; P < 0.001), and CON and APR (3,913 vs. 2,126 kg/ha; P < 0.001). A difference in CP was detected between MAR and CON (13.36% vs. 11.78%; P < 0.02). No differences were detected for ADG (1.2 kg/day, P = 0.56), NDF (52.48%, P = 0.99), or ADF (30.82%, P = 0.4) among treatments. These results indicate that grazing will reduce forage yield, but removal date of cattle will not further affect forage yield or steer average daily gain.