Influence of Grazing on Canola Grain, Canola Forage Yield, and Beef Cattle Performance

TL;DR

Grazing winter canola reduces grain yield by 20-25%, but canola forage supports beef cattle performance without significant negative effects.

Contribution

Demonstrates the feasibility of dual-purpose grazing of winter canola with minimal impact on cattle performance despite reduced grain yield.

Findings

Grazing winter canola reduces grain yield by 25% compared to ungrazed canola.

Cattle performance and forage nutritive value are not significantly affected by grazing.

Proper grazing management is essential to balance grain yield loss and animal gains.

Abstract

Interest is increasing in grazing winter canola as an alternative crop in winter wheat rotations in the Southern High Plains of the USA and similar environments. In this study, winter cereal rye and winter canola pastures (forage) were compared for two winter growing seasons to determine the relative effect of pasture type on beef cattle performance, along with the effect of grazing on canola grain production. Canola grain yields were reduced by 25% when canola was grazed for approximately one month after grazing was initiated, but before the onset of rapid regrowth in spring. No differences existed for forage mass, nutritive value, or animal performance, although forage mineral composition of canola could be a concern. Grazing winter canola as a dual-purpose crop in semiarid environments is feasible when proper grazing management is applied; a 20–25% reduction in grain yield should be anticipated, but expect animal gains to offset that loss.

Interest is increasing in grazing winter canola (Brassica napus) as an alternative crop in winter wheat (Triticum aestivum) rotations in the Southern High Plains (SHP) of the USA and similar environments. In this stidy, winter cereal rye (Secale cereale) and winter canola pastures (forage) were compared for two winter growing seasons at New Mexico State University’s Rex E. Kirksey Agricultural Science Center at Tucumcari, NM, USA, to determine the relative effect of pasture type on late-gestation beef cows and growing yearling cattle, along with the effect of grazing on canola grain production. Canola grain yields were reduced by 25% when canola was grazed until removal approximately one month after grazing was initiated, but before the onset of rapid regrowth after winter (641 vs. 486 kg grain ha−1 for never grazed or grazed canola, respectively, p < 0.0256). No differences existed for forage mass, nutritive value, or animal performance, although forage mineral composition of canola could be a concern. Grazing winter canola as a dual-purpose crop in the SHP and similar environments is feasible when proper grazing management is applied; producers should anticipate a 20–25% reduction in grain yield, but expect animal gains to offset that loss.