Production and Economics of Grazing Steers on Rye-Annual Ryegrass with Legumes or Fertilized with Nitrogen

Cool-season legumes have potential to replace N fertilizer in annual cool-season grass pastures, thus improving returns to producers. The objective of this 3-yr study was to compare the performance and economics of stocker cattle (Bos spp.) grazing rye (Secale cereale L.)-annual ryegrass (Lolium multiflorum Lam.) under two N systems. Paddocks were planted in early September 2008 through 2010 and contained rye-annual ryegrass with 112 kg N ha(-1) (fertilized so that a total of soil residual N plus fertilizer N would equal 112 kg N ha(-1)) (RR-N) or contained a rye-annual ryegrass with annual legume mixture (arrowleaf clover [Trifolium vesiculosum Savi], field pea [Pisum sativum L.], and hairy vetch [Vicia villosa Roth]) (RR-Leg). Steers (307 +/- 55 kg initial body weight) were weighed every 28 d and stocking rates were adjusted based on forage mass with put-and-take steers. Forage mass, forage allowance, and stocker average daily gain (ADG) and total gain (TG) were measured every 28 d. Results show similar performance between RR-N and RR-Leg systems in grazing days (average 367 d ha(-1)), ADG (average 1.065 kg per head d(-1)), and TG (average 390 kg ha(-1)). While the 3-yr average total cost associated with the RR-N system (US$569.88 ha(-1)) was greater than the RR-Leg system ($550.57 ha(-1)), there were no differences in gross revenue (average $815.91 ha(-1)) or expected net returns (average $255.68 ha(-1)) between systems. Annual legumes could be a viable replacement for commercial N fertilizer in rye-annual ryegrass pastures although adoption may be limited due to ease of N fertilizer application.