276 Systems approaches to beef cattle production: maximizing use of alternative forages to optimize agricultural ecosystems.

摘要

Expanding global population will continue to change the dynamics of US beef production systems. While increased protein demand will positively influence production, changes in land use from expanded cropping systems will reduce the availability of traditional perennial forage and necessitate the use of alternative forages and new production systems to remain a viable industry. Corn residue is already a critically important forage resource for cow/calf producers in the mid-west region of the US. Previous research has demonstrated that dry, pregnant cows can maintain body condition while grazing corn residue without supplement with no negative consequences on production. Lactating cows can also maintain body condition while grazing corn residue with energy supplementation and growing calves can gain between 0.4 and 0.8 kg/d with supplemental energy and RUP. Annual forages have long been a part of the US beef production system, especially in the southern plains where wheat pasture is grazed by growing calves. Recent popularity of cover crops has created opportunities to produce forage within cash crop production systems (double crop annual forage; DCAF). There is currently little information available on management of DCAF to optimize cropping and beef systems. Information ranging from impacts on pregnancy to understanding the ramifications of high nitrate concentrations of certain DCAF is lacking in beef cow/calf systems. Impacts of grazing DCAF on crop production also needs to be elucidated. Confined cow systems have received significant attention over the past five years. While long-term profitability of a total confined system is debatable, partial confinement while crops are growing may be a viable option in an integrated cropping-beef cattle system. Crop residues, DCAF, and confinement can be combined to develop a production system that utilizes the highest quality forage during peak lactation. These types of systems will fill a niche and contribute to increased global protein requirements.