Perennial Forage Kochia for Improved Sustainability of Grass-Dominated Ecosystems

Perennial Forage Kochia for Improved Sustainability of Grass-Dominated Ecosystems

Summary

Grazing forage kochia (Kochia prostrata) during fall/winter has improved livestock condition and reduced winter feeding costs. The objectives of this study were to compare forage production/quality and livestock performance of traditional winter pastures versus pastures with forage kochia. Two kochia pastures were established in Tooele County, Utah in January 2005. Mature, pregnant, crossbred cows at both locations were body condition scored (BCS) and randomly divided into groups, then placed in either forage kochia/crested wheatgrass (Agropyron desertorum) or untreated crested wheatgrass/cheatgrass (Bromus tectorum) pastures. Grazing lasted for 84 days. Cows were combined and condition scored. Data were analyzed using the mixed procedure of SAS and considering pasture treatments (improved with forage kochia vs. control) fixed and blocks random. Forage production data showed control and study pastures with 475 kg ∙ ha-1 and 2382 kg ∙ ha-1 of forage respectively. The nutritional quality of forage kochia plants was compared to that of grass plants (primarily crested wheatgrass). In-vitro true digestibility was similar (P > 0.50) for crested wheatgrass and forage kochia (63.6% and 64.4% respectively), but crude protein was significantly greater (P < 0.001) for forage kochia than for crested wheatgrass (11.9% and 2.8% respectively). Fiber digestibility was significantly different (P < 0.001) for both acid detergent (control 40.9%, treatment 33.8%) and neutral detergent (control 64.5%, treatment 45.3%) fiber. Cattle on improved ranges with forage kochia tented to have a greater increase (+ 0.65) in BCS than cattle on unimproved rangelands (+ 0.39) comprised mostly of crested wheatgrass. Overall, this study found that both pastures had adequate forage to increase body condition; however, the most noteworthy result is the nearly five-fold increase in forage production (which translates to increased carrying capacity) in the forage kochia pastures.

Objectives/Performance Targets

Forage kochia (Kochia prostrata) is a perennial half shrub native to the arid rangelands of central Eurasia. It is an important grazing species because it is relatively high in protein and has the ability to thrive in harsh climates. It is competitive against winter annuals such as cheat grass (Bromus tectorum) and because it stays green throughout the summer, effective in stopping wildfires when planted in greenstrips (Harrison et al., 2002).

A major challenge for beef producers in the Western United States is high winter feed costs (DelCurto and Olson 2000 and Hathaway 2003). Maximizing utilization of low-quality forage while minimizing use of expensive supplements is one way to reduce feed costs. Arthun et al. (1992) reported that a way to do this is include forbs and shrubs in low-quality forage-based diets. Improving winter grazing is important economically because it can reduce costs associated with feeding stored hay (Waldron et al., 2006; Gade and Provenza, 1986; Waldron, 2004).

Otsyina et al. (1984) reported that shrubs are particularly important in winter grazing systems. During winter, dormant grasses are high in energy (fiber) but low in protein (Waldron et al., 2006; Cook, 1972). Simultaneously, shrubs such as forage kochia are low in energy and high in protein (Waldron et al., 2006; McKell et al., 1990). Combining grasses and shrubs can optimize protein and energy levels by meeting microbial crude protein requirements of 7% (Van Soest, 1994) during nutritionally stressful times (Arthun et al., 1992).

Reported benefits of forage kochia prompted researchers and local entities to conduct a study in Tooele County, Utah of traditional winter pastures versus pastures with forage kochia. Two locations were selected and seeded with forage kochia. Initial establishment progressed more slowly than anticipated. One of the sites had excessive snowfall after beginning the study. Because cows were fed hay no data could be collected from that site in 2007.

Objectives:
To assess differences between:

• forage quality
• forage production
• cow body condition

Accomplishments/Milestones

Two kochia pastures were established in Tooele County, Utah in January 2005. Mature, pregnant, crossbred cows at both locations were body condition scored (BCS) and randomly divided into groups, then placed in either forage kochia/crested wheatgrass (Agropyron desertorum) or untreated crested wheatgrass/cheatgrass (Bromus tectorum) pastures. Grazing lasted for 84 days. Cows were combined and condition scored. Data were analyzed using the mixed procedure of SAS and considering pasture treatments (improved with forage kochia vs. control) fixed and blocks random. Forage production data showed control and study pastures with 475 kg ∙ ha-1 and 2382 kg ∙ ha-1 of forage respectively. The nutritional quality of forage kochia plants was compared to that of grass plants (primarily crested wheatgrass). In-vitro true digestibility was similar (P > 0.50) for crested wheatgrass and forage kochia (63.6% and 64.4% respectively), but crude protein was significantly greater (P < 0.001) for forage kochia than for crested wheatgrass (11.9% and 2.8% respectively). Fiber digestibility was significantly different (P < 0.001) for both acid detergent (control 40.9%, treatment 33.8%) and neutral detergent (control 64.5%, treatment 45.3%) fiber. Cattle on improved ranges with forage kochia tented to have a greater increase (+ 0.65) in BCS than cattle on unimproved rangelands (+ 0.39) comprised mostly of crested wheatgrass.

Impacts and Contributions/Outcomes

Overall, this study found that both pastures had adequate forage to increase body condition; however, the most noteworthy result is the nearly five-fold increase in forage production (which translates to increased carrying capacity) in the forage kochia pastures.

The impact of this study has far-reaching implications as forage kochia has been shown to decrease winter feeding costs on rangelands which could translate into millions of dollars in savings for livestock producers. Additionally, although this study did not investigate the use of forage kochia for wildlife and fire suppression these are of perhaps even greater economic significance to the Intermountain west.

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