Yield, nutrient composition, and horse condition in integrated crabgrass and cool-season grass rotational grazing pasture systems
Authors: Weinert-Nelson Jennifer R, Meyer William A, Williams Carey A
Journal: Translational Animal Science
Summary
# Editorial Summary: Integrated Crabgrass and Cool-Season Grass Rotation for Equine Pastures Researchers at Rutgers University investigated whether incorporating warm-season crabgrass into traditional cool-season pasture rotations could improve summer forage availability and maintain horse condition—a practice already established in cattle grazing but largely unexplored for equines. Over a full grazing season, two 1.5-hectare rotational systems were compared: a control system with cool-season grasses throughout, and an integrated system alternating three cool-season sections with three crabgrass sections, each grazed by three horses across spring, summer and autumn periods. The integrated system produced substantially more total forage (9,125 kg versus 6,335 kg) and supported 41% greater carrying capacity (390 versus 276 horse days), with crabgrass delivering particularly impressive yields during the problematic mid-July to mid-September slump period when cool-season productivity typically crashes. Notably, both systems maintained equivalent horse body condition scores (around 5.8–6.1), and whilst crabgrass sections showed lower water-soluble carbohydrate content during summer (4.46% versus 7.92%), non-structural carbohydrate levels remained consistently low across all pasture types, indicating no metabolic disadvantage for horses prone to insulin dysregulation. For practitioners managing grazing systems during extended dry periods, integrated crabgrass rotation offers a practical strategy for bridging the summer forage gap without apparent nutritional trade-offs, though autumn production warrants further optimisation.
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Practical Takeaways
- •Integrate crabgrass into cool-season pasture rotations to dramatically increase grazing availability during summer months when traditional pastures decline, boosting your carrying capacity by 40%
- •Crabgrass sections are most valuable July–September; cool-season grasses remain superior in late autumn, so plan your rotation accordingly to match seasonal strengths
- •Both systems kept horses in good condition, so integrated grazing provides more flexibility and productivity without sacrificing horse welfare
Key Findings
- •Integrated rotational grazing with crabgrass provided 9,125 kg total forage versus 6,335 kg in cool-season grass only, increasing carrying capacity from 276 to 390 horse days
- •Crabgrass sections dramatically outperformed cool-season grass during summer slump (SLUMP period), providing 4,758 kg/ha and 196 horse days/ha compared to 1,086 kg/ha and 32 horse days/ha in cool-season sections
- •Both systems maintained adequate horse body condition scores (IRS: 5.78, CON: 6.11) with no significant difference, despite different forage availability
- •Water-soluble carbohydrates were lower in crabgrass during SLUMP (4.46%) versus cool-season grass (7.92%), but non-structural carbohydrates remained similarly low across all sections