Rumen conditions that predispose cattle to pasture bloat

Area of Science:

• Ruminant nutrition
• Animal physiology
• Agricultural science

Background:

• Pasture bloat is a common metabolic disorder in cattle.
• Legume pastures, particularly alfalfa, are a primary cause of bloat.
• Understanding predisposing factors is crucial for prevention.

Purpose of the Study:

• To identify factors in rumen contents that predispose cattle to pasture bloat.
• To investigate the relationship between rumen parameters and bloat incidence.

Main Methods:

• Rumen contents from the dorsal sac were analyzed before alfalfa ingestion.
• Measurements included chlorophyll concentration, particulate matter buoyancy, and gas production rates.
• Fermentation rates were assessed in the presence of glucose.

Main Results:

• Cattle that subsequently bloated had significantly higher chlorophyll concentration and particle buoyancy.
• Higher fermentation rates (with glucose) suggested greater microbial colonization of feed particles.
• Elevated chlorophyll levels 4 hours post-feeding were observed in bloated animals.

Conclusions:

• Increased buoyancy and microbial colonization of feed particles contribute to rapid legume digestion.
• Trapping of fermentation gases by frothy ingesta leads to pasture bloat.
• Rumen content analysis can identify cattle at higher risk for bloat.