Effect of Cobalt Chloride on Fermentation of Alfalfa and Smooth Bromegrass Hays by Horse Cecal Microorganisms.

The research studied the impact of Co, or Cobalt Chloride, on the digestion and fermentation of alfalfa and smooth bromegrass in horses. The findings suggested a differential impact of Cobalt Chloride on the two types of hay, with specific attention to Co’s effect on gas production, potential impact on volatile fatty acids (VFA), and dry matter disappearance.

Research Methodology

• The experiment involved cecal fluid taken from four cannulated Quarter Horses—animals known as a cesophageal, or cecum, used for digestive fermentation.
• Five grams of dry matter (DM)—either alfalfa or smooth bromegrass—were introduced as substrate, along with varying amounts of Co ranging from 0.0 to 50.0 mg per kg of substrate DM.
• Both elements—10 milliliters of cecal fluid and 140 milliliters of buffer solution—were incubated for 48 hours, after which pH, VFA concentrations, and IVDMD were measured.
• Gas production, measured every 15 minutes, was interpreted as an indication of fermentation activity.

Findings and Interpretation

• The final pH remained unaffected by Co or type of forage, suggesting that Co does not alter pH levels in equine cecal microorganisms.
• Dry matter disappearance was higher in cultures containing alfalfa (at 29.2%) than in those with smooth bromegrass hay (at 19.4%).
• A notable interaction was observed between the types of forage and Cobalt, where alfalfa cultures displayed increased gas production. This result was also seen in cultures that used bromegrass and they received treatment with 5 mg Co/kg substrate DM. This reveals that Cobalt exerted a differential effect on the fermentative potential of the two types of hays.
• Gaseous byproduct production was influenced by the type of forage, Cobalt levels introduced, and time.
• The ratio of two major VFAs, acetate and propionate, as well as the overall production of VFA increased in cultures of alfalfa. However, Cobalt Chloride did not meaningfully alter VFA concentrations. This indicates that the type of forage, not Co, mainly affects the composition of VFAs.
• Lastly, while cultures of brome were influenced by Co in terms of gas production, no significant effects were noticed on pH, VFA concentration, or IVDMD. This finding suggests that the influences of Cobalt Chloride might be dependent on the type of hay being fermented.