Removing dietary sodium bicarbonate increases rumination time but does not affect intake or milk yield

Area of Science:

• Animal Science
• Ruminant Nutrition
• Dairy Cattle Management

Background:

• Low-roughage diets in dairy cows can challenge rumen function.
• Sodium bicarbonate (SB) is often used as a buffer in dairy rations.
• The efficacy of SB in wheat-based, low-roughage TMRs requires further investigation.

Purpose of the Study:

• To evaluate the impact of varying sodium bicarbonate (SB) levels on feed intake, milk production, and digestive parameters in lactating dairy cows.
• To determine the effects of SB supplementation on rumen pH and rumination time in cows fed a low-roughage, wheat-based total mixed ration (TMR).

Main Methods:

• Forty-two mid-lactation cows were fed a low-roughage TMR with three levels of SB (0, 0.74, 1.47% of dry matter) for seven weeks.
• Feed intake, milk yield and components, energy-corrected milk (ECM), whole-tract apparent digestibility, rumen pH, and rumination time were monitored.
• Rumen pH was measured at specific intervals, and fecal samples were collected for digestibility analysis.

Main Results:

• Dietary SB supplementation did not significantly affect feed intake, ECM yield, apparent digestibility, or feed efficiency.
• Increasing SB levels showed a negative correlation with daily rumination time.
• Rumen pH, measured before and after feeding, was not affected by dietary SB concentration.

Conclusions:

• Removing SB from a wheat-based, low-roughage TMR does not negatively impact feed intake or milk production in lactating cows.
• Lactating cows may increase rumination time to compensate for the lack of buffering capacity when SB is removed.
• Further research may be needed to fully understand the long-term effects of SB on rumen health and cow behavior in specific dietary contexts.