Sodium sesquicarbonate for early lactation dairy cows fed corn silage-based diets.

An experiment was conducted to evaluate the effects of dietary sodium sesquicarbonate on milk production and composition, feed intake, ruminal fermentation, and urine pH and composition in 32 multiparous Holstein cows in early lactation. Cows were fed high energy diets of 50% corn silage: 50% concentrate containing 0 or .75% sodium sesquicarbonate (total ration DM basis) for 84 d postpartum. Sodium sesquicarbonate increased milk fat percentage (3.46 vs. 3.27%), milk fat yield (1.39 vs. 1.26 kg), and 4% FCM yield (37.1 vs. 34.7 kg) but did not affect milk yield, milk protein percentage or yield, feed intake, ruminal fluid pH, or ruminal VFA profile. Urine composition was not affected by sodium sesquicarbonate, but urine pH (8.14 vs. 8.04) and total urine output as estimated by creatinine concentration were higher than that of controls. In summary, sodium sesquicarbonate, added as .75% of the ration DM, was effective in improving milk fat percentage, milk fat yield, and 4% FCM yield in early lactation dairy cows fed corn silage-based diets.