Comparison of marine algae-based rumen buffer with sodium bicarbonate buffer and its role in increasing milk value.

This study aimed to evaluate the effect of marine-based rumen buffer (Lithothamnium calcareum) supplementation on rumen health as well as milk yield and composition and also behavioural and metabolic parameters of dairy cows. Thirty-six lactating multiparous Holstein cows were used with a milk yield average of 39 kg/d and 64 d in milk. The experiment was conducted over 60 d using two groups: control (CON; n = 18) was supplemented with sodium bicarbonate at 1.1% dry matter and a treatment group that received Lithothamnium calcareum at 0.5% of dry matter (LITHO; n = 18). Each group was fed daily with the buffers mixed to the total mixed ration containing 29.28% starch. Ruminal fluid collections were performed weekly to evaluate pH and volatile fatty acids. Feeding behaviour data were obtained through automatic feeders, while overall behavioural data were obtained using monitoring collars. Milk yield was recorded daily and adjusted for fat and energy. Milk samples were retrieved once weekly for analysis of fat, protein, lactose and total solids. Blood samples were collected weekly for metabolic analysis and faecal samples were collected weekly to evaluate pH and starch concentrations. LITHO produced more fat- and energy-corrected milk (P ≤ 0.01) as well as the highest percentage of fat and solids (P < 0.05) when compared to the CON group. Data on feeding behaviour showed an increased eating time (P ≤ 0.01) in the LITHO group but a higher eating rate (P < 0.01) in the CON group. Animals from the LITHO group had lower faecal pH (P < 0.05). The treatment did not affect dry matter intake, animal behaviour, ruminal acid-base balance, or faecal starch. In summary, Lithothamnium calcareum supplementation at 0.5% of dry matter improved milk yield, milk composition and, presumably, feed conversion efficiency.