Effect of Dietary Buffers Supplementation on Milk Yield and Composition in Dairy Cows: A Meta‐Analysis of Randomized Controlled Trials

Feeding high concentrates to high producing animals usually change the rumen environment and compro-mises the productivity of ruminants. Different feed additives are used to prevent the occurrence of sub-acute ruminal acidosis, among these additives, buffers are commonly used. The aim of this meta-analysis was to investigate the effects of buffer supplementation on milk yield and composition in dairy cows. PubMed, Scopus, Web of Science and Google Scholar databases were searched from 1969 to 2020. A total of 86, 91, 94, 85, 27 and 34 trials were included to buffer supplementation effects on dry matter intake (DMI), milk yield (MY), fat, crude protein (CP), solid not fat (SNF) and lactose, respectively. The magnitude of the ef-fect (effect size) was assessed using standardized mean differences (SMD) for continuous results, between the buffer supplementation addition and control treatments. The addition of buffer supplementation had no significant effect on DMI (SMD=-0.002, P=0.16), MY (SMD=0.001, P=0.99), CP (SMD=-0.002, P=0.34) and SNF (SMD=0.006, P=0.32), respectively. Milk yield increased in the group receiving the buffer sup-plementation in comparison with the control group. The percentage of fat (SMD=-0.185, P=0.001) signifi-cantly decreased in the control group compared to the group receiving the buffer. The dietary buffers sig-nificantly increased the content of lactose (SMD=0.008, P=0.014) in dairy cows’ milk. This meta-analysis indicated that buffer supplementation improved milk yield and composition in dairy cows.