Meta分析作为一种科学客观的定量综述形式，已经广泛应用于国外农业研究。本文利用这一方法，分析奶牛干物质采食量（DMI）与日粮阴阳离子差（DCAD）的潜在关系。研究所用资料取自已发表的8篇关于泌乳前期奶牛日粮阴阳离子平衡对DMI影响的文献数据，对实际观测值进行了研究间效应的校正。分析结果表明，泌乳前期奶牛校正后的DMI随DCAD增加呈二次增加（P<0.01，R2=0.74)，在DCAD为298.3 mmol/kg DM时达到最高值；校正后的DMI随血液HCO3-浓度以及血液pH增加而二次增加（P<0.01，R2=0.91；P<0.01，R2=0.87），在血液HCO3-浓度为29.2 mmol/L时达到最大。校正后的DMI与血液HCO3-以及血液pH的关系分析表明，DMI与泌乳前期奶牛体内酸碱平衡相关性很大。DCAD通过影响机体的酸碱平衡，并最终影响奶牛的自由采食量。

The Meta-analysis has been widely used in the agriculture research abroad and is considered to be a new scientific way for quantitative summarizations of literature data. A meta-analysis was conducted to examine the potential empirical relationships between dietary cation-anion difference (DCAD) and the dry matter intake (DMI). The database was developed from 8 studies in which the effect of the DCAD was observed in the early lactating dairy cows. Observed DMI values were adjusted for study effects. The results showed that, adjusted DMI increased with increasing DCAD (quadratic; P<0.01, R2=0.74), peaking at 298.3 mmol/kg DM; adjusted DMI also increased with the increasing blood HCO-3 concentrations (quadratic; P<0.01, R2=0.91) with peaking at 29.2 mmol/L; adjusted DMI increased with the increasing blood pH, too (quadratic; P<0.01, R2=0.87). These relationships indicated that DMI was closely associated with acid-base status in early lactating dairy cows, and that DCAD affected systemic acid-base balance, which in turn affected voluntary intake of lactating dairy cows.［Chinese Journal of Animal Nutrition, 2010，22（1）:46-50］