Global comprehensive review and meta-analysis of goat milk composition by location, publication year and lactation stage

The composition of goat milk is influenced by various factors, including geographical location, breed, stage of lactation, season, and animal diet. In this study, we employed statistical methods such as meta-analysis, ANOVA, Pearson correlation, and principal component analysis (PCA) to assess goat milk composition based on eightytwo references spanning from 1975 to 2023, collected from online sources such as PubMed, Web of Science, and Google Scholar. Our findings indicate that, according to ANOVA and meta-analysis, the composition of goat milk includes 12.65% and 12.81% total solids (TS), 4.06% and 4.13% fat, 3.53% and 3.52% protein, and 4.42% and 4.44% lactose, respectively. The grade of evidence for total solids, protein, and lactose was high, while fat received a moderate grading. Pearson correlation analysis and PCA demonstrated a positive correlation among fat, total solids, protein, and ash. No significant correlation was found between lactose and ash content with the other components. PCA analysis disclosed that compositional variations in goat milk during early and late lactation stages were mainly related to changes in TS, fat, and protein. This review provides valuable insights for the goat milk dairy industry, aiding in the understanding of variations in the composition of goat milk.