Comparative study of milk compositions of cattle, sheep and goats in Nigeria
Variations in the milk composition of Nigerian cattle, sheep and goats (Bunaji, Yankasa and Red Sokoto breeds, respectively), as well as residual phenotypic correlations between the milk constituents, were investigated. Results indicated that sheep and goats differed significantly (P < 0.05) from cattle in all constituents except protein percentage, which averaged 5.43%, 5.43% and 5.49%, respectively. Caprine milk contained the highest percentages of fat (5.80%), total solids (15.37%) and ash (0.77%), and bovine milk contained the least percentages of fat (0.68%) and lactose (1.84%). Overall, the milk compositions of sheep and goats were very similar as they were not statistically different from each other (P > 0.05). Residual phenotypic correlations between the milk constituents revealed highly significant (P < 0.01) and positive relationships between total solids and solids-not-fat (0.97 and 0.98 in cattle and sheep, respectively). All other correlations were positive in cattle (ranging from 0.12 to 0.77), except between protein and total solids (−0.44) and protein and solids-not-fat (−0.64). Multiple linear regression equations were fitted to predict the percentages of protein and fat. It was demonstrated that the protein percentage could be predicted from total solids and solids-not-fat with the highest accuracy of 94%, 86% and 82% in cattle, sheep and goats, respectively. On the other hand, the accuracy of prediction of fat percentage was very low in all the species (R2 = 0.01, 0.3 and 0.37 in cattle, sheep and goats, respectively).
Document Type: Research Article
Publication date: December 1, 2002