Data on the comparative composition of proteins
and their components in the milk of goats and cows
have been reviewed byJenness (1980)andHaenlein
(1996, 2001), documenting many unique differences
between the two species, and showing a wide diversity due to genetics of different breeds within each
species, influences of stage of lactation, feeding, climate, and subclinical mastitis. Compounding this diversity is the use of different testing methods and
standards. It has been found that goat milk has a significantly higher dye-binding capacity per unit protein (1% more than cow milk) and a lower infra-red
absorption (4% less than cow milk) (Grappin et al.,
1979), making it necessary to use different calibration curves for each species to measure milk protein content. This has been confirmed in studies by
Zeng (1996), when testing with cow milk standards resulted in 0.04% less fat and 0.27% less protein in goat
milk