Protein and nutrient composition of dog milk throughout lactation

A. J. Lepine, Y. Adkins, B. Lönnerdal

Research output: Contribution to journalArticlepeer-review


There is limited knowledge about the protein and nutrient composition of dog milk and how it changes during lactation. In this study, milk samples were collected on days 1, 3, 7, 14, 28, 35, and 42 from 10 beagle dogs. Samples were analyzed for nitrogen, non-protein nitrogen (NPN), protein and casein/whey ratio by a micro-Kjeldahl method and precipitation at pH 4.6, lipids and fatty acids by extraction and gas chromatography, lactose by a lactase assay, citrate by a commercial assay and minerals and trace elements by atomic absorption spectrometry. Protein concentration was very high in day 1 samples (144±60 g/L) then decreased through day 21 (68±13 g/L); a modest increase was then observed. There was no change in the concentration of NPN (approx. 6-10% of total N). The casein/whey ratio was about 70/30 and stayed constant throughout lactation. Lactose concentration increased during early lactation; dl samples contained 17±4 g/L, while d7 to d42 samples contained 34-40 g/L. Lipid concentration was high in early lactation (approx. 13%) and then decreased slighly (approx. 11%). Citrate concentration increased from d1 to d7 (4.8±1.2 to 6.6±1.0 mM), then gradually decreased by d42 (3.9±1.2 mM). These data will be valuable when establishing the nutrient requirements of puppies during the suckling period.

Original languageEnglish (US)
JournalFASEB Journal
Issue number5
StatePublished - Mar 20 1998

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology


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