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Research on donkey milk · Study 122
Odd-chain fatty acids: donkey milk compared
In eight donkey milk samples, odd- and branched-chain fatty acids amounted to 2.36 g/100 g fatty acids – less than in ruminants (3.33–4.51), more than in human milk (1.34). Undecanoic acid (C11:0) reached 0.895 g/100 g.
At a glance · tap the cards
The key figures
Study design
How it was studied
Laboratory comparison of 282 individual samples: 8 donkey milk samples (Sarda breed), 70 cow, 61 buffalo, 69 goat and 55 sheep milk samples from earlier surveys in Sardinia (buffalo from Campania), 11 donated human milk samples and 8 commercially purchased infant formulas. All samples were stored at −20 °C. After fat extraction and esterification, the fatty acid methyl esters were determined by gas chromatography with a flame ionisation detector and expressed as g/100 g total fatty acid methyl esters. 11 odd- and branched-chain fatty acids (OBCFA) were evaluated by ANOVA with Tukey’s test and by principal component analysis. Details of the jennies’ lactation stage and feeding are missing.
Interactive chart · values from the study
Total odd- and branched-chain fatty acids
Means from Table 1 (donkey n = 8, human milk n = 11, infant formula n = 8, ruminants n = 55–70). Shares of the fat, not of the milk.
Second analysis
Selected fatty acids: donkey, cow and human milk
Means from Table 1. anteiso-C13:0 was not detectable in cow’s and human milk (shown as 0).
Results
What the study measured
Fat content was 0.39 % in donkey milk and 1.08 % in human milk, significantly below that of ruminant milk (cow 3.75 %, buffalo 7.58 %). All eleven fatty acids considered were detectable in donkey, buffalo, goat and sheep’s milk.
Total OBCFA were higher in ruminants than in donkey, human and infant formula: sheep 4.51, buffalo 3.78, cow 3.38, goat 3.33, donkey 2.36, human milk 1.34 and infant formula 0.18 g/100 g fatty acid methyl esters.
Linear odd-chain fatty acids in donkey milk (1.62 g/100 g) were at the level of cow, buffalo and goat milk. Undecanoic acid (C11:0) was higher in donkey milk, at 0.895 g/100 g, than in all other types of milk; C15:0 (0.374) and C17:0 (0.353) roughly matched the values of human milk.
Branched-chain fatty acids in donkey milk, at 0.74 g/100 g, were markedly lower than in ruminants. Among the iso fatty acids, iso-C16:0 dominated in donkey and buffalo milk; anteiso-C13:0 reached the highest value of all types of milk in donkey milk, at 0.154 g/100 g.
Relative to total OBCFA, 68.7 % in donkey milk was accounted for by linear odd-chain fatty acids (human milk 59.0 %, ruminants 44.5–51.9 %) and 37.9 % by C11:0 alone.
In the principal component analysis (first component 47 %, second 19 %), donkey milk formed its own group, mainly due to high shares of C11:0 and anteiso-C13:0. The authors proposed these two fatty acids as possible markers for identifying donkey milk.
Authors’ conclusion: In the view of Carta et al. (2022), ruminant milk, milk from non-ruminants and infant formula differ clearly in their content of odd- and branched-chain fatty acids; donkey milk forms its own group with high shares of C11:0 and anteiso-C13:0. The authors found the lowest content in infant formula. Health effects were not examined.
Critical assessment
Strengths and limitations
Only eight samples of one breed from an existing sample collection were available for donkey milk; lactation stage, feeding and husbandry are not described. The types of milk come from different surveys and regions, so differences need not be due to species alone.
The discussion gives 40 % C11:0 and 6.5 % iso-C13:0 of the OBCFA for donkey milk; according to Table 2, it is 37.9 % C11:0, and the 6.5 % is anteiso-C13:0 (iso-C13:0: 1.1 %). According to the abstract, iso-C17:0 is the most frequent iso fatty acid except in donkey and buffalo, but according to Table 1, iso-C15:0 is higher in infant formula.
In the results, sheep and buffalo milk have positive values on the first principal component, whereas the discussion names sheep and goat as the first group. The table footnote gives p < 0.001 as the significance threshold, the methods section p < 0.05.
All values refer to the fatty acid share, not to the amount of milk. With 0.39 % fat in donkey milk, the shares correspond to very small absolute amounts; human milk was obtained only as single samples, and its fat content was below literature values.
The introduction and conclusion refer to literature on health effects of these fatty acids; only the composition was examined. The marker proposal C11:0/anteiso-C13:0 is based on eight samples; an earlier study on Chinese donkeys found C15:0 and C17:0 to be the most frequent OBCFA.
All samples were measured with the same gas chromatographic method and internal standards. Table 1 gives means with standard deviations; by our editorial recalculation, the totals for donkey milk are consistent.
Editorial assessment: The study describes the fatty acid pattern of a small number of donkey milk samples in a species comparison. No statements about health effects, suitability for particular groups of people or individual commercial products can be derived from it. To the research archive.
Research question for DON DONKEY’S®
Does the high share of undecanoic acid (C11:0) and anteiso-C13:0 persist in donkey milk from other breeds, feeding regimes and lactation stages, so that it is suitable as a reliable indicator of origin?
Original publication
Comparison of Milk Odd- and Branched-Chain Fatty Acids among Human, Dairy Species and Artificial Substitutes
Original title of the publication.
Carta S., Correddu F., Battacone G., Pulina G., Nudda A.
Foods · 2022 · 11(24), 4118
Dipartimento di Agraria, University of Sassari, Sassari, Italy
10.3390/foods11244118: 10.3390/foods11244118
Transparency: FAR2020 – Fondo di Ateneo per la Ricerca 2020 of the University of Sassari. The authors declare no conflicts of interest. No product-related statement for DON DONKEY’S®.
Summarised and reviewed by the DON DONKEY’S editorial team on the basis of the original publication · as of October 2026
The study summarised above was carried out independently of DON DONKEY’S® and does not relate to our products. It serves solely to inform about the state of research.
DON DONKEY’S® donkey milk and donkey milk powder are foods. They are not intended to prevent, treat or cure any disease and do not replace medical advice.
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