Milk composition of white rhinoceros over lactation and comparison with other Perissodactyla

Abstract

The proximate composition of milk from fifteen free‐ranging white rhinoceroses at different lactation stages is reported with detailed analysis of fatty acid composition and minerals. Lactose is the main component at 7.93 ± 0.53%, followed by 0.93 ± 0.19% protein, 1.76 ± 0.39% fat, 0.40 ± 0.18% ash, 0.05 ± 0.01% glucose, and 0.04 ± 0.02% non protein nitrogen The interindividual variation of all the components is high, showing no trend of change over lactation. The K and P content decreased over lactation. The fatty acid composition of rhinoceros milk is characteristic with a high saturated fatty acids content of 62%–84%, of which the medium chain fatty acids form the major portion. The C10:0, C12:0, C16:0, and C18:1c9 are the major fatty acids in the milk fat. The results are compared with the two other Perissodactylae families, the Equidae and Tapiridae. Differences in gross composition are small, but the milk of the Rhinocerotidae have the lowest gross energy, while the milk fats consist of the highest amounts of saturated fatty acids, while the low levels of C16:1c9 and C18:1c9 indicate the lowest mammary Δ9‐desaturase activity.

Life in a Central European warm-temperate to subtropical open forest: paleoecology of the rhinocerotids from Ulm-Westtangente (Aquitanian, early Miocene, Germany)

“…The carbon depletion might however be relatively limited in the case of rhinoceros, as the milk of living individuals has a very low lipid content (Osthoff et al, 2021).…”

“…Indeed, milk has a higher δ 18 O than drinking water due to the preferential loss of the light oxygen isotope ( 16 O) through expired and transcutaneous water vapor fluxes (Kohn et al, 1996), as well as a lower δ 13 C than plants due to the presence of lipids, which are depleted in 13 C relatively to other macronutrients (DeNiro and Epstein, 1977). The carbon depletion might however be relatively limited in the case of rhinoceros, as the milk of living individuals has a very low lipid content (Osthoff et al, 2021).…”