Milk composition of a free-ranging white rhinoceros (Ceratotherium simum) during late lactation

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

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.

Characterization of gross composition, energy value, and fatty acid profile of milk from lowland tapir (Tapirus terrestris) during different lactation periods

We evaluated gross composition, energy value, and fatty acid profile of colostrum, transitional, and mature milk of lowland tapir (Tapirus terrestris (L., 1758)) from Argentina. Samples were obtained from six healthy animals kept in captive or semicaptive conditions. Protein content varied over time from 6 to 19 g/100 g of milk; carbohydrates varied from 2.4 to 5.4 g/100 g of milk; fat varied from 2.4 to 17.3 g/100 g of milk. Energy value also varied over time, with colostrum having the highest value. Fatty acid profile revealed a unique pattern in tapir milk, characterized by the presence of higher amounts of lauric, myristic, and pentadecanoic acids than in milk from other equids. Traces of conjugated linoleic acid (CLA) were measured, being the only trans fatty acid detected in tapir milk. Neither butyric acid (C4:0) nor fatty acids longer than C18 were found in tapir milk. The characteristics of tapir milk include high concentration of fat, caseins, and whey proteins. Gross composition and saturated fatty acid to unsaturated fatty acid (SFA/UFA) ratio of tapir milk were more similar to that of horse milk than rhinoceros milk. The present study sheds light on tapir fatty acid metabolism and on nutritional requirements of their newborns, which can be used to improve conservation and management strategies. Furthermore, different periods of lactation were evaluated in this species for the first time, thus contributing to the general knowledge of milk from other members of the order Perissodactyla.