The milk produced by Chilean Corralero horses (CCH) possesses distinct nutritional and immunological characteristics, according to a study conducted on breeding farms in southern Chile. This research aimed to meticulously analyze the milk’s nutritional composition, fatty acid profile, and immunoglobulin G (IgG) concentration, providing valuable insights for both foal health and potential human consumption. The study’s robust dataset, derived from 45 mares across three farms, positions it among the top-ranking research in this field, offering a representative view of CCH mare milk.
Understanding the Factors Influencing CCH Mare Milk Composition
Several factors significantly influence the composition of CCH mare milk. Days in milk (DIM), a measure of lactation stage, showed a notable negative association with ash, milk protein, milk solids, saturated fatty acids (SFA), and gross energy (GE). Conversely, a positive association was observed between DIM and monounsaturated fatty acids (MUFA). While DIM affected these components, milk fat, lactose, and overall energy content varied independently of DIM, suggesting other influencing factors such as farm-specific management practices. The sex of the offspring also played a moderate role in GE content, with milk from mares carrying female offspring exhibiting higher GE. Age and birth number, however, did not appear to impact milk composition.
Differences in milk composition among the three farms were most pronounced in fat content, with Farm A yielding the highest levels. These farm-specific variations, despite differences in average DIM, underscore the complexity of factors affecting milk quality. While differences in DIM between farms might be attributed to reproductive management, the independent effect of the breeding farm on milk fat, lactose, non-fat solids, and GE highlights the multifaceted nature of milk composition.
Nutritional Comparison: CCH Mare Milk vs. Other Sources
The macronutrient profile of CCH mare milk, encompassing fat, protein, lactose, and ash, aligns with reported ranges for other horse breeds. However, it tends to exhibit lower fat and total solids content compared to many other equine breeds. When compared to human and cow’s milk, mare milk is characterized by a higher lactose content and lower levels of fat and protein. This unique profile, particularly the higher lactose and lower fat content, means that mare’s milk, while having a lower caloric density than cow’s milk, derives most of its calories from sugars rather than fats. Furthermore, mare milk is rich in Omega-3 and Omega-6 fatty acids, which are easily metabolized and aid in nutrient absorption, while also containing all nine essential amino acids crucial for human health. The milk also boasts a higher level of immunoglobulin A (IgA) than human and cow’s milk, contributing to defense mechanisms against pathogens.
Fatty Acid Profile and Health Implications
The fatty acid profile of CCH mare milk also presents distinct characteristics. Saturated fatty acids (SFA) were prevalent, followed by polyunsaturated fatty acids (PUFA) and MUFA. The concentration of specific fatty acids, such as capric acid (C:10:0), was found to be on the lower end of reported ranges and may be influenced by breed. Odd-chain fatty acids, like pentadecanoic acid (C15:0), were detected in lower concentrations, suggesting minimal absorption of microbial fatty acid origins. Eicosenoic acid (C20:1n9 Cis-11) was also identified, likely originating from the pasture-based diet.
A significant finding relates to the atherogenic index (AI) and thrombogenic index (TI) of CCH mare milk, which averaged 0.95 and 0.35, respectively. These indices were negatively influenced by DIM and were lower than those reported for cow’s milk. This suggests that mare’s milk may pose a reduced risk to cardiac health compared to cow’s milk, a relevant consideration for consumers with cardiovascular concerns. The fatty acid profile also showed changes with lactation stage, with SFAs decreasing and MUFAs increasing as lactation progressed.
Immunoglobulin G (IgG) Concentration
The concentration of IgG in CCH mare milk varied among the farms, with higher levels observed in milk from Farm B. While the precise reasons for this variation remain unclear, dietary factors and pasture composition are potential contributors. Unlike some studies, maternal parity (number of foalings) did not show an association with milk IgG concentrations in this research. The provision of IgG through mare’s milk is critical for foals, as the equine placenta does not effectively transfer immunoglobulins in utero, necessitating high levels in colostrum and milk for passive immunity.
Conclusion
The study on Chilean Corralero horse milk reveals a unique nutritional and immunological profile, influenced by lactation stage, farm management, and offspring sex. CCH mare milk exhibits a favorable composition with high lactose and lower fat content compared to human and cow’s milk, coupled with potentially lower cardiac risks due to its fatty acid profile. The variations observed among farms highlight the importance of management practices and environmental factors. Further research into the specific dietary components and their impact on milk composition could unlock even greater potential for both equine health and human applications of mare’s milk.
Supporting Information
- S1 Table: Pearson’s correlation matrix detailing significant correlations between various milk components and fatty acids.
- S2 Table: A comprehensive list of references from a Web of Science search related to mare milk composition studies.
- S1 Dataset: The raw dataset used for the analysis in this study.
