Dietary carbohydrates and fat influence milk composition and fatty acid profile of Mare’s milk.

This research investigates how dietary carbohydrates and fats affect the composition and fatty acid profile of mare’s milk, with comparisons made to the milk of bovines.

Introduction

• The research acknowledges that the production and composition of milk—including fatty acids, amino acids and vitamins—can be influenced by various factors, which include lactation stage, age, the number of pregnancies (parity), and nutrition.
• Previous studies are cited showing that milk from mares fed a diet high in forage, as opposed to those fed a concentrate-rich diet, showed different compositions. Specifically, forage-fed mare’s milk had higher levels of fat, protein, and linolenic acid, and lower levels of linoleic acid.

Fatty Acid Composition

• The research suggests that in hind-gut fermenting animals—like horses—there is little to no conversion (hydrogenation) of unsaturated fatty acids by intestinal microbes before absorption. This means that the long-chain fatty acid composition of the milk produced by these animals should directly relate to the fatty acid content in their diet.
• This is contrasted with bovine milk, which consists mainly of saturated fatty acids due to extensive hydrogenation of dietary fats by ruminal microbes before absorption.
• It is also noted that the content of roughage in the diet can impact the extent of hydrogenation. Low-roughage diets, for example, tend to reduce the proportions of saturated fatty acids, while increasing the proportions of other acids like oleic, linoleic, and linolenic acids in bovine milk.

Objective and Methodology

• The overall objective of this study is to compare the concentrations of specific elements in the milk of mares fed on different diets. These include protein, immunoglobulin G (IgG), fat, fatty acids, lactose, and solids not including fat.
• The diets tested involve pasture with added concentrates rich in either starch and sugar or fat and fiber, both of which have previously been found to influence growth.