Carbohydrates in Powdered Milk

Replacers

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Dietary considerations

Digestible carbohydrates are essential for growth and development, as well as being a substantial source of dietary energy. Digestible carbohydrates include lactose, starches and other sugars. The types and amounts of carbohydrates vary in the milk composition of species and include lactose, oligosaccharides, glycolipids, glycoproteins, mucins. Research continues on the types, digestibility and potential consequences of various carbohydrates fed to young animals. 

Lactose, the predominant carbohydrate in milk, has been and continues to be researched extensively. It has been found to have many nutrient benefits, including a significant and sustained promoting effect on absorption of calcium and other minerals. Other carbohydrates in milk are also being found to have functions besides nutrition.

Oligosaccharides are a complex mixture of carbohydrates that make up the third most abundant constituent in milk.  They also change in concentration during the period of lactation. Milk-derived oligosaccharides have been found to help many factors in the body including to: promote immune response, influence gastrointestinal health, reduce inflammation, affect brain development, and more. In addition to being found in milk components (e.g., whey, dried cream), various oligosaccharides have been identified in vegetables, grains, honey, and more. Oligosaccharides are getting considerable attention as a food product, supplement, probiotic, medication, and more. Research on oligosaccharides is expected to offer more insights into their role in milk, as well as many other functions and sources.

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Calculating carbohydrate concentrations

The lab tests and results discussed in WildAgain's research are reported values for primary dietary components such as proteins, fats and ash (minerals) as assessed in a 'Proximate Analysis.  To measure carbohydrates (as a group of sugar and starches), an equation is used to determine the value. It is referred to as a Nitrogen-free extract (NFE) and is a vital part of animal feed assessment. It is not analyzed, but rather calculated. And contrary to the name, this analysis does not pertain to nitrogen. The equation used to measure NFE is straightforward - simply subtract the concentration values for moisture, protein, fat, ash and fiber from 100. For example, for a dry milk powder, if the values for moisture (5%), protein (33%), fat (40%), ash (8%) and fiber (0%) added to 86%, then the estimated value for total carbohydrates would be 14%.

Lab tests are available to analyze and measure specific carbohydrates, such as oligosaccharides mentioned above, but are generally fairly expensive. And if such a test is performed, it may just provide the knowledge that a certain carbohydrate is either absent, or present in a measured concentration. And for most wildlife species, a baseline concentration is likely unknown.

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Milk replacer analysis

The two primary manufacturers of the milk replacer products used by wildlife rehabilitators appear to approach managing carbohydrate levels using different formulations. PetAg®, with the exception of adding very small amounts of dextrose and maltodextrins, appears to manage carbohydrate levels through blending low protein value dried milk protein concentrate, dried whey concentrate and skim milk powder that have relatively high carbohydrate concentrations, primarily lactose (see second table below). Alternatively, it appears that Fox Valley chooses to formulate their products with the addition of dried corn syrup solids, and in some products, also with dried lactose. Unfortunately, since the product labels do not contain detailed information as to types and amounts of specific carbohydrates included in the formulation, the only manner to determine such data is through expensive lab testing and beyond the scope of this current research study.