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Dairy Pipeline: February 2005
Robert E. James
Extension Dairy Scientist,
Dairy Nutrition
(540) 231-4770
email: jamesre@vt.edu
How do you evaluate milk replacers for your feeding program? The first question asked is: What's the cost of a bag? It's amazing to see the difference in prices of milk replacers from one manufacturer to another. In the case of the calf less than one month of old, economizing by purchasing the cheaper milk replacer may not be the best decision. Did you feed your children the cheapest food during their early childhood? The same logic should apply to the young calf. These animals require highly digestible diets. How do you evaluate the milk replacers being considered? There are several key things to consider in evaluating a milk replacer. The primary nutrients in milk replacers are protein, fat and carbohydrate. Most milk replacers are based upon whey proteins (a byproduct from cheese making). They will appear as dried whey, whey product and whey protein concentrate. The principal difference in the three forms is the amount of lactose and mineral removed from the dried whey. Dried whey contains only 12% protein, while whey protein concentrate can be as high as 80% protein. Unfortunately there can be significant variation in the digestibility of whey proteins due to type of cheese being made, drying temperatures and handling procedures. The best quality milk replacer manufacturers know the source of their whey proteins and test frequently for quality. Although skim milk may appear on the tag, it is usually present in amounts less than 1% of the total mixture and is included as "tag dressing" to create the impression of higher quality. Soy proteins are of lower digestibility and amino acid content and cause allergic reactions by the gut tissue. Soy flour is indicative of poorer quality even if protein levels in the milk replacer are above 20%. At the present time, there is not enough research to suggest that egg proteins are advisable due to their lower digestibility, particularly when the egg product contains the albumin. Fat is usually supplied by animal fats such as tallow or lard. High digestibility is assured when the fats are homogenized to produce small fat droplets and an emulsified such as lecithin is included. There is only limited research supporting use of vegetable fats. Carbohydrate is supplied by lactose, the only carbohydrate that is digestible by the young calf. The "intensive" milk replacers commonly contain higher levels of protein (24 to 28% vs. 20%) and require that they be fed in higher amounts. It's hard to believe that the extra cost of these "intensive" milk replacers can be worth it, but successful adopters of this feeding strategy report higher gains and better body condition of calves which results in lower mortality and quicker recovery if calves get sick. With your baby calves, cheaper is not always the most advisable strategy. Closely check the ingredients and ask for research which supports the use of their products.