Articles

"Selecting A Milk Replacer"
Mike Watkins, Ph.D.
Dairy Manufacturers, Inc.

Dairy producers, professional calf raisers and other milk replacer buyers can learn about milk replacers from several sources including information given on milk replacer labels and brochures, user testimonials, and comments from salespeople and/or dealers. There are two types of milk replacers, those containing all-milk proteins and those containing milk proteins plus non-milk proteins. Then, there are different formulations within each type.

All-Milk Milk Replacers

Milk replacers using only milk-derived proteins are the “gold standard” by which all other milk replacers are measured. “All-milk” milk replacers use one or more of the following protein sources for all of the protein: dried non-fat skimmed milk, dried whey, dried whey protein concentrate, or dried milk protein concentrate. When price permits, dried buttermilk or dried buttermilk product may be included. Protein and fat guarantees vary from 18.0% to 28.0% and 10.0% to 25.0%, respectively. Label information gives the nutrient content and the ingredients used, but the quality of ingredients used may depend on the integrity of the manufacturer.

Milk + Non-Milk Protein Milk Replacers

In the other type of milk replacer, non-milk proteins provide part if not all of the protein. Calves fed products containing non-milk proteins do not consistently perform (growth, health, feed efficiency) as well as calves fed an all-milk product. Non-milk proteins are usually cheaper than milk proteins; thus, these milk replacers should be cheaper than all-milk milk replacers. Soy flour is the primary plant protein used; however, other soy proteins (soy concentrate or soy isolate), other plant proteins (i.e. potato protein), and still other non-plant proteins such as brewer's yeast, dried whole egg, fish solubles, etc. may be prominent in the ingredient statement of these products. Dried red blood cells and animal plasma are now disallowed as a measure to prevent the spread of BSE (as of Spring 2004).

Two percent more protein for each 1.0% increase in fiber is recommended to help compensate for the lower digestibility of milk replacers containing soy flour and other similar non-milk proteins. In addition to being less digestible and higher in fiber, milk replacers made with plant proteins may contain anti-nutritional factors, have an inappropriate amino acid pattern, and be less palatable. Calves are better equipped to digest these products when their rumen is sufficiently functional, about three weeks of age or older.

Decision Factors

First, decide which type of milk replacer you want to feed to your calves. Second decide which formulation will help your calves deliver the performance sought within the feeding season.

The most popular milk replacers contain 20.0% protein and 20.0% fat. Mixing directions usually recommend mixing 1 pound of powder with warm water to make a gallon of milk (about 12% dry matter) ready to feed. Feeding directions recommend feeding the milk at 8% to 12% of body weight. Calves fed one gallon of this milk daily consume about 1 pound of milk replacer dry matter. As will be noted in the table below, potential calf performance is restricted at this feeding level and formulation.

Milk replacers containing 28% protein and 15% fat all-milk and mixed to contain higher dry matter content (17.50%) are being adopted by progressive feeders. One and one-half pounds of the powder is mixed with enough warm water to make a gallon of liquid milk. Feeding rates are similar to those for conventional milk replacers. Calves on this feeding regimen grow faster, the gain is of more lean muscle, and the calves are reported to be healthier (fewer scour days) and have a greater number of cells with milk- producing potential in their mammary glands. The performance is nearer that of calves fed whole milk or allowed to nurse free choice. Nursing calves consume 16% or more of their body weight daily.

Environmental temperatures, especially low temperatures, impact the nutrient needs of newborn calves. Newborn calves have a large surface area to body volume, minimal body fat and light hair coat. Calves require more energy in cold weather to maintain core body temperature, and this additional energy has to come from milk. (Don’t expect a young calf to increase its starter intake to compensate because it can’t). A calf nursing its dam can nurse longer and more frequently to get additional energy needed to maintaining body temperature. Unfortunately, a bottle-fed calf will likely suffer because the feeder feeds the same amount of a 20-20 milk replacer day-in and day-out regardless of how cold it gets. Calves also use energy in summer to cool themselves, but much less additional energy is required for cooling, unless the heat is extreme. Summer heat depresses appetites, lowers feed intakes, and lowers growth rates. Calf performance can be compromised as temperatures move below the lower critical temperature (<21 days old - 68º F, >21 days old - 42º F).

Variation in Calf Performance Depending on Milk Replacer Type, Amount Fed, and Environment Temperature

Performance of a 95 lb. calf fed a 20-20 or a 28-15 milk replacer at 4, 6, 8 and 10 quarts daily, during cold, ambient and hot weather is used to illustrate the points above (Dairy Model, NRC for Dairy Cattle, 7th Ed., 2001).

Milk Replacer ADG Feeding Rate* 4 qt. 6 qt. 8 qt. 10 qt.
20-20 Lb. Powder 1.0 1.5 2.0 2.5
Temperature 100ºF
Energy Allowable 0.45 1.21 1.87 2.50
Protein Allowable 0.53 0.92 1.31 1.70
Temperature 70ºF
Energy Allowable 0.51 1.27 1.95 2.50
Protein Allowable 0.54 0.93 1.32 1.70
Temperature 10ºF
Energy Allowable Wt. Loss 0.13 0.96 1.65
Protein Allowable Wt. Loss 0.92 1.31 1.70
28-15 Lb. Powder 1.5 2.25 3.0 3.75
Temperature 100ºF
Energy Allowable 1.15 2.11 2.99 3.82
Protein Allowable 1.46 2.31 3.16 4.01
Temperature 70ºF
Energy Allowable 1.15 2.11 2.99 3.82
Protein Allowable 1.46 2.31 3.16 4.01
Temperature 10ºF
Energy Allowable 0.02 1.23 2.18 3.03
Protein Allowable 1.46 2.31 3.16 4.01

*Each quart of reconstituted milk replacer weighs approximately 2.15 lb. Calves fed at 8% to 12% of their body weight would receive from 3.5 qt. to 5.3 qt. daily. The calculations are for intakes indicated by the feeding rate and dry matter (lb. of powder) delivered.

Calves fed the 20-20 in ambient and hot conditions produce equivalent allowable gains from energy and protein when fed one pound of dry-matter per day; however, feeding greater amounts of dry-matter skews the gain toward fat and away from lean tissue. Feeding the 20-20 at this rate during very cold conditions requires that the calf use body tissue to maintain body temperature. These data indicate that the feeding rate must be increased by about 50% just to keep from losing weight.

Feeding the 28-15 at the lowest level during cold weather allows the calf to maintain itself with a little gain. As the amount of 28-15 fed is increased, the allowable gain for fat and for protein remains in balance rather than skewing toward more energy available for fat deposition. Additionally, calves fed on a higher plane of nutrition use the nutrients more efficiently.

The advantages of following a feeding program using a 28-15 milk replacer as opposed to a 20-20 are becoming more apparent as more heifers raised on the program calve and enter milking herds around the U.S . The cost of feeding a 28-25 is greater, but this initial investment must be weighed against the returns of having heifers enter the milking herd earlier (23, 22 or 21 months old as opposed to 24+ months old) and producing at a higher level.

Making an informed decision about which milk replacer to buy is more important than some people realize. The decision affects not only the future value of the investments made in breeding decisions, semen cost, calf mortality and morbidity, but it also affects the performance of the heifers months later when they enter the milking herd.