The first part of this series, which appeared in the February 2017 issue, explored the importance of knowing the components and their concentrations in milk or milk replacer. This installment will focus on how the processes of mixing and feeding can affect consistency in dairy calf nutrition. 

The mixability of the milk replacers are extremely variable.  Some milk replacers are difficult to get into solution and then tend to settle out soon after mixing.  Most of the reputable milk replacer companies have the option of purchasing product that has gone through an “agglomeration” process.  This greatly enhances the ability of the product to go into solution and stay in solution after mixing.  This is obviously an extra expense for the manufacturer and will add approximately $1 to $2 to the cost of each bag.

A mixing system that has excellent agitation is necessary to thoroughly mix the mixed ration (MR) into the water and get a uniform product.  It is also important to check the percent solids at the time of feeding, in case the product has settled out during the process of filling the bottles or when transported out to the calves.  Large dairies that are filling hundreds of bottles in a trailer should check the first and last bottles filled to see if there is a difference.  Some dairies have seen as much as a 2% difference in percent solids from first to last bottle.  This can be due to a poor mixing system and/or a poor quality MR that does not stay in solution.

The next challenge comes during the feeding process.  Calves need more milk than was previously thought.  A general recommendation is to feed the calf about 15% of its birth weight the first week of life and then increase that to 20% of its birth weight at eight days of age until starting the weaning process.  This would be approximately three quarts twice a day for the first week and four quarts twice a day starting the second week of life for Holstein calves. 

Weaning should be based on the dry matter intake of starter and not on the age of the calf.  Research has shown that feed conversion is improved when the calves are fed more times per day.  For this reason, some dairies are feeding two quarts three times per day for the first week and then increasing that to three quarts three times per day starting the second week of life.  These calves can gain approximately 2.0 pounds per day from birth until weaning on this program.

If the calves are fed with bottles, then the amount fed per feeding is fairly accurate if they are all filled to the same level.  Nursing bottles are available in two-, three- and four-quart sizes which should work in almost every situation.  However, if feeding in pails, then the amounts fed are often quite variable, especially if delivering the milk in a tank with a hose.  Many calf hutch systems come with their own feed buckets or pails that are specifically designed to fit the holders for that hutch.  It is very common on large dairies to see different brands of hutches on the farm with different styles of pails.  If the feeder is filling the pail to a specific level, then the actual volume of milk delivered may vary significantly depending on the shape and size of the pail.  It would be advantageous to purchase a system that would meter out the exact amount of milk desired to each calf.  One such system currently on the market is called the Feed-R-Meterä.  Feeding the exact amount to each calf each day will greatly reduce digestive upsets in the calves.  The temperature of the milk at the time of delivery should be 100 to 105 degrees Farhenheit to improve digestibility and reduce the energy cost to the calf.

Another challenge is automated calf feeders.  Because these feeders are computerized, it is often assumed that there is no need to monitor the percent solids, volume fed or temperature at delivery to the calf.  Research has shown that there is a tremendous amount of variability in these systems.  It is very important to routinely check the consistency of these feeding systems and record the information.  If the system has more than one nipple, each nipple should be checked for percent solids and temperature.  It is recommended that the nipple height be 15 cm (5.9 inches) higher than the mixer outlet, and a maximum height of 60 to 70 cm (23.6 to 27.6 inches) above the nursing platform.  If less than 75% of the solids measurements are out of the desired range, the machine should be recalibrated. These systems should also be routinely checked for cleanliness.  Some have wash in place systems and others have to be manually cleaned.  Nipples and hoses should be changed on a routine basis.

Besides monitoring the percent solids, temperature, and volumes fed, it is extremely important to monitor the bacteria counts in the milk at the time it is being fed.  Current recommendations for pasteurized waste milk is less than 20,000 cfu/ml (colony forming units per millimeter) and less than 1,000 cfu/ml total coliform bacteria and less than 100 cfu/ml of E.coli.  Milk replacer should be less than 10,000 cfu/ml and less than 1,000 cfu/ml total coliform bacteria and 0 cfu of E.coli.  The total bacteria count for automated calf feeders should be less than 20,000 cfu/ml and the total E. coli should be 0 cfu/ml.  These samples should always be collected at the point where the milk is being fed to the calf.  If the bacteria numbers exceed the recommended levels, then additional samples must be collected from mixing to delivery to determine the point of contamination.

Free choice water is absolutely essential in all feeding programs.  When milk is fed, the esophageal groove closes and the milks goes directly to the abomasum.  Water in the rumen is necessary for proper rumen development, to provide the correct environment for anaerobic bacteria to grow.  It also improves hydration of the calf, especially when the calf is experiencing issues with diarrhea.  Water also helps to correct feeding errors if the calf is accidentally fed milk that is too high in solids, or the solids content is higher than the previous feeding.  Calf starter intake also improves when free choice water is available.  The water should be fed warm in the winter.  This decreases energy loss to the calf, reduces cold stress, and increases the time that it takes for the water to freeze.  It is obviously important to use water when calves are being fed oral electrolyte solutions.

There is a substantial amount of research published that proves the relationship between the amounts of milk fed, growth rates, and future milk production.  A higher plane of nutrition will result in decreased morbidity and mortality rates in milk-fed calves, improved growth rates, and higher levels of milk production when entering the milking herd.  Percent solids, protein and fat levels, and volume of milk fed are all important in maximizing the health and growth rates of the calves.  Maintaining the quality and consistency of the milk being fed will reduce digestive upsets during the milk-fed phase.  Consistency is important for stomach emptying, intestinal motility, and optimal digestion and absorption of nutrients.  Monitoring the consistency and quality of the milk on a routine basis is essential in a well-managed calf nutrition program in order to allow every calf to grow according to its own genetic potential and produce the maximum amount of milk possible as a lactating adult.