It has been a common practice to feed non-salable hospital milk to dairy calves. It is obviously much more economical to feed this milk than it is milk replacer or milk from the bulk tank that can be sold.
The general consensus among the dairies that are feeding hospital milk is that there are no adverse effects on the health and growth of the calves. However, recent studies have shown that pasteurizing hospital milk results in lower morbidity and mortality rates as well as improved growth rates. As a result, many dairies have installed pasteurizers on their farms to pasteurize hospital milk. The majority of these dairies have observed a distinct improvement in the health and growth of their calves.
However, pasteurization of the milk is not the same as sterilization. Pasteurization will usually reduce the numbers of bacteria by 90-98%. If the bacteria numbers in the hospital milk are extremely high, then there could still be significant numbers of bacteria in the milk following pasteurization. It is important to collect samples of the hospital milk before and after pasteurization in order to monitor both bacteria counts and the proper function of the pasteurizer.
Pasteurization also does not have any effect on reducing the amount of antibiotics that may be in the milk from treated cows. Because of the new Veterinary Feed Directive, or VFD, going into effect this month, there has recently been an increasing level of interest in the presence of antibiotics in animal feed. Under the new regulation, antibiotics will no longer be allowed to be added to animal feed as growth promotants.
Hospital milk and saleable milk are considered by the FDA to be feeds. The only antibiotics that can be added to milk are those that are specifically approved for addition to milk. These can only be added with a VFD from a licensed veterinarian to treat a specific disease condition for a limited amount of time.
However, the antibiotic residues that are present in hospital milk from treated cows are not considered to be illegal feed additives by the FDA. Therefore, at this current time, there are no restrictions in place that would prevent hospital milk containing antibiotics from being fed to dairy calves.
The VFD is a direct result of concerns about low levels of antibiotics being routinely fed to food producing animals, and the potential for antibiotic resistance being developed by pathogenic bacteria that could cause disease in both animals and humans. Because of this concern, it is very likely that in the near future, hospital milk containing antibiotic residues may no longer be allowed to be fed to dairy calves.
Are there any detrimental effects when calves are fed milk that contains antibiotic residues?The answer is yes. All animals have bacteria in their gastrointestinal tract. These bacteria play an important role in maintaining the normal, healthy status of the intestinal lining, and the development of the local immune response in the intestinal wall. They are also involved in stimulating the production of a layer of mucous that lines the intestine and prevents the contact of pathogenic bacteria with the cells of the intestinal lining.
Antibiotic residues in hospital milk can have a negative impact on the normal flora of the intestine. This can have a negative impact on the animal's immune system, increase inflammation in the intestinal wall, reduce the amount of mucous protecting the intestinal wall, and reduce the competitive inhibition that these organisms have on pathogenic bacteria. This could result in a number of different signs in the calves, like loose stools, reduced growth rates, decreased feed efficiency and decreased nutrient absorption. Some cases may result in severe diarrhea and dehydration.
Note: This story appears in the January 2017 issue of Dairy Herd Management.