How to Evaluate Hospital Milk

By Dr. Joe Menicucci, TDA veterinarian

The younger the calf, the less room there is for error when it comes to the quality of milk fed. And while non-saleable milk, also called “waste milk” or “hospital milk,” is an inexpensive feed source for pre-weaned calves, the nutritional value, total milk solids, and bacterial load are all highly variable.

Milk from a healthy fresh cow that is not yet ready to go into the bulk tank is very different from milk from a mastitis cow, a treated cow, or a cow sick for other reasons. But on a lot of dairies, all of that milk ends up in the same bulk tank and is fed to calves. Hospital milk fed to pre-weaned calves should be treated like any other feed source on the dairy and have quality control guidelines.

Pasteurization of hospital milk is a good first step. It reduces the bacterial load, but it cannot turn poor-quality milk into good milk. Therefore, do not include milk from cows that are shedding BVD, or Johne’s. The same applies to cows with Mycoplasma or Salmonella. The goal should be to limit the exposure of young calves to those pathogens as much as possible.

Feeding milk from cows treated with antibiotics can also be a concern. Pasteurization does not remove antibiotics from milk, so feeding milk from cows treated with antibiotics potentially exposes the calf’s intestinal bacteria to antibiotic residues over and over again. I recommend every dairy develop a clear protocol for how they will handle milk from cows treated with antibiotics.

Daily SOPs

Each day, calf feeders should evaluate hospital milk for:

• Appearance and smell.
• Milk temperature.
• Total milk solids using a digital refractometer.
• How long the milk was sitting before pasteurization.

Nutritionally, I like to see hospital milk remain close to 12.5% milk solids, and even more importantly, consistent from one feeding to the next. Milk from mastitis cows, or diluted hospital milk can fall well below that level. If total solids are low, first determine why. Look for water contamination from flush water, inconsistent milk sources, or changes in the proportion of transition, mastitic, and hospital milk entering the tank.

Once those problems are addressed, the milk can be standardized using an appropriate milk balancer or milk replacer powder. The amount added should be weighed and calculated based on the product’s actual solids rather than simply adding a scoop to every batch. The goal is to provide calves with a consistent concentration of protein, fat, vitamins, minerals, and total nutrients at every feeding. After fortification, use the refractometer again to make sure the final product contains the milk solids you want.

Testing pays

Periodically collect milk samples after pasteurization and send them to the lab for a total plate count. As a practical goal, I want to see post-pasteurization milk below 20,000 CFU/mL. In addition, I recommend periodically sampling milk at the point where the calf actually receives it. If the bacterial count rises substantially from the pasteurizer to the calf, the problem may be in the storage tank, hoses, milk taxi, bottles, nipples, or buckets used to feed the calves.

To make sure the pasteurizer is actually doing its job, periodically collect milk samples before and after pasteurization for testing. If the total plate count in milk is extremely high before pasteurization, then I start looking at how the milk is collected, stored, and handled before it gets to the pasteurizer. But if the bacterial count before pasteurization looks reasonable, but the count after doesn’t decrease to your goal of 20,000 CFU/mL or below, then I start looking at the pasteurizer itself—cleaning, calibration, holding time, hoses, tanks, or even contamination after pasteurization.

When calf health problems develop, increase the frequency of milk sampling and testing. Collect samples from several points within the system, as this can help determine where bacterial contamination occurs.

Remember, not all hospital milk is the same. For best results when feeding hospital milk, always evaluate for nutrition, bacteria, and biosecurity – what cows are contributing to that milk and are we comfortable feeding the milk to replacement heifers or to beef on dairy animals headed for the food supply. Contact your vet, or one of the Dairy Authority veterinarians, to learn more on how to evaluate and safely feed hospital milk to pre-weaned calves.