Milk quality defined

Target areas for optimal health in goat operations


AMES, Iowa — Milk quality in goat operations goes beyond what is found in the dairy section at the grocery store. Since many dairy goat producers utilize milk for artisanal body products like lotion and soaps, milk quality is important to those industries as well.

Dr. Fauna Smith presented information on the definitions and benefits of high-quality goat milk in a webinar Dec. 21, 2023, hosted by the Iowa State University Extension and Outreach.

There are five target areas to consider when thinking about milk quality in dairy goat herds. The first is that the milk be free of debris and sediment. The easiest way to achieve this is to keep animals clean while milking. When there is a lot of hair on the mammary system, it is easier for debris to get caught in it and therefore make its way into the milking system.

“A good dairy clipping can help with this,” Smith said. “In addition to keeping the udder clean, this also stops any product that they continue to pass after kidding from getting caked onto the udder.”

If a goat is not long-haired or has been shaved but still comes into the parlor dirty, it is recommended that she be cleaned off before the milking procedure is started.

For producers using sawdust for bedding, Smith recommended opting for the kiln-dried variety, since it aids in preventing bacteria growth.

To be considered high quality, milk must also be free of off-flavors and abnormal color or odor. Nutrition can play a big part in this, Smith said. While she was practicing medicine in New Zealand, some of the dairy animals grazed on cover crops, the most common being turnips.

“You actually have to limit the amount of time animals spend grazing on brassicas,” Smith said. “Otherwise you will get a brassica-flavored milk that is very obvious.”

Mastitis or other inflammation can cause a salty tasting milk. Even a subclinical case that does not necessarily have an abnormal appearance will taste salty if there is a high enough amount of sodium chloride in the system.

Additionally, a severe infection or breakdown of the blood-milk barrier will cause a discoloration of milk, resulting in a brown or red appearance. Some severe cases of infection can change the color of milk to yellow or clear.

Handling of the milk post-harvest has an impact on the quality and flavor of the milk. Quick cooling achieves the greatest reduction in souring of the milk.

“If you’re a homesteading operation, an ice bath can help and be faster than a freezer,” Smith said. “It improves the quality and longevity of the milk as well.”

Keeping a low bacteria count is also important in the production of high-quality milk. Smith said there are two sources to think about for bacteria ending up in the final milk product: the milking environment and the animal itself. Clean, disinfected teats and clean, properly maintained equipment are both key factors in keeping bacteria counts low.

As an example, Smith said that coliform problems are often assumed to stem from animals. However, it is more likely that the equipment is not being maintained and cleaned properly.

“One thing a lot of people forget about is changing gaskets in the joints of the pipeline system,” Smith said. “Those can break down over time and end up becoming pockets for bacteria to hide in.”

Milk should always be free of chemicals, Smith said. This can include antibiotics, detergents, disinfectants and other medications that are administered along with dewormers and anti-inflammatories. Drug withholding is important, Smith said.

“One of the challenges with goats is that we have very few drugs that are actually labeled for use in goats,” Smith said. “Many producers use a withdrawal period that is prescribed for cattle. Your vet who prescribes the drug should be giving you a withholding period.”

For example, Smith said that the withdrawal period for Liquamycin LA-200 is about 10 days in dairy goats and only 96 hours for cattle.

Finally, high-quality milk should have normal composition and acidity. Butterfat, lactose and protein make up the composition. Different stages of lactation and the age of the goats can impact what is considered normal for an animal. Somatic cell count should also be considered. For herds not on DHIA test, Smith recommends a California mastitis test or a strip cup to help determine the quality of the milk being harvested from the herd.

Smith even uses the CMT test if a goat appears ill. She will administer the test and take the goat’s temperature as part of an overall exam.


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