Volume 6 Issue 1
Dr. Susan Kerr, WSU Regional Livestock and Dairy Extension Specialist
There seems to be a resurgence of interest in small-scale/backyard/family dairies. Several breeds of dairy cows, goats, and even sheep are well-suited to this type of management system. Dairying involves a huge commitment of time, labor, infrastructure, and finances for many months; it should not be undertaken on a whim. Caring for dairy animals is not a lifestyle for those who like to travel, be spontaneous, or be away from home for extended periods. However, dairying can be a rewarding experience for those who enjoy routines, staying home, and working closely with animals.
Selecting the best species and breed for a given situation will depend on daily consumption (unweaned livestock offspring and humans), interest in making cheese for long-term milk storage, integration with other farm operations (e.g. pig production) and opportunities for legal sales. A future article will delve into this issue in more depth; this issue will focus on milking practices.
Quality Milk Starts with a Clean Environment
When dairy animals lie down, their udders are in direct contact with the floor. It is crucial that this surface be clean, dry, and comfortable. The risk of mastitis (udder inflammation and/or infection) increases greatly in dirty environments. Adequate bedding also helps reduce animals’ nutritional maintenance requirements. Straw, sawdust, or sand bedding should be cleaned of manure daily and supplemented as needed. Resting areas should be situated in areas not prone to flooding or accumulating wetness.
Teat and Udder Anatomy
Knowledge of udder and teat anatomy is needed to understand the milking process. Milk is synthesized from specialized epithelial cells in the udder using nutrients in the bloodstream. As shown in Figure 1, these cells are found in clusters (alveoli), which are surrounded by smooth muscle cells. The milk-producing cells secrete milk into the lumen (open center) of the alveolus. When a dairy animal is properly stimulated, the hormone oxytocin is released from her brain and causes the smooth muscle cells to contract, sending milk from the alveoli into ducts to the gland cistern of the udder, where it is stored until milking or suckling occurs. For optimal udder health, it should be regarded as a milk production system, not a milk storage unit.
The teat sphincter is critical to udder health and protection from infection. Within about one hour after milking, it has contracted and thereby helps prevent bacterial invasion of the teat and udder. If it is damaged by trauma, overmilking, or other poor practices, that portion of the udder is at greatly-increased risk of mastitis.
Interestingly, fear or stress just prior to milking can interfere with oxytocin release and milk letdown. For this reason, the milking area should be a calm and quiet place and animals should not be stressed getting into the parlor. Yelling, loud music, new people, or any changes in the milking routine can interfere with milk letdown.
Characteristics of Good Milkers
Many human factors are involved with an efficient milking process. First, good milkers are patient with animals and pay attention to details. They need to follow routine practices and be observant for any indications of mastitis or other animal health issues. They should wear disposable gloves to help prevent disease transmission from humans to animals, animals to humans, and animal to animal. Milkers must understand the importance of each step in the milking process and recognize that taking shortcuts puts animal health and milk quality in jeopardy. If children are milkers, they must be taught what constitutes normal and abnormal milk and to contact an adult if they observe any problems. Animals can die from mastitis.
Getting Ready to Milk
Long udder hairs should be clipped regularly to help keep udders clean. If udders are visibly dirty, they should be cleaned with dry paper towels if possible. When possible, avoid using water to clean udders because water will travel down the dirty udder onto the teat, possibly contaminating the teat opening. If it is necessary to wash the udder, use a disinfectant wash and dry the udder and teats thoroughly before continuing with the pre-milking protocol.
After teats are visibly clean (no obvious dirt or manure), apply a pre-dip half-way up the teat, ensuring a drop is observed hanging from the teat end. Pre-dips are commercial preparations proven to be effective germicides. Common products include chlorhexidine or one-percent iodine. Products must be licensed for this use; organic producers should contact their certifying organization to confirm use of approved products. Pre-dips can be sprayed on or applied with a dip cup; the former method is more sanitary but the latter is more effective. If dip cups are used, they should be stored in sanitary locations, dumped and cleaned if visibly contaminated, and disinfected periodically.
Leave the pre-dip on for the amount of time specified by the manufacturer—this is often about 30 seconds. After that, thoroughly remove the pre-dip by drying the teat with a new paper towel or clean, single-use towel; pay particular attention to cleaning and drying the teat end.
Fore-milked is Forewarned
After removal of the pre-dip, milk three or four squirts of milk onto a strip cup (Photo 1). This is a container with a black strainer that helps identify animals with abnormal milk. Also, it is good to remove these first squirts of milk because they tend to contain the highest number of inflammatory cells if they are present. Never check milk by squirting it onto the floor or your hand or boot—this is a good way to spread mastitis.