This article topic also appears in Progressive Dairyman. This article has been written specifically for dairy employees. The article in Progressive Dairyman is written for dairy owners and herdsmen. El Lechero recommends dairy teams read the articles and then discuss how to apply these principles on their own dairies.

The science behind harvesting high-quality milk

by Norm Schuring

The process by which a cow makes milk is complicated, but knowing the basic biology can help you better understand how to improve milk harvest. To achieve the goal of maximum milk production, cows must be handled correctly from the time they leave the pen for the milking parlor until the time they return. Ultimately, your actions around the cows have a direct impact on milk letdown, stimulation and udder health.

Biology basics
Before milk is released from the udder, many steps take place inside the cow’s body. First, cows must eat the feed and drink the water used for maintenance of their body’s functions as well as milk production. Once cows have consumed the feed, microbes in their stomachs, especially the rumen, break feed down to be used as energy. The breakdown will also produce important nutrient building blocks, like amino acids, which are necessary for quality milk production.

These nutrients are then carried to the mammary gland where they encounter multiple hormones and processes that turn them into milk. Once the milk is made by the cow, it’s your job to harvest it. Focusing on proper cow handling, stimulation and comfort will help cows successfully let down milk at the highest yields without negatively impacting milk quality.

Milk letdown
Proper milking procedures not only promote high-quality milk production, but also stimulate the udder for milk letdown. Don’t take milk harvesting for granted – just because the milk is in the udder doesn’t mean your job is just to attach the milking unit. The majority of the milk in the udder cannot be harvested unless the cow provides it through a process called “milk letdown”.

Milk letdown is caused by the hormone oxytocin, which is released when cows are comfortable and experiencing a familiar milking process. If operator routines do not provide a consistent and properly completed procedure, some cows will begin oxytocin release as soon as they see or hear the parlor. Other cows wait for stimulation from touch, which is done through the premilking routine of predipping, forestripping and wiping. Milking units should be attached in the first 60 to 90 seconds after the start of udder stimulation, which is when oxytocin levels are at their highest.

If cows feel stressed when entering the milking parlor their bodies release the hormone epinephrine, which blocks oxytocin and slows the milk letdown process. Loud noises and rough handling can trigger epinephrine release, which can impact milk flow and quality as well as teat end health.

Why focus on milk letdown?
Proper milk letdown is one of the key components to your job because milk letdown has such a critical role in the overall success of the milking parlor. Improving milk letdown in the parlor can positively influence:

• Milk quality. Without proper letdown, milk doesn’t flow when the milking unit is first attached. The result is stress to the teat ends and cows kicking off the attached units, which can increase the risk of more cases of mastitis.

• Harvest. When proper letdown occurs, cows will completely milk out, which can result in more milk harvested. You can also spend less time dealing with individual cows that don’t milk out properly.

• Parlor throughput. If cows milk out faster because of proper udder stimulation through predipping and wiping and oxytocin letdown, the time each cow spends in the parlor is lowered. This results in improved parlor throughput.

• Profitability. Improved parlor throughput, fewer udder health problems and more milk harvested all lead to additional profits for the dairy.

Tips for proper milk harvest
Making changes in the milking parlor can improve milk letdown. Now that you understand the biology behind letdown, focus on the following areas to ensure you’re providing the best environment and procedures for optimal letdown.

• Proper milking procedures. Utilizing proper udder stimulation will encourage faster milk letdown. Include predipping, forestripping and wiping in your premilking procedures so the milk is ready to harvest when the machine is attached.

• Handle cows with care. Pushing cows into the parlor and rough handling can slow release of oxytocin and milking time. Treat all cows with care so they are comfortable once they’re in the parlor.

• Avoid loud noises. Loud noises can have an impact similar to rough handling, which means shouting and loud radios can negatively affect the cows. Remember that the cows are the highest priority in the parlor, so providing the proper atmosphere can ensure better performance.

As a milker your number one responsibility is harvesting high-quality milk from cows that are performing to their potential. Focus on milk letdown through proper stimulation and the right environment to take advantage of all the milk the cows produce. EL