The adoption of automatic milking systems, or robots, on dairy farms across the country and the world has resulted in changes to cow comfort, management techniques, labor control, and producer lifestyles. But what about changes to our product — whole milk?
Why might robots affect milk cleanliness?
When contemplating transitioning to or adding robotic milkers, it’s important to realize the new system could have effects on your somatic cell count (SCC) and bacteria count. Consider the changes to the milking process that come with robots:
- More frequent milkings
- Adjusted, and often variable, intervals between milkings
- No human control for observing and recording signs of clinical mastitis
- No human control for cleaning teats
- Unit is removed from each quarter as it finishes, rather than all at once
- Collection of more, individualized data
The use of robots does not appear to have much of a direct influence on milkfat, protein, lactose, or casein levels. However, each of the milking procedure factors listed above has the potential to influence milk quality, positively, negatively, or even both. A recent paper published in the Journal of Dairy Science from authors at the University of Milan compiled results from a variety of studies to analyze how these effects of automatic systems influence milk quality.
Somatic cell counts
The paper cites experiments from the Netherlands, Denmark, and Finland that all found elevated herd SCCs after introduction of robotic systems. A common explanation for this jump was the increased milking frequency correlated with robots. With additional milkings, the teat end is open for more time throughout the day and could allow for more bacteria to enter the mammary gland.
Conversely, another Danish study was included that found a slow drop in the number of high-SCC cows three months after the adoption of robots had initiated a slight uptick. The authors explained that longer periods of open teats could also give bacteria more opportunities to drain out of the udder, preventing potential infections from festering too long.
Other more recent studies have found no significant difference in SCC between conventionally harvested milk and robotically harvested milk.
The progression of these studies suggests that robotic technology advances in the past decades have resulted in more consistently low-SCC milk. An adequate adjustment period after the transition must also be expected and accounted for in terms of milk quality in addition to cow comfort.
The authors of the paper suggest that with no human controls in the parlor, current automatic milking technologies can easily malfunction and do not always obtain optimal teat cleaning. They provide this reason to support multiple studies finding raised bacterial levels in milk harvested by robots.
But if the system operates with regular line flushing and teat brush cleaning, there is evidence of little change in bacteria levels. It’s important to remember that bacteria levels are also heavily influenced by the rest of a cow’s environment, including the cleanliness of human milkers.
The paper concludes that most changes seen in these studies are small or even subject to variance from other factors. Therefore, there is no immediate threat to milk quality from robotic milkers. Farmers who use robots now, or may in the future, need not hold off because of concerns to milk cleanliness.
As with any other tool, though, automatic systems must be managed effectively to ensure the best possible results.