by Bill and Mary Weaver
Extension veterinarians like Dr. Ernest Hovingh get to see a lot of milking parlors over the years, and come to expect certain problems crop up. Dr. Hovingh has seen ways milkers could, but often don’t, prevent parlor-acquired mastitis. Let’s look at this potentially costly problem.
1. Gloves are great to protect sore, chapped hands and to make sure bacteria (including Staph. aureus) from workers’ hands don’t contaminate the teats or equipment. “But the really big thing with gloves is that they’re easy to clean and sanitize. If you have dirty gloves and aren’t cleaning and sanitizing them, they’re not really doing much good,” stated Hovingh. In fact, the gloves may be doing harm. “A common problem I see is that milkers with dirty gloves can cause exposure to mastitis pathogens as they go from cow to cow.”
2. Strip those teats. Get some milk out and examine it, preferably in a strip cup. Otherwise, you could miss subtle signs of mastitis in mildly clinical cows. If you see flakes or clots or stringiness, report it. Unreported mastitis, for all intents and purposes, does not exist. Forestripping also stimulates milk let-down, which is important to achieve high milk-flow rates, and decrease unit on-time.
3. Use a predip and a postdip that have been demonstrated to work against the particular pathogens in your herd. This is most important if you have contagious pathogens in your herd, like Staph. aureus or S. agalactiae. Make sure the predip has adequate contact time to kill the pathogens.
4. Using either a non-return dipper or a foamer means it’s much easier to get good coverage of the teat. Sprayers can work, but it’s much more difficult to get good coverage.
5. Don’t use contaminated predip. Even though predips kill bacteria, they can become contaminated with yeasts and molds and other nasty stuff that can also cause mastitis. Scrub and sanitize your dipper at least every milking, and sanitize your foamer regularly too.
6. Final wipe — actually look at that teat end. “Workers tend to clean the teat barrel well, but may skip that all-important teat end if they’re in a hurry or not paying attention.”
7. Make sure the final wipe of the teats is done so as not to re-contaminate sanitized teats — start with the far teats, and then do the near teats. “Especially if I have a cow with a low-hanging udder, my forearm can contact an already-cleaned teat. Then I’ve wrecked everything I’ve been trying to do. I see this very commonly.”
8. Dr. Hovingh prefers cloth towels for their stimulation and absorbency. He believes they should be washed with hot water and good quality sanitizer soap, in a washer that is not overloaded. “Take a Sharpie,” he advises, “and put a line inside the washer to show maximum loading capacity.” It’s best if the towels are dried. Moist towels, left for any length of time, can start growing bacteria again, and it’s more difficult to dry a teat well if the cloths are wet.
9. Check up on the cleaning. You can do this in several ways. Culture small pieces of “clean towel.” If they’re culture-positive straight out of the washer, you kind of wonder if you need to look at procedures. You can also check clean-looking teat ends by scrubbing them with gauze. “If I see a little discoloration, a little predip, I can live with that. But I shouldn’t see manure. A nice visual for your milkers is to touch the teat ends to a culture plate after they’ve been prepped, and see what grows. You can also hang the milk filter out for workers to see. You can assume that all the bacteria did not stay on that filter!”
10. Don’t let the teats get filthy in the first place. “If you start with 10 bazillion bacteria, and get 95 percent of the bacteria cleaned off, you still have a lot more left than if you started with a relatively clean teat and cleaned off 90 percent of them.”
11. Put the unit on promptly — but make sure you wait at least 60 seconds — and preferably 90 — after the initial stripping of milk from the udder.
12. Unit alignment is important in preventing parlor-acquired mastitis. The challenge is to put the unit on without twisting, and make sure it’s hanging straight under the cow. If you put on the inflation, and the unit twists at all, the milk flow in the twisted quarter can drop dramatically, and you get unevenly milked out quarters.
13. A twisted unit can also cause linear squawks and slips. When you have a linear slip, the teat end can be held open a little, and you have the potential of bacteria shooting up into the teat, as the air rushes in through the slip on one quarter to neutralize the vacuum. It’s possible the pathogens could be caught on the side of the teat cistern, and end up becoming resident. If you had Staph. aureus in a previous cow, and get Staph. aureus on the inside of the inflation of the claw, the results could be costly. Slips can also be caused when the vacuum in the system or the claw is too low.
14. Get the unit off quickly after the milk flow slows. Left on too long, the unit can cause irritation of the teat end and hyperkeratosis, leaving cracks and fissures in the teat skin in which bacteria can hide and be difficult to remove.
15. “We tend to prefer to milk cows wetter, removing the unit somewhere around 1.8 to 2 pounds per minute flow rate. That’s pretty aggressive, so you have to do a good prep job and achieve good stimulation for a quick let-down.”
16. Your goal is to take the milk film that’s on the teat and replace it with postdip. Anywhere the inflation contacted the teat there will be a thin milk film, and it should be covered with dip. Don’t take the short-cut of holding two teats together to postdip them. Check yourself or your milkers’ technique by wrapping a paper towel around a dipped teat to see if there is coverage all the way around the teat.
17. Because the teat end could still be open for a while, feed the cow immediately after milking. This will give the cow an incentive not to lie down until the teat end has had a chance to close.
Supervisors who make sure all milkers follow these steps in detail can prevent a lot of potentially serious and costly udder problems.
Through a vet’s eyes: your parlor at milking time
by Bill and Mary Weaver