Editor's note: This item ran in the October 2008 edition of Dairy Herd Management.
Driving to farm calls, I am often reminded how fall is my favorite time of year. I enjoy seeing my producers chopping corn silage, harvesting the last cutting of hay and finishing out the rest of their crops. Harvest time is the end of the yearly farm cycle — and we hope for good yields and good quality feed.
But for dairy producers, milk harvest happens two to three times a day. How you conduct that harvest influences milk yield, milk quality and udder health.
The milking system is one of the most-used pieces of equipment on the dairy, but often producers provide better maintenance to a less-used tractor!
Milking system tests
A series of tests can help you evaluate your system. Begin with a self-test.
1. Unit fall-off test. Turn on the system vacuum and allow one unit (if your parlor is less than 20 units) or two units (if your parlor is over 20 units) open to full air admission. Check with your manufacturer regarding vacuum stability when this occurs. A common rule-of-thumb says if the system vacuum drops more than 0.6 inches, you do not have enough reserve air to maintain a stable vacuum. The vacuum should return to system vacuum with less than 0.3 inches override in 1 to 2 seconds.
2. Inflation changes. Liners should be changed every 1,000 milkings or 90 washings, whichever comes first.
3. Listen to your system. Do you hear leaks? Is the pulsation rate set to manufacturer guidelines? Does the vacuum pump make abnormal noises?
Your milking system should have a thorough, professional analysis every six to 12 months, following NMC (formerly National Mastitis Council) standards.
Common tests include reserve air, regulator efficiency, vacuum pump output, pulsator evaluation, and teat-end vacuum.
It’s important, as well, to evaluate the people doing the milking. One of the advantages of testing your milking system during milking is that we can also see how cows are milked. Milker evaluations include pre-dip and post-dip assessment, udder cleanliness, udder prep, milking routine and lag time.
Why is this important?
1. If reserve air, regulator efficiency or vacuum pump output is not adequate, we see vacuum instability during milking. This unstable vacuum causes inefficient milk-out, as well as teat-end damage, which increases mastitis risk.
2. If teat-end vacuum is too high, teat-end damage can occur. If teat-end vacuum is too low, which is more common, we see teat-end damage and slower milk-out. Longer unit on-times are also associated with an increased risk of mastitis.
3. I often find improper milking system or milker performance in herds with contagious mastitis like Mycoplasma and Staph. aureus since both of these pathogens are spread in the parlor.
4. Improperly pre-dipped cows have increased amounts of bacteria on the teat ends, which may lead to mastitis, especially in combination with liner slips and vacuum instability.
5. Cows that are not fore-stripped or have the unit attached too soon after fore-stripping will have abnormal milk-flow rates. Abnormal milk-flow rates will cause teat-end damage at the start of milking, as well as increase the total time it takes to milk the cow.
6. Over-milked cows can have teat-end damage, which allows bacteria access to the udder and increases mastitis risk.
How you harvest your milk influences milk quality, which in turn influences milk yield. Consult with your milking equipment dealer and veterinarian to assist you in attaining your goal of a bountiful milk harvest this fall.
Fred Gingrich is a practicing veterinarian and owner of Country Roads Veterinary Services, Inc. in Ashland, Ohio.