Massage at the parlour

What happens in the teatcup is probably the most significant experience every day for every milking cow. In my last column I described how poor let-down can damage teats by increasing the time that cups are on teats without milk flowing. This damage makes the teat vulnerable to mastitis.

This month I’ll discuss some other factors that affect teats during milking.

If you have ever put your finger in a teatcup under vacuum you’ll know the discomfort you feel after a minute or two.  The effect of vacuum is to draw fluid – your finger starts to become red and sore. The same happens to teats under vacuum – fluid is drawn down the teat – milk flows out of the teat end, and blood fluids are pulled into the teat tissue itself.

In machine milking, there has to be a mechanism to relieve this blood congestion if the teat ends are to remain healthy.

Massage please. All teatcups are made up of a solid shell and an inner flexible, elastic (usually rubber) liner that is designed to squeeze the end of the teat in a massage action about 60 times per minute throughout milking. Milk flows out of the teat when the liner is open, and blood and tissue fluids are massaged away when the liner closes.

The liners are critically important parts of the whole milking system, but they are also the most subject to wear and tear.

I was recently working with a farmer who had lost over $4000 in milk income in 3 months, primarily because he had avoided paying less than $400 for new liners. It was a costly decision and we spent quite a while discussing how to assess liner condition and choose replacement dates.

Everyone agrees that liners are “consumables” and must be replaced regularly, but the key question is how do you know when that is?

The reality is that as soon as they start work, liners begin to lose tension, absorb fat and hold bacteria.

If you use liners for too long, the deterioration of the liner will cause reduced speed and completeness of milking and increased risk of mastitis. Teat ends will have poorer health and more bacteria will be held and spread to other cows. But these changes occur well before they are apparent to even a keen observer.  

If you can see or feel change you’ve almost certainly passed the replacement date by a long way. If you notice an improvement in milking characteristics when you change, you’ve missed the date by too far too.

The most reliable current method is to estimate the amount of work liners have done by counting cow-milkings.

The rubber components in liners are selected for their suitability for use in food producing systems (like dairies). They allow liners to operate properly for about 2500 cow-milkings before they start wearing out.

Many people are surprised at just how quickly 2500 cow-milkings pass, and the cost and work of changing liners often seems like a deterrent to doing the job. But it shouldn’t be.

The message is simple – be serious about replacing liners based on the work they have done (estimated by cow-milkings), not on appearance. And operate on 2500 cow-milkings as the life-span for rubber liners, given that each cow-milking has probably involved the liner flexing 400 to 500 times!

Use your calendar or diary to remind you. When you change the liners, work out when the NEXT 2500 cow-milkings will have occurred and write the NEXT replacement date on the calendar, to help ensure there is always enough massage in the parlour for everyone’s comfort.

Old liners cost money 

A farm was using liners that had done twice the recommended milkings.

The herd was out of premium payment category for 3 months with a cell count that had just edged up (but was always below 300,000). With 230 cows doing 20 litres for 90 days, missing 1 cent per litre led to a loss of approximately  $4100.

Investigation of the milking system indicated that the liners were an appropriate match for the shells, but not performing well. Records showed they were fitted about 8 months previously and in the 18 unit swing-over, each liner had completed over 5600 cow-milkings.

The cost of replacement at the correct date 4 months earlier would have been $396. 

Check your liners weekly

Check for twisted liners: align marks on the mouthpiece and stem of liner, or place your thumb in each liner.

Check liner condition: look particularly for distortion of the mouthpiece lip or holes in the short milk tube. Split liners lead to fluid between the liner and the teatcup shell

How long does your liner last?

(Heading for attached graphic from Guidelines.)  

John Ryan:

John Ryan has been an enthusiastic supporter of Countdown Downunder since its instigation. He is one of Countdown’s team of experienced presenters working with advisers and farmers around the country.

 John and his wife Robyn are joint principals of two veterinary practices: at Beaudesert and Jimboomba, south of Brisbane. Their company, Pro-V Dairy systems, provides nutrition, reproduction, and milk quality advice. It also sells and services milk harvesting and other equipment in South-east Queensland.

John presented seminars to farmers and advisers in Tasmania, Queensland, and NSW last year. This year he has led the Adviser Short Courses in Tasmania and Northern Victoria.

John encourages farmers to seek out advisers who have participated in Countdown training. He says, “The adviser courses bring together vets, techs, and other dairy advisers The courses help the skills advisers need to work as a team and provide consistent, professional help with mastitis and milk quality issues.”

 [Box – Previous Australian Dairyfarmer columns are available on the Countdown Downunder website at www.countdown.org.au]