How safe are your liners?
Most people would not drive their car or tractor once the tread on the tyres becomes worn. �ey know that worn tyres are dangerous, increase the likelihood of having an accident and reduce the handling performance and efficiency of their vehicle. However, there is another piece of rubber on a dairy farm that is o�en not treated with such respect. �e milking liner, which is ultimately the nal point of contact between the sensitive teat tissues of the cow and the milking machine is frequently not changed when worn and remains un-changed as the performance of the liner starts to decline.
�e liner is the only component of the milking machine that comes into direct contact with the cow ' s teat. �erefore, it is one of the key components in the process of milking cows quickly, gently and completely. Although many people try to squeeze a few more weeks or months from the liners in a dairy, this is almost always a poor option for the most important component of the milking machine.
As liners age, their shape, tension and surface condition changes gradually. �is gradual deterioration can have subtle but signi cant effects on their milking characteristics. Both the internal surface and the milking performance of liners tend to deteriorate more quickly soon a�er they reach their designated use-by date.
Replacing liners
If there is an improvement in milking performance when the liners are changed, it is a sign they are being changed too late. Visual signs of deterioration should lead to immediate liner replacement. If a liner is cracked or torn, it is long past its usefulness. However, o�entimes, liner deterioration signs are invisible to the naked eye, making them difficult to detect and, as a result, we have to look at other cues. Liners should milk the cow with minimal discomfort to the teats. Adequately massaged teats should feel so� and not swollen when the cup is removed. Discoloration of teats a�er milking is a sign of inaccurate vacuum or pulsation settings, or poor liner function. A liner that does not correctly compress on the teat will not reduce uids that accumulate near the teat end during the milking phase.
�is can lead to congestion of the teat canal, restricting the downward ow of milk. When liners are not changed on proper intervals, the mouthpiece and barrel become distorted, causing poor massaging of the teat, which is o�en combined with an increase in liner slips. �is, overall, results in an inefficient and ineffective milking performance on your herd. Efficient milking is desired, and essential, for the dairy operation. �ere are key performance indicators in uenced by liners which can be monitored to determine performance. Here are a few to keep an eye on:
· Peak milk ow should be 8 to 12 pounds per minute within the rst two minutes on 80 percent of the cows.
· Average milk ow of 6.5 to 8.5 pounds per minute is desired on more than 80 percent of the cows.
· Teat color change, red or blue, should occur on less than 10 percent of the teats. Quarters should milk out evenly within 1.5 minutes of each other on 90 percent of the cows.
· Teat-end scores of 1 and 2( healthy teat ends) are desired on at least 80 percent of teats.
· Liner slips should be less than 2 percent of the quarters milked.
As tempting as it may be to eke out extra milkings from the liners, you never want to sacri ce performance or cow health. Any effect on teat end condition or any increased liner slips are particularly signi cant for increased
risk of mastitis. As a general rule of thumb, if you notice an improvement in milking performance a�er replacing liners, the old ones were used for too long!
Choosing a liner
Choosing a liner is a complex and difficult task – and an extremely important one. Liners have a huge impact on teat-end health as well as parlor efficiency. O�en a particular liner is settled on by a trial-anderror process. With so many liner designs and choices, this process can be quite lengthy. I will attempt to describe the most popular types of liners available.
Getting the best use from your milking equipment begins with selecting the right liner that is matched for your operation, system settings and your cows. Both rubber and silicone liners have advantages. Rubber liners are less expensive up-front compared to the silicone variety, although the cost per milking calculated over time may not be signi cant. Rubber is a more durable material, with greater resistance to cuts.
�ey deteriorate faster but can be a viable option for dairies in need of a robust compound. Silicone liners have a longer life and improved surfaces. �ey are less prone to deterioration and cracking, as they hold up better against butterfat in the milk. But even highquality silicone will eventually succumb to cleaning chemicals and hot water. �e key is a product that will maintain consistent milkability throughout its use life. In summary, a reluctance to change milking liners at the appropriate interval can be false economy. It can lead to slower milking, longer milking sessions and increased liner slippage. �e internal surface of the liner becomes harder to clean, increasing the risk of the transmission of mastitis pathogens and cleaning related quality problems. Most sensible people would not put their family at risk by driving with worn tyres – perhaps we should give the dairy herd the same consideration!
www. farmersreviewafrica. com January- February 2017
FARMERS
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