Why do cows get mastitis?
Mastitis originates from an infection in the cow's udder. The path for the invasion of that infection is through the cow’s teat end opening and up the canal. Cows have natural defense mechanisms against this invasion. The first line of defense is the muscle in teat end opening. This muscle, the sphincter muscle, closes the teat end when the cow is not being milked. The second line of defense is the lining of the teat canal.
Both of these defense mechanisms become compromised when milking a cow with a conventional milking system. The conventional system damages these defenses by failing to properly relieve the canal of the milking vacuum causing swelling and effectively sucking them away. This is evident not only from the calloused and distended teat ends but in the occurrence of slow milking quarters.
The constant sucking of the teat during the inadequate rest phase of a conventional system destroys the teat canal. This results in the formation of scar tissue that not only blocks the flow of milk but damages the protective nature of the canal lining.
Conventional dual pulsation driving bacteria into teats
The conventional milking system also fails to adequately remove all of the milk each milking. The scar tissue blockage and the pain and irritation from the poor rest phase prevent the proper removal of the milk. This reduces milk production and creates uneven udders and mastitis. The remaining milk enables the bacteria to thrive and cause mastitis.
Commonly accepted methods of dealing with mastitis include milking three times a day and the use of oxytocin. These approaches are aimed at getting the cow more milked out. It therefore follows that fully milking the cow each milking will work to prevent the problem in the first place except that conventional systems cannot achieve that.
Another source of mastitis is dual pulsation. When one set of liners collapse they cause a pressure pulse that drives the milk particles and any bacteria present back up against the open teats of the two that are milking. This effect is known to cause mastitis and is a means of infecting a healthy cow with Staph aureus.
The problem of mastitis has increased in recent years, even with the increased use of teat dips, automatic retracts and improved management. In fact, the annual percentage of all dairy cows becoming dairy beef has grown to 43% according to USDA statistics.
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Milking performance problems
When you see udders like this, you have a problem!
If you milk cows with a conventional milking system you experience problems with incomplete milkouts, liner slip, slow milking quarters and uneven udders. These conditions lead to mastitis, either clinical or subclinical cases.
Mastitis causes not only SCC problems but also breeding problems and other health issues.
Every farm with a conventional system has a problem with mastitis and poor milk performance!
The problem is a universal one impacting all dairies milked with a conventional milking system. The fact that 43% of all dairy cows in the US end up in beef each year is a clear indication that the problem is on every farm. Poor production, breeding problems, slow milking and mastitis are all related and caused by the inadequate performance of a conventional milking system.
The farms with the lowest cell count have simply found a way to manage part of the problem. The cost of that management is a high cull rate that leaves the farm milking mostly first and second calf heifers. A review of the many herd dispersals advertised in farm magazines reveals the high cost of low SCC/quality milk. Those herds consist of primarily first and second calf heifers with a nearly equal number of replacements and cows being milked.
Even the universities have the same problems with their staff of experts and veterinarians. Their herds have problems with slow milking quarters and mastitis. Most universities are unwilling to make public their detailed herd records leaving farmers to believe that cows can be successfully milked by following proper procedures.
One example is a well managed small herd of cows at Cornell University. Although the herd has an average bulk SCC of about 200,000, mastitis is still prevalent. Thirty cows were identified in the herd as being highly likely to last at least one more year in the herd before being culled. Of that thirty, ten were first calf heifers. There were 24 confirmed cases of mastitis, 5 of them Staph aureus, in the group of 30 cows. This provides further evidence that even the best management with a staff of veterinarians in ideal conditions cannot overcome the poor performance of a conventional milking system.
Ask your neighbor with the low cell count or your local university to provide you with their detailed herd records to understand what their milk quality and herd performance really is. These records should include production, cell count and butterfat for every cow and the actual cull rate.
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DHI Herds
Annual data published by the USDA collected from all US herds on DHI shows that over 32% of all herds have an SCC over 400,000 on test day! The data from the past several years shows that the mastitis problem is getting worse.
University Herds
DHI data from several Southern and one New England university herd show that herds milked with conventional milking systems with the best of management practices suffer from mastitis problems. DHI data from the three Southern university herds shows that the annual herd bulk SCC levels were as follows: herd 1 with a low of 261,000 to a high of 508,000, herd 2 with a low of 184,000 to a high of 583,000 and herd 3 with a low of 268,000 to a high of 512,000 and an average of 424,000. DHI data for the New England university herd for annual bulk SCC levels was 285,000 to 464,000 and an average of 367,000.
Why is mastitis profitable for everyone but the farmer?
Mastitis costs the US dairy industry (dairy farmers) at least $1 billion a year. The average cost is an average of about $200 per cow per year based on lost production, reduced milk quality, culling and cost to treat. The real profit is for the other segments of the industry. The pharmaceutical companies that manufacture the drugs to treat the mastitis and help with the poor production (oxytocin and BST) make significant profits. The veterinarians profit from the visits to treat and evaluate animals and to consult on milking facilities and management practices. The universities are funded millions of dollars annually for quality milk programs to visit farms with mastitis problems. The equipment suppliers sell liners and teat dips claiming to solve the problem.
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