Reproduced from UW Extension - Outagamie County Agriculture - August-September, 2004 Issue

Introduction
The production of high quality milk from healthy cows is the primary objective of most dairy farmers. Despite the objective, mastitis remains a significant problem because of numerous opportunities for exposure to mastitis pathogens. Exposure to mastitis pathogens occurs in the cow's environment and during the milking process. The milking process is influenced by cow hygiene, animal handling before, during and after milking, and machine function. The influence of milking machines on the development of mastitis has been recently reviewed. Potential direct and indirect mechanisms of mastitis infection related to milking machines include:

1. Facilitating exposure to pathogens.

2. Reducing the ability of the teat canal to resistant bacterial invasion on changing characteristics of the teat canal (vacuum fluctuations or liner slips).

3. Supplying forces to increase penetration of bacteria through the teat canal (vacuum fluctuations or liner slips).

4. Enhancing dispersion of bacteria present in the teat sinus throughout the udder.

5. The frequency and amount of times that milk is removed.

While these machine related mechanisms exist, only 6-20% of new mastitis infections in an average herd can be attributed to machine issues. Most new infections are caused by factors other than the milking machine and management of the milking process is a critical control point for prevention of mastitis.

Regardless of herd size, most dairy managers depend on employees of family members to milk and care for cows. The quality of milk is directly dependent upon the ability of the farm manager to motivate employees to use management practices that reduce exposure to environmental pathogens and eliminate transmission of contagious pathogens during milking. The farm image projected to employees will either motivate or discourage employees. Dirty facilities create the perception that hygiene doesn't mattter. An emphasis on parlor throughput rather than quality cow preparation sends the message that speed of milking is more important than cow care. Dairy farms are unique because efforts to produce high quality product must occur every day and the task will never be completed. Clear communication of expectations of employees needs to be supported with training and resources to help the employees meet those expectations. Efforts to standardize the milking routine and train employees to consistently meet farm expectations can result in improved milk quality, better job performance, and enhanced employee retention. No single milking practice will independently result in improved milk quality in the face of overwhelming exposure to mastitis pathogens. Good milking practices that are consistently applied to clean, well-handled cows will result in the production of high quality milk. Management practices used to improve milk quality are interdependent and the secret of producing high quality milk is to consistently use well-defined milking practices that reduce exposure to mastitis pathogens.

Management of the Milking Process
Statistics from Wisconsin farms that use freestalls and participated in a milk quality program during 2001-2003 (n=101) indicate that management of the milking parlor is often neglected. In this dataset, the reported use of recommended milking practices was generally high. Of the farms, 89.1% always wore gloves when milking, 97% applied postmilking teat dips, 98% used predips, and 89% reported that milkers forestripped cows before attaching milking units. On participating farms (average herd size of 377 milking cows), there were approximately 6.4 different people milking cows each month, with a range of 2 to 16 separate individuals working in the parlor throughout the month. Training of milking technicians occurred relatively infrequently. Only 22% of the farms indicated that they held frequent training sessions for their milkers, 49% indicated that they trained milkers only at hiring and 29% indicated that milkers were never trained. It is difficult to understand how employees are expected to perform adequately because less than half (41%) of the farms reported that they had a written milking routine. Operators of stall barns (n=78) used less personnel to milk cows (3.0 separate people each month) but few (6.4%) had a written milking routine and 54% indicated that they never trained milkers.

Many milking parlors on large dairy farms are used continuously and farmers often focus on increasing parlor throughput. Data from Wisconsin freestall operations indicate that the largest influences on cows per hour per operator are training frequency and the presence of a written milking routine. Frequent training of milking technicians resulted in the fastest milking speeds and the lowest monthly rate of clinical mastitis. The use of a complete milking routine (includes forestripping, predipping and drying before unit attachment) also resulted in the most efficient parlor throughput. Cows were milked at a rate of 52 cows per hour per operator when a complete milking routine and frequent training was used in contrast to 38 and 35 cows per hour per operator for herds that used an incomplete milking routine and frequent training or incomplete routine without training, respectively.

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