Use of pre and post dipping during the milking routine.

The milking time is the roundabout of the dairy farm: it is a traffic junction, an obligatory passage, fluent if well managed! Every day, 2 or 3 times, the cows are milked. Adapted to the cows, the milking is a tool to optimize milk production. Adapted to people, the milking is an important moment to manage mastitis.

I. The milking routine.

A. A pleasure moment for the cow
To release the milk, the cow needs a specific hormone acting on the mammary tissue: the oxytocin. Stressful parameters slow and even diminish milk release, because adrenaline (the hormone released by fearful animals) blocks the action of oxytocin on the udder. It means that the harvesting of the milk is more efficient when animals, people and facilities interact smoothly. Comfortable milking procedure (correct vacuum, teat preparation miming the calf stimulation) is a pleasure for the cow. The milking time must be associated to a positive feeling.On the other hands, uncomfortable milking, stressful ambiance, are associated with negative feeling and, finally, with a reduction of production. Previous bad experiences are remembered and the same circumstances (the milking parlour, the voice of the milker) lead to fearful reaction.

B. An essential practice but also a risk for mastitis
Well managed, the milking process is the best practice against mastitis, because it allows directly to remove bacteria from the teats, 2 or 3 times a day. Moreover, an early detection of clinical mastitis signs (udder swelling, flakes in the milk…) is necessary in order to provide an early treatment and increase recovering chances. However, bad milking routine can be a direct source of infection for animals as well. Non hygienic teat preparation leads to infections by environmental pathogens such as Strept. uberis or E. coli. Furthermore, the milking machine is on of the main vector of contagious pathogens such as Staph. Aureus or Strept. Aglactiae.

C. Get quality milk
The milking time is the moment when the farmer obtains the milk, the endproduct of the dairy farm. All farmers are looking for an efficient production and high quality milk. High quality milk consists of milk that meets specific quality standards for somatic cell count (SCC), and bacteria. The basic requirements in the EU and in the Pasteurized Milk Ordinance are shown in Table 1[1].

Table 1. Basic milk hygiene requirements in the EU and USA[1].

EU PMO
Drugs/ml Drugs/ml <0,004µg<0,004µg No detectable
Somatic cells/ml 400.000 750.000
Bacteria/ml 100.000 100.000

II. Impact of Pre-dipping products.

A. Fight against bacterial contamination
With the decrease in mastitis caused by contagious organisms such as Staph.aureus and Strep. agalactiae, concern has increased regarding mastitis caused by environmental microorganisms. The main objective of the pre-dipping is to achieve an acceptable level of decontamination of teat skin before the milking. It has been developed to fight environmental pathogens that colonize teat
skin between 2 milkings.Pre dipping was found to reduce the incidence of new IMI with environmental pathogens by greater than 50% compared with udder washing and drying with individual paper towels[2].

B. Milking time management
Time management is a crucial point in milk harvesting. Indeed, in between 2 milkings, the milk is stored in the udder alveoli and has to be transferred to the cistern during milking time. The milk releasing is possible thanks to a specific hormone, the oxytocin, which is released into the blood after teat stimulation. Action of this hormone is maximum after 60 to 90 seconds. This time-lap allows to get the most efficient milking process, in term of production, flow and animal welfare. 3-5 minutes stimulation has been shown to reduce milk production by 16%, whereas a 5-8 seconds hand wash with water was shown to be ineffective in milk let-down stimulation. In comparison, a good stimulation of the teats during 30 seconds increases milk production from 26 to 33%[3]. Finally, indirectly, the process of preparing teats before milking also has an impact on contagious pathogens prevention, by reducing the “time on machine” for the cow.

C. Milk quality
Pre-dipping products have mainly been developed to avoid cows’ infection from environmental pathogens during milking. However, they also have an impact on the quality of the milk. Because he milk is a great source of food for bacteria, bacterial numbers in the milk can double within half an hour at  a temperature of 35°C. So, within two hours, 1,000 bacteria in a mL of milk become 16,000 bacteria [4]. High levels of bacteria in milk affect both its manufacturing properties and its shelf life, that’s why; limits have been established in the bacteria count of the milk, and especially for coliforms. Coliforms are environmental bacteria, coming from mud or manure. They contaminate the teats between 2 milkings and can be transferred into the raw milk if the teats are not clean enough prior to milking. Irrespective of the thresholds set by the dairy company, bactoscan should be kept below 30,000 bact/ mL[4].

REFERENCES
1. HILLERTON, J. Eric et BERRY, Elizabeth A. Quality of the milk supply: European regulations versus practice. In : NMC Annual Meeting Proceedings. 2004. p. 207-214.
2. NICKERSON, Stephen C. Choosing the best teat dip for mastitis control and milk quality. In : NMC-Milk quality conference proceedings, april 2001, pg. 2001.
4. LAVEN, Richard. Mastitis Part 5- Bactoscan Problem and Solutions. Mastitis Control and Management. NADIS. 2016.

Leave a Reply