Use of pre and post dipping during the milking routine

I. 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 .

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%. 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 the 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 . 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.

II. Impact of Post-dipping products
A. Disinfection + barrier effect
Post-milking teat disinfection has been adopted more than 60 years ago as an essential part of mastitis management. The purpose of these products is, first, to disinfect teat skin from contagious pathogens deposited by the teat liners, thereby preventing cross contamination from “cow to cow” during milking. Some studies show that the rate of new intramammary infection can be 50% lower by disinfecting teats with an effective product immediately after every milking compared to no disinfection. The second purpose of these post-dipping products is to protect cows against environmental bacteria after the milking, thanks to a “barrier effect”. Barrier teat disinfectants are formulated to stay longer on the teats, and for some formulations, to leave a persistent film on teat till the next milking. Several of these products have proven effective in trials using NMC protocols, in addition with others management practices such as maintaining cows stand-up in a clean and dry environment during 30 minutes for instance.

B. Which post dip for which situation?
The use of a post milking disinfection has been validated as a standard good milking practice. However, the choice of product and its main characteristics (such as the active ingredient and viscosity) is still too often done without considering the milking routine, the bedding, the teat skin condition or the weather situation. That’s why a farm visit is recommended to take into account the parameters of the farm. It allows to bring the best specific solution for each farm. As an example, to bring a teat dip with a strong disinfecting activity and a low level of emollients on a farm having poor teat condition can worsen the situation and increase the risk of mastitis.

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