Increasing the revenues from automatic milking by using individual variation in milking characteristics.

The objective of this study was to quantify individual variation in daily milk yield and milking duration in response to the length of the milking interval and to assess the economic potential of using this individual variation to optimize the use of an automated milking system. Random coefficient models were used to describe the individual effects of milking interval on daily milk yield and milking duration. The random coefficient models were fitted on a data set consisting of 4,915 records of normal uninterrupted milkings collected from 311 cows kept in 5 separate herds for 1 wk. The estimated random parameters showed considerable variation between individuals within herds in milk yield and milking duration in response to milking interval. In the actual situation, the herd consisted of 60 cows and the automatic milking system operated at an occupation rate (OR) of 64%. When maximizing daily milk revenues per automated milking system by optimizing individual milking intervals, the average milking interval was reduced from 0.421 d to 0.400 d, the daily milk yield at the herd level was increased from 1,883 to 1,909 kg/d, and milk revenues increased from euro498 to euro507/d. If an OR of 85% could be reached with the same herd size, the optimal milking interval would decrease to 0.238 d, milk yield would increase to 1,997 kg/d, and milk revenues would increase to euro529/d. Consequently, more labor would be required for fetching the cows, and milking duration would increase. Alternatively, an OR of 85% could be achieved by increasing the herd size from 60 to 80 cows without decreasing the milking interval. Milk yield would then increase to 2,535 kg/d and milk revenues would increase to euro673/d. For practical implementation on farms, a dynamic approach is recommended, by which the parameter estimates regarding the effect of interval length on milk yield and the effect of milk yield on milking duration are updated regularly and also the milk production response to concentrate intake is taken into account.

[A closer look at the milking machine]. / De melkmachine nader bekeken.

Machine milking has changed enormously in the past decades. The simple milking machine developed at the end of the nineteenth century has become a complex appliance which removes milk from the udder in a fast and efficient way. There is no doubt about the importance of a well functioning milking machine as regards milk quality and udder health. This article reviews the literature on the basic mechanics of machine milking, with special emphasis on the action of the cluster during milking. The movement of the teat cup liner is particularly important in influencing the efficiency of milk extraction and udder health. Therefore special attention is paid to the operation of the liner, how it works, and how the opening and closing of the liner affects the milking process. The functioning of the pulsator, the vacuum fluctuations occurring during milking, and the effect of these fluctuations on the opening and closing of the liner are discussed. The maintenance of the milking machine is also described.

[Machine milking and udder health: a literature review]. / Melkwinning en uiergezondheid: een literatuuroverzicht.

This article reviews the influence of machine milking on udder health. The main risks are transmission and penetration of pathogens during milking. Pathogens can be transmitted via the hands, cloths, and liners. Irregular fluctuations in the vacuum can cause penetration of mastitis pathogens into or through the teat canal. Such fluctuations are caused by air blasts in the milking machine. Machine milking can also cause teat lesions, although only severe lesions give rise to new infections. Preliminary research results on the influence of the frequency and degree of udder evacuation show that the clinical symptoms of mastitis generally decreases as the frequency and completeness of milking increase. It is concluded that machine milking can influence udder health but that the influence strongly depends on the exposure to pathogens and the quality of the milker.