Authors: Karin Knappstein. Nele Roth, Hans-Georg Walte, Joachim Reichmuth
During an investigation on teat cleaning efficiency of different Automatic Milking (AM) systems working in practice differences were detected not only between systems of different brands but also between farms working with the same AM system. In addition, teat contamination before cleaning was of significant influence on teat cleaning efficiency. Therefore the second part of the study focused on management factors to determine which measures are significantly associated with teat contamination.
The investigation was performed on 18 farms. Differential
bacterial counts in bulk tank milk were determined to find potential failures
in milk quality. High coliform counts on 8 farms indicated insufficient teat
cleaning and/or failures in system cleaning. On 14 farms thermoduric bacteria
exceeding 200 cfu/ml showed potential problems with system cleaning although
TBC was well below 10000 cfu/ml, but thermoduric bacteria may also have
originated from bedding material.
In fresh bedding material different levels of bacterial contamination were
found, with lowest total bacterial counts in specially treated sawdust and in
sand. Coliform bacteria on teat surfaces are not necessarily due to faecal
contamination, because these bacteria were also found in fresh bedding.
The hygiene management on farms was evaluated by means of a
questionnaire-based interview with the farmer. In addition, a checklist was
used to determine the actual hygiene status of certain areas on the farm. An
analysis of variance was performed including 45 questions of the questionnaire
and 17 aspects of the hygiene checklist.
AM specific management factors associated with high average teat contamination
on farms were: replacement of teat cleaning device < once per year,
moderate/poor status of the teat cleaning device, average milking frequency
per day < 2.5 and no selection of cows for robot acceptance (p<0.10). Factors
not directly related to AM involved contamination of cubicles: less than one
cubicle per cow, cows lying on alleys present in the herd, addition of fresh
bedding material less than once per day, no selection of cows for udder
health, moderate/poor status of bedding material and moderate/poor status of
claws were significantly related to high teat contamination.
Additional factors like the general impression of the robot, cleaning
frequency of the milking box, status of teat cups and the use of cow brushes
in the barn were probably more closely related to the general attitude of the
farmer towards hygiene than to teat cleanliness. Other factors can be regarded
as generally accepted hygiene measures, because nearly all farmers practised
cubicle cleaning twice per day, shearing of udders and cutting of tail heads.
These factors should therefore be considered as basic hygiene measures.
Although the cause and effect relationship between parameters used to evaluate hygiene management on farms and teat cleanliness was not always very strong these factors should be considered when improvements of teat cleanliness are intended. Even with very good conditions it will be unavoidable that individual cows will have soiled teats, but farm management should aim for clean udders in the majority of cows. Apart from those factors which are specific for AM systems (e.g. frequency of replacing teat cleaning devices, milking frequency) it can be expected that the factors mentioned above can also improve teat cleanliness on farms with conventional milking systems.
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© Animal Sciences Group -
Wageningen UR. Last update:
20-02-2008 10:03. |
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