Dynamics of teat-end vacuum during machine milking: types, causes and impacts on teat condition and udder health – a literature review
| Autor: | O. Lind, Johanna Franziska Besier, Rupert M. Bruckmaier |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty General Veterinary Vacuum pressure Ultra-high vacuum 0402 animal and dairy science Automatic milking 04 agricultural and veterinary sciences 040201 dairy & animal science Surgery Milking 03 medical and health sciences 030104 developmental biology Animal science medicine.anatomical_structure medicine Animal Science and Zoology Milk flow Udder |
| Zdroj: | Journal of Applied Animal Research. 44:263-272 |
| ISSN: | 0974-1844 0971-2119 |
| Popis: | Most of the available scientific literature concerning claw vacuum drops and fluctuations (identical to teat-end vacuum) during machine milking has been published in the 1960s and 1970s. Fewer studies have been carried out more recently on modern types of dairy cows, and milking machines, and have been evaluated with modern statistical methods and software. Based on the accessible information, there are indications that reduced milking performance, leading to long machine-on time mainly as a consequence of a combination of vacuum drops and different types of fluctuations, may influence udder health in a negative way although scientific proofs are scarce. Based on an ISO note, the claw vacuum should remain within a range of 32–42 kPa during peak milk flow to ensure fast, complete and gentle milking. This range of vacuum pressure allows adequate liner movement and a sufficient pressure on the teat during the massage (d-) phase is guaranteed. Thus, liner slips caused by too low claw vacuum are avoided. On the other hand, the teat-end vacuum should not be much higher than 42 kPa as it can cause damage of teat tissue mainly during periods of low milk flow when it is almost identical with the system vacuum. Depending on the used system of milk transport through the tubes, the teat-end vacuum drops to some extent, intensified during periods of high milk flow and reduced during periods of low or absent milk flow at the start and end of milking. Hence, a general increase of system vacuum throughout milking is not suitable, as high teat-end vacuum acting on the teat during milking phases with low milk flow rates have to be avoided. However, a reduction of machine-on time and high vacuum load on the teat during low milk flow can potentially be achieved by early cluster removal, before complete cessation of milk flow. Ideally, this goal can be reached at quarter milking (as used in automatic milking systems) where each teatcup is individually removed based on the milk flow of the individual teat, and milking at very low or no milk flow can easily be avoided. |
| Databáze: | OpenAIRE |
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