School of Agriculture, Food and Ecosystem Sciences - Theses

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Start date: 2000 × End date: 2019 × Type: Masters Research thesis × Subject: Australia × Subject: Dairy farming ×

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    The effect on some milking characteristics of cows of changing the flow rate thresholds of automatic cluster removers in a seasonally calving dairy herd
    Shoesmith, David ( 2004)
    An experiment to investigate the effects of altering the end-of-milking point values of automatic cluster removers (ACRs) from 0.40 kg/min (Control) to 0.70 kg/min (Fixed ACR), or 1.00 kg/min (Rising ACR) over an extended period from the peak until the end of lactation of a seasonally calving pasture based herd has been conducted at the Victorian Department of Primary Industries Ellinbank research dairy. One hundred and ninety two cows. and heifers were used in the experiment (64 animals statistically allocated to each treatment group). A comparative analysis of results for each treatment group is presented for average milk yield, average milking duration, average maximum milking duration, average milk flow rate, average peak milk flow rate and udder health. The Fixed ACR treatment reduced the average daily milking duration by up to 7.6%, but only for a small portion of the treatment period. The Rising ACR treatment reduced the average daily milking duration significantly by up to 15.3%, for the majority of the treatment period. The Fixed ACR treatment did not reduce the average daily maximum milking duration whilst the Rising ACR treatment reduced the average daily maximum milking duration significantly by up to 17.9%, for the more than half of the treatment period. A marginal increase in average milk flow rate was observed for the Rising ACR treatment. Even though the Rising ACR treatment began the experiment with higher average peak flow rate for AM and PM it declined less than the Fixed. ACR or Control treatment throughout lactation, providing a mechanism for the, removal of the same amount of milk in a reduced time when compared with the other treatments. However the difference observed in peak flow rates was not statistically significant. No difference was found amongst the treatment groups when analysed for new cases of sub-clinical or clinical mastitis. The geometric mean of individual cow cell counts was significantly reduced for the Rising ACR treatment in the latter stages of lactation. Flow rate curves have been constructed from real milking data and are presented as examples of the large variation of actual- flow rate from a cows udder. The flow rates curves are used to track individual cows through lactation to observe changes in the cow's milking characteristics. Theoretical consideration is given to how particular types, or brands, of ACR operate under various conditions and it is shown that the results from this experiment could be replicated by using other types of ACR if they are managed correctly. This study has shown that significant labour productivity. benefits could be achieved by, increasing the ACR end-of-milking point settings to 1.00 kg/min without impacting milk yield. However, further work is suggested to ensure that udder health is not compromised. This is to certify that the thesis comprises only my original work except here indicated in the preface; due acknowledgement has been made in the text to all other material used; the thesis is 19400 words in length, inclusive of footnotes, but exclusive of tables, maps, appendices and bibliography.