Effects of machine milking on udder health in dairy ewes

https://doi.org/10.1016/j.smallrumres.2020.106096Get rights and content

Highlights

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    Milking machine settings that increase vacuum fluctuations under the teat must be avoided to reduce the intramammary infection risk.

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    Although a high milk pipeline causes higher vacuum fluctuations at teat level, no relation with bulk milk SCC have been found.

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    Milking machine settings that increase teat thickness would reduce the local defence mechanisms and should be avoided.

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    Post-milking teat disinfection, milking animals with intramammary infections last, and avoiding over-milking for longer than 2 min can affect mammary gland health status by reducing the incidence risk of mastitis.

Abstract

The aim of this article is to review factors associated with machine milking that would increase mastitis incidence risk and the effects of milking machine, milking management and routine in sheep. Machine milking settings that increase vacuum fluctuations under the teat or teat thickness and help to disseminate infectious agents would increase the risk of intramammary infection. Vacuum fluctuations are caused by a low effective reserve, low air and milk line diameters, low milk tube diameters, sudden air leakages caused by high milking cluster weight, teatcup slippage, excessive liner mouthpiece diameter or inadequate machine stripping. The milk line height (low vs mid line) has no relation with SCC if the rest of the settings are adequate, although higher vacuum fluctuations have been recorded in high line. The settings that increase teat thickness include an excessively high vacuum level, lack of effective massage on the teat (high pulsation ratio), liners too soft, hard, narrow or old, and overmilking for longer than 2 min. Regarding milking management, the reduction of milking frequency to 1 milking per day has an effect on yield and SCC due to a concentration effect, and some milking practices such as post-milking teat disinfection or milking animals with intramammary infections last, despite the drawbacks in overall farm management (identification and separation of infected animals), can lower the risk of mastitis incidence.

Introduction

Machine milking is a significant factor that may affect mastitis incidence (Bramley, 1992). Transmission of bacteria can occur during milking passively, by contact of contaminated liners with the teat, or actively, associated with various factors, e.g. reverse flow, impacts or reverse pressure gradient. All these can be exacerbated during malfunction or improper use of the milking machine, as it may affect teat status, causing changes or even lesions, which would facilitate onset of mammary infection. The aim of this article is to review factors associated with machine milking that would increase the risk of mastitis incidence, the effects of the milking machine and the milking management and routine in sheep.

Section snippets

Factors associated with machine milking that increase mastitis incidence risk

In sheep, the most frequent causal agents of mastitis are staphylococci (Staphylococcus aureus and coagulase negative staphylococci), which penetrate the interior of the gland through the teat canal (Bergonier and Berthelot, 2003; Contreras et al., 2007; Vasileiou et al., 2018). These organisms can survive and colonise the teat canal and skin, and even more so if wounds or lesions are present in there (Ziluaga et al., 1998).

Several factors are related with the incidence of intramammary

Effects of milking machine

Three machine milking-related aspects may be responsible for causing important alterations in the teat: excess vacuum level, unsuitable teat massage and overmilking.

Milking management

Milking management is as important for udder health of ewes as the milking machine characteristics.

Machine stripping (massage on the udder before removal of the teatcups) should be considered a risky operation, as if it is not done carefully it may cause sudden intakes of air through the teatcups, which can give rise to impacts. Udder conformation may predispose to appearance of mastitis (Gelasakis et al., 2012), as it will affect suitability for MM and may lead to a higher rate of teatcup

Concluding remarks

The features of machine milking that increase vacuum fluctuations under the teat and teat thickness and help disseminate infectious agents would increase the risk of intramammary infection. So, all these features must be considered when dimensioning a milking machine, carrying out periodic maintenance and determining the milking routine to practise in sheep in order to reduce the risk of transmission or establishment of mastitis.

A low effective reserve, low air and milk line diameters and milk

Author contribution

We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed.

We further confirm that the order of authors listed in the manuscript has been approved by all of us.

We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to

Declaration of Competing Interest

The authors declare no conflict of interest.

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