7 Point Plan for Mastitis Control

A Proposal

Over the past 40 years, since the adoption of the 5 Point Plan for Mastitis Control, there has been a significant reduction in the number of clinical cases of mastitis, in levels of bulk tank somatic cell counts and in the prevalence of mastitis caused by contagious bacteria.

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Monitoring coverage of teat spray systems and maintenance

Monitoring coverage of teat spray systems and maintenance


Post milking teat disinfection is an essential part of any mastitis control plan, and over the last 40 years has been shown to be very effective in controlling the spread of mastitis.  With the correct product, it also has major benefits in improving and maintaining teat skin condition so that the teat can withstand the rigours of milking.  Dry and cracked teat skin is not only more difficult to keep clean, but also harbours populations of mastitis causing organisms.  In addition during the milking process cows suffer discomfort and even pain when teat skin is dry and cracked.  This impacts on the milk let down response and leads to ineffective milking out.  This in turn can then go on to cause damage to the integrity of the teat and therefore the first line of the udders defence.

Pre-milking teat disinfection can also have benefits in improving teat cleanliness prior to unit attachment, can help in the control of environmental mastitis, in particular, and aid the milk let down response as part of a complete milking routine.

Manual teat spraying with a vacuum operated lance is arguably the most common form of teat disinfection, although automatic systems in all their guises are becoming more popular.

However, what constitutes teat disinfection?  The 2013 study funded by Ambic into the efficacy of teat barrel coverage by manual spraying found significant variation in both teat end and teat barrel coverage.  With some farms they were technically carrying out teat disinfection, but in practice it was totally ineffective and a waste of time and resources.  So how can effective teat spraying be monitored.

The simplest method is to check chemical use.  With manual teat spraying the average volume recommended per cow per milking is 15 ml, which was confirmed in the Ambic funded study in 2013.  Automatic teat disinfectant systems are designed to use different amounts per cow per milking, with some allowing the volume to be altered.  This information will be readily provided to you by the manufacturer/supplier.  The following table is a guide to how long the various sizes of containers should last, based on twice and three times per day and two herd sizes and 15 ml per cow per milking.

Table 1.  Teat disinfectant use (days).

  Size of container Average number of cows in milk/day
150 400
2x/d milking 3x/d milking 2x/d milking 3x/d milking
25 litre 5.5 3.7 2.1 1.4
200 litre 44.0 29.6 16.6 11.1
1000 litre 222 148 83 55

If containers are lasting much longer then insufficient chemical is being applied and the benefits of teat disinfection are being lost.  However, use is just one part of the story.  How effective is the chemical being applied?  Spraying udders is not particularly effective!  Observation is all – when teat spraying look at how effective the task has been done.  The aim is to not only cover the teat end but also all the teat barrel.  So often it is only the side of the teat nearest the operator that gets covered with disinfectant, with little or none applied to the front plane.  The problem is more noticeable in rotary and 90° rapid exit parlours, due to the position of the teats in relation to the operator.

This can easily be checked by using a piece of paper towel to “dab” the far side of the cows’ teats (but choose your cows carefully). If little disinfectant appears then you realise the task is not being effectively carried out.  With labour at a premium on many farms it is tempting to rush this part of the milking routine – but reflect on how long one case of mastitis adds to each milking.  A more detailed monitoring of the effectiveness of teat disinfection can be carried out, where teat end and teat barrel coverage is scored.  Coverage of the teat end is either a Hit or Miss and the front and rear planes of each teat are scored out of 50 – so if half the front side of the barrel is covered the score is 25.  If all the rear side is covered the score is 50, giving 75% teat barrel coverage.  This assessment can be done by farm staff or by using consultants.

Although the aim is for 100% of teat ends and teat barrels to be covered, a realistic target is 100% of teat ends and at least 50% of each side of the teat barrel.   These targets are the same for manual or automatic teat spraying – and teat dipping.

Besides the human element, equipment has to be regularly serviced.  The ends of the vacuum operated lances often become worn as the spray head usually ends up scraping along the operator pit floor.  A good spray pattern is essential. The spray nozzle can also get blocked – removing and thoroughly washing out is a simple but effective job.  Do not unblock with a needle or similar as this will adversely affect the spray pattern.

Teat disinfection is a vital part of a mastitis control programme, but is must be followed and applied effectively.  Simple monitoring and observations will help ensure success.

How effective is post-milk teat spraying?

How Effective is Post-Milking Teat spraying?



Effective use of a post-milking teat disinfectant was a critical element of the Five Point Mastitis Plan developed by NIRD in the UK in the 1970’s.  The importance of good teat barrel coverage with a post-milking teat disinfectant now forms a fundamental part of mastitis control programmes throughout the international dairy industry.

Besides the bactericidalproperties of a post milking teat disinfectant, complete teat coverage with the product is essential to help ensure that the teat skin is kept as soft and supple as possible to withstand the rigors of milking.  When teat skin is not in a satisfactory condition, not only is the teat more difficult to clean, it can also harbour bacteria that can adversely affect the keeping quality of milk and increase the risk of mastitis.  Added to this is the physical aspect of a liner opening and closing on a teat two or three times each day. Poor skin condition can increase the prevalence of lesions such as hyperkeratosis that impact on milk quality, milking out time and udder health.

Over the years there has been a move away from post dipping to manual teat spraying. This has occurred as herd size has increased while the amount of labour per cow has fallen.  Spraying can be carried out more quickly than dipping, but anecdotal evidence suggests that dipping is more effective in achieving better coverage than spraying and is considered to be less operator dependent.   In a busy parlour, a quick spray by many operators is considered to be sufficient and is believed to “tick the box” for a mastitis control protocol.  In addition there are an increasing number of automatic teat spraying systems available on farm.  Ideally an automatic system will provide 100% teat barrel and teat end coverage, after every milking.

In 2013, The Dairy Group carried out on-farm studies, commissioned by Ambic, to measure post milking teat barrel and teat end coverage where the operator was manually spraying with disinfectant, mainly using vacuum operated teat sprayers.

Teat barrel and teat end coverage were assessed post application of the teat disinfectant product on ten farms, each with a minimum of 150 cows.  To assess barrel coverage, the front and back of the teat was scored as a maximum of 50, i.e. if all one teat side was completely covered this equated to a score of 50 (100% coverage of that plane), whereas a score of 25 meant that only half of that plane was covered in chemical.  If both sides of the teat barrel were completely covered this equated to 100% teat barrel coverage.  Teat end coverage was assessed as either covered or not covered (hit or a miss).  The volume of teat disinfectant product applied during the monitored milking was measured and a calculation of chemical usage / cow / milking was made.

The study highlighted a wide range in efficiency of teat spraying between farms (Table 1).

On average just over 50% of teat barrels were coated with the post milking teat disinfectant, with the range from 19.8% to 83.4%, with no operator achieving complete teat barrel coverage all the time.  Although there was no arithmetic difference in teat barrel coverage between left and right teats, more than half of rear teat barrels were covered with disinfectant compared to less than half for the front teats.

There were also differences in the coverage of the front and rear planes of the teat barrel with disinfectant (Table 2).  Just over 80% of the rear of teat barrels was coated with disinfectant in this study but only 40% of the front plane of the teat barrel was covered.  Coverage of the front plane of cows’ teats tended to be worse where cows stood at 90° to the operator – such as in rapid exit and external rotary milking parlours.

Only on one farm out of the ten were all teat ends covered with disinfectant (Table 3), arguably the most important part of the teat.  The worst farm was covering on average only 80% of teat ends, again highlighting the considerable range in the effectiveness of spraying.  There was little difference in the percentage of teat ends covered between teats on the left and right, or front and rear teats.

The quantity of teat disinfectant applied per cow per milking varied from a maximum rate of 21.8ml, which was almost 3.5 times greater than the minimum of 6.3 ml.  The average use at 15.3 ml, is in line with often quoted rates.  There was no clear relationship between the amount of disinfectant applied and teat barrel coverage, although teat end coverage was worse where low amounts of disinfectant were used (less than 7 ml).  Interestingly, there was no apparent relationship between owner and employee operators responsible for teat spraying with regard to volume used or teat end and teat barrel coverage.

Statistically, the data suggests (Figure 1) no strong correlation (R2 = 0.39) between disinfection use and teat end coverage, although good teat end coverage can be achieved with around 14 ml of teat disinfectant.  Rates below this threshold lead to increasing numbers of teat ends not having any disinfectant applied.  The correlation was even less between the quantity of teat disinfectant used and teat barrel coverage, again indicating the efficiency of the operator is more far more important.

Conclusions

  1. There is a significant range in the skill with which post milking teat disinfectants are applied with a hand held, vacuum operated teat sprayer.
  2. The level of variation in applying post-milking disinfectant confirms  on many farms the objectives of teat spraying are not being achieved.
  3. The majority of mastitis control programmes and protocols in place involve complete post-milking teat disinfection.

Table 1.  Teat end and teat barrel coverage with disinfectant

Teat end coverage (average number of teat ends)

Average percentage cover of teat barrel

Left teats

Right teats

Rear teats

Front teats

All teats

Study average

3.77

50.1

50.5

52.4

48.2

50.3

Minimum

3.2

18.7

20.9

20.6

18.9

19.8

Maximum

4.0

82.3

85.1

86.2

80.6

83.4

Table 2.  Teat barrel coverage

Rear Left

Front Left

Front Right

Rear Right

Back

Front

Back

Front

Back

Front

Back

Front

Average teat coverage (score out of 50)

42.9

21.9

42.0

17.5

42.1

18.5

43.3

21.9

Number of teat barrels with no coverage

7.1

40.9

8.3

60.2

6.6

58.2

6.2

42.7

Average number of teats scored (excludes cows with missing teats)

166.1

165.7

166.0

166.4

Table 3. Percentage teat end coverage

Rear Left

Front Left

Front Right

Rear Right

Average

Teat end only covered

95.5

92.2

94.2

96.2

94.5

Figure1.  Disinfectant use and teat end coverage