The Establishment of a Milking Parlour Routine
Mastitis is one of the three big causes of loss in the dairy industry, along with poor fertility and lameness. There are many ways in which a mastitis problem can be investigated including bacteriology, sensitivity tests and analysis of farm records. All these techniques are available and are used but perhaps the most useful, certainly the quickest and one which seems to show good results is that of developing a sound parlour protocol. This is most useful when dealing with a high bulk milk somatic cell count problem.
Rising bulk milk cell somatic cell counts are becoming a real concern for dairy farmers and this is perhaps one of the topics that we are asked for advice about most frequently. Apart from the penalties imposed by the milk buyers, the cost of treatments and the cost of the time taken to deal with those affected cows, it has been shown that for every 100,000 BMSCC rise over 200,000 cells/ml, 1% of milk yield is lost - and this loss is permanent.
The golden rule when milking cattle is that cleanliness is of paramount importance. This applies to the cows, the parlour and its equipment and, of course, the farmer. Dirty cows milked in a dirty parlour by a worker with dirty hands are a recipe for trouble. Providing good cubicles in sufficient numbers and of adequate size will help to keep the cows clean whilst they are indoors. A dedicated cow track from the pasture to the concrete of the farm yard will help in the summer time. A clean collecting yard in which the cows are not packed too tightly is also essential all the year round. The milking parlour should be hosed down frequently during milking and afterwards. People milking the cows should wear gloves at all times. Hands, still wearing the gloves, should be washed after the cows on each side of the parlour have been milked before more cows are brought in.
Mastitis is passed into the udder of a ‘clean’ cow from either a contaminated environment or from another infected cow. In the case of the former, if the milking unit is put onto a teat which is coated with bacteria, then the infection will enter the udder of that cow during the milking process. If, in the case of the latter, the cluster has just been taken off a cow which already has mastitis, then unless that cluster is cleaned that unit will be capable of passing the infection on to the next cow to be milked. In fact, it has been shown that infection can be passed on to the next 8 cows to be milked with that unit.
An effective parlour routine rigorously followed by all the milkers on a unit can go a long way towards reducing the spread of mastitis. Basic hygiene is paramount in this regard.
Examination of the foremilk
Firstly, you need to know if the cow about to be milked is infected with mastitis. The udder should be palpated to detect any obvious hardness or swelling. Then the foremilk should be examined. This is often achieved by drawing the first milk on to the parlour floor, and some floors have a black tile inserted for that purpose. However, this method can cause splash back on to other cows whose teats have been cleaned in preparation for milking and very small clots in the milk are not easy to see. A better method is to draw that first milk into a strip cup where a closer examination can be made. More recently, black plastic gloves have been used where the milk is drawn onto the gloved hand. If these gloves are used they should be washed in peracetic acid after each infected cow has been detected. A much more accurate, precise method is to use a Californian Mastitis kit. This involves a cowside chemical reaction but is the method of choice for detecting sub-clinical mastitis where no clinical signs of mastitis are apparent. There is often a change of colour in affected milk and also the milk has a slight salty taste but these two signs are very subjective and not now considered reliable. Whichever method is used, early detection is essential to prevent spread throughout the herd. If a clinical case of mastitis is detected, a separate unit kept for the purpose connected to a dump bucket or line should be used.
Cleaning the teats
If the teats are very dirty, they must be cleaned. If the teats need to be washed they must also be dried. If they are not dried, then drops of water will run down the teat to produce a bead of dirty water on the tip of the teat – so called magic milk – which will then be taken into the udder during the milking process, subsequently causing mastitis.
Pre-milk disinfection of the teats
Once the teats have been cleaned, they need to be disinfected. This is achieved by applying a pre-milk teat disinfectant either by use of a spray or a teat dipping cup. The whole teat should be covered and this is best achieved with the cup rather than the spray but it is important that a ‘non-return’ cup is used. This prevents dirty dip contaminating the unused dip still in the cup. The dip needs to be left on the teat for 30 seconds to achieve disinfection. The milking unit can then be applied and the milking process commenced. The whole operation, from examining the foremilk to attaching the milking unit should take about 60 seconds which will coincide with the time it takes the average cow to let down her milk.
We would recommend that only 5 or 6 cows should be prepared in this way before the moving on to the next group of cows in the line. This will economise on time spent walking about in the parlour and maximise the advantages of attaching the units at the time of milk let down.
It is important that cows should not be overmilked. This can cause damage to the teat lining and increase the cell count. To avoid overmilking, the use of Automatic Cluster Removers is recommended. Once the units have come off the teats, the teats should be covered with a post-milk teat dip. This should be applied immediately or at least within the first 60 seconds after the units have come off the cow. This is because the teats start to involute after milking and it is important that the whole teat gets covered quickly. After the cows leave the parlour they should be encouraged to remain standing in a suitable, clean, sheltered environment to allow the teat dip to dry on. This can take 20 minutes and it is important that the last cows to be milked are allowed this standing time.
It is important to realise that the units which have just come off the cows should also be cleaned, especially if any infectious mastitis is suspected, before they are attached to the next cow. This can be accomplished by hand dipping them in a solution of per-acetic acid. This can be time consuming and can add 20 minutes to the milking time of 100 cows. Modern units now have one of the types of back flush systems fitted into the parlour. These work well but are expensive. A cost/benefit calculation, balancing the time spent hand dipping units against the cost of any back flush system, is recommended before deciding to install such a system
It is important to record all cases of mastitis and treatments used, together with cow identity and date. Apart from being a legal requirement, this will help in any further investigations. These, however, are outside the remit of this article.