Farm Ireland

Monday 23 July 2018

Be careful and take your time when drying off

John Donworth

The last few months have been very good from a somatic cell point of view. For the first five months of the year, the figures were disappointing due, no doubt, to the very harsh conditions at farm level.

However, we are now at the time of the year when some of you will be starting to dry off cows. In-calf first lactation animals are generally the first group to be dried off. This type of animal needs at least 12 weeks dry and, while body condition score is generally the chief reason for drying off, heifers that are showing high reading for somatic cell count should also be dried off.

Obviously, if you want to know which heifers are high you must be milk recording. Alternatively you will have to take a sample from each animal if you want individual readings. However, if you are milk recording, you have a serious amount of data to help you in your decision making.

I have extracted the information in Table 1 (right) from the very useful Milk Recording – Summary Farm Report. As well as giving you the overall herd situation, it also breaks the herd down into their different lactation number.

The table tells us the average somatic cell count (SCC) reading for heifers is 360,000. It also reveals that four of these heifers have had readings over 250,000 and one was treated for clinical mastitis.

On the strength of that report, what would you do? Well, firstly from a somatic cell count point of view, the four heifers should be dried off immediately. There are three reasons for this:

1.The longer the four heifers are dry, the greater the chance that they will calve down cured next spring;

2.Their impact on the bulk tank SCC reading;

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3.Low yielding heifers can have very low lactose levels.

I would use a long-acting dry cow tube on these heifers, followed by a teat sealer. The danger period for picking up new infections is the period immediately after drying off and the 10 days before calving. This is where the sealer comes into play. It will prevent any dirt getting into the teat canal when the cow "bags up" prior to calving.

Should one carry out a sensitivity test to determine what dry cow tube you should use? Yes. However, you need to be extremely vigilant from a hygiene point of view. Use the following procedures:

1.Select the three cows in the herd with the highest cell count. Ideally these should be three animals with three different lactation numbers.

2.Also take a 5ml milk sample from the bulk tank (1/3 of a sample bottle). The reason you are doing this is to see if there are any other bugs floating around. You now have 4 samples for the lab.

3.When you are sampling the three worst cows, do the following:

* Label a sterile bottle with the date, cow identification and cow udder quarter;

* Disinfect the teat ends before sampling by vigorously rubbing the teat ends for 10-15 seconds with cotton wool soaked in methylated spirits;

* Allow the teat to dry;

* Discard three strips of milk from the quarter in order to flush out any teat canal contaminants;

* Strip one or two good squirts of milk (5-10ml) into the sterile bottle. Ensure dirt does not fall into the sample bottle;

* If the storage period is short (less than 24 hours) place the sample in the refrigerator prior to transport to the lab. Otherwise postpone sampling until you are sure the sample can get to the lab quickly.

This procedure is all about hygiene and if you go to the bother of doing it, do it right.

Drying off cows is a slow job and farmers generally do it in batches. Leave the mobile phone in the kitchen when you are doing it. Mistakes have been made at drying off.

It is easy to be confused which teat was infused with a long-acting dry cow tube if you take a 10-minute phone call in the middle of it.

Long acting tubes can last up to 60 days and if you make a mistake and use two long-acting tubes on the same teat, then the withdrawal period is now 120 days, plus the withdrawal period after calving.


The other major report you should have in front of you is the Mastitis Incidence Problem Cow Report. This report is a mine of information as it ranks cows from the worst offenders and their percentage SCC contribution to the bulk tank. Use the California Milk Test (CMT) kit here to identify the worst quarters.

Don't forget the National Dairy Conference, which takes place over two days. The Limerick conference is on November 12 at Limerick Racecourse and the Cavan conference is on November 14 in the Slieve Russell Hotel, Ballyconnell, Co Cavan.

John Donworth is Teagasc dairy specialist and regional manager in Kerry and Limerick.

Irish Independent