With the end of the year rapidly approaching we are into our winter routine so I thought I would do something different in this article rather than cover what we’ve done in the last few weeks, discuss what routine means here at the Drum and why we (rightly or wrongly) do things the way we do.

Paradoxically, probably the best place to start is with the period of time when the cows aren’t producing any milk. After all, it’s the dry period that really sets the cow up to perform (or not) during her next lactation.

We normally aim to dry our cows off at about five to six weeks before their due date, although if a cow’s daily yield falls below 15 litres/day we will generally dry them off a bit earlier.

The normal routine for drying off is for Stuart to lift all the feet and treat as required and then I’ll do the teat treatment. Up until four years ago all the cows would have received a tube of intramammary antibiotic (AB) as well as a tube of teat sealant in every teat. However we have become more comfortable using “Selective Dry-Cow Therapy” (SDCT) we’ve progressively reduced the number of tubes of antibiotic we use, such that more than 90% of cows now just receive teat sealant.

In fact, unless there’s an obvious need to use a dry cow AB tube on a cow (ie mastitis in the last three months or SCC at milk recording chronically over 200) then we would much prefer just to use sealant.

The main reason is that we have found that cows given AB at drying off seem to be more prone to acute E. coli mastitis in the following lactation presumably because we’ve disturbed the natural equilibrium of flora/fauna in the udder.

Also, I think that the sealant works better without the AB, the carrier in the AB tube seems to stop the sealant from getting a good “grip”. I think success with SDCT though is really about going overboard with the preparation. I’ll dip and wipe each teat twice to get them looking clean, then give them a wipe with surgical spirit and finally use an individual wipe just before I insert the tube.

I think that the administration instructions for the sealant miss one thing – after pinching at the base of the teat, I find it best to then squeeze the teat to remove any milk, and then wipe it with the individual wipe and insert the tube. Doing it this way seems to stop the pressure building up in the teat and sucking the sealant into the teat when I release the pinch.

If you’re wondering what the reason for using sealant at all is, it serves two main functions. Firstly it provides a barrier to prevent bacteria from entering the udder during the dry period, the cow will naturally produce a keratin plug to do the same thing as she drys off but this takes time and is less likely to happen in cows producing more than 20kgs of milk at drying off (<55% will form a keratin plug even after a month).

The second reason is that in the days following “drying off” the cows' udder is still producing milk. The sealant reduces the leakage of this milk increasing the pressure in the udder, this in turn feeds back to the pituitary gland and reduces the release of the hormone Prolactin stopping milk production.

There is a pharmaceutical product (Velactis) that uses this mode of action to aid in drying off cows but unfortunately, it was only on the market in the EU very briefly about six years ago.

The cows in the “dry group” get a very specialized diet, a key part being the DCAB (Dietary Cation-Anion Balance), which looks at the ratio of Na and K (the cations) to Cl and S (the anions) in the ration.

By adding calcium chloride we skew this ratio in favour of the anions. This apparently encourages calcium resorption from the bones and increases dietary calcium absorption. Overall this should make the cow less prone to a whole host of disorders (milk fever, retained placenta, displaced abomasum) early in the following lactation.

Although the DCAB is relatively easily calculated it can take a bit of fine tuning to get the amount of calcium chloride in the diet exactly right, and we can monitor how we are doing by measuring the pH of the dry cows’ urine. Normally it should be around 8-8.5 but if we have the diet right it should fall to 6-6.5 (ie slightly acidified).

Another major difference between the dry cow ration and the standard cow ration is that it is mainly based on hay/straw. This is because we want to keep the energy density of the ratio quite low.

Not only does this stop the cow from getting fat, which would lead to problems at calving; but it also encourages her to keep her rumen full as she tries to get enough energy from the ration. This is important as we don’t want the rumen to get smaller as the calf competes for space inside the cow, because having that large well-functioning rumen is going to be critical for her getting the nutrition she requires post-partum. Anyway I hope that has been of some interest, and I’ll continue talking about new life (ie calving) in the New Year. So I just want to finish by wishing you all a Merry Christmas and best wishes for 2024.