Heavy and widespread rain last weekend hastened the housing of dairy stock up and down the country.

With a lot of grass on most farms, it remains to be seen whether these stock will go back out to grass again.

From an animal health perspective, the next couple of months are very important in terms of implementing appropriate animal health strategies.

Body condition score

Most farmers don’t associate body condition score (BCS) with animal health but it is inextricably linked. Cows in low BCS have less resilience and are more susceptible to illness and poor fertility.

Doreen Corridan, Munster AI, speaks about body condition scoring and winter feeding during an Arrabawn Co-op open day in 2017. \ Donal O'Leary

Managing BCS begins in the autumn. There are a number of key targets when it comes to BCS and the most important is BCS at mating as this has a big bearing on subsequent fertility performance.

The target is for cows to have a BCS of 2.75 at breeding. Losing BCS after calving is inevitable, with 0.5 of a BCS usually lost in the month or six weeks after calving. This mean that the cows need to be at a BCS of 3.25 at calving.

Obviously, minimising the BCS loss after calving is important as research has found that losing more than 0.5 of a BCS has very negative consequences for animal health and fertility.

For example, it’s much worse for a cow to go from a BCS at calving of 3.5 to 2.75 at mating than it is for a cow to go from BCS of 3 at calving to a BCS of 2.5 at breeding, even though 2.5 is below target for breeding.

To ensure as many cows as possible are at BCS of 3.25 at calving means tailoring the dry period length and the dry period diet.

Cows in low BCS will require a longer dry period and vice versa. To calve at 3.25, what length of a dry period do cows need? It all depends on their BCS at drying off and the quality of the silage being offered to them over the winter.

This is illustrated in Table 1.

If cows are at BCS 2.75 at drying off and are given access to 72% DMD silage ad lib then they should calve down at 3.25 after an eight- to 10-week dry period. However, if cows are at BCS 2.5 at drying off and being fed the same silage they will need a 12- to 14-week dry period plus 1kg of meal per day in order to reach the target of 3.25 at calving.

Table 2 looks at the impact of what doing other things has on BCS.

The other things in question are a six-week longer dry period, milking once a day prior to drying off and feeding 2kg of soya hulls or beet pulp nuts while dry.

All examples were compared against a standard eight-week dry period at different levels of silage quality. Each of these tables is based on Teagasc data.

In a nutshell, silage quality is key. Cows eating 62% DMD silage will lose 0.15 of a BCS over the eight weeks while cows eating 72% DMD silage will gain 0.5 of a BCS.

Adding six weeks to the dry period will gain an extra 0.20 BCS to cows eating the poor-quality silage but those on the high-quality silage will gain an extra 0.55 of a BCS.

Milking once a day for eight weeks prior to drying off has the same effect regardless of silage quality, increasing BCS by 0.18 of a unit.

So, the advice for farmers is to analyse silage quality, do a body condition score on your cows and compare this to expected calving dates so as to tailor the dry period length for cows this winter.

Selective dry cow therapy

From next January, selective dry cow therapy will become mandatory on Irish farms. In advance of this, many farmers have chosen to implement selective dry cow therapy in order to get a head start and to also reduce their own use of antibiotics in the drive towards reducing antimicrobial resistance – a key challenge for all humanity.

Vigorously wiping the teats with disinfectant before inserting the tube will help to prevent infections.

Many farmers are understandably daunted by the prospect of not being able to use antibiotics at drying off.

The present generation of farmers were sold the message of dry cow therapy as both a treatment for existing infections and a prevention for new infections built up during the dry period. It was used as a central plank in the fight against somatic cell count.


It is worth remembering that selective dry cow therapy does not mean that antibiotics at drying off cannot be used.

As the name suggests, it is selective use of therapy rather than a blanket use of therapy. In extreme situations, a vet can still prescribe that all cows in a herd need antibiotics at drying off. This is still considered selective dry cow therapy because every cow in the herd was selected for dry cow therapy. In practice, most herds will have some cows that don’t need to be given antibiotics.

The prospect of restricting the use of antibiotics is therefore a major worry for many farmers. However, it’s a nettle that must be grasped and many other countries, particularly Holland and Denmark, have shown that herd SCC can still decline even when dry cow therapy is greatly reduced.

In Holland, just 30% of cows get antibiotics at drying off and average bulk tank SCC there is between 170,000 and 180,000 cells/mg. This is similar to Ireland but about 95% of cows in Ireland currently receive antibiotics at drying off.

Of course, some of these countries have advantages over Ireland in this regard as they have an year-round calving pattern meaning many can graze dry cows outside for six or eight months of the year, where there is much lower disease pressure.

Even where dry cows are indoors there is less disease pressure in the dry and crisp environments compared to the Irish damp and wet winters. Plus, many farms in these countries are more heavily invested in winter housing with modern facilities, which of course comes at a cost.

Having said that, many Irish farmers have successfully implemented selective dry cow therapy and have got on very well with it.

Animal Health Ireland (AHI) says suitable cows should have an average SCC of 100,000 for the lactation and not have had an SCC of greater than 200,000 at any milk recording during the lactation.

Use of teat seal as part of SDCT

Speaking at an MSD Animal Health webinar earlier this year, UK-based vet and mastitis expert Peter Edmundson said the use of teat seal is critical when using selective dry cow therapy (SDCT).

He gave the following advice when administering teat seal as part of selective dry cow therapy (SDCT):

  • Make sure there is good lighting and the operator is working at the correct height.
  • Only do one teat at a time, starting with the furthest away teat and finishing with the closest teat.
  • Wear clean gloves and keep them clean.
  • Disinfect teats using almost surgical like cleanliness. He advises farmers to pre-dip teats, wipe and disinfect with cotton wool pads and surgical spirits.
  • Apparently, 60% of all new infections during lactation can be traced back to the dry period so while hygiene at drying off is important, particularly where SDCT is practised, hygiene throughout the duration of the dry period is also important.

    Keeping beds clean and regularly disinfecting with lime or similar disinfectant will help to reduce the growth and spread of bacteria on the bed, which the teats can come in contact with.

    In brief

  • Target body condition score at calving is 3.25. The dry period duration and diet should be altered based on cow BCS and silage quality.
  • Avoid cows getting too fat during the dry period as this can lead to excessive BCS loss post-calving.
  • Selective dry cow therapy is mandatory from next January.
  • Hygiene at drying off and during the dry period is critical to prevent new infections.