Short dry cow periods promise benefits all round

There is something rather challenging about questioning established principles, writes farm vet Chris Watson.

That is exactly what is happening at present, largely led by work in the USA where the questions being asked are ‘why do we dry cows off?’ and ‘what is the ideal length for a dry period?’, he says.

Discussion about drying cows off go back as far as 1805. The ideal length of the dry period was subject to a lot of controversy even then with periods of between 10 days and two months being quoted.

The original need to dry a cow off was to allow her to put on body condition before the next lactation, as nutrition at this time was often limiting and a period of non production was needed to correct it. During the war years of the 1940s it was established that the “ideal” length for this was 60 days. In turn, this gave rise to the accepted lactation length being defined as 305 days – 60 days off in a 365 day calving pattern.

Now, things are starting to change and we need to ask the right questions about what we are doing when it comes to drying cows off; not surprisingly some very interesting answers are emerging.

Although it may seem at times rather extreme, studies in the US are showing what can be achieved when the dry period is pushed back, even as far as dispensing with it altogether. This extreme is very unlikely to be the practice adopted in the UK, but it serves to show what the science is behind the dry period and what we can expect even with more modest changes in its length.

The announcement in February that Cephaguard DC has a new datasheet claim for short dry periods will re-start the debate around dry period management in the UK. For a couple of years now, some farmers and vets have been using the product strategically and on short dry periods (35-42 days), and feedback from vet colleagues indicates there is lots of interested in the subject.

In order to prepare for the new approach to dry cow management, studying the effects and impact of short dry cow periods on UK and US farms shows that:

􀂄 8000 litre cow with a 40 day dry period means an extra 20 days milk = 4 – 6% extra milk

􀂄 At 40 days dry there will be no loss in next lactation = net gain of 5 – 6% milk

􀂄 (At 30 days dry a drop of 3% at worst = still 3% overall benefit)

􀂄 Milk solids are improved with short dry periods so could give better milk price

One Hampshire farm that has been running short dry periods with Cephaguard DC for a little over a year reckons there is an improvement in margin/cow of £35, through the additional milk sold per cow per lactation alone. Other parameters will also show benefits such as milk solids, mastitis control in the dry period, fertility in subsequent lactations and health of the cow around the time of calving.

Many producers who use short dry cow periods see one the main benefits as a simplified approach to feeding and housing. All dry cows can be housed together, and

fed one ration. It has been argued that dry cow nutrition has become too complex when

all we need to achieve is:
• Keep weight and condition constant
• Prepare the cow for the next lactation

All cows reduce their dry matter intake (DMI) just before calving and studies have shownthe effect of this is less with shorter dry periods. The result of this should be:
• The cow spends less time in negative energy balance because energy intake is improved
• There is a reduced loss of body condition score
• Less mobilisation of body fat immediately prior to calving
• Less fats laid down in the liver at calving