As dairy farmers face mounting pressure to reduce antibiotic usage and selective dry cow therapy becomes the norm, the implementation of a drying off protocol is more important than ever. Hannah Noble finds out more.
Any business owner knows the importance of drawing up comprehensive protocols to ensure every task is carried out to a consistent standard, and they are more frequently becoming commonplace on-farm too.
Bill May, of Lambert, Leonard and May farm vets, says it is one thing producing protocols, but even more important that they are followed. He adds this can be a bigger challenge on larger farms with more staff and a greater risk of inconsistency.
When creating a protocol for drying cows off Mr May says the first things which must be considered are the parameters of selective dry cow treatment.
He says: “Decide which cows are getting dried off with and without antibiotics. There are lots of guidelines out there, but the criteria really should be farm specific and drawn up with the help of your vet.
“Dry cow antibiotic therapy can be much more effective than lactating therapy for killing bacterial causes of mastitis so the dry period is a good opportunity to address the cows that have developed intra-mammary infection during lactation.”
Many factors can affect the cut-off point for treatment with antibiotics including the predominant pathogens on a particular farm.
Mr May says some farms suffer from environmental causes of mastitis much more than contagious causes and vice versa. Udder health, the history of the cow, milk yield, aiming to reduce antibiotic usage as well as the farmer’s attitude to risk should also be considerations.
There are several viewpoints regarding the best way to dry cows off, but Mr May says drying off should take place abruptly. Although this may seem difficult with a cow still producing a high volume of milk, he advises against dropping to once a day milking which can increase the risk of mastitis significantly.
He adds, separating late lactation, high yielding cows into a specific group with a change of diet will help to reduce milk yield in the final week before drying off, but admits most farms would not have the space or management capacity to achieve this.
He says: “Drying off should be carried out away from the milking parlour at a time other than milking and in a clean environment. It is important to stress this should not be carried out during milking.”
Mr May says many farmers dry cows off at the end of milking when both the parlour and the farmer’s clothing are dirty. He says if the parlour is to be used it is vital it is clean and the farmer is in the right mindset to carry out the task to a high level.
Cleanliness at drying off is absolutely critical he says, whether or not the cow is receiving intra-mammary antibiotics. However he says it is even more important if the cow is not receiving antibiotics.
Mr May explains: “In the past farmers have usually always infused antibiotics as well as a teat sealant at drying off. This meant that there was more chance of being able to get away with a poor infusion technique, however if a cow is sealed without antibiotics, any bacteria which may have become trapped in the udder due to inadequate cleanliness could cause a new infection as they cannot be treated. We cannot over emphasis that enough.”
Mr May says the person administering the infusions must be surgically clean and teats should be cleaned several times with surgical spirit.
He says it is also important that the treatment tubes are handled correctly to avoid getting the uncapped tube-end contaminated before it is put into the udder. Mr May says the teats furthest away from the administrator should be treated first before moving on to the closest teats.
“The correct way of infusing teat sealants is different to administering antibiotic dry cow tubes, you are trying to retain the sealant in the teats and not massage it into the udder, so they are infused differently which is important to note.”
The period immediately after drying off poses a high risk of new infections even with teat sealants, Mr May says.
Where the cows go after drying off is very important and they should be moved into a clean area with minimum faecal contamination.
“Just because you have used a teat sealant does not mean they can be put into a dirty straw yard.
"Cows do pick up new infections in the dry period despite widespread use of sealants, we see that in mastitis patterns in the following lactation. Environmental-type infections occurring in the first month or so are more likely to be infections picked up in the dry period.”
He says the location of the dry cow yard can also have an effect on the efficacy of drying off. He explains it is better if it is further away from the parlour to avoid external visual and audible cues such as the sound of the milking machine and cows moving towards the parlour which are triggers for oxytocin release which causes milk let down.
Mr May says: “Feed also needs to be changed abruptly. We do not want cows kept on a milking cow diet as that will stimulate milk production. They need to come onto a dry cow diet quickly, and as much as anything that will reduce their milk.”
WITH a number of farmers being asked to cut their milk production in light of changes following the coronavirus outbreak, drying cows off early may seem like a solution, but Mr May says it could actually do more harm than good.
He says: “The ideal length of dry period is 60 days. There was a vogue for having a short dry period for a while to try and maximise lifetime milk production but I think two months gives the cow a decent rest and allows the udder tissue to regenerate and provides time to treat any intra-mammary infections which exist.”
He says drying cows off early, resulting in a long dry period will lead to cows getting too fat resulting in complications after calving. However external body condition score (BCS) is not always an indicator of whether the cow is too fat or not as often there is a lot of internal or visceral fat which cannot be seen on the outside.
Mr May says: “Transition cow problems have become very common and they are often related to cows being over conditioned and suffering conditions such as ketosis, metritis and left displaced abomasum at the start of the following lactation.
On high yielding units where there are often high quality forages which make up a proportion of the dry cow ration, albeit diluted, Mr May says it gets even harder to manage weight because even when the dry period is the correct length, cows can have a tendency to put weight on.
He adds: “If you lengthen the dry period by drying cows off early that just increases the risk. It is a real warning to be aware of that, manage BCS and adjust diets accordingly.”