How a farmer uses antibiotics on just 10% of herd at dry-off

Exceptional mastitis controls and an overall infection rate of just 7.8 cases for every 100 cows is allowing one Pembrokeshire farm to use antibiotics on just 10% of the herd at drying-off.

William Hannah had routinely tubed all cows at drying-off, but he now does this selectively by working with his farm vet to only treat cows that need antibiotics.

In 2020, just 38 of the 370 spring-calving New Zealand-type Friesians were dried off with antibiotics, saving £1,350.

But the financial saving is not the main reason for reducing antibiotics – this began seven years ago with an ambition to create a healthy herd.

See also: How to dry off cows to treat mastitis successfully

William Hannah © Debbie James

“Every time we treat a quarter, we wipe out so many good bacteria, leaving the udder more susceptible to further problems in the lactation, plus there is the lost milk value,” says Mr Hannah, who farms at Mountjoy, a Farming Connect Demonstration Farm, near Haverfordwest.

He now quickly steps in with udder cream and anti-inflammatory medicine at the first sign of any problems.

How mastitis rates are kept low

To achieve the current level of 7.8 mastitis cases for every 100 cows, any animals that have had more than two cases of mastitis are removed from the herd.

The replacement rate in 2020 was 16.6%, but this included cows culled for lameness and production, as well as mastitis.

Herd fertility is good – in 2020, the empty rate was just 8% – so there is no shortage of heifer replacements to join the spring-calving herd.

And there is a value in these end-of-season culls as the business receives an average price of £500 a head.

Identifying cows  

Preparation for drying-off starts three weeks beforehand, with milk-recording data used to identify cows with cell counts higher than 250,000 cells/ml – this totalled 18 cows in the 2020-21 season.

These cows are earmarked for drying off with antibiotics before the main herd, together with animals that have had more than one case of mastitis, those with teat end damage or warts, or cows with uterine infections – they are all double-tubed.

“Drying these off separately prevents any confusion and means that, on the day, we are applying sealant only so we can concentrate on getting that right,’’ says Mr Hannah.

Reducing milk yield

In the five days prior to drying off the main herd, concentrates are reduced from 4kg a cow a day to just 1kg.

Silage is replaced with high-fibre hay or haylage to reduce milk yield. In the latest drying-off period, the average daily milk yield was reduced from 14 litres to 7 litres.

Drying-off process

Mr Hannah will monitor the weather forecast in the week leading up to dry-off, to ensure that the job can be done on a dry day to reduce the risk of bacteria transmission.

There are three people in the parlour, all fully trained in drying-off procedures.

“It is a big task – it takes about four and a half hours, but, by doing it in one go, we can be 100% focused on getting all the factors correct,’’ he says.

The process starts at midday. “We used to dry off in the morning but the cows were a bit dirtier after lying down more during the night, so we now bring them back in again around midday after they have had their morning feed, when they are much cleaner,’’ Mr Hannah explains.

Cubicle mats are topped with clean sawdust and lime prior to drying off and fresh bedding is put in place post-drying off, too.

Cows are milked again as they come into the parlour, giving around 2-3 litres, and each teat is then wiped with cotton wool pre-soaked in surgical spirit.

Sealant, supplied by the farm vet, is applied, one teat at a time, working from the front to the back to prevent contamination of unsealed teats. Gloves are worn and kept clean at all times.

“Due to availability, we have switched to a product that is softer than the sealant we had previously been using, and there is also less air in the tube,’’ says Mr Hannah.

“We are getting as good results from these tubes, so we are happy with the switch.’’

Teats are dipped and the cows are turned back into a collecting yard to stand for about an hour before re-entering the cubicles.

Improvements and future plans

He admits that perfecting the process has taken trial and error, and encourages other farmers not to give up after the first attempt.

“We haven’t always done this well. We did have problems in the beginning, when we weren’t as methodical with cleanliness as we are now, and we did lose quarters. Everything is now focused on cleanliness.”

In the future, he may test individual quarters on cows with cell counts over 200,000 cells/ml.

“We believe we may be able to reduce antibiotics usage more by only targeting the problem quarters in these cows,’’ he adds.

“Reducing antibiotics usage is an interesting and rewarding challenge, and something we can all learn from each other’s experiences.

“Through focusing on ‘prevention is better than cure’ principles, I can’t see there being much antibiotics usage at all on farms in 10 years.’’