By Debbie James

Exceptional mastitis controls and an overall infection rate of just 7.8 cases per 100 cows is enabling a Pembrokeshire dairy farm to dry off 90 per cent of the herd without antibiotics.

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

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

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

“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's 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.

To achieve the current level of 7.8 mastitis cases per 100 cows – the national average is nearer to 50 cases - cows that have had more than two cases of mastitis are removed from the herd.

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

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 are earmarked for drying off with antibiotics before the main herd together with cows that have had more than one case of mastitis, those with teat end damage or warts or with infections in their uterus; these 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.

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

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

Mr Hannah will have monitored the weather forecast in the week leading up to drying off, to ensure that it can be done on a dry day to reduce risk of bacteria transmission in water.

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 a cotton wool ball pre-soaked in surgical spirits.

Sealant is applied one teat at a time, working from the front to the back to prevent contamination of unsealed teats.

“We make up buckets of pre-soaked balls beforehand and always make sure that we have enough to do the job, keeping the surgical spirit toped up if they start to dry out,’’ Mr Hannah explains.

Gloves are worn and kept clean at all times.

Sealant supplied by the farm vet is then applied. “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 turned back into a collecting yard to stand for around an hour before re-entering the cubicles.

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 per cent focused on getting all the factors correct,’’ says Mr Hannah.

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 antibiotic usage more by only targeting the problem quarters in these cows,’’ he adds.

“Reducing antibiotic 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 antibiotic usage at all on farms in ten years.’’