Poor ventilation in too many cattle sheds

A significant number of cattle sheds in NI do not provide the proper ventilation required to keep animals healthy and maximise performance, a leading livestock housing specialist has said.

Outlining his views at a Parklands Veterinary Group event in Cookstown last Wednesday, Aberdeen-based Jamie Robertson emphasised the need to have 0.1m² per cow of outlet in the roof to let bad air out, with similar inlet space required on each side of the building.

In NI, Robertson said too many builders and farmers have opted for a raised covering over the ridge on a roof as it keeps rain out and is “quite easy to do”. But it does not achieve the proper ‘stack effect’ required to suck warm air out of the shed, which, in turn, will draw in fresh air from outside.

His preference is that the ridge in the roof is an upstand, effectively working to the same principle as when smoke is drawn up a chimney in a dwelling house.

“Wind blowing over an upstand creates a negative pressure in the chimney, which sucks the dirty air out. A top hat (a raised covering) is not what you need – don’t do it,” said Robertson.

Yorkshire board

He does not like the vented sheeting used on the side of many sheds in NI, or space boarding as it can let rain in on wet and windy days. Instead, proper Yorkshire board (two rows of space boarding) should be used, especially on the side facing the prevailing wind.

“With Yorkshire board you have double the amount of air space [compared to space boarding], but no rain gets in. You have doubled the capability of your building,” said Robertson.

In sheds where air flow is restricted by a solid wall, a ventilated tube and fan system will improve air movement on calm days. The system is also useful in calf houses, especially given that calves cannot generate enough heat to help contribute to a ‘stack effect’, said Robertson.

However, young calves must be protected from draughts, while also having access to clean water and sufficient amounts of dry bedding.

“We live in a very difficult climate for managing bacteria and viruses – keep moisture to a minimum. Keep water away,” he said.

To do that, farmers should ensure guttering and down pipes are working properly and any leaks in the roof are fixed. Simple channels cut into the floor will also help prevent the build-up of moisture.

Cleaning

When it comes to cleaning calf houses and calving areas, it is not enough to take out the bedding with a loader and then spray on a disinfectant. Biofilm that can build up inside feeders and water systems, also needs to be properly removed.

“You need to clean stuff before you can expect disinfectant to work, and then you need to leave it to dry,” advised Robertson.

He said it is often the case on farms that facilities are not easily cleaned. Over-stocking is also an issue, as it limits the window for taking out pens and cleaning them properly.

More farmers should consider routine dung sampling of cattle and sheep to test for worm burdens, Parklands vet, Rosy Owens told farmers at the Cookstown conference.

“Dung sampling can be really useful. It can save dosing for when you need to use it. You can repeat after treatment to see if products are working OK, or not,” she said.

While anthelmintic resistance is an issue for roundworms in sheep, especially to the white drenches, there is evidence it is also an increasing problem in cattle, added Parklands vet, Josh Kittle.

As well as good practice around dosing, he suggested it is important to rotate between products to avoid repeated use of the same active ingredient in the same year.

Sheep farms

On sheep farms, he suggested more farmers need to consider a quarantine dose for newly brought-in animals, using one of the new group four (orange) or group five (purple) products.

Farmers should also be aware of the risk of Haemonchus worm infection (Barber’s pole worm), which causes a disease called haemonchosis. The worms live in the abomasum and feed on blood, with blood loss leading to anaemia, loss of condition and potentially death.

“Haemonchus – all labs are now picking it up. It is endemic to the UK and Ireland, but it is not on every farm yet,” said Kittle.

Treatment

Both lambs and mature ewes can develop the disease. All groups of anthelmintics can be used to treat Haemonchus, although resistant strains of the parasite have been found, especially in countries where the disease is widespread.

Carefully selecting replacement heifers will help ensure sucklers have a long and productive life on-farm, rather than end up slaughtered at four years old, suggested Parklands vet, David McKinstry.

“Keep heifers from quiet cows that have good feet, good udders, good fertility and that calve themselves,” McKinstry advised.

He said that there is a high likelihood that problem traits, such as a curled up toe, will be passed on to offspring.

Two year calving

McKinstry is also a strong advocate of two year-old calving, although it is reliant on getting calves off to a good start in life and ensuring disease challenges such as pneumonia are avoided. As a result, he believes that the age at first calving targets in the new suckler scheme due to commence in 2025 are “very doable”, given those targets start at under 34 months in year one, falling to under 29 months by year four.

However, McKinstry acknowledged that the calving interval targets included in the scheme might be much more challenging to meet.