Pneumonia vaccinations have generated plenty of headlines in the media over the last 12 months. This has stemmed, in part, from exporters, where threats of boycotting sales were on the cards if farmers didn’t vaccinate weanlings. On the back of this, many marts have recently hosted information evenings to provide a refresher on the dos and don’ts when vaccinating.
The Irish Farmers Journal attended many of these talks, but one interesting statistic picked up was at a talk hosted by Roscommon Mart. Sarah Higgins, ruminant veterinary manager with MSD discussed some of the negative outcomes when animals become infected with bovine respiratory diseases (BRD).
Aside from the death of animals, those cattle that survive after treatment take substantially longer to finish.
Animals that are severely sick can take over 60 days longer to finish, compared to healthy animals. Even animals that were only moderately sick can take over 44 days longer to finish. Hidden lung damage can reduce average daily gain by up to 126g/day, resulting in added cost and lost performance. The big five factors when controlling BRD are management, housing, vaccination, hygiene and biosecurity.
A combination of stress and infectious agents like viruses and bacteria contribute to the increased likelihood of a pneumonia outbreak in weanlings.
On many farms where weanlings are typically sold at six to nine months of age and not housed, they can often sometimes be facing a low level of infection but not exhibiting symptoms due to lower stress levels. It is the purchaser of these weanlings that can see all the problems.
There are many different strains of pneumonia. Cattle can often be infected with more than one virus and it is generally triggered by a stressful event where clinical signs begin to show leading to animals requiring veterinary treatment.
Some of the most common pneumonia viruses are bovine herpesvirus 1 (BoHV1); the virus that causes infectious bovine rhinotracheitis (IBR); bovine respiratory syncytial virus, (BRSV) and parainfluenza virus 3 (PI3V).
The bacteria involved include mycoplasma bovis, pasteurella multocida, mannheimia haemolytica and histophilus somni.
Regular observation is key to detecting cases of pneumonia. Initial signs of pneumonia begin as weanlings being off-form, dull in their behaviour and reduced feed intake.
More clinical signs begin to show next. They include a fever (over 39.5°C), increased respiratory rate, watery nasal discharge and severe breathing difficulties.
By the time these clinical signs begin to show, the disease has advanced and treatment is less likely to be successful as significant damage to the lungs is irreversible.
If farmers begin to see some of these signs and suspect pneumonia, veterinary consultation is a must for early diagnosis and treatment.
Where cattle are grouped and one case occurs, is it highly likely that more cases are going undetected or will occur. Extra vigilance is required.
Pneumonia hitting around the time of weaning has the potential to cause significant problems and abrupt weaning can aggravate issues. Poor weaning management, sheds with poor ventilation and stressful events put the animal’s immune system under pressure – and that is when problems begin to occur.
Vaccination won’t stop all cases of pneumonia, but when cases begin to occur, vaccinated animals will have better protection, resulting in fewer clinical cases and a quicker recovery time. Good management practices at weaning that reduce stress will help prevent pneumonia.
Removing a handful of cows slowly and avoiding abruptly weaning a full group will reduce stress on the cattle being weaned. Meal feeding and getting the weanling’s stomach adapted to a diet without milk will also help ease the transition.
Many farmers will typically begin to purchase weanlings from September, and this can bring risks. New purchases should be quarantined away from existing stock on farm, ideally outdoors or in a well-ventilated straw-bedded shed.
Many of these weanlings will have been purchased from marts and may come from a number of source herds. Each herd brings the risk of introducing a new disease onto your farm.
Where possible, buy weanlings where you know the source farmer and can get the animals’ health history. Weanlings vaccinated for pneumonia and dosed for worms will present the least health risks.
Implement your farm health plan.
It is recommended to vaccinate purchased weanlings for the most common strains of pneumonia.
Vaccinate purchased weanlings as a group and avoid doing so until they have settled into their new surroundings.
Animals take time to build up immunity after been vaccinated. In some cases, it may be six weeks after first starting a vaccination programme until animals get the full benefit of the vaccine.
Consult your local vet on what’s best for your farm. Every farm is different and vaccines will vary so familiarise yourself with the product and booster dates.