Reviewing calf rearing and management protocols, including vaccination policies and lung scanning, has reduced the impact of pneumonia and improved overall youngstock performance on one family-run dairy unit
TEXT DAVID BUTLER
Supporting calf immunity through colostrum management and vaccination, as well as reviewing and changing other rearing management strategies, have halved antibiotic use for bovine respiratory disease and lowered mortality rates on one Shropshire-based unit.
Pneumonia prevention is a top priority for producer Stephen Suckley-Jones so he can produce plenty of quality heifers to maintain numbers should his 340-cow Oswestry-based herd suffer a bTB breakdown. He’s aiming to rear 120 per year.
Consequently, when calf pneumonia rates began to climb in autumn 2023, he knew something had to be done. “We were seeing, on average, two cases of pneumonia a day. We’d enter the shed and calves would be coughing, and some wouldn’t get up,” says Stephen, who farms in partnership with his wife, Sarah, and father in law, David. “They were good calves and most of them recovered, but we had the odd one or two that we lost – between 10 and 15 during a seven-month period.”
So, he decided to make a number of management changes to improve calf health, some of which were adapted due to involvement in a pneumonia vaccination study, with vet Jon Mayer, of Park Issa Vets. The alterations combined to result in a 258% drop in antibiotic use for respiratory disease, down from 107,000mg for the year to January 2023 to 41,550mg during the 12 months to January 2024.
Steps taken included: giving calves a booster vaccine against pneumonia; testing colostrum and improving quality, if necessary; feeding colostrum promptly; using calf jackets; changing management at calving; and vaccinating dams against scours.
The first change, offering calves a booster vaccine against pneumonia, or bovine respiratory disease, was introduced because calves on Stephen’s unit tended to develop pneumonia at around 50 days old, which coincided with weaning and moving to a separate unit down the road. All calves were vaccinated against bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus type 3 (PI3).
“However, any stress event can put the immune system under pressure, increasing the chance of disease. So Jon advised providing a booster prior to weaning,” says Stephen.
All calves now receive a booster between one and two weeks prior to being moved to the new farm. The effect has been significant, and Stephen estimates that post-weaning pneumonia incidence and mortality rates have halved.
Colostrum management
He also reviewed colostrum management protocols and now all colostrum is tested using a Brix refractometer to assess immunoglobulin levels. “Any that tests below 22% is ‘fortified’ with a colostrum substitute to ensure calves receive sufficient antibodies. The aim is to feed the calf colostrum from its dam. And any spare colostrum that tests above 22% is frozen as a back-up supply. This can be used for calves born to Johne’s positive cows, which are calved separately, and their colostrum discarded,” he explains.
Stephen now ensures all calves receive their first colostrum within two hours of birth. Heifer and beef calves are fed colostrum morning and night, depending on birth weight (about 10% of bodyweight for all calves). Calves are offered colostrum from a bucket with teat, and then tubed if they do not take it.
All heifers are fitted with calf jackets during the winter until they are 35 days old. “This ensures more energy is partitioned towards growth and supporting the immune system, rather than keeping warm.”
There have been changes to management at calving too. Heifers are now introduced into the calving yard, one month rather than one week before calving. This gives them time to adjust and establish their place in the hierarchy, which has had a positive impact on colostrum quality, according to Stephen. Heifer colostrum now averages between 25% and 30% on the Brix refractometer, when before it would have been about 15%.
Cows are also vaccinated for scours, with Bovilis Rotavec Corona, which raises colostrum antibodies against E coli adhesins F5 (K99) and F41, rotavirus and coronavirus. Jon says the strategy at Banhadla Farm is a good example of how an all-encompassing approach can benefit calf health and performance, adding that thoracic (lung) ultrasound scanning (TUS) also has a role to play in on-farm pneumonia control strategies.
He believes that ‘one cough is enough’ to warrant investigation into pneumonia in a calf shed. “A visual scoring system for calf health, which looks at the nose, ears and throat, only tells you so much. It doesn’t account for calves that have ‘hidden’ lung damage from respiratory pathogens and no outward signs. That’s where TUS can come in useful,” he says.
He adds that it’s typical to have a group of calves that look healthy, but scanning their lungs can reveal hidden damage. “In fact, studies have shown that only between 11% and 16% of pneumonia cases among a batch of calves is clinically visible. Anywhere between 23% and 67% could be subclinical and, therefore, invisible to the naked eye, yet calf health and lifetime performance potential are still being compromised.”
With that in mind, Jon advises lung scanning a whole group of calves to assess lung lesions as soon as producers hear a single cough. “The information gleaned can be used to make informed treatment and management decisions.”
Pneumonia protection
This approach was adopted at Banhadla Farm as part of a MSD Animal Health study that looked at the feasibility of giving the first dose of Bovilis INtranasal RSP Live to newborn calves. This vaccine is now licensed for use in calves from the day of birth onwards, reducing handling challenges and delivering the same level of pneumonia protection compared to waiting until calves are between seven and 10 days old.
Calves were visually assessed for signs of respiratory disease using a calf-health scoring system, and their lungs ultrasound scanned. This information was used to inform treatment decisions. For example, calves with lung lesions smaller than 1cm were given antibiotics and non-steroidal anti-inflammatories (NSAIDs) and then scanned a few days later to monitor treatment success. Calves with lesions measuring more than 3cm and signs of lung consolidation were unlikely to be cured with treatment, so they were put to beef or culled.
Stephen’s herd was one of three of dairy clients involved in the study that looked at the feasibility of giving the vaccine on day one. Weight gains, along with morbidity and mortality, were measured and the results showed there was no difference when vaccinating on either the day of birth or at between seven and 10 days old. This means the vaccine was not affected by maternally-derived antibody, which is important to protect the calf, but can interfere with certain vaccines when given to very young calves.
Stephen adds that being able to vaccinate from the day of birth onwards is beneficial because calves are smaller and easier to handle. The vaccine is also available in single dose bottles, which is attractive on all year-round calving units. “We may have a calf born one day and then not have another for five or six days – that’s a big gap. Previously we’d have to break into a large five-dose bottle, which would end up being wasted. So the single dose bottle is a game changer.”
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