Spring-born suckler calves generally remain with their dams at pasture until they are weaned, usually between five and nine months of age.
Weaning stress has an adverse effect on the immune system, making calves more susceptible to disease, particularly pneumonia.
It is essential for the health and performance of these calves to minimise stress around weaning by having good handling facilities and by using proper weaning procedures.
Weaning stress is often compounded by other husbandry practices occurring around the same time, such as change of environment (outdoors to indoors), change of forage diet (from grazing grass to eating silage, usually with concentrate supplementation), dehorning, castration and transport for sale.
Steps to minimise stress at weaning
Common causes and clinical signs of pneumonia in weanlings
Pneumonia in sucklers around the time of weaning involves a combination of infectious agents together with poor management and husbandry factors leading to a disease outbreak.
The infectious agents that cause weanling pneumonia are a range of viruses and bacteria, and calves may be infected with more than one of these at a time.
The viruses that most commonly cause pneumonia are bovine herpesvirus 1 (BoHV1; the virus that causes infectious bovine rhinotracheitis (IBR)), bovine respiratory syncytial virus, (BRSV), parainfluenza virus 3 (PI3V).
The bacteria involved include Mycoplasma bovis, Pasteurella multocida, Mannheimia haemolytica and Histophilus somni.
Early diagnosis is essential for the successful treatment of pneumonia, together with good stockmanship, where the calves are observed on a regular basis post-weaning.
Initial signs of pneumonia can be non-specific and include being off form, dullness, reduced feed intake and lack of gut fill.
Other signs may include fever (over 39.5°C), increased respiratory rate, watery nasal discharge and severe breathing difficulties.
By the time these later signs are noted, the disease has advanced and treatment is less likely to be successful, as damage to the lungs may be irreversible.
If you suspect weanling pneumonia, consult your veterinary practitioner for advice on diagnosis and treatment.
Pneumonia around the time of weaning has the potential to cause significant performance losses and even death in weanlings.
The risk of pneumonia is increased by a series of factors, including poor weaning management, sheds with poor ventilation and additional stressful events around weaning, including mixing newly bought animals with homebred animals.
One of the biggest factors affecting pneumonia in purchased weanlings is simply that too little is known about weanlings that are purchased
If you are buying weanlings, quarantine new animals after arrival, ideally outdoors or in well ventilated buildings, for at least four weeks before mixing with homebred animals.
Where possible, liaise with the seller prior to purchase to check how their weaning management practices match with the aforementioned list.
One of the biggest factors affecting pneumonia in purchased weanlings is simply that too little is known about weanlings that are purchased.
You can prevent pneumonia with good management of your animals and this is preferable to treating outbreaks – remember, prevention is better than cure.
This is particularly important in light of the changes in antibiotic use that will be introduced in January of 2022, prohibiting their routine use, either as a preventive treatment in advance of disease, or as a group treatment when disease is first observed.
In some situations, vaccination may also be used in the face of a viral respiratory disease outbreak
Vaccines are available against the most common viruses and bacteria that cause pneumonia. Vaccines need time to build up protection and courses should be completed before the time of weaning and housing to have the best effect.
For most vaccines, this means beginning the vaccination programme at least six weeks before the planned date of weaning.
In some situations, vaccination may also be used in the face of a viral respiratory disease outbreak.
It is worth remembering that vaccination alone won’t solve your pneumonia problem and the management factors outlined above need to be considered also.
Talk to your veterinary practitioner to discuss in more detail these management factors and develop a vaccination programme that suits your farm.