Pneumonia, The Silent Calf Killer

ONLY Bovipast® RSP protects calves that are vaccinated from two weeks of age against Pasteurella (Mannheimia) haemolytica1, RSV and PI3.


This spring, nearly one million dairy calves will be born. Sadly, not all these calves will see the fresh green grass of summer due to disease!
The word pneumonia in simple terms, means inflammation of the lungs. Pneumonia in calves is a complicated, multi-factorial disease meaning that various factors can impact the onset of a pneumonia infection. Respiratory infections are the most common cause of death in calves between the ages of one and five months old. Latest figures show that respiratory infections accounted for 49% and 33% of calf deaths in this age group in Northern Ireland and Ireland respectively in 2016 (figure 1)2.

Did any of your calves die last year as a result of pneumonia? What measurements do you have in place to prevent this from happening in 2019?

What causes pneumonia in calves?

Stressed calves are more susceptible to disease such as pneumonia. How are calves stressed? Weaning, cold and poorly ventilated housing, damp bedding, overstocking and underfeeding are all examples of how stress may be inflicted on a new born calf.
The most important types of pneumonia are caused by viral (ref 3) and bacterial (ref 1) agents. The bacterial agents, known as Mannheimia (Pasteurella) haemolytica, live in the animal’s upper respiratory tract (particularly the tonsils) without causing harm to healthy animals. However, stress or viral infections can weaken the immune system and cause these bacterial agents to multiply rapidly. As these bacteria multiply, they are inhaled into the lungs. In the lungs, there is an interaction between the bacteria and the animal’s immune system, resulting in tissue damage. Clinical signs of pneumonia will be visible in the calf after this has occurred (dull humour, dropping of the head, nasal discharge or cough).


As pneumonia can result from viral or bacterial agents, it is important to choose a broad-spectrum vaccine that provides protection against both type of infection. Bovipast® RSP provides protection against both viral and bacterial pneumonia. For full protection, calves should be vaccinated with a 5ml injection under the skin, from two weeks of age and given another 5ml booster injection four weeks later.

How does Bovipast® RSP work?

  • Bovipast® RSP is efficacious in the presence of maternally derived antibodies.
  • Bovipast® RSP contains IRP technology (Iron Regulated Proteins).
  • When bacterial pneumonia agents like Mannheimia (Pasteurella) haemolytica reach the lungs of an animal it needs iron to multiply and grow.
  • IRPs on the surface of bacteria allow absorption of iron.
  • Animals vaccinated with Bovilis Bovipast® RSP produce antibodies that bind to the IRPs and reduce the bacteria’s ability to absorb iron.

IBR virus in young calves

Upper respiratory disease must also not be forgotten. Although less common in calves, IBR infection can still be implicated in disease. We know that there is a high prevalence of IBR infection across both dairy and beef herds in Ireland today. To reduce prevalence on farm it is recommended to adopt a whole herd approach. Including young stock as part of routine vaccination improves overall herd immunity and significantly reduces the incidence of disease.
Bovilis® IBR Marker Live vaccine can be conveniently used on the on the same day as Bovipast from three weeks of age ensuring broader coverage in the young calf. When Bovilis® IBR Marker live is used in calves less than three months old, it must be administered up the nose.

How can we maximise calf health?

A combination of good calving management, hygiene, colostrum feeding, and preventative disease control reaps rewards when rearing calves.

  • Calving pens: Dry, clean, well bedded pens are a necessity. The cleanliness of the cow entering the calving pen is also a priority to reduce the disease challenge to the new born calf. Good lighting in this area allows for early identification of problem cows or calves. Having cows fit but not fat at calving time is important.
  • Removing calves: Remove calves from the calving pen and their dam as soon as possible after birth.
  • Colostrum feeding: Aim to feed 8.5% of the calves’ body weight in colostrum within one hour of birth (35kg calf requires 3 litres of colostrum). The calves’ ability to absorb the protective antibodies within colostrum is maximal at this time. The colostrum and the feeding utensils used (bottle or stomach tube) must be clean. Colostrum milked from the cow within the first hour after calving has the highest level of protective antibodies which protect the calf from disease.
  • Vaccination protocol: Discussing with your vet a calf health vaccination plan for the spring is a really good idea. They will be best able to advise you on what disease you should vaccinate against or management changes that must be made to help your calves thrive over the coming months

1. Mannheimia (Pasteurella) haemolytica A1 and A6
2. Anon 2018. DAFM Animal Identification and Movement Statistics Report 2017
3. Bovine Respiratory Syncytial virus (RSV) and Parainfluenza3 virus (PI3)

Total Calf Health Solutions Company

Over the spring period, we will be featuring a number of videos focused on calf health. Stay tuned to our social media pages as well as where we will be regularly updating with new videos! The videos will feature members from the MSD Animal Health Technical Advisory team. The team includes Sarah Campbell, Suzanne Naughton and Cara Sheridan. They will be discussing disease challenges in young calves like scour and pneumonia. These videos will outline the MSD Animal Health products that can be used to protect and treat calves against diseases. Stay tuned!

Control of calf scour – is it possible?

Adult carrier cattle are the main source of infection of cryptosporidiosis and can shed small quantities of oocysts in their faeces without showing any clinical signs. These oocysts can easily infect the new born calf during or directly after calving via the faecal-oral route. Once ingested, the parasite rapidly multiplies, damaging the cells of the small intestine. Shedding from the calf can start within four days of initial infection leading to rapid re-infection of the calf as well as other calves within the same environment. This in turn can lead to massive environmental contamination within a short period of time. Disease can occur anywhere from one to four weeks age. However, calves from seven to thirteen days old are most commonly affected.

Herds infected with a pure cryptosporidiosis infection generally have a high morbidity and low mortality. However, as most herds in Ireland typically have a concurrent infection with rotavirus for example, this in turn can result in higher mortalities. Clinical signs initially include a reduction in appetite and apathy without scour. This can progress to a mild to moderate diarrhoea over several days which is unresponsive to usual therapies. Concurrent infections can lead to a more severe dehydration, emaciation and death.


Diagnosis forms an important part of differentiating the infection from other enteric pathogens such as rotavirus, salmonellae, E. coli and corona virus, as treatment and control methods can be slightly different. On-site kits can be a convenient diagnostic tool and can give a result within minutes otherwise samples can be sent to a suitable laboratory for analysis. To do so, sample faecal content directly from a group of at least 5 affected calves and ideally, samples should be taken from twelve-day old calves.


Once cryptosporidiosis has been confirmed on farm, ensure all affected calves are isolated as quickly as possible to limit further infection. Symptomatic treatment including rehydration fluids should be administered to combat dehydration. Halofuginone lactate reduces diarrhoea cases due to diagnosed cryptosporidiosis infection. Halofuginone lactate suppresses the parasite instead of killing it and as a result does not interfere with host immunity. It also causes a marked decrease in faecal oocyst shedding thereby limiting further environmental contamination.

To prevent further infection of calves on farm after a positive diagnosis with cryptosporidiosis, halofuginone lactate can be used on all new-borns and should be started within the first 24-48 hours. It is not recommended to administer halofuginone lactate, on its own, on an empty stomach or to cases where diarrhoea has been present for more than 24 hours and should be given after feeding. For treatment of anorexic calves, halofuginone lactate should be administered in half a litre of electrolyte solution.


  • All new born calves MUST get at least 3 L of colostrum within 2 hours of birth.
  • Healthy calves must be separated from sick calves and a “hospitalisation” unit established for the sick calves.
  • Healthy calves should be fed first each day and hospitalised calves attended to last so as not to transfer disease from the sick animals to the healthy unit.
  • Designated overalls and boots should be worn when working in the hospital unit and hands should always be washed between each group of calves.
  • Strict, thorough hygiene of feeding equipment including bottles, nipples and buckets must be practised.
  • Raise feed and water troughs so that calves can eat and drink out of them but cannot defaecate into them.
  • Antibiotics are NOT effective against cryptosporidiosis. All calves clinically affected should be treated with a product licensed to reduce diarrhoea due to Cryptosporidium parvum. There is a product containing halofuginone lactate that is licensed for this purpose and administration should start within 24 hours after the onset of diarrhoea and continue daily for 7 days