Respiratory disease is estimated
to cost the UK cattle industry £80 million
annually (between £30 for mild cases to £500 when the animal dies).
Financial losses result from mortality and antibiotic
treatment costs, but the greatest loss
is from weight loss during illness
affecting a large proportion of
the group and their protracted convalescence. Respiratory
disease is also a major animal welfare concern (Fig 1).
Fig 1: Respiratory disease is a major animal welfare
Respiratory disease is best prevented by a combination of good
management, appropriate building design and ventilation, and
effective vaccination against the major pathogens on that
particular unit well before the risk period. The selectikon
of an effective vaccination strategy will form an important part of
the herd health plan drawn up in conjunction with the farmer's
Graph 1: Seasonal nature of bovine respiratory disease in the
Graph 1 shows the
seasonal nature of calf
respiratory disease in the UK. Most outbreaks of respiratory
disease occur within one month of housing in the autumn/early
winter. Autumn-born calves are generally more severely
affected than older spring-born calves.
Fig 2: Most outbreaks of respiratory disease occur within
one month of housing with autumn-born calves generally more
Respiratory disease in beef cattle is an interaction between the
various infectious agents (whether bacterial, viral or both), the
environment (Fig 2) , and immunity of the individual calf.
Adult cattle provide an important reservoir of many
respiratory tract pathogens with increased excretion during periods
of stress such as at calving and housing.
Fig 3: Disease caused by infectious bovine rhinotracheitis
The important viral causes of respiratory disease are infectious
bovine rhinotracheitis (IBR, Fig 3) and bovine respiratory
syncytial virus (BRSV, Fig 4); parainfluenza-3 virus is much less
Fig 4: Disease caused by bovine respiratory syncytial
These viruses can cause
disease by themselves or
damage the defence mechanisms of the upper respiratory tract and
predispose to secondary bacterial infections of the lungs.
There are a large number of bacteria that can cause either
primary lung disease or secondary to viral compromise of the lung
Important predisposing viral causes
- Infectious bovine rhinotracheitis (IBR)
- Bovine respiratory syncytial virus (BRSV);
- Parainfluenza-3 virus (PI3)
- Bovine virus diarrhoea virus(BVD) may be involved in some
herds (Fig 5).
Fig 5: Bovine virus diarrhoea virus (BVD) may be involved in
some herd outbreak of respiratory disease. These calves are
the same age but the calf on the left is persistently infected with
BVD virus and has developed chronic pneumonia.
The important bacterial causes of respiratory
- Mannheimia haemolytica
- Pasteurella multocida.
- Haemophilus somni
The first two organisms are often still collectively termed
"pasteurellae" and the disease "pasteurellosis".
An accurate diagnosis of the cause(s) of respiratory disease is
essential so that the correct treatments are given and that steps
can be taken to prevent future disease using appropriate vaccines.
Antibiotic selection is very important and will be carefully
considered by your veterinary surgeon.
Fig 6: Post mortem examination is only useful in cases of
sudden death (in this case BRSV infection).
Laboratory confirmation may be necessary before embarking upon a
vaccination protocol in the face of infection, and to prevent a
similar problem during the following year. Diagnosis of viral
infection may involve taking ocular and nasal swabs, collection of
lung fluid (broncho-alveolar lavage); and for future control
measures, collection of blood samples two weeks apart. Post mortem
examination is only useful in cases of sudden death (Fig 6).
Necropsy of chronic pneumonia cases is
largely a waste of money and rarely
provides meaningful data.
Fig 7: Visual assessment for signs of respiratory disease, such
a cough, nasal discharge and depression are unreliable and fail to
detect all diseased cattle.
Fig 8: In many situations selection of cattle for treatment of
respiratory disease is most cost- effective when based upon raised
rectal temperature. Ninety to 120 cattle can be checked
within one hour in well-organised units.
Secondary bacterial invasion of the damaged respiratory tract
frequently occurs which makes treatment difficult. In many
situations selection of cattle for treatment based upon raised
rectal temperature is the most cost-effective practice (Figs 7-8).
Ninety to 120 cattle can be checked within one hour in
well-organised units. All rectal temperatures and treatments are
recorded and checked the following day to monitor response to
antibiotic therapy which is consistent with appropriate use of
antibiotics on farm.
The choice of antibiotic treatment is based upon veterinary
advice and knowledge of previous outbreaks of respiratory disease
on the unit. Recurrence of bacterial infections is common (up
to 25 per cent) often necessitating repeat antibiotic
treatments 5-14 days later. It is very important to recognise that
this situation is not caused by antibiotic treatment
failure but re-infection of the physically
compromised respiratory tract once antibiotic levels have fallen
below effective concentrations after several days. It is
important to recognise this fact and not blame the manufacturer of
the antibiotic or the veterinary surgeon who recommended its
While antibiotic treatment of the whole group of calves is
undertaken in some situations this practice greatly increases
treatment costs because many calves are injected unnecessarily as
they would not have succumbed to disease. In most respiratory
disease outbreaks whole group antibiotic treatment is undertaken
for labour reasons and convenience, and is not based upon
veterinary evidence. This practice cannot be justified for those
antibiotics considered of critical importance in human
Concerns over antimicrobial resistance dictate that farmers and
veterinary surgeons must be more selective when using antibiotics
to treat respiratory disease and monitoring of calves shoud be
undertaken to assess treatment efficacy and cure.
RUMA recommends that fluoroquinolones, 3rd and 4th generation
cephalosporins and long acting macrolides should only be used
therapeutically not for prophylaxis.
Infectious bovine rhinotracheitis (IBR)
Disease typically affects store cattle infected at the time of
purchase from markets but clinical signs generally first appear 2-3
weeks following housing.
When first recognised in the UK
during the late 1970s in its most severe
form the morbidity rate (percentage of cattle affected) could be
100% with up to 5% deaths. The first two or three cattle
to show clinical signs are invariably the worst affected.
Affected animals do not eat, are very depressed, slow to rise,
and stand with the head held lowered. There is a purulent discharge
from the eyes and nostrils.
Treatment is based upon veterinary advice and it is essential
that the vet is contacted as soon
as disease is suspected
because the first cattle
affected are the most severely affected and accurate diagnosis,
treatment, and timely vaccination are essential to prevent further
Disease is best prevented by vaccinating all purchased cattle as
soon as they arrive on the farm and turning them out to pasture for
several weeks whenever possible.
Maintenance of disease-free status is possible for closed beef
herds but virus can be transmitted by direct contact over fences
etc. from neighbouring farms. Annual vaccination of all cattle on
the farm costing around £2-3 is a valuable insurance policy against
The clinical signs attributable to BRSV infection are highly
variable. In severe outbreaks some animals may be found in
respiratory distress with mouth-breathing (Fig 1) and rapid
abdominal movements leading rapidly to death. In some studies
involving housed beef calves infection has occurred without any
clinical signs of respiratory disease. In these situations
exposure to the virus is detected by measuring serum antibody
concentrations and recording significant rises.
There are a number of vaccines widely used to control
BRSV-induced respiratory disease and veterinary advice should be
sought for the most appropriate prevention strategy. Vaccine can be
administered intra-muscularly on two occasions, four weeks apart,
prior to the anticipated challenge (e.g. housing) although the
second vaccine is often administered at housing. Single intranasal
vaccination may be helpfulin the face of a BRSV-induced respiratory
General control of respiratory disease
Control of respiratory disease is likely to be best achieved by
attention to general husbandry practices especially the
ventilation system which can often be greatly improved on most
farms, and correctly-timed administration of vaccines. Reducing
stocking density, wherever possible, would improve the respiratory
disease situation on most units. Stressful events such as
disbudding, dehorning and castration are best undertaken before
housing or delayed until calves have been housed for at least
six weeks. Most beef calves are now disbudded with caustic paste
and castrated with rubber bands within the first few days of
Details of these control measures must be included in the
veterinary herd health plan. Expert advice on ventilation of
buildings may be necessary.
Main points of building
- Air enters below the eaves and exits at the ridge (natural or
stack effect whereby spent warm air rises to the ridge out to be
replaced by fresh air drawn in from below the eaves).
- Minimum of 6 air changes per hour on a still day Air should
appear fresh and free of ammonia or slurry smells when you walk
through the shed especially during still winter nights.
- The ridge opening should be 300 mm (minimum) with a cap at
least 150 mm above.
- Buildings should not exceed 20m width. Multispan buildings
should be avoided.
- Minimum airspace allowances 10 cubic metres for calves up
to 90 kgs.
- Upturned corrugated sheeting on roof with a 25 mm gap.
- Spaced boarding all round building including gable ends (Netlon
polypropylene mesh also popular).
- Ensure adequate drainage
to prevent high humidity.
Condensation on underside of roof and cobwebs over outlets
are indicators of poor ventilation.