Finding calves early in the course of disease and applying the appropriate intervention is imperative to minimize the consequences associated with common calfhood conditions.
However, identifying calves with early signs of diseases can be a challenging proposition, as the first signs of illness are very subtle and can be difficult to recognize.
This difficulty has led to the development and implementation of new tools and protocols on farms to identify subtle signs associated with disease.
Two key concepts
When creating a protocol to assess calf health, try to ensure that it is both standardized and timely. Standardized so that approach is administered the same way on each calf evaluated, no matter the day or the person working with the animal.
This will ensure that each calf has the same chance to be found as ill and, if required, an intervention can be applied.
The approach used also needs to be timely so that interventions are applied at the correct time to ensure the best treatment result.
Thus, the approach used to assess calves needs to be done frequently during periods of high risk for sickness and death such as at parturition and during the pre-weaning period.
Assessing calf health at parturition is critical, as it is one of the most traumatic events in the life of a calf.
Difficult calvings can cause fractures, internal bleeding, reduced oxygen supply and an inability for the calf to respond to cold stress, which all combine to create a newborn calf with poor vitality.
A calf with poor vitality will be at risk for short- and long-term consequences that include:
- High stillborn rate
- High rate of failure of passive transfer
- High pre-weaning mortality
- Reduced first-lactation milk production
In order to assess calves at parturition in a standardized and timely fashion, Christine Murray-Kerr from the University of Guelph developed a calf vitality score sheet.
Some of the key indicators that a calf is suffering from poor vitality following birth include: swollen head and tongue, poor responsiveness to straw poking into the nasal cavity, grey mucus membrane colour, low heart rate, high or abnormal breathing pattern and a decreased ability to perform certain tasks at birth such as righting itself into a sitting posture, standing and suckling.
When calves with poor vitality are identified, it is important to apply a swift intervention.
The intervention steps to be taken in order of importance are to establish an airway, stimulate breathing and circulation, place the calf in sternal dog sitting position, feed colostrum as soon as possible, and warm the calf through drying off, covering with straw or putting the calf under a heat lamp.
Applying proper pain management in calves born from difficult calvings is another important intervention to be taken. It has been shown to improve the vigor, suckling reflex, pre-weaning weight gain and overall calf health.
A change in appetite is one of the first changes to occur when calves begin to become ill.
Robotic milk feeders do an excellent job at tracking key appetite monitors like drinking speed and total daily feed consumption and are able to flag calves that require a more thorough examination.
However, a robotic feeder is not necessary to monitor feeding behaviours and can be done manually. When using pail and bottles, monitor total refusals of milk and the speed at which the milk is consumed by the calves.
Flag the calves that do not drink their total daily allotment of milk or are slow to consume the milk for further examination.
Diarrhea is responsible for almost 60 percent of mortality occurring in the pre-weaning period and can have several long-term impacts including a reduced growth rate, increased age at first calving and lower first-lactation milk production.
In order to prevent some of its impact, it is important to find diarrheic calves early and apply the appropriate interventions.
An abnormal fecal score will provide the first indicator of diarrhea. A calf that has manure with a watery consistency that does not retain form is considered to indicate diarrhea.
However, the fecal score will not solely provide the complete picture; assessing the level of dehydration will be the most important indicator of severity in diarrhea cases.
There are three components to dehydration: prolonged skin tent on the neck, attitude and eye recession into the skull. Applying interventions when the earliest signs of dehydration are present will prevent some of the impacts associated with diarrhea (Table 1).
Work with your veterinarian to create a protocol that fits your farm to aid in the decision of when fluids, antibiotics and other supportive therapy should be given to diarrheic calves.
Pneumonia is also responsible for a significant proportion of deaths in the pre-weaning period and is the most common cause of death following weaning.
Like diarrhea, pneumonia has several long-term impacts resulting in a decreased growth rate, increased age at first calving and increased risk for dystocia at first calving.
Sheila McGuirk from the University of Wisconsin – Madison put together an excellent resource (Figure 1) to find calves showing early signs of pneumonia.
The basis is to use a combination of visual and physical observations to decide whether the calf should be treated for pneumonia.
Nasal discharge, discharge around the eye, ear drooping, inducing a cough through applying gentle pressure to the trachea and the rectal temperature are all assessed and each is placed into a category of severity.
Each category is then tabulated into a total respiratory score where, if the calf has a score of 3 or less, then no respiratory disease is present; if a score of 4 is found, re-check the calf the following day.
If it has a score of 5 or more, it should be treated for respiratory disease.
Evaluating the navel/umbilical cord for infection is often a forgotten part of the exam when evaluating sick calves, and navel infection is often under-diagnosed.
When evaluating the navel, it must be felt, as it cannot be appropriately evaluated just through visual assessment. When feeling the navel, evaluate for thickness, heat, pain and malodourous discharge to determine if the calf requires therapy.
Other key severity indicators for navel infections are the calves’ attitude and rectal temperature.
If the calf with an enlarged navel is dull or has a high temperature, it will often indicate that the infection has spread into the bloodstream from the umbilicus and requires an immediate intervention.
Putting it all together
When evaluating calves, it’s important to put all the factors together to have a complete assessment of their health status.
Thus, appetite, nasal discharge, ocular discharge, ear position, induction of a cough, attitude, fecal score, navel score, dehydration score and rectal temperature are all key identifiers of disease in calves.
When looking at calves daily, create a routine where each calf is evaluated visually.
If sick ones are suspected, do a complete physical exam based on the steps mentioned earlier and tailor a treatment protocol to fit your farm in consultation with your herd veterinarian.
PHOTO: Photo provided by David Renaud.
- DVM, Ph.D. Candidate
- University of Guelph
- Email David Renaud
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