Most people who have dealt with beef cows at calving time have occasionally had to deal with a weak, dopey calf.
These calves may be unable to stand or have difficulty standing without assistance. They have poor muscle tone and seem to have no idea where to put their feet or how to stand or move. Most of them seem dopey and are unable to suckle, even when given a bottle or having a teat placed in their mouths.
These “dummy calves,” also called “weak calves,” require a great deal of care and attention to get through the first few days of life and are often a major inconvenience at a busy time of year.
A variety of conditions can make a newborn calf appear weak, including selenium deficiency, hypothermia, infectious disease and trauma, such as being stepped or laid on.
Weak calf syndrome has also been associated with cows in poor body condition in late pregnancy that are being fed inadequate protein or energy.
However, a common cause for the weak “dummy calf” is a condition known as acidosis. It refers to a drop in the pH of the blood, which can be triggered by a lack of oxygen that might occur during a difficult calving.
Calves under normal calving conditions go through a transition in how their oxygen is supplied. The oxygen supply to the calf from the placenta stops during delivery, which results in a temporary increase in carbon dioxide in the bloodstream. This is a trigger for the calf to start breathing on its own. The act of breathing allows the calf to expel the carbon dioxide from the blood and begin to restore normal oxygen levels.
However, this process can be delayed when calving is prolonged or difficult. The carbon dioxide levels may rise in the blood without the calf being able to “blow off” the carbon dioxide by breathing. The drop in blood oxygen and high levels of carbon dioxide create a severe drop in the pH of the bloodstream, which is known as “respiratory acidosis.”
The major clinical effect of acidosis is severe depression or weakness. These calves often cannot stand and many cannot even roll up onto their chests into sternal recumbency on their own.
A Scottish study used the time from birth until the calf was able to get itself into sternal recumbency as an indicator that a calf might be suffering from acidosis.
Normal calves will usually roll onto their chest within the first few minutes after birth, while calves suffering from acidosis tend to take more than 15 minutes to get into sternal recumbency. It’s an easy diagnostic test that can help identify calves that might need further attention.
The weak newborn calf is less likely to suck, is often unable to stand and therefore is at greater risk of suffering from hypothermia in cold weather, of being stepped or laid on or of not getting adequate colostrum and succumbing to infectious diseases such as scours.
Lying down for long periods makes these calves more susceptible to navel infections and other complications. Calves with severe acidosis can appear to be in a coma or stupor and eventually die.
To prevent this from occurring, producers should use all of the methods for preventing dystocia, such as bull selection, adequate nutrition and growth for replacement heifers and early intervention in any dystocia cases.
If the occasional case does occur, producers should make sure they are truly dealing with acidosis.
Work with a veterinarian to ensure that these calves are not suffering from an infectious disease, selenium deficiency or another condition that may mimic the clinical syndrome of acidosis.
Producers who are dealing with a difficult calving should try to get the calf breathing as soon as possible.
Don’t hang calves upside down after calving to drain fluid from their lungs. Most of the fluid that comes out is from their digestive tract, and the pressure of the abdominal organs makes it more difficult to breathe when the calf is hanging upside down.
Place the calf in sternal recumbency and stimulate breathing by rubbing the calf, stimulating the nostril with a piece of straw or pouring a small amount of cold water on the calf’s head.
Consider using a breathing bag, which is also called an Ambu bag, to help the calf start breathing sooner.
These manual respirators, which can be bought for calves, are a self-inflating ventilation bag with a mask that fits over the calf’s nose and mouth. Get a lesson from a veterinarian on how to use an Ambu bag on calves.
Veterinarians might also administer oxygen in their clinics.
Once breathing is established, make sure these calves are tubed with colostrum and protected from hypothermia.
Producers who are dealing with severe acidosis may want to ask their veterinarian to give an intravenous solution containing sodium bicarbonate to help correct pH levels in the blood. Many oral electrolyte solutions also contain sodium bicarbonate, but it isn’t clear that oral electrolytes are able to correct the severe acidosis that sometimes occurs after a difficult birth.
Producers shouldn’t have to deal with a lot of these cases, but if clusters occur, ask a veterinarian to make an accurate diagnosis and rule out other conditions.
Prompt action following prolonged calving should help improve the survival rate of these calves and reduce the incidence of infectious diseases.