Drost delivers Mythbuster message on newborn calves

Just like Jamie and Adam on the Discovery Channel's Mythbusters television show, Maarten Drost, D.V.M., of the University of Florida told those attending the fifth annual Dairy Cattle Reproduction Council meeting that suspending a newborn calf by the hind legs to clear the lungs of fluid is a myth. This practice does not clear mucus from the lungs. In fact, until a calf is born, the lungs have never inflated and have never had fluid in them. When a newborn calf takes its first breath outside the dam, this is the first time the lungs have inflated.

So, where does the fluid come from when the calf is suspended by the hind legs? Drost says most of the fluids that drain from the mouth in these calves comes from the stomach and is called amniotic fluid which calves normally swallow during their development in the uterus.

Suspending a newborn calf by the hind legs actually places more pressure on the lungs because the weight of the stomach and intestines places added pressure on the diaphragm which makes expanding the lungs more difficult. The most effective, immediate way to clear the airways is to run your thumbs from the eyes to the nostrils and express the fluid from the nasal passages, to extend the head and neck, and to pull the tongue out straight. Suction is also helpful, says Drost.

So what can be done for a calf that is having difficulty breathing? Sudden cooling is a very important respiratory stimulus that can be elicited by simply pouring cold water over the head of the calf. Cold water elicits (to draw or bring out) the gasp reflex that aids in the expansion of the lungs. Brisk rubbing of the skin or tickling inside the nostril with a piece of straw also has a favorable effect. Once breathing, sit the calf in a position so that its front and rear legs are positioned directly underneath the abdomen. This position will best allow the calf's lungs to expand as shown in the above photo. Do not lay the calf on its side. This will limit the expansion of the lungs, as well.

To learn more about delivering and handling newborn calves, check out the obstetrics section of Drost's website at www.drostproject.org.

Calves get more than one kind of scours

Scours is probably the most predictable part of raising calves – so predictable that maybe the only way to not have scours is to not have calves.

Dairy producers tend to see scours arrive on their farms at the same days of age for each batch of newborns, but that age tends to vary for each dairy. Few are likely to know what kind of scours they’re dealing with, even though the age at onset and the severity are big clues to which bacteria are involved.

There are actually four main pathogens that cause scours and several other minor ones, says Jerry Olson, a senior veterinarian with Pfizer Animal Health:

• During the first week of life, the prime suspect of scours is Escherichia coli K99.
• In later cases (up to a month of age) the prime suspects are rotavirus serotypes G6 and G10.
• Coronavirus also tends to be seen in calves over a week old, but it generally produces more severe scours because it affects both the small and large intestine, whereas rotavirus affects only the small intestine.

The most efficient way to manage scours is to prevent it. Veterinarians recommend doing this by vaccinating the dam against all four pathogens, so that passive immunity is transferred to the calf in its colostrum.

Ideally, says Olson, this should occur far enough ahead of the closeup cow’s “colostrum concentration window” which peaks about two weeks before calving, so that maximum antibody levels are also present in the blood.