Calf Vigor

Barry Whitworth, DVM Area Food/Animal Quality and Health Specialist for Eastern Oklahoma

The initial overall physical strength and good health of a newborn, referred to as calf vigor, is very important to the future health of a calf.  In order for a calf to thrive, it must accomplish several things within hours immediately after being born.  The calf must be able to sit up (sternal recumbency), stand, locate the teats and nurse.  Any delay in nursing will have a major impact on the calf’s future since the immunoglobulins that are present in a cow’s colostrum are best absorbed in the first four hours of life.  Immunoglobulins are what protect a calf from disease causing agents, and the absorption of immunoglobulins rapidly declines 12 hours after birth.  Calves that are vigorous at birth have a much better outlook on a healthy future than those that are less vigorous and are not able to stand and nurse soon after birth. 

Assessing a calf’s vigor and recognizing when to intervene and help a calf is something all producers need to be able to do.  In human medicine, newborn babies undergo an APGAR test following birth.  APGAR stands for appearance, pulse, grimace, activity, and respiration.  The test is given one and five minutes after birth.  The purpose of the test is to assess how well the baby tolerated the birthing process and how well the baby is doing outside the mother’s womb.  An APGAR test for calves similar to the one in human medicine would give cattle producers a clue when to intervene in a newborn calf’s live.  Unfortunately, most attempts to develop such a test for calves have not been successful; however, there are several studies that provide some practical advice on when to intervene with a newborn calf. 

In two studies Dr. Homerosky and associates in Canada found two good predictors of calf vigor.  Consuming colostrum within the first four hours following birth was dependent on calving ease and suckle reflex.  Most producers have the ability to assess both components.  First, was the calf born in a timely manner and required no assistance?  Calves that require assistance are more likely to have acidosis.  Acidosis is associated with failure of immunoglobulin absorption, sickness and death in calves.  Dr. Homerosky found a correlation between acidosis and the inability of a calf to withdrawal its tongue after being pinched.  A producer can check a calf for acidosis by pinching the calf’s tongue.  If a calf cannot withdraw its tongue after being pinched, it is likely acidotic and is a good candidate for early colostrum intervention.

The second predictor producers can check for is does the calf have a strong suckle reflex?  Suckle reflex can be determined by inserting two fingers in the mouth and rubbing the roof of the calf’s mouth.  A calf that has strong jaw tone with a rhythmic suckle would be determined to have a strong suckle reflex.  The opposite of this would be considered a weak suckle reflex and may indicate the need for intervention. 

In another study, Dr. Murray found that calves that did not sit up (sternal recumbency) within 15 minutes of birth had reduced absorption of immunoglobulins.  Also, calves born to cows that had difficulty birthing took longer to stand.  These would be clues that the calf will require more care and colostrum intervention to increase the chance of survival.

Read more in the February 2020 issue of Oklahoma Farm & Ranch.