The greatest risk period for dairy calf death occurs before weaning. Despite some improvement in the reported calf mortality rate between 48 hours of age and weaning within the last five years, perinatal death — defined as that occurring within the first 48 hours of life — is a problem of increasing magnitude and may be prevented with better identification of and attention to at-risk calves, says Sheila McGuirk, veterinary clinician at the University of Wisconsin.

The causes of death among calves in this age group, which include combined respiratory and metabolic acidosis, hypothermia, hypoglycemia, parturient trauma from dystocia, hypoglobulinemia, congenital conditions, sepsis or systemic disease, and blood loss, can be prevented with prompt attention and the delivery of critical care.

With improved knowledge, equipment and skills, critical care can be delivered on the farm or at the veterinary clinic or hospital.

Clinical signs exhibited by calves with critical care needs
Within minutes of delivery, a normal calf is head righting and works its way to sternal recumbency within five minutes. Shortly thereafter, it begins making attempts to stand, and most are standing within an hour of a normal vaginal delivery. The selected clinical parameters of newborn calves shown here correlate well with vitality and are useful to assess newborn calves.

  • Rectal temperature: 102 - 103 degrees F (38.8 -39.4 degrees C) right after calving, stable at 101-102 degrees F (38.3 - 38.8 degrees C) within one hour.
  • Heart rate: 100-150 beats per minute, rhythm is regular, and pulse is strong.
  • Respiratory rate: 50-75 breaths per minute, primarily thoracic effort.
  • Hair coat appearance: Placenta covered but not discolored.
  • Head, limbs and tongue: No swelling, edema or discoloration.
  • Mucous membranes: Pink, moist and refill time less than 3 seconds.
  • Responsiveness: Responds to stimulation with head shaking and movement of limbs, strong corneal reflex, suck reflex is present.
  • Muscle tone: Able to maintain sternal recumbency by five minutes, attempts to stand within 15 minutes, standing by 60 minutes.
  • Suckling: Ready to nurse within two hours.

Some of the most important clinical signs that alert you to a calf requiring critical care are severe depression, hypothermia ( less than 100 degrees F; 38.3 degrees C), bradycardia (less than 80 beats per minute), dilated, unresponsive pupils, inactivity or flaccidity. While not considered a sensitive indicator of cardiopulmonary arrest in small animals, cyanotic mucous membranes or prolonged capillary refill time can be an indication of the need for circulatory support in newborn calves. Tachypnea (75 beats per minute) with expiratory cycle accentuation, an abdominal lift or snap, or expiratory grunting may indicate the need for respiratory support. An erratic breathing pattern, with long periods of primary or secondary apnea, should also be viewed as a need for critical respiratory support in the young calf.

Not all of the clinical parameters or clinical signs discussed above need to be present to initiate a resuscitation protocol or begin the procedures for critical care. The initial evaluation is abbreviated so that prompt intervention is initiated. Once the critical need calf has been stabilized, a complete physical examination by a veterinarian can help establish the primary cause, a prognosis, the need for further diagnostic testing, and/or the plan for longer term care.