The collapsed neonate

Etiology

• In normal instances the newborn calf is born oxygenated and only upon rupture of the umbilicus will the animal become hypoxic Hypoxemia, accompanied by an increase in blood carbon dioxide tension Hypercapnia.
• This increase in carbon dioxide, in addition to a decreased oxygen tension, will result in a metabolic acidosis and serves to initiate breathing through the induction of gasping reflexes and inflation of the lungs Anesthetic monitoring: acid base and electrolyte.
• However, should the birthing process be prolonged, such as occurs in cases of dystocia Dystocia, the resultant acidosis whilst in utero may be sufficient to severely depress central nervous system function and compromise the initiation of breathing. Such animals are therefore born severely compromised.

Predisposing factors

General

• Dystocia Dystocia.
• Calves born to periparturient dams.
• Dam hypocalcemia / hypomagnesemia Hypocalcemia and hypophosphatemia: overview Magnesium: overview.
• Vit E / Selenium deficiency Selenium and vitamin E: overview.
• Iodine deficiency Iodine: overview.

Pathophysiology

• Dystocia or prolonged birthing results in fetal hypoxia and acidosis in utero. This may be sufficient to suppress central nervous system function and compromise the establishment of breathing.

Timecourse

• In cases of dystocia, fetal hypoxia and acidosis may occur in utero resulting in the birth of compromised calves.
• Clinical manifestations of disease may last the first few days of life dependent upon the degree of acidosis experienced and initiation of measures to correct this clinical syndrome.