Identify 'at-risk' calves early to improve prognosis


Identify 'at-risk' calves early to improve prognosis

Oct 01, 2004

Christine B. Navarre, DVM
The earlier "at risk" neonates are identified and treated, the better the prognosis for a healthy and productive life.

Any calf that is born following a dystocia, even if it appears normal, should be considered at risk. Many of these calves will look normal for a few hours but deteriorate quickly. I advise that immediately following the dystocia, while the cow is still restrained, milking the cow (if possible) and bottle or tube feeding the calf. This ensures colostrum intake and precludes having to restrain the pair later if the calf has not nursed. It also helps prevent hypothermia and hypoglycemia.

Calves born following dystocia can be depressed due to hypoxia, metabolic acidosis and/or hypothermia. Calves with mild depression can be warmed and given intravenous sodium bicarbonate inexpensively, and this can greatly improve the chances of survival of these calves. If only mildly hypothermic (>96 F), heat lamps and hot water bottles may work. However, if severely hypothermic, peripheral perfusion is poor and external warming is not effective. These calves need to be warmed from the inside. Warm oral and intravenous fluids (balanced electrolyte solution with 1.5 percent dextrose) are best, along with external sources of heat.

Up to 15 percent of first-calf heifers and roughly 5 percent of mature cattle show signs of dystocia, medical experts say. Quick medical monitoring in calves can dramatically improve neonate health and survival rates, experts add.
Correcting for a base deficit of 10 is usually safe. Concentrated sodium bicarbonate (5 percent to 8 percent) can be administered undiluted at a rapid rate through a needle if a catheter for other fluids is not needed. Calves with more severe depression might require oxygen therapy, which will increase the cost of treatment. However, many times a small amount of early supportive care prevents more extensive, prolonged care later.

First days of life Hypoglycemia is less of a problem in the first hours of life and more of a problem later, secondary to inadequate nutritional intake, septicemia, etc. If severe, hypoglycemia can mimic meningitis with signs such as miotic pupils, ophisthotonus and seizures. Glucose levels can be low in both conditions. If other causes of weakness and neurologic signs have been eliminated (hypothermia, acidosis), a slow infusion of 0.5 mls/10 lbs body weight of 50 percent dextrose IV can be administered without the need of a catheter.

If calves have simple hypoglycemia, they usually will respond to the dextrose by improving. If they do not respond, a CSF tap can be easily performed. If the fluid is grossly abnormal and the prognosis is poor, the owner can factor this into treatment decisions. If the fluid looks grossly normal, the calf might still have meningitis, but the prognosis is good with treatment. If treatment is continued, these calves must have an IV 2.5 percent to 5 percent dextrose since the 50 percent dextrose will cause a rebound hypoglycemia if dextrose isn't continued. Calves should be weaned from dextrose slowly.

First weeks of life Once calves are a week old, their chances of survival increase. However, morbidity due to septicemia, umbilical problems, pneumonia and diarrhea can cause increased veterinary costs and poor weight gains. Failure of passive transfer (FPT) increases the incidence of these diseases.

In an individual calf with FPT, the most important problems are decreased growth rates and septicemia. Diagnosis of FPT can be made at 24 hours up to about 1 week of age. One of the cheapest tests is serum protein, which should be >6.0 g/dl in beef calves. There are now newer whole-blood tests that can be run without the need of a centrifuge. These tests are more expensive, but allow for immediate on-farm diagnosis.

The only specific treatment for FPT is plasma or, more practically, a whole-blood transfusion (since bovine RBCs don't separate from plasma, which necessitates spinning the blood).

Plasma is of questionable benefit in healthy calves for prophylaxis because even with high volumes, immunoglobulin levels don't reach those of calves that received colostrum, and this is further magnified if whole blood is given because of volume limits.