EFFECT OF BIRTH-WEIGHT, TOTAL PROTEIN, SERUM IGG AND PACKED CELL-VOLUME ON RISK OF NEONATAL DIARRHEA IN CALVES ON 2 CALIFORNIA DAIRIES

The objective of the study was to determine if there was a relationshi p between hematological, immunological and physiological variables of newborn calves and risk of diarrhea during the neonatal period. Four h undred and seventeen heifer calves from two dairies (A and B) in the S an Joaquin Valley of California were enrolled at birth and scored dail y, to 28 days of age, for evidence and severity of diarrhea (0 to 3). Calves were weighed at birth and blood sampled at two to five days of age to determine packed cell volume (PCV), total protein (TP) and IgG serum concentration. The Cox proportional hazards model was used to de termine if age at onset of the first diarrhea episode and length of th e first episode were associated with the hypothesized variables (PCV, TP, IgG and birthweight). The IgG concentration was not associated wit h the age at onset of diarrhea (p = 0.6052, Dairy A; p = 0.4393, Dairy B) but a high IgG concentration was associated with a decreased lengt h of episode (p = 0.0325, Dairy A, p = 0.0912, Dairy B), particularly for calves born in the winter on dairy A (p = 0.021 1). For calves bor n in the winter, those with either a high or a low birthweight had dia rrhea at a younger age (p = 0.0102, Dairy A; p = 0.0020, Dairy B). Ass ociations were also found for PCV and TP with both the age at onset an d length of the first episode of diarrhea. Results suggest that parame ters measurable at, or shortly after birth may have important prognost ic value in evaluating risk of calf diarrhea.