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• Feeding colostrums of marginal or low quality (containing reduced IgG concentration) supplemented with dried concentrated bovine serum can result in higher calf serum IgG concentrations and higher apparent IgG absorption rates than feeding high quality colostrum.
• This result is in contrast to previous studies of supplementation of poor quality colostrum with dried colostrum, where calf serum IgG concentrations and absorption efficiency were not enhanced compared with feeding un- supplemented colostrum.

INTRODUCTION

Calves are able to absorb immunoglobulins for a limited time after birth. Failure to absorb sufficient immunoglobulin results in low serum concentrations of immunoglobulin and increased risk of disease and mortality. In addition to the timing of colostrum ingestion, the level of serum immunoglobulin concentration reached in the calf depends upon the mass of immunoglobulin consumed, which in turn is determined by the volume of colostrum fed, the immunoglobulin concentration in colostrum, and the efficiency of immunoglobulin absorption by the calf. Recommendations have been made for calves to receive 100 g of immuno- globulin in the first 12 h after birth. Nearly one quarter of Holstein cows producing £8.5 kg colostrum at the first milking have colostral immunoglobulin concentrations <35 mg/ml. On US dairy farms, 26 percent of producers who hand-feed their calves feed <2 L of colostrum and 74 percent feed <3.84 L. Under current feeding practices, failure of calves to absorb adequate concentrations of immunoglobulin should occur frequently. In fact, >40 percent of US dairy heifer calves have <10 mg immunoglobulin/ml of serum.

Supplementation of colostrum with dried sources of bovine immunoglobulins, typically from milk or colostrum, has been a common approach in attempting to overcome the limitations of colostrum feeding. Our previous results suggested that addition of a dried bovine colostrum supplement to a colostrum of marginal immunoglobulin quality did not result in elevated serum immunoglobulin concentrations and even reduced absorption efficiency (see 1996 Illinois Dairy Report). The current study evaluated immunoglobulin G absorption in newborn calves fed colostrum of varying quality which was supplemented with a USDA food-grade dried bovine serum.

MATERIALS AND METHODS

First milking colostrum from dairy cattle was pooled to provide a high quality colostrum (55.1 g IgG/L). Second and third milkings were pooled to provide colostrums of marginal quality (28.8 g IgG/L) and low quality (16.6 g IgG/L). Dried concentrated bovine serum product was provided by American Protein Corporation (Ames, IA). This dried serum contained 28.8% IgG and had a solubility of about 93% in water and in milk.

Holstein bull calves were removed from their dams immediately after birth to prevent consumption of the dams colostrum. Calves were assigned to one of three treatments (Table 1). Mean birth wt. for all calves was 41.8 kg; mean birth wt. by treatment group were not different (P > .05). All colostrum treatments were fed only once and fed within 3 h after birth. Colostrums were fed by esophageal tube to assure consumption of the entire meal. Calves were fed milk replacer (at 5% body wt) at 12 h after the colostrum feeding and then fed milk twice daily for the remainder of the experimental period. Calves were bled via jugular venipuncture at 12 and 24 hr after colostrum feeding and serum collected. Serum samples were stored at -20°C until analysis. All colostrums and serum samples were assayed for total IgG by radial immunodiffusion assay.

TABLE 1. Treatments of calves fed colostrums with or without dried serum product.

RESULTS

Mean serum IgG concentrations and mean IgG absorption efficiencies (Table 2) were higher for calves in treatments B and C than for calves in treatment A (P < 0.05). Treatments B and C did not differ for serum IgG concentrations or IgG absorption efficiency.

TABLE 2. Apparent efficiency of absorption and concentrations of IgG in sera from colostrum-fed calves¹.

¹ Mean ± standard error.

² Calculated at 12 hr after feeding, based on plasma volume of 6.5% of calf birth weight.

^a,b Different superscripts indicate significant difference (P <0.05) among treatments.