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The objective of this study was to evaluate the rate and extent of Cu repletion in Holstein heifers using two Cu sources (organic and inorganic) at two levels (15 and 30 mg/kg). An additional repletion treatment included a Cu oxide bolus. Heifers (n = 50) were individually fed a total mixed ration fortified with S and Mo at 0.40%, and 15 mg/kg of dry matter of the total diet, respectively. After 111 d of depletion, heifers were stratified by liver Cu concentration and randomly allotted to one of five repletion treatments. Four treatments consisted of feed sources of Cu (feed-Cu), 1) CuSO4 at 15 mg/kg; 2) CuSO4 at 30 mg/kg; 3) Availa-Cu at 15 mg/kg; and 4) Availa-Cu at 30 mg/kg. Availa-Cu is an organic Cu source that produces a Cu-amino acid complex. A fifth treatment, consisting of an intraruminal bolus (IB), provided a single dose of 25 g of CuO needles. Repletion treatments were delivered in the same total mixed ration without supplemental S and Mo. Copper status was assessed in blood and liver samples collected on 14-d intervals for 70 d. Irrespective of treatment, all heifers increased in body weight during the repletion period. Liver Cu increased in each feed-Cu treatment over time. Heifers treated with an IB reached a peak in liver Cu concentration (165.5 mg/kg) on d 28. Mean liver Cu concentrations were higher in heifers receiving 30 mg/kg of Cu compared with heifers receiving 15 mg/kg of Cu. Red blood cell superoxide dismutase (SOD) activity was higher (P < 0.001) in heifers receiving CuSO4 than Availa-Cu (0.98 vs 0.87 U). Also, SOD activity was higher when heifers were supplemented with 30 vs 15 mg/kg Cu (0.98 vs 0.87 U). Heifers receiving the Cu IB had higher SOD activity than heifers receiving feed-Cu sources (1.03 vs 0.92 U). Plasma ceruloplasmin concentration was higher (P < 0.001) in IB-treated heifers vs. other treatments. No differences in plasma ceruloplasmin were detected for feed-Cu source or level. These results indicate that all Cu sources evaluated in this study elevated Cu status of depleted heifers, particularly when provided at higher dietary levels.

The objective of this experiment was to investigate the therapeutic efficacy of a supplemental bovine serum protein blend fed to calves challenged with virulent coronavirus. Twelve Holstein bull calves (approximately 3 wk of age) were allocated by initial body weight to Control (n = 5) and treated (n = 7) groups. On d 0, all calves were orally challenged with 1 x 10(7) plaque-forming units of virulent coronavirus isolate. Infection was allowed to progress for 24 h before treatment was started. On d 1, treated calves began receiving 160 g of dry bovine serum powder (16 g IgG) mixed into milk replacer powder (67 g) at both an a.m. and p.m. feeding. Control calves received only milk replacer powder (227 g) at both feedings. Response to coronavirus challenge and dietary treatment was monitored prior to a.m. and p.m. feeding by the collection of multiple clinical measures. Fecal consistency was decreased by coronavirus challenge but was not affected by dietary treatment. Mean daily rectal temperature and heart rate were not affected by dietary treatment. Average packed cell volume was higher in treated calves than in control (35.0 and 27.0%). Coronavirus challenge resulted in an immediate increase in respiration rate, decreasing by d 7. Control calves tended to have a greater average respiration rate compared with treated (28.7 vs. 26.8 breaths/min). Treated calves had a higher average feed intake than control (0.57 vs. 0.44 kg/d). These data suggest that bovine-serum supplemented milk replacer may decrease the severity of disease in young calves exposed to coronavirus.

The effects of the addition of nonimmunoglobulin protein on absorption of immunoglobulin G (IgG) from colostrum or colostrum supplement products were determined in two experiments. In experiment 1, 48 Holstein calves were fed 4 L of pooled maternal colostrum or 4 L of reconstituted colostrum supplement with 0, 200, or 400 g of added whey protein concentrate or casein. In experiment 2, 38 Jersey calves were fed 2 L of pooled maternal colostrum with 100 or 200 g of whey protein concentrate or casein added immediately before feeding. Blood was collected at 24 h of age and plasma IgG concentration, total protein, hematocrit (experiment 1 only), and plasma urea N were determined. In experiment 1, blood samples were also collected at 4, 8, 12, 16, and 20 h to evaluate absorption of IgG and protein and urea N concentrations. The addition of 400 g of casein to colostrum supplement in experiment 1 reduced plasma IgG from 5.66 g/L (0 g of casein addition) to 3.88 g/L, increased plasma urea N at 24 h, and reduced the change in plasma total protein from 0 to 24 h. Hourly plasma IgG concentrations increased with the consumption of colostrum or supplements but increased more rapidly in calves fed whey protein concentrate and more slowly in calves fed casein. The addition of 200 g of casein or whey protein concentrate to colostrum supplements had no effect on plasma IgG concentration at 24 h of age. The addition of 100 or 200 g of casein or whey protein concentrate to maternal colostrum had no effect on plasma urea N, total protein, or plasma IgG in experiment 2. The addition of nonimmunoglobulin protein to colostrum supplements or maternal colostrum did not affect IgG absorption from the intestine of newborn calves unless the amount of total protein exceeded 500 g of protein.

Two experiments were conducted to investigate the effect of serum-derived immunoglobin (Ig) source and the effect of colostrum supplementation with serum-derived Ig on the attainment of passive immunity in newborn colostrum-deprived calves. In experiment 1, colostrum-deprived Holstein bull calves were fed pooled colostrum (PC, n = 9), spray-dried bovine serum (BS, n = 11), or spray- dried porcine serum (PS, n = 9). All treatments were balanced to provide 45 g of IgG in a 2-L volume at birth and again 12 h later. Calves receiving BS had higher 24-h serum IgG concentrations than did calves receiving PC or PS (8.3, 5.7, and 4.2 g of IgG/L for BS, PC, and PS, respectively). In experiment 2, the effect of supplementing bovine colostrum of varying quality with BS on Ig absorption was assessed. Thirty-two colostrum-deprived Holstein bull calves and four freemartin heifer calves were allotted by birth order to receive one of three treatments. Treatments consisted of 1) 2 L of pooled high quality colostrum (95.8 g of IgG, 0% from BS), 2) 2 L of pooled medium quality colostrum mixed with BS (95.2 g of IgG, 47% from BS), or 3) 2 L of low quality colostrum mixed with BS (98.8 g of IgG, 70% from BS). Serum IgG concentrations at 24 h after treatment were greater for calves receiving medium and low quality colostrum supplemented with BS (6.2, 9.6, and 9.6 g of IgG/L for high, medium, and low quality colostrum, respectively). Similarly, apparent efficiency of IgG absorption was greater for calves receiving medium and low quality colostrum supplemented with BS (25, 37, and 38% for high, medium, and low quality colostrum, respectively). The results of these studies suggest that dried BS contains a concentrated source of Ig, which is efficiently absorbed by newborn calves. Supplementation of marginal or low quality colostrum with dried BS is an effective means of improving passive transfer of IgG in newborn calves.

This study was designed to compare the absorptive efficiency of IgG from a commercial bovine serum product (bovine serum), cow colostrum (positive control), and two commercial milk-derived IgG supplements (supplement 1 and supplement 2). Newborn Holstein calves, collected at birth and prior to the consumption of colostrum, were allotted to treatment by alternating birth order. Colostrum supplement treatments were fed according to manufacturer's recommendations at birth and again at 12 h. This strategy resulted in varying masses of total IgG being offered to the calves (200, 90, 50, and 60 g of IgG for colostrum, bovine serum, supplement 1, and supplement 2, respectively). Blood samples were collected at 0, 12, and 24 h after the end of treatment administration. Plasma volume was estimated as 9.10% of birth weight. Apparent efficiency of IgG absorption at 24 h was determined. Plasma IgG concentrations at 24 h differed for each treatment (12.1, 6.8, 2.2, and 3.5 g of IgG/L for colostrum, bovine serum, supplement 1, and supplement 2, respectively). Apparent efficiency of IgG absorption was greatest for bovine serum compared with colostrum and supplement 1. No treatment differences were detected on the occurrence of mortality. However, calves fed bovine serum tended to have fewer treatments for illness compared with calves fed colostrum and supplement 1. Calves receiving bovine serum-derived IgG had improved IgG absorption efficiency and a tendency toward fewer medical treatments compared with calves consuming colostrum or a dried colostrum product.

Calves are born hypogammaglobulinemic and rely on immunoglobulin (Ig) from colostrum to obtain passive immunity. Previous research has indicated that colostrum supplements derived from milk are less effective than is maternal colostrum in providing adequate IgG to neonatal calves. Our objective was to determine the absorption of IgG by newborn calves fed a USDA food-grade colostrum supplement derived from bovine serum or fed pooled maternal colostrum. Holstein calves (n = 20; 10 bulls) were removed from the dam within 1 h of birth and were housed in individual stalls for the 24-h study. Calves were fed 2 L of colostrum or colostrum replacer at 1.5 and 13.5 h (+/- 0.1 h). Calves were blocked by colostrum pool, and replacer was fed to provide equal intakes of IgG within blocks. Jugular blood was collected at 1 and 24 h (+/- 0.1 h) for analysis of IgG by radial immunodiffusion. At 24 h, calves were injected with 1.5 ml of Evans blue dye to estimate plasma volume. Mean plasma IgG at 24 h of age was 7.3 +/- 0.4 g/L and was affected by an interaction of block and treatment. Apparent efficiency of IgG absorption of 24 h was reduced when 750 g of the colostrum replacement product were fed but was increased when 266 g of colostrum replacement product were fed. Mean plasma volume was unaffected by treatment and was 3.5 +/- 0.2 L or 9.1% of BW. These data indicate that efficiency of IgG absorption from the colostrum replacement product may be affected by amount of material fed. Proteins other than IgG in the colostrum replacement product might have reduced the efficiency of IgG absorption.