Acquisition of high quality colostrum is an important factor influencing neonatal calf health. Many methods have been used to assess the Ig concentration of colostrum; however, improved, validated evaluation tools are needed. The aims of this study were to evaluate both optical and digital Brix refractometer instruments for the measurement of Ig concentration of colostrum as compared with the gold standard radial immunodiffusion assay laboratory assessment and to determine the correlation between Ig measurements taken from fresh and frozen colostrum samples for both Brix refractometer instruments. This research was completed using 288 colostrum samples from 3 different farms. It was concluded that the optical and digital Brix refractometers were highly correlated for both fresh and frozen samples (r=0.98 and r=0.97, respectively). Correlation between both refractometer instruments for fresh and frozen samples and the gold standard radial immunodiffusion assay were determined to be very similar, with a correlation coefficient between 0.71 and 0.74. Both instruments exhibited excellent test characteristics, indicating an appropriate cut-off point of 22% Brix score for the identification of good quality colostrum.

The objectives of this study were to evaluate the effects of free-access acidified milk replacer feeding on the pre- and postweaning health of dairy and veal calves. Individually housed calves were systematically assigned at birth to 1 of 2 feeding programs: free-access feeding (ad libitum) of acidified milk replacer (ACD, n=249) or traditional restricted feeding (3L fed twice daily) of milk replacer (RES, n=249). Calves were fed milk replacer containing 24% crude protein and 18% fat. Acidified milk replacer was prepared to a target pH between 4.0 and 4.5 using formic acid. Calves were weaned off milk replacer at approximately 6wk of age. Weaning occurred over 5d, and during this weaning period, ACD calves had access to milk replacer for 12h/d and RES calves were offered only one feeding of milk replacer (3 L) daily. Calves were monitored daily for signs of disease. Fecal consistency scores were assigned each week from birth until weaning. A subset of calves was systematically selected for fecal sampling at 3 time points between 7 and 27d of age. Fecal samples were analyzed for enterotoxigenic Escherichia coli F5, Cryptosporidium parvum, rotavirus, and coronavirus. Hip width, hip height, body length, heart girth, and body weight were measured at birth and weaning. Postweaning body weight measurements were collected from the heifers at approximately 8mo of age. Postweaning body weight and carcass grading information was collected from the veal calves at slaughter once a live weight between 300 and 350kg had been achieved. The odds of ACD calves being treated for a preweaning disease event tended to be lower than that of the RES calves (1.2 vs. 5.2%, respectively). Preweaning mortality, postweaning disease treatment, and postweaning mortality did not differ between feeding treatments. The ACD feeding treatment supported greater preweaning average daily gain (0.59 vs. 0.43kg/d) and structural growth than RES feeding. Postweaning average daily gain and carcass characteristics were similar for ACD and RES calves. These results indicate that free-access acidified milk replacer feeding tended to support improved health, and greater body weight gain and structural growth during the preweaning period; these effects did not persist in the postweaning period. The growth advantage observed before weaning in the ACD calves likely disappeared due to the weaning methods used.

The objective of this research was to examine the efficacy of supplementing colostrum with sodium bicarbonate for improving passive transfer, health, and growth. An additional objective was to evaluate the effects of calving difficulty on calf vigor. A total of 543 heifer and bull calves from 9 commercial dairy herds were enrolled in this randomized double-blind field trial. At birth, calves were assessed for vigor by the dairy producer, using a prototype calf vigor assessment tool which rated Visual appearance, Initiation of movement, General responsiveness, Oxygenation, and Rates of heartbeat and respiration (VIGOR). Subsequently, calves were fed colostrum supplemented with either 20 g of sodium bicarbonate (SB) or placebo powder. Blood was collected from each calf between 1 and 8 days of age for serum total protein (STP). Each calf was assessed with a standardized clinical score for general health, and measured for growth using a heart girth weight tape at 1, 2, 3, and 6 weeks of age. The findings suggest that calves born with assistance, or that were malpositioned at calving, had lower vigor than those born unassisted. Yet, calf vigor improved with time following birth. Measures from the VIGOR score, including slower responsiveness and a higher heart rate, were associated with reduced health. There was a significant interaction between sex of the calf and SB supplementation of colostrum with STP. Sodium bicarbonate supplementation of colostrum was not significantly associated with improved passive transfer, and had no significant effect on weight gain. Assessment of calf vigor in calves born with assistance may be an important management tool for dairy producers as an indicator that further intervention may be needed to improve health.