No abstract

An alternative protein ingredient based on spraydried, hydrolyzed red blood cells was evaluated in calf milk replacers. Two experiments were conduced to determine the value of the ingredient on intake, growth, and feed efficiency in dairy calves. In experiment 1, Holstein bull calves (n = 120) were fed calf milk replacer containing 0, 11, 22, or 43% of crude protein as spray dried hydrolyzed red blood cells. Calves were fed 454 g/d of experimental milk replacer reconstituted to 12% dry matter plus a conventional calf starter for 28 d. Body weight gain, intake of milk replacer and calf starter, feed efficiency, fecal scores, and days scouring were unaffected by source of protein. In experiment 2, Holstein calves (n = 69) at the University of Minnesota, Crookston and Waseca were fed milk replacer containing 0, 22, or 43% of crude protein as spray dried hydrolyzed red blood cells. Calves were fed 454 g/d of experimental milk replacer reconstituted to 12% dry matter plus a conventional calf starter containing 0 or 25% alfalfa meal for 35 d. No calves died during the study. Body weight gain, feed efficiency, intake of calf starter and milk replacer, fecal scores, and days scouring were unaffected by increasing hydrolyzed red blood cells in milk replacer. Similar performance of all calves indicated that spray dried hydrolyzed red blood cells can replace up to 43% of crude protein from whey protein concentrate without detrimental effects on animal performance. 788Abbreviation key: CMR = calf milk replacer, CON = CMR containing no SDHRBC, CS = calf starter, HIGH = CMR containing SDHRBC at 43% of CP, LOW = CMR containing SDHRBC at 11% of CP, MED = CMR containing SDHRBC at 22% of CP, SDHRBC = spray-dried hydrolyzed red blood cells, SDRBC = spray-dried red blood cells.

and Implications The objective of this experiment was to investigate the therapeutic efficacy of feeding a supplemental bovine serum protein blend to calves challenged with virulent coronavirus. Twelve Holstein bull calves were orally challenged with 1 x 10 7 PFU of virulent coronavirus isolate. Infection was allowed to progress for a period of 24 h prior to the initiation of treatment. On d 1, treated calves began receiving 160 g of a blood serum protein blend (16 g IgG) mixed into milk replacer powder (67 g) at both the AM and PM feedings. Control calves received only milk replacer powder (227) at both feedings. Response to coronavirus challenge and dietary treatment was monitored prior to AM and PM feeding by the collection of multiple clinical measures. Fecal consistency was decreased (P<0.01) 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 (P<0.01) in rreated calves compared to 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 (P=0.06) average respiration rate compared to treated (28.7 vs. 26.8 breaths / min.). Treated calves had a higher (P=0.02) average feed intake versus 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 ability of a dietary treatment to potentially alleviate symptoms of a viral enteric disease is of great importance to the dairy industry.

Acquisition of adequate passive immunity is essential to calf health and growth. Factors that influence acquisition of passive immunity include metabolic state of the animal, age at first colostrum feeding, amount and lgG concentration of maternal colostrum (MC) consumed, and chemical and physical characteristics of the MC. Colostrum supplement (CS) products have been developed to supplement or replace MC and increase lgG and nutrient concentration. However, the apparent efficiency of lgG absorption (AEA) from some CS is poor, while the AEA of CS derived from ediblegrade bovine serum is equivalent to MC. Differences in AEA and lgG absorption from CS may be due to chemical composition or mass of lgG fed to calves. Our objective was to determine the absorption of lgG from CS derived from bovine serum or processed lg concentrates containing 10% to 27% lgG.