SafmannanTM and ActiSafTM supplementation in milk replacer modulates health and performance in high-risk, pre-weaned Holstein calves

Abstract Text:

The objectives of the study were to determine if supplementing milk replacer with Safmannan (SM) and ActiSaf (AS) would affect calf growth and health throughout the pre-weaned and immediate post-weaned periods. The study was performed over 67 d, with 39 Holstein, bull calves. Calves were housed in individual pens in an environmentally-controlled barn, and were provided ad libitum access to a texturized calf starter and water, as well as offered 350g of milk replacer solids, 22% CP and 20% fat, at 0700 and 1600 from d 0 to 56. Calf starter and water refusals were recorded daily and intakes calculated. Calves were randomly assigned to treatments that included; CON: milk replacer with no added supplements; SM: milk replacer with 5g SM/calf/d; SM + AS: milk replacer with 2g SM/calf/d and 3g AS/calf/d. Individual BW was measured on d 0, 21, 42, 56, and 67. Blood samples were collected and analyzed for hematology on d 10, 28, and 56; while plasma and whole blood were collected and analyzed for plasma haptoglobin concentrations, neutrophil surface expression of CD62L, and neutrophil phagocytosis and oxidative burst capacity to an environmental E. coli on d 0, 10, 28, and 56. All data were reported as CON, SM, and SM + AS, respectively. The LSMeans with various superscripts differ (P≤0.05). Individual calf starter intake did not differ over the entire study, although from 0 d to 21 d, calves receiving the SM + AS supplement consumed more starter (0.025^a, 0.034^ab, 0.074^b ± 0.018 kg/d; P<0.05). Neither ADG (0.63, 0.68, 0.69 ± 0.054 kg/d; P=0.699)), nor feed:gain (1.74, 1.74, 1.73 ± 0.070 kg/kg; P=0.990) differed among treatments. Total leukocyte counts were greater in the CON calves on d 10 than the other treatments (14.2^a, 9.2^b, 11.1^b ± 1.2 10⁶/mL; P<0.05) and was lower in the SM calves on d 28 than the CON and SM + AS treatments (10.4^a, 7.9^b, 10.6^a ± 0.87 10⁶/mL; P<0.037). Neutrophil surface expression of CD62L was greatest in SM calves when compared to CON calves (92,772^a, 110,441^b, 94,526^ab ± 5,334 mean fluorescence intensity; P=0.052). Additionally, there were treatment x time interactions on neutrophil phagocytosis and oxidative burst P≤0.024), whereas SM calves had greater percentages of neutrophils phagocytizing and producing an oxidative burst on d 28. These data suggest that both yeast supplementation strategies may influence the health of high-risk, pre-weaned Holstein calves.

Keywords: calf, growth, yeast