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Impact of supplementary trace mineral source on immune cell function of dairy cows and its association with postpartum diseases.

L. Ogilvie




Impact of supplementary trace mineral source on immune cell function of dairy cows and its association with postpartum diseases.
L. Ogilvie*1, J. F. W. Spricigo1, B. Mion1, B. Van Winters1, M. A. Steele1, B. W. McBride1, S. J. LeBlanc2, E. S. Ribeiro1. 1Department of Animal Biosciences, University of Guelph Guelph, ON, Canada, 2Department of Population Medicine, University of Guelph Guelph, ON, Canada.

Our objectives were to evaluate the impact of supplementary trace minerals source, inorganic (ITM; Co, Cu, Mn, Zn sulfates and sodium selenite) or organic (OTM; Co, Cu, Mn, Zn proteinates and Se yeast; Bioplex Sel-Plex, Alltech Inc.), fed at 100% of recommended levels, on neutrophil function in vitro and their association with postpartum disease. Heifers and cows (n = 240) were enrolled at 45 � 3 d before expected calving date, blocked by parity and BCS, and allocated randomly to ITM or OTM supplementation. Cows in both treatments were fed the same diet, except for the source of supplementary TM. Automatic feeding gates were used to assign treatments to individual cows. Blood was collected on days −10 � 3 and 7 � 3 relative to calving in a subgroup of cows (n = 104) to measure neutrophil phagocytic capacity in vitro using fluorescence-labeled beads and flow cytometry. Diagnoses of clinical diseases were performed by the research team and farm personnel. To evaluate the association of in vitro assay responses with the incidence of postpartum disease, cows were categorized as low response (below median) or high response (above median). Continuous data were analyzed by ANOVA and binary data were analyzed by logistic regression using the GLIMMIX procedure of SAS. Statistical models included the fixed effects of treatment, parity, season, and their interactions. Treatment did not affect (P > 0.60) the percentage of neutrophils performing phagocytosis on d −10 or 7, which averaged 24.6 and 23.9% respectively. However, the mean fluorescence intensity of phagocytosis on d 7 was greater for OTM than ITM (SQRT scale: 91 vs. 85 � 1.8, respectively; P = 0.03). Cows classified as low prepartum phagocytosis intensity tended to have greater incidence of postpartum diseases (low = 33.3 vs. high = 15.3%; P = 0.06). In conclusion, replacement of inorganic sources of supplementary TM by organic sources modestly improved one measure of phagocytic capacity of neutrophils in vitro. In addition, phagocytosis intensity response of our in vitro assay was negatively associated with incidence of postpartum diseases.

Keywords: trace minerals, immunity, health.

Biography: My name is Lori Ogilvie. I completed a Bachelor's degree in Animal Biology with a minor in Nutrition and Nutraceutical Sciences from the University of Guelph in 2019. I began my Master's in the same year with the University of Guelph's Department of Animal Biosciences focusing on health and immunology in transition cows and their neonatal calves, with a special interest in the association between the two.