Reactivity of phagocytic cells during lactation of dairy cows: their implication on the establishment of pregnancy.

PERALTA, M.B.; CAINELLI, S.; ANGELI, E.; STASSI, A.F.; SALVETTI, N.R.; ORTEGA, H.H.; REY, F.; VELÁZQUEZ, M.M.L.

Congreso; LXVII Reunión anual de la Sociedad Argentina de Inmunología (SAI); 2019

The health problems detected during peripartum period could be due to impaired leucocyteactivity related to systemic factors such as hormones and metabolic components highlymodified in this period. Throughout lactation period in dairy cows, little information is availableabout reactivity of phagocytic cells. The aim of this study was to analyze the phagocytic activity(PA) of monocytes/macrophages throughout lactation and their implication on the index ofdays to conception considering the hormonal and metabolic context. Blood samples werecollected at different postpartum days. Cows were grouped according to the length of days toconception period: fewer (83±6 days) and greater (128±32) days. All procedures wereapproved by the Ethics Committee (FCV-UNL). Plasmatic concentrations of cortisol, estrogen,progesterone, non-esterified fatty acids and glucose were measured. The differential leukocytecounts were performed by blood smears. The PA and mean fluorescence intensity (MFI) ofmonocytes/macrophages were determined by flow cytometry. A Generalized Linear Model withrepeated measures was used to analyze different effect on leukocyte count andimmunoreactivity. Kaplan?Meier test was used to evaluate the effect of PA and MFI on the delayto conception time. The results showed that the hormonal and metabolites levels there were nosignificant effects on the counts of monocytes/macrophages over time. However, estradiol andglucose concentrations had a significant effect on the PA and MFI. Finally, cows with lower MFIwere pregnant earlier than those with higher MFI. These results suggest a relation between thereactivity of monocytes/macrophages and the delay to conception time.