Identification of serum innate immunity reactants in transition dairy cows before clinical signs of laminitis
Laminitis (LAM) is prevalent in dairy cows and early diagnosis and timely treatment of the disease can lower animal suffering, improve recovery rate, increase longevity, and minimize cow loss. However, there are no indications of disease until it appears clinically and presently the only approach to deal with the sick cow is intensive treatment or culling. The objective of this study was to identify potential predictive biomarkers of LAM in transition dairy cows. Blood samples were collected from the coccygeal vein once per week before morning feeding from 100 multiparous Holstein dairy cows during -8, -4, disease diagnosis, and +4 wks relative to parturition. Six healthy cows (CTR) and 6 cows that showed clinical signs of disease (i.e., LAM) were selected for intensive serum analyses. Concentrations of 3 cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α); 3 acute phase proteins (APPs) haptoglobin (Hp), serum amyloid A (SAA), and lipopolysaccharide binding protein (LBP); as well as 3 metabolites lactate, non-esterified fatty acids (NEFA), and β-hydroxybutyrate (BHBA) were measured in serum by ELISA or colorimetric methods. Health status, feed intake, rectal temperature, and milk yield was monitored for each cow during the whole experimental period. Data were processed statistically by MIXED procedure of SAS 9.2. Results showed that cows affected by LAM had greater concentrations of lactate, IL-6, SAA, and LBP in the serum vs CTR. Most interestingly, enhanced serum concentrations of lactate, IL-6, SAA, and LBP at -8 and -4 wks before parturition were significantly different in cows with LAM as compared with the CTR ones. The disease also lowered the overall milk production and feed intake as well as milk fat and fat:protein ratio. In conclusion, LAM affected serum concentrations of the several parameters related to innate immunity and carbohydrate metabolism that might be serve to monitor health status of transition dairy cows. At this point we are not certain whether these are typical LAM biomarkers or indicators of general disease state. More research is warranted to validate these data.
Keywords: Dairy cows, Innate immunity, Laminitis