Associations between lameness and the metabolic and hormonal profiles in dairy cows

Dairy cows lameness represents a significant welfare issue for the dairy industry. The aim of this study was to investigate metabolic and hormonal parameters associated with lameness in cows. The study included two treatment groups of 10 multiparous Holstein–Friesian dairy cows each. The control group consisted of cows with locomotion score 1 and in the experimental group cows with locomotion scores 3 and 4 were included. Milk, urine and blood samples were collected to determine the fat, protein, urea, creatinine, electrolytes and copeptin vasopressin (AVP) content. The milk fat, protein and energy-corrected milk (ECM) levels were higher in lame animals compared with non-lame cows. The blood urea nitrogen (BUN) and BUN/serum creatinine ratio were lower at the start of the trial in lame animals suggesting a metabolic acidosis state. There were significantly lower serum Na levels in the lame cows, from the start until the end of the trial (p < 0.011), as well as between lame and non-lame groups at the end of the trial (p = 0.041). A lower copeptin AVP was detected in lame compared with non-lame cows at the end of the trial (p = 0.004). The decrease of serum Na levels as the comfort improves indicates that the animals started to recover from the effect of cortisol on mineralocorticoid receptors. Our data also indicates that the BUN and BUN/serum creatinine ratios are associated with lameness. Further investigations involving a larger number of cows would be recommended to confirm these results and to evaluate these parameters in the early stages of lameness.