This study investigated changes in the real-time measured levels of milk β-hydroxybutyrate according milk yield, lactation number and status of reproduction in dairy cows. A total of 378 cows were selected. According to their reproductive status the cows were classified as belonging to the following groups: Fresh (1 – 44 days after calving. n=43). Open (45 – 65 days after calving. n=78), Inseminated (1 – 35 days after insemination. n=133). Pregnant (35 – 60 days after insemination and pregnant (relatively pregnant) (n=124). The cows were milked with DeLaval milking robot (DeLaval Inc., Tumba, Sweden) in combination with a Herd Navigator (Lattec I/S. Hillerød. Denmark) analyser. We observed that milk β-hydroxybutyrate (BHB) had a tendency of increasing with an increase of lactation number. The average BHB in multiparous cows was 11.111% higher in comparison with primiparous cows (p<0.001). We found higher BHB concentration in the multiparous cows in all reproduction status groups (p<0.001). A strong positive statistically significant (p<0.001) relationship has been found between BHB and the average milk yield within all groups of primiparous cows although we found a statistically unreliable coefficient of correlation (from -0.202 to 0.057) between highest milk yield and BHB in primiparous and multiparous cows.

Inflammation together with lipolysis and ketogenesis in early lactation can cause low productivity and may be harmful to the cow health. The objective of the study was to determine if ketoprofen treatment in the first days following parturition would positively affect the milk production and whether it was associated with the metabolic and inflammatory response. The study was conducted on 30 cows divided into two groups of 15 cows each. The experimental group was treated with 3 mg × kg. bw. -1 ketoprofen for three consecutive days after parturition. The blood samples were collected on the first day of treatment and in the first and second week postpartum and they were analyzed for non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), tumour necrosis factor-a(TNF-a) and haptoglobin. The results suggested that ketoprofen-treated cows with a higher milk production had a significantly lower concentration of NEFA, BHB, TNF-a and haptoglobin in the first and second week postpartum. No differences were found in the control group in metabolic status regardless of the achieved level of milk production. Ketoprofen administration in postpartum cows can enhance the milk yield. The higher milk yield in the experimental group might be associated with a lower degree of lipolysis, ketogenesis and reduced inflammatory response in the first two weeks postpartum.