Veterinarija ir Zootechnika

Postpartum metabolic and inflammatory disorders, including ketosis, puerperal paresis, and mastitis, profoundly affect milk composition and have significant implications for dairy herd productivity and health. This study aimed to investigate breed-related differences in milk chemical composition between Holstein-Friesian and Simmental cows during early lactation prior to therapeutic intervention. A total of 360 cows were examined and grouped by disease and breed. Milk was analyzed for fat, protein, casein, lactose, solids-not-fat, fatty acid profiles (saturated, unsaturated, polyunsaturated), BHB, acetone, minerals (Ca, P, Mg), milk urea, citrate, somatic cell count, and pH (mastitis). ANOVA assessed breed differences, while correlation and regression analyses evaluated associations among metabolic markers and milk components. Chi-Square tests examined breed-specific differences within disease categories. Holstein-Friesian cows with ketosis showed higher BHB (450±30 μmol/L) and acetone (2.5±0.2 mmol/L) compared to Simmental (BHB 380±25 μmol/L; acetone 1.8±0.2 mmol/L; p<0.001), reflecting enhanced lipid mobilization. In mastitis, reductions in protein (Holstein 2.9±0.2% vs Simmental 3.0±0.2%; p<0.002) and lactose (4.0±0.1% vs 4.1±0.1%; p<0.001) were more pronounced in Holstein-Friesians. Puerperal paresis was associated with lower milk calcium (95±5 mg/100 mL vs 100±4 mg/100 mL; p<0.001), phosphorus, and magnesium in Holstein-Friesians. Regression models showed that BHB and acetone explained up to 72% of protein variation, while Chi-Square tests confirmed significant breed-specific metabolic differences. However, mechanistic explanations for breed differences remain unclear, and potential confounders such as diet, housing, and environmental factors were not fully controlled, limiting causal inference. These findings highlight milk composition as an integrated biomarker system for monitoring postpartum metabolic and inflammatory stress. Understanding breed-specific responses may inform targeted nutritional strategies, early detection, and precision herd management, enhancing both animal welfare and milk productivity.

The study was carried out to determine the influence of ketosis in cows during early lactation period, immediately after calving, on the occurrence of mastitis as a secondary disease and potential risk factor of recurrent mastitis, through monitoring of such udders during one lactation period. The research included 156 cows grouped into three groups of 52 cows from the Holstein Friesian and Simmental breeds. The first is a group with primary postpartum ketosis and secondary mastitis, the second group is with mastitis and free of ketosis, while the third is a control group of healthy cows. In order to prove ketosis, blood, milk and urine samples were examined for the presence of ketone bodies proven through laboratory tests. For the purposes of mastitis detection basic clinical evaluation of the affected udder was conducted and milk samples were taken for microbiological identification of causes of mastitis. Cows included in the first group, were monitored during the entire lactation in order to determine the number of cows with recurrent mastitis and the main risk factor that leads to the occurrence of recurrent mastitis, which is also the main goal of this paper. According the results in this study the recurrent mastitis was detected in total of 24 cows included in both groups for which, the common pathogens like Staphylococcus aureus is considered as the main cause for mastitis recurrence (87,5%). Statistical significance in milk yield was detected between control group and the groups with mastitis (p<0.05). The results in this study reveal that the metabolic disorder can be considered as a factor for recurrence of mastitis caused by the common pathogens and also mastitis can have significant impact on milk yield in dairy cattle.