The role of ketosis on the occurrence of mastitis and their mutual influence on milk yield in one lactation period in cows
Dejan Janevski
, Miodrag Radinović, Jovana Krivokapić
, Miodrag Radinović, Jovana KrivokapićAbstract: Ketosis, as a primary metabolic disorder that occurs postpartum in cows, is a risk factor for the occurrence of mastitis as a secondary disease.
To prove the objectives of the conducted study, two groups of East Friesian cows were examined.
The first group included 104 cows with ketosis, of which 60 cows in correlation with ketosis developed mastitis. Further studies were conducted only on these 60 cows. Ketosis was proven by the method of enzymatic catalysis by determining beta- hydroxybutyric acid in blood serum. Mastitis was proven by determining the number of somatic cells and by identifying the type of microorganisms, which was carried out by applying the MALDI-TOF/SARAMIS™ platform using structural ribosomal proteins that are specific for each type of microorganism.
The second group was a control group of cows, which also consisted of 60 completely healthy cows for which milk yield data was regularly collected throughout the entire lactation period.
By isolating microorganisms from mastitic milk, the most common causative agent was Staphylococcus aureus, which was isolated in 40% of the samples, followed by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, and Pseudomonas aeroginosa.
Both diseases have a negative impact on milk yield, where a statistically significant difference is observed using analysis of variance (p<0.05).
The analysis of the data in the conducted research showed a decline in milk yield, with a decrease in milk yield of 8.56 l/day, which is one quarter less than in a healthy population of cows for one lactation period.
To prove the objectives of the conducted study, two groups of East Friesian cows were examined.
The first group included 104 cows with ketosis, of which 60 cows in correlation with ketosis developed mastitis. Further studies were conducted only on these 60 cows. Ketosis was proven by the method of enzymatic catalysis by determining beta- hydroxybutyric acid in blood serum. Mastitis was proven by determining the number of somatic cells and by identifying the type of microorganisms, which was carried out by applying the MALDI-TOF/SARAMIS™ platform using structural ribosomal proteins that are specific for each type of microorganism.
The second group was a control group of cows, which also consisted of 60 completely healthy cows for which milk yield data was regularly collected throughout the entire lactation period.
By isolating microorganisms from mastitic milk, the most common causative agent was Staphylococcus aureus, which was isolated in 40% of the samples, followed by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, and Pseudomonas aeroginosa.
Both diseases have a negative impact on milk yield, where a statistically significant difference is observed using analysis of variance (p<0.05).
The analysis of the data in the conducted research showed a decline in milk yield, with a decrease in milk yield of 8.56 l/day, which is one quarter less than in a healthy population of cows for one lactation period.
Keywords: bacteria; cows; ketosis; mastitis; Staphylococcus aureus
Citation: Janevski, D., Radinović, M. & Krivokapić, J. (2026). The role of ketosis on the occurrence of mastitis and their mutual influence on milk yield in one lactation period in cows. Bulg. J. Agric. Sci., 32(3), 723–727
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Date published: 2026-06-25
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