The Concentration of Immunoglobulins A, G, and M in Cow Milk and Blood in Relation with Cow Seasonal Keeping and Pathogens Presence in the UdderRecent studies show that immunoglobulins A, G, and M contribute significantly to the maintenance of udder health. Unfortunately, the concentration of immunoglobulins in cow milk during the middle period of lactation is low therefore the question of how to stimulate and maintain a sufficient level and spectrum of antibodies in the udder is topical. The aim of the present study was to evaluate the dynamics of the amount of immunoglobulins A, G, and M in cow milk and blood serum in relation with the cow seasonal keeping and presence of pathogens in the udder. The experimental part of the study was carried out on the dairy farm "Pērles", Valmiera region. Cows were kept in a cold loose housing system, grouped and fed differently depending on cow productivity and lactation period. Two times in the housing period and two times in the grazing period milk and blood were sampled from 16 dairy cows and examined for the concentration of immunoglobulins A, G, and M and for the presence of pathogens. Cows for the study were selected with the aim to analyze the milk obtained from clinically healthy udder quarters of cows of similar-age and productivity in the middle stage of lactation. It was determined that seasonal keeping of cows had significantly affected the concentration of immunoglobulins G and A in milk (p<0.001), and of immunoglobulins A, G, and M in blood serum (p<0.001). Some pathogenic bacteria species infecting the udder quarters had considerably influenced the values of immunoglobulins G, A, and M (p<0.05,p<0.001, andp<0.001, respectively) in blood serum. A wide variation amplitude of immunoglobulin G, A, and M concentration in milk and blood serum was observed, which indicates the important role of the individual factor of an animal in the formation of animal defence response.

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Abstract. The aim of the study was to evaluate the effectiveness of the Mastitis Detection index (MDi) for detection of cows with a high somatic cell count (SCC) during milking in the milking box of the DeLaval milking robot. The MDi takes conductivity, milking intervals and blood presence into consideration. All these factors and SCC dynamics were analyzed in 20 cows during a three-week period. The MDi was compared between the experimental group (cows with initial MDi 1.4 or more, n = 10) with the control group (cows with initial MDi from 1.0 to 1.3, n = 10). Results have indicated that the MDi and milk conductivity in the experimental group were significantly (p < 0.05) higher compared with the control group cows (mean (SD) 1.40 (0.29) vs 1.06 (0.06) and 4634 (469.4) vs 4562 (366.9) µS·cm -1 ). There were significantly longer milking intervals (12 hours and more), and consequently less number of the milking sessions per day in the experimental group (2.3 (0.74) vs 2.6 (0.72) (p < 0.05). In total, the experimental group has significantly higher log 2 SCC 3.4 (1.53) vs 2.4 (1.45). To characterize the overall effectiveness of the MDi for detection of cows with SCC above 200 000 cells ml -1 of milk the Cohen`s kappa from 430 milking sessions were calculated and the agreement was found to be less than moderate (kappa = 0.28 ± 0.048). Besides that, the threshold values of the MDi for automatic divert of abnormal milk were modeled. If the threshold is set as high as 2.0, the SCC of diverted milk would be around 422 000 cells ml -1 and total amount of diverted milk would be 2.3 % of all milk production. At the same time, the bulk tank SCC would be as low as 155 000 cells·ml -1 . Any lover threshold would increase the amount of diverted milk, however, the somatic cell count in the bulk tank would decrease even lower.

The objective of this study was to evaluate performance of automated measurement of whole milk somatic cell count (SCC) by the viscosity method. Gel viscosity of mixture from a small portion of whole milk and SCC indicator reagent was assumed to be related to the number of somatic cells in milk. The principle of detection was based on the length of the time necessary for the magnet to pass through the mixture. One farm with a milking robot equipped with an in-built processor for viscosity detection and permanent use was selected. Viscosity SCC data of 111 dairy cows were obtained from the management system of the milking robot for 4 consecutive days around the milk recording test-day. Whole milk samples from all cows were sent to the accredited dairy laboratory for detection of SCC by the fluoro-opto-electronic method (reference method). To characterize the performance of automated measurement of the viscosity method used to detect cows with high SCC (more than 200 000 cells•ml-1), measured by the reference method, the Cohen's kappa for all milking sessions was calculated. Qualitative agreement of SCC measurement by the viscosity method for the values below 100 000 or above 500 000 cells•ml-1 shows a reliable result already at one separate milking, whereas for the values between 100 000 and 500 000 cells•ml-1 an affirmation that SCC is more than 200 000 cells•ml-1 can be based on a calculated mean over 3 to 5 consecutive milkings (kappa = 0.81 ± 0.09).Quantitative agreement of the SCC results of the viscosity method is only moderate when compared to the laboratory method results. Viscosity method in robotic milking system for detection of milk somatic cell count as a possible tool for the evaluation of the cow udder health status is objective, informative, and has relatively low costs.

Q-fever is widespread globally. The goal of this study was to estimate the prevalence of Q-fever infection in Latvia among dairy cattle in 2018–2020, in comparison with that in 2012–2015. The shedding of Coxiella burnetii DNA in milk was assessed. Screening of blood samples of abortion cases for the presence of antibodies against Q-fever and testing of aborted fetuses for C. burnetii DNA were also carried out. Additionally, serum samples from clinically healthy cattle, sheep and goat were included. Overall, 18.34% of milk samples were positive, representing 11.02% of all tested sheds. In total, 20.62% of serum samples from the cattle that suffered abortions were positive or suspicious, representing 12.63% of all sheds. Only 3.33% of serum samples from clinically healthy cattle and 3.42% from sheep and goat were positive. The highest proportion of serologically positive and suspicious samples was observed in cattle that suffered abortion with age from three to nine years, and in the first and third gestation period. One dominant genotype of C. burnetii (MST61) was detected. Ruminant import from abroad was identified as a significant risk factor, as well as the dairy cattle population density.