Estimation of Risky Lobe Rates and Milk Yield Losses in Holstein Cows Based on Somatic Cell Count: The Case of the Middle Black Sea Region of Türkiye

Abstract

Somatic cells are a combination of white blood cells and epithelial cells in milk and are usually expressed in numbers. High somatic cell count (SCC), which is used as an important criterion in the evaluation of udder health and diagnosis of subclinical mastitis, is considered as an important indicator of milk production loss. This study was carried out to estimate SCC-induced risky lobe ratio (RLSCC) and milk yield losses (MLSCC) in Holstein raw milk collected from some provinces in the Middle Black Sea Region of Türkiye. Bucket milk samples collected by stratified random sampling during January-February 2024 in Amasya (n=18), Çorum (n=26) and Samsun (n=34) provinces from member farms of the Cattle Breeders’ Association (CBA) were subjected to SCC analysis. SCC value of each sample was taken into consideration in recording RLSCC data (SCC˂200 thousand cells/ml, RLSCC: 6%; SCC: 200 thousand-500 thousand cells/ml, RLSCC: 16%; SCC: 500 thousand-1 million cells/ml, RLSCC: 32%; SCC˃1 million cells/ml, RLSCC: 48%). At the end of the study, the mean SCC and RLSCC were found as 7.02±0.346% and 16.94±0.913%, respectively. SCC data were converted to logarithm base 10 (logSCC) to ensure homogeneity and uniformity in the statistical study. Pearson correlation estimation method and simple linear regression method were used to calculate the relationships between traits. While there was a strong relationship between SCC and milk RLSCC (r=0.964 and R2=0.929), the regression model was estimated as Y=-68+13.716X. As a result, it is recommended that managerial practices to improve milking, shelter cleaning and milk storage conditions in the enterprises should be fully implemented.