Correlation between body condition and ultrasound-measured backfat in lactating Holstein cows

Background: Ultrasonography has been developed to reduce the subjectivity inherent in body condition scoring and to provide more accurate and objective assessments. Objective: To examine the relationship between body condition score (BCS) and backfat thickness measured by ultrasound in Holstein dairy cows raised on the high plateaus of eastern T & uuml;rkiye. Methods: Ultrasound measurements were obtained from two sites on the right side of the body, specifically the thurl and the lumbar regions, for a total of 112 measurements. Results: A decrease in mean backfat thicknesses was observed in both regions from the close-up period to early lactation, followed by an increase in mid lactation. The lowest value of backfat thickness was also observed during early lactation. Overall, backfat thickness showed the same temporal trend. Pearson correlation coefficients between both regions ranged from 0.73 to 0.99, indicating a significant relationship (p < 0.01). A strong positive correlation was found between BCS and the measurements of thurl and lumbar backfat, with values of 0.79 and 0.83, respectively (p < 0.01). The linear regression coefficients between BCS and fat thickness in the thurl, lumbar regions, as well as the average of thurl and lumbar measurements were also statistically significant (p < 0.001). Conclusion: Ultrasound measurements are a reliable and adequate method for determining the nutritional status and body energy reserves of cows across different lactation stages, given the strong correlation between BCS and ultrasound backfat thicknesss. This method reduces the likelihood of errors inherent in visual assessment methods.