The Correlation Between Body Condition Score and Ultrasound-Measured Backfat Thickness in Holstein Friesian Cows at Different Lactation Stages

Background: Ultrasonic methods have been developed to reduce the subjectivity inherent in body condition scoring and to provide more accurate and objective assessments. Objective: The objective of this study was to examine the relationships between body condition score (BCS) and back fat thickness measured by ultrasound in Holstein dairy cows reared on high plateaus of eastern Türkiye. Methods: Uultrasound measurements were taken from two different parts of the right side of the body, specifically the thurl and the lumbar regions, for a total of 112 measurements. Results: The research findings indicate a decrease in mean fat thicknesses in the thurl and lumbar regions from the close-up period to the early-lactation period, followed by an increase in the mid-lactation period. The lowest value of back fat thickness was also observed during the early-lactation period. The back fat thickness followed a similar trend. Pearson correlation coefficients between the fat 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 back fat, 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). Conclusions: It has been concluded that ultrasound measurements are a reliable and adequate method for determining the nutritional status and body energy reserves of cows in different periods of lactation, due to the high and significant correlation of BCS and back fat with ultrasound measurements. This method reduces the likelihood of errors inherent in visual assessment methods.