A method for measurement of subdermal fat thickness in dairy cows by digitizing cross-sections of ultrasonic scans was investigated. A commercial ultrasonic system was modified for acquiring and presenting A-mode and B-mode ultrasonic images. Two sites were selected for a series of successive measurements: one was on the fiat area of the rear of the rump between the pin bone and the tail head; the other was between 12th and 13th ribs, below the back rump. Several points were measured in each site. Two probe holders were fabricated to fit each site and to ensure successive measurements at exactly the same points. A 7.5-MHz probe was used. Both A and B scans were conducted and recorded on videotape. A computer program was written to acquire and digitize data from A-mode scans to a depth of 30 mm. An algorithm located signal peaks to distinguish among skin, subdermal fat and muscle, and then calculated thickness of layers at each point. A trial was conducted to evaluate the use of this system to detect body condition changes of the dairy cow during lactation. Six cows were monitored and measured from calving to late lactation: subdermal fat was ultrasonically measured weekly, and cows were scored weekly for body condition and weighed daily. It was concluded that successful ultrasonic measurements for body condition assessment, to detect energy balance changes, depend on accurate and reliable standardization of measurements, at a responsive site. The between-ribs site was more responsive, and a single point (usually just below the spine) provided sufficient data for the required purpose. Given the conditions described, the system can measure quantitatively changes of subdermal fat thickness in lactating dairy cows.
|Original language||English (US)|
|Number of pages||8|
|Journal||Transactions of the American Society of Agricultural Engineers|
|State||Published - 1999|
- Subdermal fat
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)