80 (1) pp 31-37

Measuring body energy reserves stored as fat in high yielding dairy cows

The aim of the present study was to examine the correlation between the subcutaneous and intra-abdominal fatdeposits in dairy cows and, furthermore, to determine how these fat deposits can be accurately measured in the livingcow using methods applicable in the field. In 74 dairy cows, the amount of subcutaneous fat was measured justbefore slaughter, using three different techniques: determination of the body condition score (BCS), measurementof the ultrasonographic back fat thickness (BFT), and measurement of the bio-electrical impedance (bioelectricalimpedance analysis, BIA). After slaughter, the amount of fat stored in the omentum was determined using a newomental fat score (OFS) based on a 5-point scale. The results revealed that there is significant correlation betweenthe different methods tested to measure the amount of subcutaneously stored fat (BCS-BFT: r = 0.71; p < 0.001; BCSBIA:r = 0.39; p < 0.01; BFT-BIA: r = 0.57; p < 0.001). Remarkably, however, no correlation was found between theOFS and the amount of fat stored in the subcutis as measured by the BCS and the BFT (r = 0.20; p = 0.08 and r =0.10; p = 0.39, respectively). Also, the BIA results were not correlated with the OFS (r = 0,10; p = 0,40), a fact whichcould be due to the electrode placement along the dorsal midline of the cow instead of on the limbs. The conclusionof this study is that both farmers and veterinarians should be aware that, although the BCS and the BFT may bescored as optimal in relation to their stage in lactation, some cows may hide a significant amount of fat in theiromentum, which may put them at a higher risk of suffering from metabolic diseases. More research is required inorder to develop new techniques to measure accurately and in a practically applicable way the total amount of fatstored in the body of a living cow.

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