Scientific Papers Animal Science and Biotechnologies (Jun 2025)
Parameters of Abdominal Vein and their Association with Milk Production in Dairy Cows
Abstract
In this observational study we investigate morphological and blood flow parameters of milk vein and their associations with milk production stage in high milk-producing Holstein Friesian cows. Morphological parameters: distance of the milk vein from skin surface (parameter 1); vertical diameter from intima to intima of milk vein (parameter 2) in cm; and vein area in cross-section (parameter 3) in cm2 were measured from B-mod images. Blood flow parameters of milk vein were investigated with Spectral Doppler. Linear regression model was used to evaluate relationship between diameter of milk vein and blood flow volume (BFVol) in end of lactation, dry period and early lactation stages of milk production of dairy cows. Also, the same procedure was employed to investigate relationship between diameter, BFVol and maximum velocity (MaxV) of milk vein and milk yield in early lactation stage. Parameter 1 and Parameter 2 of milk vein had constant values in each lactation stage. Parameter 3 of milk vein in early lactation stage was significantly different compared with that in dry period. A very strong direct relationship was found between diameter of milk vein and BFVol in each lactation stage. R–Squared (R2) means that 84.1%, 78.5% and 95.4% of the variability of BFVol of milk vein in each lactation is explained by its diameter. An increase of the diameter of milk vein by 1 cm the value of BFVol increases by 3.315 l/min in the end of lactation, 2.9 l/min in dry period and 1.09 l/min in the early lactation stage of dairy cows. A very strong direct relationship was found between diameter, BFVol and MaxV of milk vein and milk yield of dairy cows in early lactation stage (R = 0.867, 0.924, and 0.947 respectively). R-Squared (R2 = 0.752, 0.853, and 0.898 respectively) means that 75.2%, 85.3%, and 89.8% of the variability of milk yield is explained by diameter, BFVol and MaxV of milk vein respectively of milk vein in early lactation of dairy cows. An increase of this parameters by 1 unit increases milk yield by 7.335 kg, 6.982 kg and 0.210 kg respectively. This study showed that ultrasonography is a useful tool in calculating morphological and blood flow parameters of milk vein as indicators of high milk production in Holstein Friesian cows.
