Wilhelm et al. (2013) compared BHBA concentrations
in blood samples taken from 4 different sampling
locations (mammary vein, jugular vein, and left and
right V. saphena externa lateralis). The authors found
higher concentrations of BHBA in samples taken from
the jugular vein and Vv. saphenae compared with the
mammary vein in lactating dairy cows. Redetzky et
al. (2003) also found higher levels of BHBA in blood
drawn from the jugular vein compared with the mammary
vein in lactating dairy cows. Interestingly, BHBA
concentrations in nonlactating cows showed an inverse
relationship (Wilhelm et al., 2013). The authors speculated
that different BHBA consumption rates in the
tissues drained by these veins (i.e., especially brain and
udder) caused this difference. However, the tail vessels were not included in both of these comparisons,
although this sampling location has practical benefits
(e.g., easier handling) and has been used in previous
research trials (Enjalbert et al., 2001; Iwersen et al.,
2009; McArt et al., 2012).