Because comparison among different organs involves several
different tissue types, coordinated organ growth cannot be
expected, as observed for the other parts of body, such as
muscle and bone (Gore et al., 1994).
Breed differences for the organ weight to BW ratios
were rather small and not consistent during gestation. Liver
weight to BW ratio in German Holstein at 9 mo of gestation
was significantly greater than in Belgian Blue and Galloway,
and similar in German Angus. No significant differences
among the breeds were found for kidney at 9 mo, for lung at
3 and 6 mo, and for heart at 6 mo of gestation.
In the current study, different organ weights, occurred
among certain breeds at 3 mo of gestation and maintained to
birth. Regarding organ weight to BW ratios, the
relationships among breeds show a large variation during
gestation, indicating different growth patterns. These results
were also found by Gore et al. (1994), who demonstrated
that no clear relationship to breeds was observed for organ
weight to BW ratios. Organ growth is influenced by breed,
but interestingly not by the type of cattle (dairy or beef).
The heavier liver in Holstein Friesian and Belgian Blue and
the greater liver weight to BW ratio in Holstein Friesian
indicate the higher metabolism of these high productivity
breeds. According to that, Pfuhl et al. (2007) reported a
greater weight of liver in adult Holstein Friesian compared
to Charolais.