Agriculture Reference
In-Depth Information
Table 9.4
Indicative summary of comparisons of digestibility and intake in goats and sheep.
Animal species with higher
digestibility
Animal species with
higher intake
Reference
Animals
Doyle et al., 1984
Angora goats; Merino sheep
Diet A,C — Neither
Diet B — Goats
Diet A; Goats (g/d, not
g/kg W
0.75
)
Brown and Johnson,
1985
Toggenburg × Saanen castrated
kids; Suffolk cross wether
lambs
Overall, neither; sheep digested
65% wheat straw diet better
Goats (g/d); Neither
(g/kg W
0.75
)
P fi ster and
Malechek, 1986
Free - ranging castrated “ hair
sheep ” ; undefi ned goats
Overall, neither; sheep ate higher
digestibility diet, wet season
Neither
Domingue et al.,
1990
Angora
feral castrated goats;
Border Leicester
×
Goats (winter only)
Summer — Goats
Winter — Neither
×
Romney
castrated sheep
Reid et al., 1990
Toggenburg
Alpine goats;
Suffolk sheep
×
Neither
Neither
Tolkamp and
Brouwer, 1993
Literature survey
Goats, but by mean of only
0.8 percentage units
ND
Papachristou, 1994
Free - ranging — breeds not defi ned
Cleared pasture — neither overall,
sheep October only slashed/
native pastures — goats
ND
Perez - Maldonado
and Norton, 1996
Castrated Cashmere goats;
castrated Border Leicester
Neither (OM, NDF, ADF, N)
Sheep (g/d)
Neither (g/kg W
0.9
)
×
Merino sheep
Hadjigeorgiou et al.,
2001
Castrated Blackface sheep;
castrated Cashmere goats
Sheep (for DM, OM, NDF, ADF
and N)
Goats (g/kg W
0.75
)
ND = not determined.
on digestibility and concluded that while goats did tend to
show higher digestibility capability than sheep, the mean
difference between species was only 0.8 percentage units
of digestibility, an amount which can be regarded as too
small to be of any practical signifi cance.
(1.6-3.2% live weight); and lactating goats 31.7-151.3 g/
kg
0.75
(1.0-6.3% of live weight).
In comparisons of feed intake by goats and sheep, it has
sometimes been asserted that goats have the higher intake
and that this is because of their higher ME requirement for
maintenance, compared with sheep. There is strong evi-
dence that goats do have a higher ME requirement for
maintenance (AFRC, 1998; Sahlu et al., 2004) and that
their requirement/kg
0.75
is more like that of cattle than of
sheep. From this, it would follow logically that to maintain
weight, goats would have to eat more of a given diet than
sheep. However, this does not necessarily mean that
vol-
untary
feed intakes will be higher in the goat. This distinc-
tion between “the intake required to maintain weight” and
“voluntary feed intake” needs to be more clearly acknowl-
edged in future comparisons of the voluntary feed intake
of goats with other species.
A selection of direct comparisons of voluntary intakes
by goats and sheep is given in Table 9.4 (column 4). There
are more instances where the intake by goats is higher, but
F
ORAGE
I
NTAKE
On sown pastures dominated by perennial ryegrass,
Merchant and Riach (1994) reported daily DM intakes
of 26 - 88 g/kg
0.75
(1.1-3.7% of live weight) for castrated
Cashmere goats. Intakes in lactating mixed-genotype goats
were 57 - 140 g/kg
0.75
, similar to ranges reported elsewhere
for lactating sheep. Intakes by unweaned kids of 25-30 g/
kg
0.75
are lower than published values for lambs and were
also markedly lower than daily DM intakes in weaned
kids, as might be expected. In general, all the above values
are similar to those cited in the extensive review by
Luo et al. (2004), which were as follows (minimum-
maximum): growing goats 42.6 - 97.2 g/kg
0.75
(1.8 - 4.5% of
live weight); mature, nonlactating goats 27.6-92.0 g/kg
0.75
