New Zealand Journal of Agricultural Research abstracts
Short-term ingestive behaviour of sheep and goats grazing grasses and
legumes
2. Quantitative relationships between sets of sward and ingestive
behaviour variables
Y. GONG1
J. HODGSON2
M. G. LAMBERT1
I. L. GORDON2
1AgResearch Grasslands
Private Bag 11008
Palmerston North, New Zealand
2Plant Science Department
Massey University
Private Bag 11222
Palmerston North, New Zealand
Abstract Components of short-term ingestive behaviour (bite
weight, rate, depth, area, and volume) were recorded for six sheep and six
goats grazing five grasses and four legumes each at two stages of growth
(vegetative and reproductive). Animals were individually confined in metabolism
crates and were offered prepared turves (41 x 27 cm) extracted from small
monoculture field plots. Correlation relationships between sets of sward and
ingestive behaviour variables were assessed using canonical analysis to
evaluate the relative importance of individual variables within their own set
in contributing to the sward effects (sward set) on ingestive behaviour, or to
the animal responses (behaviour set) to sward variation. Overall, sward
characteristics had a strong impact upon ingestive behaviour (canonical
correlation = 0.95). In general, sward height had a greater effect (absolute
value of standardised coefficient: AVSC = 1.184) on ingestive behaviour than
did other sward characteristics (AVSC = 0.001-0.212), and bite depth was more
responsive (AVSC = 0.840) than other behaviour components (AVSC = 0.030-0.355)
to changes in sward attributes. However, sward bulk density, in particular leaf
frequency bulk density (AVSC = 0.928), had a substantially greater effect on
ingestive behaviour than did sward height (AVSC = 0.436) in leguminous swards
grazed by sheep. Although the ingestive behaviour of goats grazing legumes was
influenced principally by sward height (AVSC = 0.756), the effect of leaf
frequency bulk density was substantially increased compared with that in
grasses (AVSC = 0.460 versus 0.119). Herbage mass had more impact in legumes
than in grasses for both sheep (AVSC = 0.623 versus 0.084) and goats (AVSC =
0.242 versus 0.141). Bite weight was a more important response variable than
bite depth for both animal species when grazing legumes (sheep: AVSC = 2.153
versus 0.539; goats: AVSC = 1.182 versus 0.493).
Keywords grasses; legumes; sward height; bulk density; sheep;
goats; ingestive behaviour; bite weight; bite rate; bite area; bite depth;
canonical correlation
New Zealand Journal of Agricultural Research, 1996, Vol. 39: 75-82
0028-8233/96/3901-0075 $2.50/0 (c) The Royal Society of New Zealand
1996
PDF file of entire paper: medium quality (670K); (scanned from paper original: notes about this process)
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