Abstract:
The ban on open-air burning of agricultural by-products
by the European Union created disposal problems on many
farms. Success was limited in attempts at feeding
agricultural by-products like cereal straws to previously
grazed livestock. This initial reluctance to accept
unfamiliar feeds was also reported when livestock were
fed whole-grain cereals in drought, or when grazed on new
pastures and shrubs. It is suggested that previous exposure
to feed might speed up the rate at which it is accepted,
particularly if such experiences take place at pre-weaning.
This study aimed at establishing the veracity of this
assertion, and whether an early learning experience is
carried over into adulthood. Two feeding trails were carried
out with lambs not exposed (NE) to straw and those given
access to straw at 12 weeks of age for either 10 (E-10) or
28 (E-28) days. At 24 weeks (Experiment 1), 10 lambs
from each of the three treatment groups were tested,
over 21 days, on their readiness to accept straw as feed.
At 36 weeks (Experiment 2), another batch of lambs
(from the E-28 and NE groups only) were similarly tested.
For each, the lambs were penned individually (in view of
lambs from their own treatment group) and also offered a
concentrate supplement to meet daily nutrient
requirements. In both experiments, intake of straw OM,
N and DOM, as well as leaf to stem ratio in reject straw,
were assessed for each penned lamb. Animal behaviour
pattern was monitored once every 5 min, over an 8-h
period, immediately after first confinement. Frequency
of eating, idling, ruminating, or drinking were all found to
be significantly greater (P<0.001) for previously exposed
lambs. Intakes of OM, N, DOM, and leaf fraction in
straw were also significantly greater (P<0.01) over the
1st week of assessment. However, the differences
(P>0.05) between lambs exposed for 10 or 28 days were
not significant in all the parameters measured. Results
from these trials support the belief that animals exposed
to feeds, pre-weaning, recognize such feeds and accept
them later in life more readily than those given such
feeds for the first time. The study implies that production
systems that expose animals to a wide range of feeds
early in life may be advantageous to them later. Research protocols may need to look more into the feeding history
of experimental animals, particularly those assembled from
different backgrounds. It may also be possible to exploit
this observed behavioural pattern to “prepare animals”
early in life to either accept or reject particular feeds
they may meet later in life
