Rit Búvísindadeildar - 15.10.1996, Blaðsíða 39

Chopped vs. long grass, conserved as
round bale silage and fed to sheep
SUMMARY
A comparison was made between chopped and long grass conserved as forage for
ewes. The grass was from the Ist cut, mostly Descampsia caespitosa, wilted and
baled at 57-66% DM. A WELGER GP 200 fix-chamber-baler, equipped with
chopping knives was used. The rated copping length (-distance between knives)
was 74 mm. The beles were wrapped with 6-layers stretch-film and stored
outdoors. Afeeding trial with 2 x 60 ewes was conducted. The cutting time ofthe
grass was adjusted according to the nutritional requirements ofthe ewes at various
times ofthe indoor feeding period. Through the last 4 weeks before the mating
season a hálfofeach experimental group got fishmeal - 2 kg/ewefor the period - in
addition to the forage which wasfed ad libitum.
The main results ofthe experiment were:
• The DM-density ofthe bales made ofchopped material was 4% higher than of
bales made ofunchopped material, the difference being significant in two out of
three experiments (p<0.05);
• The visible mould was slightly less pronounced in the chopped bales than
unchopped ones. The visible mould in the bales increased with increased storage
time. In each treatment >98% ofthe hay in the bales could be usedforfeeding;
• With respect to the feeding value after conservation and storage, there was an
insignificant difference between the two experimental treatments. The dry matter
digestibility (DMD)fell by 0-4 units(%), proportional to the dry tnatter digestibility
ofthe silage at baling;
• The weight changes ofthe ewes and their body condition scores were unaffected
by the experimental treatments ofthe forage. On the other hand, the fishmeal-groups
gained 2 kg/ewe to their weight, a difference which they kept throughout the indoor
feeding period;
• Ihefertility ofthe ewes were 190 and 170 lambs/100 ewes, on unchopped and
chopped material respectively (0.10>p>0.05). The fish-meal treatment gave 192
lambs/100 ewes compared to 172 lambs/100 ewesfed silage only;
• This study did not reveal any important economic factors which could compensate
the extra costs ofbuying and using chopping equipment on the big baler, butfor all
that, further research is needed
33