Rit Búvísindadeildar - 15.10.1996, Síða 26

The effect of dry matter content on the nutritive
value of round bale silage fed to sheep
SUMMARY
Two DM-levels of round bale silage, 34-35% (A) and 50-65% (B), resp., were
compared with respect to the conservation quality and feeding potential. The bales
were wrapped with 6-layers of stretch-film and stored uncovered outdoors.
Changes in nutritional value from cutting to feeding were measured as well as ihe
storage losses. Mold formation in the bales was estimated. DM-intake of sheep
(group-feeding) was measured as well as their production. The comparison was
carried out in three experiments during the years 1990/1991 and 1991/1992. The
material was afairly leafy first cut grass in two experiments, and second cut grass in
the third. The experimental feed was offered mainly in two periods of the indoor
feeding: From housing to the middle ofJanuary, and fromApril to lambing in May.
The main results can be summarized as follows:
• With limited wilting (A) there was 50% probability ofbaling on the cutting date;
for heavy wilting (B) one more day was needed under normal weather conditions;
• On the average the energy value decreased from 0,82 FE/kg DM at cutting, to 0,76
at baling - independent ofthe DM-level. The reduction was more pronounced in
energy-rich material, concentrated to the very first hours ofwilting;
• The DM-density of the bales increased with the DM-level up to 55% DM. The
DM-density ofB-bales was 12% higher than ofA-bales;
• The relative number of mould-free bales was higher in B- than A-bales; decreasing
with the storage time. The mould occurance was significantly less in the balesfrom
the second cut than from the first cut material;
• The DM-storage loss was very low (<1,5%) and there was insignificant difference
(p>0,05) between DM-levels (A and B). The changes in energy value from baling to
feeding was <1%, but the increase in crude protein (%) was somewhat higher in A
than B (5% vs. 2%);
»In all cases the DM-intake ofthe heavy wilted material was higher, with 1,48 kg
DM/d. (A) and 1,65 kg DM/d. (B) as the average values. The difference was
significant infive out ofeight measuring periods.
• The differences between treatments with respect to weight changes ofthe ewes and
their conditional scores were insignificant;
• The average fertility in the B-group was 173 lamb/100 ewes, resp. 167 lambs/100
ewes in A, being higher in B in two ofthree experimental groups. The birth weight
of lambs was 1-6% higher in B than A; the difference was insignificant;
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