Abstract:
The effect of cut number, and heat treatment on chemical composition, in
vitro gas production, organic matter digestibility (OMD), and
metabolizable energy (ME) of Berseem Higazi were investigated. Berseem
Higazi (Medicago sativa) samples were collected from two cuts (first and
second cut) from the same field, in Hillat Kuku, at middle bloom stage on
February 2. 2007, for the first cut, and on April 17. 2007, for the second
cut. Hay were heated in a forced-air oven at different temperatures and
heating intervals, to determine the effect of cut number, and heat treatment
on chemical composition, in vitro gas production, organic matter
digestibility (OMD), and metabolizable energy (ME) of Berseem Higazi.
Gas production was measured at 3, 6, 9, 12, 24, 48, 72, and 96 hours, and
.gas production kinetics were estimated
Number of cut had a significant effect on chemical composition, in vitro
gas production, OMD, and ME, second cut had the highest dry matter
(DM), neutral detergent fiber (NDF), and acid detergent insoluble nitrogen
(ADIN) content (95.59%, 53.05%, 7.59%, respectively), while the total
nitrogen (TN) and crude protein (CP) contents were not affected by cutting
number. Second cut had a significantly (P<0.05) higher gas production
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from quickly soluble fraction (a) (3.11), than the first cut (-2.73), while
first cut had a higher gas production from slowly degradable fraction (b),
gas production rate (c), OMD, and ME, (39.45, 0.11, 64.21%, and
8.49MJ/kgDM, respectively), than the second cut (33.43, 0.08, 59.46%,
and 4.92MJ/kgDM, respectively). There were no significant differences
.(among cuts in term of potential gas production (a+b
Heating the hay increased its DM, NDF, ADF, and ADIN, while TN and
.CP decreased with increased temperatures
Gas production rate (c), OMD, and ME, decreased with raised
.temperatures
Optimal heat treatments as indicated by the greatest increase in OMD and
ME were140o C for 120 minutes (66.78%, 9.10MJ/kgDM) and130o C for
.(120 minutes (65.85%, 8.90MJ/kgDM
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