: t*\,,., .-, i , . > . ‘ . _ -\ ...
:
t*\\,,.,
.-, i , . > . ‘ . _
-\\ -‘y c.. , . ~ , .i;a/-,
Jb, : ! (. ,. i, (. ,_, c-, ’ ’ , --j rJ i 41
t \\ ! (1 y:., . \\i t , . ( ( ( , ,: : , . I
,
’ :‘; -,;
‘ 3
I, . ~ .j;. i <” Rum1.nal N degrada-t;ion o f br0WSe ancï *
temperate f o r a g e s ,
and p a r t i t i o n o f N Into
carbohycirates
-:5 5 ‘,,
og
B.MICHALET-DOREAU,
S.TOURE-FALL*
Valeur Alimentaire, SRNH, INRA Theix, 63122 Ceyrat, France
$ ISRA LNERV, BP 2057 Dakar, Sénégal
The lower N digestibility of browse forages cari be explained by the presence of
polyphenol compounds (tanins) (Ho Ahn et al., 1989) or by the partitioning herbage N
into
structural
carbohydrates.
Van Soest
and Sniffen (1984) suggested that
partitioning herbage N into neutral and acid-detergent-soluble and -insoluble
portions may explain rumina1 N degradability. Our objective was to examine this last
hypothesis. We measured in the rumen the in situ N and ce11 wall N (NDFN, ADFN)
degradability of 2 forages harvested in a semi-arid zone of Senegal (Acacia albida
and Balanites aegyptiaca leaves) and 2 temperate forages (Cocksfoot and Alfalfa
hays). The forages ground through a .8 mm screen, and previously the browses were
dried at 60-C. In situ measurements of degradation (10 incubation times spread
between 1 and 96 h) were carried out on using 3 non lactating cows receiving 7 kg DM
/animal/day of a diet of hay and concentrate (70/30). After incubation, the bags were
washed, beaten for 7 min in a "stomacher" and washed again, to decrease the bacterial
contamination of the bag residues. Rumina1 degradability of different components was
calculated by fixing particle turnover rate at .06/h-l.
The N distribution is more homogenous in the temperate forages than in' the
studied browses. Consequently, the variations in N degradability is more important
for the browses (from 26.7 to 82.6%) than for the temperate forages (from 62.6 to
75.8%). The lowest N degradability of Acacia albida is due to high ADFN content
(35.1%) and to undegradability of NDFN -ADFN fraction, In our study, the lower N
degradability of browses could be explained by N content in ce11 wall.
REFERENCES
.
HO AHN J., ROBERTSON B.M., ELLIOTT R., GUTTERIDGE R.C., FORD C.W. (1989). Anim. Feed
Sci. Technol. 27, 147-156
VAN SOEST P.J., SNIFFEN C.J. (1984). Proc. Distillers Feed Conf, .39, 73-81.
Table 1: Chemical composition and degradability of N and detergent-soluble and
insoluble N of forages
Degradability (%)
I Forages
1
AtiiW
N
mm
NDFN-ADFN
%N
Acacia
35.1
26.7
0
0
Balanites
5.5
82.6
17.7
20.7
Cocksfoot
7.2
62.6
26.1
26.8
Alfalfa
8.0
75.8
43.4
51.7
.
.
t*\\,,.,
.-, i , . > . ‘ . _
-\\ -‘y c.. , . ~ , .i;a/-,
Jb, : ! (. ,. i, (. ,_, c-, ’ ’ , --j rJ i 41
t \\ ! (1 y:., . \\i t , . ( ( ( , ,: : , . I
,
’ :‘; -,;
‘ 3
I, . ~ .j;. i <” Rum1.nal N degrada-t;ion o f br0WSe ancï *
temperate f o r a g e s ,
and p a r t i t i o n o f N Into
carbohycirates
-:5 5 ‘,,
og
B.MICHALET-DOREAU,
S.TOURE-FALL*
Valeur Alimentaire, SRNH, INRA Theix, 63122 Ceyrat, France
$ ISRA LNERV, BP 2057 Dakar, Sénégal
The lower N digestibility of browse forages cari be explained by the presence of
polyphenol compounds (tanins) (Ho Ahn et al., 1989) or by the partitioning herbage N
into
structural
carbohydrates.
Van Soest
and Sniffen (1984) suggested that
partitioning herbage N into neutral and acid-detergent-soluble and -insoluble
portions may explain rumina1 N degradability. Our objective was to examine this last
hypothesis. We measured in the rumen the in situ N and ce11 wall N (NDFN, ADFN)
degradability of 2 forages harvested in a semi-arid zone of Senegal (Acacia albida
and Balanites aegyptiaca leaves) and 2 temperate forages (Cocksfoot and Alfalfa
hays). The forages ground through a .8 mm screen, and previously the browses were
dried at 60-C. In situ measurements of degradation (10 incubation times spread
between 1 and 96 h) were carried out on using 3 non lactating cows receiving 7 kg DM
/animal/day of a diet of hay and concentrate (70/30). After incubation, the bags were
washed, beaten for 7 min in a "stomacher" and washed again, to decrease the bacterial
contamination of the bag residues. Rumina1 degradability of different components was
calculated by fixing particle turnover rate at .06/h-l.
The N distribution is more homogenous in the temperate forages than in' the
studied browses. Consequently, the variations in N degradability is more important
for the browses (from 26.7 to 82.6%) than for the temperate forages (from 62.6 to
75.8%). The lowest N degradability of Acacia albida is due to high ADFN content
(35.1%) and to undegradability of NDFN -ADFN fraction, In our study, the lower N
degradability of browses could be explained by N content in ce11 wall.
REFERENCES
.
HO AHN J., ROBERTSON B.M., ELLIOTT R., GUTTERIDGE R.C., FORD C.W. (1989). Anim. Feed
Sci. Technol. 27, 147-156
VAN SOEST P.J., SNIFFEN C.J. (1984). Proc. Distillers Feed Conf, .39, 73-81.
Table 1: Chemical composition and degradability of N and detergent-soluble and
insoluble N of forages
Degradability (%)
I Forages
1
AtiiW
N
mm
NDFN-ADFN
%N
Acacia
35.1
26.7
0
0
Balanites
5.5
82.6
17.7
20.7
Cocksfoot
7.2
62.6
26.1
26.8
Alfalfa
8.0
75.8
43.4
51.7
.
.