Journal of American Science
2010;6(6)
Replacement Value of Urea Treated Corn with Cobs for
Concentrate Feed Mixture in Pregnant Ewes Rations
Hamad M.R; Safaa Nadi Abed-Elazeem ; A.M. Aiad; S . A. Mohamed; and N. A. M. Soliman.
Animal Production Research Institute. Agriculture Research Center Ministry of Agriculture, Dokki,Giza,Egypt.
Dr_mona_zaki@yahoo.co.uk
Abstract: Two trials were carried out to evaluate the effect of feeding urea treated corn with cobs (UCC) as 50%
(T2) or total replacement (T3) of pelleted concentrate feed mixture (CFM) compared to the conventional diets
(CFM) on its production and reproduction performance. Rice straw was offered separately from the concentrate.
Evaluation criteria included DM intake and utilization, ruminal fermentation characteristics, milk yield, birth,
weaning and marketing weight and feed efficiency. In the first trial, 27 Ossimi, ewes beginning 45 days before
expected day of lambing were assigned to the control, T2 and T3 diets. The milk was measured on day 14 post
partum and once every week up to the 12th week. The growth experimental periods were 137 day in duration using
15 weaned lambs. The selected lambs were allocated to the same three. In digestibility trial, 9 adult rams were
allocated to three tested diets. In vivo digestibility, nutrients digestibility were different among diets. Feeding values
(TDN) was greater for T3 followed by control diet whereas the highest DCP was recorded for T2. Feeding UCC had
no effect on ruminal parameter in terms of pH, NH3 and total FVA`s across the sampling time except for NH3-N.
The replacement of CFM by UCC resulted in insignificant higher (p≤0.05) lambs birth weight T3 (3.44 kg) but
lower milk yield T3 (436 g /day). The lower birth weight lambs control group (p ≤ 0.05) tended to grow faster and
perform higher weaning as compared to the treated group. In growth trail, feeding UCC diets reduced ADG
approximately 10% compared to control. The results indicated that DM, TDN and DCP needed produce 1 kg gain
almost 5 to 10% better than the corresponding items from T2 and T3. Replacement of CFM in pregnant and growing
lamps rations with UCC would be cost effective as cost UCC is only at 60% less than cost of CFM. [Journal of
American Science 2010;6(6):166-178]. (ISSN: 1545-1003).
Keyword: Sheep, feed, urea treated Corn-cobs, digestibility, nutritive value, growth, milk yield, performance.
sources of protein used extensively in Egypt to feed
ruminants and represent the most expensive
ingredients in ruminant rations. There are large
quantities of maize cobs which could be fed to
ruminants instead of being wasted. Collection of
maize cobs is easier than that of maize stalk which is
left in the field where the maize is harvested while
the cobs are gathered before dehusking and shelling.
In order to improve the low quality
byproducts the most pragmatic and UCCeptable is
chemical treatment. This treatment disrupts the cell
wall by solubilizing hemi cellulose, lignin and silica,
hydrolyzing uronic acid and acetic acid esters and
swelling cellulose (Jackson 1977). The use of urea or
ammonia to upgrade straws and other low quality has
been world wide spread in the last three decades.
Urea, the most commonly used an inexpensive NPN
source are an attractive protein replacement
compared with nowadays tremendously expensive
natural proteins (Oji` et al 2007) stated that fertilizer
grade urea can be used to improve the nutritional
value of maize residues for small ruminant feeding
during off season periods.
On the other hand, the relationship of birth
weight to weaning and weans weight to slaughter
weight is economically very important in lamb
1. Introduction
Sheep populations in Egypt are almost 5
million, (MOA 2005). During the last two decade the
importance of sheep production as a source of animal
protein in Egypt has been increased. Meanwhile, the
mutton price has also increased. In fact, the small
ruminants are mainly associated with small farmers.
Therefore there is need to research and develop stallfeeding systems for small ruminants based on crop
by-products.
In Egypt, maize for grain is planted on
approximately 1.68 million feddan producing 5.8
million metric tons averaged 3.47 ton per feddan).
Importation is 4.7 million tons. Almost 70% home
production whole-crop maize is utilized by ruminants
(MOA 2005). Cobs (as residues) were estimated to
about 1.7 million tones (represent 25% of ear corn).
A major
constraint facing livestock
development is the lack of adequate supplies of
feedstuffs at economic prices. Feeds represent the
greatest proportional cost in livestock production and
its availability is affected by seasonal variation in
feed quantity and quality which causes fluctuations in
animal nutrition and productivity throughout the year
in particular during the summer season. Moreover,
soybean meal and cottonseed meal are two important
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production and is affected by genetic, physiological
and feeding of ewes and fetal growth affect by
feeding her mother during pregnancy stage (Wu.G
2006 ).
The experiments reported here studied the
possibility of replacing concentrate feed mixture
(CFM) in diets of pregnant ewes and growing
lambs with ammonia treated corn with cobs.
ewe was calculated as the sum of milk produced on
each day of milking.
Digestibility trials:
The metabolism trial included 9, each lamb
was placed in a separate metabolism cage designed to
collect with a 2 wk adjustment period and a 7 days
collection period. Three rams were randomly
assigned to each of the same ration as in feeding trial.
Feeds offered, output of feces was recorded daily
during the last 7 days of the collection period. Fecal
trays were placed for total fecal collection during the
7 days collection period. Feed was offered twice
daily and water was refreshed at 0700 and 01500.
Fecal output was weighed, sub sampled (10% of wet
weight), and composted across 7days within lamb for
each period. Samples were stored frozen (– 20°C)
until dried in a forced-air oven for 48 h. The
collections were made concurrently with the meals.
Samples of feed were taken daily at 10% of the total
offered and the residues were collected. A subsample (20%) of feces was composed, kept each day
in plastic bags in the freezer (-20 °C) until the end of
the experiment. Feed ingredients and dried feces
were ground to pass a 1-mm screen in a hammer mill
before analysis. The following chemical analyses
were determined: dry matter (DM), Crude protein
(CP), Crude fiber (CF), Ether Extract (EE), Ash and
Nitrogen Free Extract (NFE) UCCording to AOAC
(1990). The feed offered to each ram during the
preliminary and collection period was set to 90% of
average feed intake during the second week of the
adjustment period. There were no feed refusals
during the 7-d collection period.
2. Material and Methods:
The present work conducted at sedes
Experimental Station and By-Product Utilization
Department , Animal Production Research Institute
(APRI) to study the effect of including urea treated
corn with cobs in small ruminant diets on
performance of Ossimi ewes (lactation and new born
lambs performance) and considering a simple
economical evaluation of urea treated corn with cobs
supplemented rations . Nutrients in the CFM, UCC
and RS were chemically measured before
formulating the experimental rations.
Ewes feeding trails:
Twenty seven pregnant Ossimi ewes were
selected 2-3 years old averaged 50.0 kg live body
weight (LBW) in the last six week of gestation. The
selected animals divided based on their live weight
into three similar groups 9 ewes each and randomly
allocated to diets of either control, T2 and T3.
Animals were group-housed and the diets were
offered in two portions at 8 am and 16 pm and had
free UCCess to water. Animals were weighed at the
beginning and at the end of the trial. The animals
were healthy during the experimental period.
Survival rate:
Live lambs per born lambs and live lambs per
ewe were determined after parturition and 30, 60 and
84 days after lambing.
Weaning weight:
The born lambs were weighed every two weeks
up to the 84th days of age.
Growth trial:
The growth of 15 weaned lambs 84 days old
was evaluated for 137days. The lambs were divided
into 3 equal groups five each group with initial body
weight 19.06, 18.87 and 19.18 kg given UCCess to
the tested diets for control, T2 and T3, respectively
similar to those used in ewes trial. Lambs were fed at
0700 and 01500 daily and the basal diet (CFM and
UCC) and RS were offered separately at each feeding
and were allowed free UCCess to lick mineral blocks
and water. Animal weights were recorded at the
beginning and in 15dayes interval throughout the 137
days growth period. To minimize variation due to
drinking, feeding, and defecation, lambs were
weighed full on the morning of the first day of the
experiment and every 15 days before morning
replenishment of feed.
Milk recording:
The 24-h milk production of each ewe was
measured on d 14 (2weeks post partum) and once
every week by hand milking throughout a 70-d of
lactation period at 7-d intervals. On the day of
parturition, ewes and lambs were weighed. Lambs
were weaned at 84 d of age and both the ewe and
lambs were weighed at this time. Milk production
was measured using procedures described Rusev and
lazarov,(1967) and Farage,(1979). UCCording to this
methods the ewes have been milked twice daily by
milking one teat while the lamb suckle the other one.
The morning and evening milked yield multiplied by
2 to calculate the daily output. The weight of the
collected milk was recorded and used to determine
24-h milk production. Total milk production for each
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The amount of feed provided for the lategestation and lactating ewes was based on the
guidelines put forth (APRI) to be applied y the
experimental stations and was determined for per
group based on BW measured biweekly. The
standard practice for the sheep flock at the Animal
production research institute to feed adult, no
lactating, no pregnant ewes in confinement a
maintenance ration of 2% of BW/d. During the ewes
and growth trials the basal levels were adjusted so
that diets were completely consumed each day; orts
consisted solely of straw.
Urea treatment was effective in upgrading the
nutritional value of corn with cobs. Treated corn with
cobs had higher (N x 6.25) 13.99% as compared
to7.59 to for untreated represent 85% increment.
Meantime, ether extract and ash content decreased
from 5.60 and 2.27 to 4.16 and 1.76% respectively
(Table 1). The moisture content of the treated corn
with cobs upon opening the stack was approximately
27% reduced to 14.85% after exposing to air for 24
hrs.
The formulated tested diets were isonitrogenous
(almost 10% CP) containing 0.00, 16.86 and 32.4
gram nitrogen (NPN) originated from urea treated
corn with cobs for control, T2 and T3, respectively.
These values represent 19.2 and 38.5% for the total
nitrogen for T2 and T3, respectively.
Rumen fluid:
Approximately 15 ml of ruminal fluid was
collected using ruminal tube, and pH was measured
immediately using a portable pH meter. Ruminal
fluid samples representing 0, 3 and 6 h after feeding.
Ruminal parameter (pH, ammonia nitrogen and
VFA's)
Ruminal kinetics (pH, Ammonia nitrogen and VFA's)
were determined using liquor collected by rumen
tube via esophagus three times before morning
feeding (zero time, 3 and 6 hrs after feeding)
This ruminal fluid sample (15 ml) was acidified with
1.0 ml of 6 N H2SO4 and frozen (-10°C) ; this
sample was later thawed at room temperature,
centrifuged at 10,000 x g for 10 min, and a portion of
the supernatant was analyzed for NH3- N UCCording
to Broderick and Kang (1980). The resulting NH3
concentrations were converted to NH3 - N. for
statistical analysis, and NH3 - N concentrations are
reported in. Total VFA's concentrations were
determined using.
The data were statistically analyzed using
GLM produces of SAS (1990). Duncan's test (1955)
was applied in experiment whenever to test
differences.
Digestibility trial
Data presented in (Table 2) revealed that the
intake from the concentrate (CFM and / or UCC) for
T2 and T3 during the digestibility trial was 3 and 7%
lower as compared to the control ration. Also, there
was tendency for straw intake to decrease (20 and
27%) by feeding 50% and 100% urea treated corn
with cobs, respectively. These together resulted in 10
and 15% decrease in the total dry matter intake for
T2 and T3, respectively. There was slight difference
(3 and 6% lower for T2 and T3, respectively as
compared to control) regarding the DMI of straw
among the three groups. The fecal nitrogen excretion
was 6.2, 6.8 and 5.3 g/d/h represent 38, 44 and 39%
from the N intake for control, T2 and T3,
respectively. The almost similar percentage of
digested N retained (as percentage of intake) for
control and 100% UCC group revealed that NPN
urea source has no effect N efficiency.
The apparent digestibility coefficients are
presented in (Table 2). Highest DM and OM
digestibility (69.67 and 71.96%) were recorded for
the control ration being 9% and 6% and 7 and 3%
higher than T2 and T3, respectively. Crude protein
exhibited almost similar digestibility for control and
100%UCC diet (61.42 and 60.60%, respectively)
being 8% lower than 50% UCC group. The
digestibility for crude fiber ranged between 69.94%
(control) and 53.05 for T3. The CF in control diet
was highly digestible (16 and 32%) than T2 and T3,
respectively. control group. The EE digestibility for
T3 was 9 and 5% higher than the values recorded for
T1 and T2, respectively. The values for NFE showed
similar coefficients for control and T3 diets being 7%
higher than T2.
The following model was used:
Yij = μ + Ti + eij
Where : Yij = observed trait,
μ = overall mean,
Ti = effect of treatment,
eij = random error.
3. Results
Chemical Composition
The analyzed composition of dietary
ingredients is reported in Table (1). The concentrate
feed mixture (CFM) contained 87.11 OM, 14.04%
CP, 18.95% CF, and 2.46.0% EE (DM basis).
Treated Corn with cobs averaged 98.24%OM,
13.99% CP, 17.10% CF and 4.16% EE, and rice
straw 81.5% OM, 3.92% CP, 35.24% CF and 0.46%
EE on DM basis.
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Table (1): Chemical composition of experimental concentrate feed mixture, rice straw, urea treated corn cobs
with corn cobs
DM composition
Item
Moisture
%
OM
CP
CF
EE
NFE
Ash
Concentrate feed mixture
8.45
87.11
14.04
18.95
2.46
51.66
12.89
CFM
Rice straw RS
7.85
81.50
3.92
35.24
0.46
41.88
18.50
Urea treated corn cobs UCC
14.85
98.24
13.99
7.71
4.16
72.38
1.76
Corn cobs CC
9.75
97.73
7.59
7.70
5.60
76.84
2.27
CFM : 26%, undecortecated cotton seed meal , 44% wheat bran, 19% yellow corn, 5% rice bran, 1% salt
mixture, 2% lime stone and 3% molasses.
Table (2): Dry matter intake, nutrient digestibility and nutritive values of different experimental diets.
Item
Experimental Diets
T2
T3
50 %UCC
100%UCC
39.51
38.18
0.458
---0.426
0.852
0. 507
0.461
1.391
1.313
T1
Animal weight , kg
40.50
CFM
0.916
UCC
-----RS
0. 627
Total DMI kg /head /day
1.543
Nutrient Digestibility %
DM
69.76 a
63.72 b
65.92 b
OM
71.96
67.23
69.88
CP
61.41 b
66.09 a
60.60 b
CF
69.94 a
60.28 b
53.05 c
b
b
EE
77.46
79..90
85.10 a
NFE
75.06
69.93
76.37
Nutrient Values
TDN
62.78
60.81
64.92
DCP
6.12
6.46
5.80
TDN intake g/h/day
968
846
852
DCP intake g/h/day
94 a
90 a
76 b
a , b, c
Means in the some row having different superscripts are significantly different at, (p< 0.05).
±4.90
…..
……
±2.42
±1.26
±0.61
±0.68
±0.39
±1.42
±1.26
±1.21
± 0.25
±0.22
±2.44
±0.03
ammonia concentration compare to the treated group.
Statistically, the differences were significant (P <
0.05) at 6 h.
Total VFA concentration in ruminal fluid
(Table 3) was lower in the control ration at zero time
being 6.07 as compared to T2 and T3 (7.26 and 7.34
respectively). Meanwhile, it tended to be greater up
to 11.3 at 6h after feeding as compared to 10.7 and
10.80 for T2 and T3, respectively.
Statistically, neither pH nor total VFA concentration
significantly differed among diets while ammonia
concentration only displayed a weak tendency
towards reduction with the 50% UCC (T2) diet.
Rumen fluid parameter:
Rumen pH values at zero time ranged between
7.42 and 7.43 (Table 3)and tended to slightly increase
3h after feeding to7.5, 7.7 and rose by 6 h to 7.9, 8.0
and 8.0 for T1, T2 and T3, respectively. This result
revealed that the rumen pH values are not affected by
the source of nitrogen.
Ruminal ammonia concentration was 16.4, 13.6
and 15 (mg/100 ml) for control, T2 and T3 at zero
time tended to increase up to 22.9, 23.5 and 23.6 at 3
hrs after feeding (Table 3). At 6 hrs after feeding the
concentration showed remarkable decrease up to
13.3, 9.5 and 11.5 for control, T2 and T3,
respectively. The control group presented higher
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±SE
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Table (3): Rumen fluid parameter of lambs fed the experimental diets
Item
pH
Experimental Diets
T2
50 %UCC
T1
CFM
±SE
T3
100 %UCC
hrs
Overall mean
NH3-N(mg/dl)
0
3
6
7.42
7.54
7.92
7.63
7.43
7.68
8.04
7.72
7.42
7.70
7.99
7.70
±0.06
±0.07
±0.05
±0.11
0
3
6
16.36 a
22.87
13.27a
17.50
13.58 b
23.53
9.53b
15.55
14.95 a
23.64
11.50a
16.70
±1.10
±0.20
±0.49
±1.11
hrs
Overall mean
VFA`s (meq / dl )
hrs
0
3
6
6.07
7.26
7.34
10.25
8.91
9.70
11.30
10.70
10.80
Overall mean
9.21
8.96
9.34
a , b, c
Means in the some row having different superscripts are significantly different at (P< 0.05).
±0.75
±0.65
±0.12
±0.42
group (968 g/h/d) was approximately 15% higher
than the T2 and T3 groups, respectively.
Corresponding values for DCP intake (94.4 g/h/d)
was 5 and 24% higher for control group than T2
(89.9 g/h/d) and T3 76.2 g/h/d).
Ewes feeding trial and milk yield:
Data presented in (Table 4) showed that
intake from control ration and T2 were almost similar
being 720 and 702 concentrate and 480 and 470g rice
straw, respectively. The T3 ration presented much
lower intake 677 and 451g concentrate and rice
straw, respectively.
The calculated feeding values in terms of TDN
and DCP resulted for the digestibility trial (Table 2)
showed that feeding 100% UCC plus RS increased
TDN content (64.90) by 3 and 7% compared with
the control (62.78) and T2 (60.81), respectively. On
the other hand, DCP for the same diet (5.80) was 5
and 10% lower than T1 and T2, respectively.
However, feed intakes for the selected late pregnant
ewes were in the range 3 and 3.2% of body weight
indicating that the diets were palatable.
UCCording to the feeding values (in terms of
TDN and DCP) of the tested diets extracted from the
digestibility trial (Table2), the TDN intake for control
Milk yield:
Over the 70 - d lactation (begin from the third
week post partum) , average estimated (7 days
interval) milk production for the nine selected ewes
rearing single lambs (Table 4) was 527, 497 and 436
g/h/d, for the control, T2 and T3, respectively.
The differences between control group and 50% UCC
group were reduced by mid and late lactation. In fact,
average estimated milk production in the first month
of lactation for control group was slightly (almost
5%) higher than the other two tested groups. The
level of milk production was declining and continued
to decline after d 49.
Table (4): Ewes feeding and milk yield
Item
Experimental groups
T2
T3
50 %UCC
100 %UCC
T1
CFM
Ewes feeding g / h / d :
Concentrate
720
702
677
Rice straw ( RS )
480
470
451
Total dry matter intake (DMI)
1200
1172
1128
Average milk yield g/h /d
527
497
436
a, b,c
Means in the some row having different superscripts are significantly different at (p< 0.05).
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14.69
16.36
14.17
3.20
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study (Table 5) lambs mortality rates for T1, T2 and
T3 were 18.2, 0.0 and 11.1 % for the first stage,
respectively, being nil for the other stages for the
three groups.
Survival rates
Lambs survival rates normally derived from the
number of lambs/ewe present at 4 stages: born alive,
30 days after birth, from 30 up to 60 and end weaning
(84 day). UCCording to the results obtained in this
Table (5): Effect of feeding the experimental diets on lambs survival rate %.
Experimental groups
Item
T1
T2
T3
CFM
50 %UCC
100 %UCC
At first day
81-------82
100.00
88--------89
Form day 1 up to 30
81------82
100.00
88-------89
Form day 30 up to 60
81------82
100.00
88--------89
Form day 60 up to 90
81-----82
100.00
88-------89
Lambs survived at weaning per 100.00 ewes
100.00
111.1
88-------89
±SE
-----------------------------------
and treatment groups T2 and T3 were found to be
172, 164 and 156 g, respectively. However, the
differences were not significant.
Respective to the effect of sex on birth weight and
daily gain up to weaning, regardless from the
different treatments, born male lambs showed higher
average birth weight for the three groups (3.80 kg)
and lower average daily gain 156.04g/h as compared
to female born lambs 3.08 kg and 155.8g/h,
respectively).
Growth trial - Lambs performance
Weaning period
Although lambs born from ewes fed on the
control ration were significantly light in weight (2.48
kg/h) than those on tested rations (3.17 and 3.44 kg /h
for T2 and T3, respectively) , it tended to grow faster
than those suckled from ewes fed on T2 and T3
rations and had higher daily gain and weaning body
weight of 18.13kg compared to 18.08 and 17.63kg
for T2 and T3 (Table 6). Mean daily live weight gain
(from birth up to weaning, 84 days) for the control
Table (6): Average total weight gain for male and female lambs and some reproductive performance of ewes.
Experimental groups
Item
(T1) CFM
(T2) 50 %UCC
(T3) 100 %UCC
♀
♂
♀
♂
♀
Birth weight
BW kg
2.48
3.77
2.58
3.80
3.08
Average (M and F)
2.44
3.18
3.44
Weaning weight
WW kg
18.25
18.00
20.25
15.92
18.00
17.25
Average (M and F)
18.3
18.1
17.6
Total gain
TG kg
15.78
15.52
16.48
13.33
14.20
14.18
Average (M and F)
15.65
14.91
14.19
Average daily gain
ADG gm
173.41
170.55
181.10
146.48
156.04
155.82
Average (M and F)
171.98
163.79
155.93
No .of ewes / treat .
9
9
9
No. of lambs born / teat.
11.00
10.00
9.00
Average litter size / ewe
1.22
1.11
1.00
Average of lambs birth weight, kg
2.24
3.12
3.16
Average litter weight, kg
2.73
3.46
3.16
weaning period = 84 days
BW = birth weight WW = weaning weight
TG = total gain
♂
2.48
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T2 and T3 consuming 5% DM higher than the control
(5.82, 6.20 and 6.1 Kg DMI/ 1Kg gain, respectively).
The TDN conversion rate comparable for control and
T2 groups being slightly better than T3 representing
3.7, 3.8 and 4.0 Kg TDN per kg gain weight. The
conversion rate for DCP was similar for control and
T3 being 11% lower than T2 in terms of kg gain /kg
DCP intake. The DCP amount needed for 1kg gain
for T2 was 356, 401 and 353 g/ kg gain for control,
T2 and T3, respectively. However, the different were
in significant among rations (Table 7).
Providing that the production cost are similar
except the feed cost changed UCCording to variation
in the price of its components, therefore the
economical efficiency well calculated from the input
(feeding cost) and output (gain per unit feed). The
calculated feeding cost based on the price of CFM,
UCC and Rice straw (year 2003) were in average of
0.473, 0.391 and 0.313 per head daily for control, T2
and T3, respectively. UCCordingly, the cost (of feed)
for producing 1 Kg gain was in average of 3.02, 2.76
and 2.26 LE/h/d for control, T2 and T3, respectively.
The calculated decrease in feed cost / kg gain relative
to the control was 9 (50% AAC) and 33% (100%
UCC).
Growth period
All weaned lambs used in the growth trial were
fed almost at 3.0% of BW throughout the trial and the
quantity of feed refusals (data not shown) was very
minimal and did not differ among treatments.
Feeding cost based on*
per ton
CFM
900 LE
CC
500 LE
RS
100 LE
Urea treatment
50LE
For the period from weaning up to the end of
growth period (137 d), the lambs fed the control
ration consumed more concentrates and rice straw
than those fed on treated groups. The data presented
in (Table 7) showed that the rice straw and the basal
diet (CFM and/or UCC) was for control group almost
3 and 8% higher than T2 (50%UCC) and T3 (100%
UCC). Organic matter intake did not differ among the
groups ranged between 772.5 and 776 g/h/d, whereas
CPI varied between 84.0 and 87.8 g/h/d across
treatments (Table 6).
The CP intake ranged between 90g/h/d (control) and
84g/h/d for T3. Because of their numerically higher
DMI of CFM as well RS for control group, lambs
consumed a greater quantity of crude fiber (231.8
compare to 194.5 and 158.0g/h/d for T2 and T3,
respectively. These figures represent 15 and 33%
higher for control than T2 and T3, respectively.
Ether extract intake for the all urea treated ear corn
group (T3) was 60 and 24% higher than control and
T2, respectively. It could be observed from the
recorded DMI figures that there was a tendency for
straw DM intake to decrease as UCC in the diet
increased. However, the concentrates in three tested
diets represent almost 60% of the total dry matter
intake.
Feeding the tested weaned lambs on the
experimental rations for 137days resulted in slight
differences in ADG between the control (9 and 12%)
higher than T2 and T3, respectively. Based on initial
and final BW of the tested animals (Table 7) during
the 137 days growth period, the average daily gain
was 156., 142 and 139 g/d/h. for control and 50% and
100% UCC groups, respectively.
The weaned lambs light in weight in
particular those fed on control and 100% UCC diet
exhibited higher growth rate than the heavier lambs.
The lambs over 20kg weaning weight in the three
tested groups were the lowest ADG across the growth
period as compared to those less than 20 kg fed the
same diets. It seems that the low weaning weight
lambs have the capacity to grow at rates at least
approaching, if not equivalent to, the high weaned
weight during the growth period.
Feed efficiency ratio in terms of (Kg of DM
intake need to produce 1 kg gain was comparable for
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4. Discussions
Using urea as an agent to improve the
nutritional value of low quality by products still
considered as the most favorable up till now. Oji et
al, (2007) stated that feed grade urea or the
equivalent weight of fertilizer grade urea can be used
to improve the nutritional value of chopped cobs
(approximately 1 cm length) in terms of N, DM,
NDF, ADF and OM for small ruminant feeding
during off season periods. Moreover, Koster et al,
(2002) concluded that, urea could replace between 20
and 40% of the degradable intake protein (drawn
from values presented by NRC 1996).Also, Sahoo et
al, (2002) reported that treatment with urea (storage
time 21 days) improve the nutritive values as
compared to urea supplementation just prior to
feeding. Concerning the treatment period and
moisture level, it was found that at least two weeks
and 25-45% moisture level is sufficient for maximum
response during summer months (Hadjipanayiotou
and Economides1997 and Lines et al,( 1996). The
authors added that covered urea treated straw (UTS)
is superior to non-covered, and UTS is also superior
to urea-spraying prior to feeding. Lines et al, (1996)
added that most of the changes caused by
ammoniation were completed by 21 d after
ammoniation. In this study, the stack opened was
open after 28 days after treatment.
Increase the nitrogen content in urea treated
corn and cobs by almost 185%. Wanapat et al.,
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2010;6(6)
(1985) reported significantly increased up to 7-fold
by urine and urea treatments. It could be due to the
lower nitrogen content in the treated material.
The tendency, in this study, for rice straw and
concentrate) to decrease by feeding 100% UCC and
hence total DM, OM, and N intake decreased was
similar to the results observed by Matejovsky and
Sanson (1995) using ear corn as basic diets. The
decrease of DMI and CP digestibility for T3 could be
due increasing energy (T3) without adequate protein
availability which was associated with depressed
intake and digestibility (Del Curto et al, 1990).
reported upgrading of straw by ammoniation.
Treatment of straw with 3% NH3 improved
digestibility and energy value, the contents of crude
protein (CP) and digestible crude proteins (DCP) by
withers. Also, Zinn et al, (2000) found that total tract
OM digestion was slightly greater for diets
containing 20% of N as NPN (partial replacement of
fish meal). Moreover, the tendency for CP
digestibility for urea treated corn and cobs (as source
of NPN) to be greater for T2 has been reported by
Bohnert et al, (2002a)
The lower DMD of the T2 and T3 could be
due, as explained by Tuah ¹ and Ørskov (1989), to
that with the cobs, most of the material was cell wall
while the cell content was about 6.04 and the
hemicellulose very high (46.4%). They stated that
the cellulose and the hemicellulose of the maize cobs
may therefore not be made readily available for
microbial degradation, thus decreasing its DMD and
DCF values.
The lower DMI for T2 and T3 (in particular
during digestibility trial) should be taken in UCCount
when comparing the tested diets since intake has
great effect on digestibility (Tyrrel and Moe 1975).
UCCording to Kauffmann et al (1980) and Hoover
WH, (1986) and Galina et al., (2007) who stated that
major factor appears to be responsible for the
decrease in fiber digestion are the rumen pH.
Moderate depression in pH, to approximately 6.0,
results in a small decrease in fiber digestion and
considered as the lowest limit to adequate activity of
the celullolitic bacteria.
The lack of an effect of NPN source on fecal N
excretion agrees with other research using urea as CP
supplements to low-quality forage (Coleman and
Wyatt, 1982; Bohnert et al., 2002b). Joy et al., (1992)
and Hammadi (2007) observed that increasing urea
dosages up to 8 % DM basis and different levels of
moisture content (up to 40%) increased total N
content as well as a significant effect on the DOM in
low quality roughages and improvements in ADG
and gain/feed (Brown et al., (1995)
The higher CP digestibility for T2 (50%
UCC) compared with other two groups could be due
to the associated effect the two sources of nitrogen
(soybean in the CFM and urea in the treated corn and
cobs. Ammerman et al. (1972), observed an increase
in N balance and digested N retained (expressed as a
percentage of N intake) in wethers consuming lowquality forage (2.6% CP) and supplemented with urea
and soybean meal (50:50 N basis), or biuret and
soybean meal (50:50 N basis) compared with withers
receiving just forage.
The relative lower CP digestibility for T3 (100%
UCC) have been explained by Oltjen et al, 1969;
Ammerman et al, 1972; Bohnert et al, 2002b. The
Ration formulation
Forage to concentrate ratio
The diets used in this study generally have
about 60% concentrates during 137 d growth period.
It should be mentioned that the forage concentrate
ratio does not take into consideration the quality of
the forage, particle size of the forage, the type and
processing of the cereal grains, and the concentration
of non forage fiber sources in the diet to affect
dietary starch concentration as the case in using corn
and cobs in the study.
Ludden and Cecava (1995) formulate diets
contained 12.5% CP using cracked corn (70%),
ground corn cobs (15%), and different source of
protein supplement (included urea). The results
suggest that corn-based diets may be limiting in
ruminally degradable N, especially when high
ruminal escape protein sources are fed as
supplemental
CP.
The digestibility data concerning the fibrous portion
tended to decrease as the proportions of CF content
decreased as described by Woodford et al (1986).
The lower DM and CF digestibility observed
in this study for 50% and 100% UCC was reported
by Sanson et al. (1990). The authors stated that
reported a decrease in DM and hemicelluloses
digestibility as dietary level of corn increased from
0.26 to 0.52% of BW in steers consuming lowquality meadow hay.
Feeding urea as protein supplement to starchbased energy diet (corn) has been shown to cause
depressions in forage intake as well as negative
associative effects on dry matter and fiber
digestibility (Chase and Hibberd, 1987; Pordomingo
et al, 1991 and
Matejovsky and Sanson
(1995).Similar DMD for T2 and T3 (Table 2) was
found by Nelson et al (1984) . The authors used
maize cobs containing 40% moisture reported 61.30,
61.69 and 65.94% DMD for 2, 3 and 4% ammonia
treatment, respectively.
Contrary to the negative effect of ammoniation
on nutritive digestibility mentioned previously,
Cottyn and De Boever (1988) and Genin et al, (2007)
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2010;6(6)
authors stated that NPN source did not affect N
balance or digested N retained suggest that urea or
biuret can be effectively used as a source of
supplemental N by ruminants consuming low-quality
forage 7% CP.
and forage decreased ruminal pH below 6.0 and
reduce the activity of cellulolytic bacteria which
could reduce forage fiber digestibility. In this study,
although the T3 (100% UCC) diet has been
formulated from corn and cobs and rice straw, the
ruminal pH was comparable to the other tested diets
averaged 7.7compared to 7.6and 7.7 for the control
and T2. Therefore, the lack of effect of feeding corn
on ruminal pH could be due urea treatment.
Weaning and growth period
The effect urea treatment on lamb birth
weight and on ADG during weaning and growth
periods observed in this study are matched with the
results of Koster et al, (2002). The authors
concluded that Prepartum urea treatment did not
affect pregnancy rate, calf birth weight, or
ADG.Rapid Concerning the rapid growth of the
lower birth weight born lambs for control group in
this work (Table 6), Greenwood et al., (2002)
concluded that low-birth-weight lambs are less
mature than their high-birth-weight counterparts in
some aspects of endocrine and metabolic
development at birth which may enhance their
capacity to utilize amino acids for energy production
and to support gluconeogenesis during the immediate
postpartum period. The authors added that under
appropriate environmental and nutritional conditions,
vital life support systems can mature sufficiently to
allow extremely low birth weight lambs to survive
and achieve growth.
Meanwhile, Sidwell et al, (1964) reported
positive correlation between birth and weaning
weights which contradict the results of this study.
Also, Greenwood et al., (1998) stated that average
daily gain tended to be greater in the high- than in the
low birth-weight lambs given ad libitum UCCess to
feed.
However, differences in weaning weight due to
breed, sex, month of birth and litter size were
reported by Bodisco et al (1973) and Gonzalez
(1972). On other hand, Bodisco et al (1973) reported
differences due to year and litter size but not to sex.
Refer to the results presented in Table (6); sex of
born lambs gave insignificant differences for both
birth and weaning weight.
The higher ADG of male born lambs compared
the female was in UCCordance with the finding of
Yilmaz (2007) who reported that at birth, 90 and 180
days of age, ram lambs were heavier than ewe lambs.
Zinn et al., (2000) reported that overall, ADG was
17% greater for cattle consuming diets containing 20
vs 40% NPN. Overall, gain efficiency was 6%
greater for diets containing 20% NPN.
Ammonia- N
The concentration of ruminal NH3-N seems to
be adequate and maintained fermentation of diets in
this experiment, as long VFA concentrations was
within the optimal range of 2.0 to 5.0 mg/dL ruminal
NH3- N as suggested by Satter and Slyter (1974) to
maintain microbial growth.
The statement of Ludden and Cecava (1995)
could explain the CF digestibility by the treated
groups. The author consider a 3.6 mg/dL for urea as
supplemental protein sources for steers fed cornbased diets as evidence for possible shortage of
ruminally degradable N, in the present work the
rminal ammonia was far below this concentration.
The lack of effect feeding urea treated corn and cobs
on ruminal ammonia nitrogen as compared to the
control has been documented by Lines and Weiss
(1996) who stated that cows fed the urea diet had
higher concentrations of ruminal NH3 than did cows
fed urea treated hay.
TFVA΄S
The higher total VFA concentration for control
ration at 3 and 6 hrs after feeding could be a result of
a greater supply of fermentable material that have
been made available than the other tested rations.
Breeding and lambing season:
UCCording to the breeding plan in Sids
experimental station, the ewes averaged three
lambings over two years. It was originally decided to
synchronize breeding to takes place in January, Mai
and September so lambing would occur in June,
October and February , respectively and hence births
group between October and February when there is
green
forage (berseem) provide sufficient
nourishment for the ewes to have enough milk and
for their lambs to develop normally. Births group
between June and July when feed availability is low,
reducing the chances of lamb survival (mortality rates
are as high as 25%). Weaning percentages are low
(under 70%). On the other hand, it should be taken in
UCCount that the conception rate for ewes bred in
January are higher than in Mai and September.
Lambing in October could be early that the lambs
may be born before the Berseem could provide
sufficient nourishment for the ewes to have enough
Rumen parameter
pH value
Ruminal fluid pH was not affected by dietary
treatment and averaged 7.6 across treatments. It has
been reported (Ørskov 1992) that feeding grain (corn)
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2010;6(6)
milk and for their lambs to develop normally.
However, considering lambing percentages and lamb
survival and growth, breeding in March-April and
August-September is preferable. Breeding takes place
throughout the year, most breeding is linked with the
highly seasonal availability of Berseem.
especially during months of elevated environmental
temperatures (Eastridge 2006).
The effectiveness of ammonia in inactivating
aflatoxins in contaminated livestock feed stuffs has
been investigated by several authors brekke (1977),
Grove (1984), Fremy (1988), Bailey et. al., (1994),
Hoogenboom et. al., (2001) The authors stated that
ammoniation of contaminated ingredients of
livestock feed resulted in efficient reduction of
aflatoxin levels and abolished the detectable transfer
of AFM1 or AFB1 into milk, and greatly reduced the
carcinogenic risk posed by any carry-over of
aflatoxins or their derivatives into milk. which most
likely caused by a decreased bioavailability of the
degradation products.
Further work is required to investigate other
sources that could enhance the nutritive value of the
residues in order to stimulate intake and production.
Feeding Ossimi ewes on UCC around parturition
during the summer season did not seem to enhance
ewe or lamb production traits but the feed costs for
lactating ewes and growing lambs can be minimized.
Strategic timing of feeding urea treated by products
for Ossimi sheep ewes may provide a method for
increasing the weight of lambs weaned during
periods of limited green forage availability.
Whether ammoniation of the by products is
economical depends on relative costs of anhydrous
NH3 , Urea and alternative feedstuffs, such as cereal
grains. However, this system is only UCCeptable if
the value of the response is higher than associated
costs of processing and treatment. However, the use
of urea is up till today is feasible.
There was little difference in average daily gain
or feed efficiency between lambs fed the rations
based on CFM and those included UCC but reduced
feed cost per kg of weight gain by 15% (50% UCC)
or 35% (100% UCC), suggesting that a crude protein
level near 14% based on UCC would be optimal for
25 - 40kg growing Ossimi lambs. Replacement of
CFM in pregnant and growing lams rations with
UCC would be cost effective as cost UCC is only at
60% less than cost of CFM.
Moreover from feeding management such
ruminant exposed once to urea treated any feed stuff
performed better when exposed later on to treated
feed stuffs. As stated by Wiedmeier et al, (2002).
Thus, managers should consider previous exposure to
treated material (in particular the low quality) when
considering applying this technology to reduce food
costs.
Survival rate
UCCording to Dwyer and Morgan (2006),
the worldwide rate of mortality in newborn lambs is
in excess of 15% of lambs born and represents a
challenge to sheep production and welfare. Dwyer
and Morgan (2006) added that especially in prolific
ewes the mortality rates are high in lambs with low
birth weights and that after birth the absolute growth
rates are lower in the surviving light lambs than in
the heavier lambs. However, in this study low birth
weight lambs exhibit faster growth than the heavier
born lambs.
Milk production
Respective the effect of ammoniation on the
milk production, it was found that feeding lactating
cows tended to gain more weight and produce more
milk when fed dehydrated alfalfa meal than did than
did cows supplemented ammonia treated corn cobs or
soybean
(Rock.
et
al.,1991).
However,
Hadjipanayiotou et al, (1993) found that feeding
Awassi ewes on urea treated straw (AS) diet
produced significantly less milk than those on the
control diet (AS, 432 vs 462 g milk/ewe/day).
Meanwhile, Lines and Weiss (1996) stated that use
diverse sources of dietary N (ammoniation, urea,
soybean meal, or a commercial blend of animal
protein meals) did not greatly influence N utilization
by dairy cows.
Conclusion
Urea treatment improved the nutritive value
of corn with cobs and made it at least equivalent to
CFM respective CP content (14%) and when offered
alone proved better efficiency compared to the
control and the 50% UCC. The increased milk
production of the ewes given CFM, before and
during, lactation was limited in but type of feeding
had an effect on the birth weight and weaning weight
of lambs born and raised by these ewes.
In addition, treatment at the time of ensiling
high-moisture grains may decrease mold growth and
DM losses, especially in grains with less than 80%
DM. Reducing particle size of these grains prior to
ammoniation is important in UCCelerating anaerobic
fermentation and improving feed stability during
storage and may increase aerobic stability of these
high-moisture grains at the time of feeding,
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References
1. Ammerman, C. B., G. L. Verde, J. E. Moore,
W. C. Burns, and C. F. Chicco. (1972). Burette,
urea and natural proteins as nitrogen
175
editor@americanscience.org
Journal of American Science
2010;6(6)
supplements for low-quality roughage for sheep.
A.O.A.C.(1990). Official Methods of analysis
of the association of official agricultural
chemists Wash., D.C., USA.
3. Bailey GS, Price RL, Park DL, Hendricks JD
(1994). Effect of ammoniation of aflatoxins B1contaminated cottonseed feedstock on the
alfatoxin M1 content of cows milk and
hepatocarcinogenicity in the trout bioassay.
Food Chem. Toxicol. 1994 Aug; 32(8):707-15.
4. Bohnert,D.W.C.S.Schauer
and
T.DelCurto(2002). Influence of rumen protein
degradability and supplementation frequency on
performance and nitrogen use in ruminants
consuming
low-quality forage : cow
performance and efficiency of nitrogen use in
wethers Journal of Animal Science, Vol 80,
Issue 6 1629-1637, Copyright © 2002 by
American Society of Animal Science .
5. Bohnert, D.W.,C.S. Schauer, M. L. Bauer, and
T. DelCurto. (2002 a). Influence of rumen
protein degradability and supplementation
frequency on steers consuming low-quality
forage: I. Site of digestion and microbial
efficiency.J.Anim.Sci.80:2967–
2977.[Abstract/Free Full Text]
6. Bohnert, D. W., C. S. Schauer, S. J. Falck, and
T. DelCurto. (2002c). Influence of rumen
protein degradability and supplementation
frequency on steers consuming low-quality
forage: II. Ruminal fermentation characteristics.
J.
Anim.
Sci.
80:2978–2988.[
Abstract/Free Full Text].
7. Brekke OL, Sinnhuber RO, Peplinski AJ, Wales
JH, Putnam GB, Lee DJ, Ciegler A. (1977).
Aflatoxin in corn: ammonia inactivation and
bioassay with rainbow trout. Appl Environ
Microbial. Jul; 34(1)34-7.
8. Broderick, G. A., and J. H. Kang (1980).
Automated simultaneous determination of
ammonia and total amino acids n ruminal fluid
and n vitro media. J. Dairy Sc. 63:64-75.
(Medline)
9. Brown W. F., and M. B. Adjei (1995) .Urea
ammoniation effects on the feeding value of
guineagrass (Panicum maximum) hay. Journal
of Animal Science, Vol 73, Issue 10 3085-3093.
10. Chase. C.C. Jrand A.C. Hibber (1987).
Utilization of low quality native grass by Beef
cows increasing quantity of corn grain.
11. Coleman, S. W., and R. D.Wyatt (1982).
Cottonseed meal or small grain forages as
protein supplements fed at different intervals to
cattle. J. Anim. Sci. 55:11–17.
J. Anim. Sci. 35:121–127.
12. Cottyn B.G.and De Boever J.L(1988).
Upgrading of straw by ammoniation. Animal
feed Science and Technology 21:287-294.
13. Del Curto, T. R. C. Cochran, D. L. Harmon, A.
A. Beharka, K. A.Jacques, G. Towne and E. S.
Vanzant (1990). Supplementation of dormant
tallgrass-prairie forage: I. Influence of varying
supplemental protein and(or) energy levels on
forage utilization characteristics of beef steers in
confinement Journal of Animal Science, Vol 68,
Issue 2 515-531, Copyright © 1990 by
American Society of Animal Science .
14. Dwyer ,C. M., and C. A. Morgan (2006). the
worldwide rate of mortality in newborn lambs is
in excess of 15% of lambs born and represents a
challenge to sheep production and welfare.
Freetly2 H. C. and K. A. Leymaster J. Anim.
Sci. 2004. 82:612-618© 2004 .
15. Eastridge M. L. 2006. (Major Advances in
Applied Dairy Cattle Nutrition). J. Dairy Sci.,
89:1311-1323.
16. Farage, M. A. A. M. (1979). Milk production
from local breeds of sheep. MSC. Theses,
Animal Production department faculty of
Agriculture, Zagazig Univ.
17. Fremy JM, Gautier JP, Herry MP, Terrier C,
Calet C.(1988). Effect of ammoniation on the
carry-over of aflatoxins into bovine milk. Food
Addit Contam. Jan; 5(1):39-44. Effect of
ammoniation on the carry-over of aflatoxins into
bovine milk. Food Addit Contam. Jan; 5(1):3944.
18. Galina M.A. M. Guerreroa and C.D. Puga
(2007). Fattening Pelibuey lambs with sugar
cane tops and corn complemented with or
without slow intake urea supplement Small
Ruminant Research Volume 70, Issues 2-3,
July, Pages 101-109.
19. Greenwood P. L. 3,4, A. S. Hunt5, R. M.
Slepetis, K. D. Finnerty, C. Alston6, D. H.
Beermann7 and A. W. Bell8 (2002). Effects of
birth weight and postnatal nutrition on neonatal
sheep:
III.
Regulation
of
energy
metabolism1,2.J.Anim.Sci.80:2850-2861.
20. Greenwood,P.L., A. S. Hunt, J.W. Hermanson
and A. W. Bell (1998). Effects of birth weight
and postnatal nutrition on neonatal sheep: I.
Body growth and composition, and some
aspects of energetic efficiency. Journal of
Animal Science, Vol 76, Issue 9 2354-2367.
21. Grove MD, Plattner RD, Peterson RE. (1984).
Detection of alfatoxin D1 urea treated corn by
mass spectrometry-mass spectrometry. Appl.
Environ. Microbiol. Oct; 48(4):887-9.
2.
http://www.americanscience.org
176
editor@americanscience.org
Journal of American Science
2010;6(6)
22. Hadjipanayiotou M., L. Verhaeghe, A. R.
Kronfoleh, L. M. Labban, A Shurbaji, M. Amin,
A.R Merawi, A. K. Harress, M. Houssein, G.
Malki and M. Dassouki (1993). Feeding urea
treated straw to cattle and sheep in Syria
Development Volume.
23. Hadjipanayiotou, M. and S. Economides (1997).
Assessment of various treatment conditions
affecting the ammoniation of long straw by
urea.Livestock
Research
for
Rural
Development, Volume 9, Number 5.
24. Hoogenboom LA, Tulliez J, Gautier Jp, Coker
RD, Melcion JP, Nagler MJ, Polman TH,
Delort-Laval J. (2001). Absorption, distribution
Addit Contam. Jan; 18(1):47-58.
25. Hoover W H (1986) Chemical factor involved
in ruminal fiber digestion. Journal of Dairy
Science 69:2755-2766.
26. Jackson, M. G. 1977. Review article: The alkali
treatment of straws. Anta. Feed Sci., Technol.
2:105.
27. Joy M., X. Alibés and F. Muñoz (1992).
Chemical treatment of lignocellulosic residues
with urea. Animal Feed Science and
Technology Volume 38, Issue 4, 31 August,
Pages 319-333 .
28. Koster H.H, Woods B .C, Cochran R.C,
Vanzant E.S, Titgemeyer E.C, Grieger D.M,
Olson K.C, G. Stokka (2002). Effect of
increasing proportion of supplemental N from
urea in prepartum supplements on range beef
cow performance and on forage intake and
digestibility by steers fed low-quality forage. J
Anim Sci. Jun;80(6):1652-62.
29. Lines L. W., M. E. Koch 1, and W. P. Weiss 1(
1996). Effect of Ammoniation on the Chemical
Composition of Alfalfa Hay Baled with Varying
Concentrations of Moisture J. Dairy Sci. 79
2000-2004.
30. Lines and Weiss (1996). use of Nitrogen from
Urea treated Alfalfa Hay, Urea, Soybean Meal,
and Animal Protein Meal by Lactating Cows J.
dairy Sci. 79. 1992-1999 .
31. Ludden P. A. and M. J. Cecava (1995).
Chemical factors involved in ruminal fiber
digestion. Supplemental protein sources for
steers fed corn-based diets: I. Ruminal
characteristics and intestinal amino acid flows.
Journal of Animal Science, Vol 73, Issue 5
1466-1475, Copyright © 1995 by American.
32. Matejovsky K. M. and D. W. Sanson (1995).
Intake and digestion of low-, medium-, and
high-quality grass hays by lambs receiving
increasing levels of corn supplementation.
Journal of Animal Science, Vol 73, Issue 7
2156-2163.
http://www.americanscience.org
33. MOA (2005); Ministry Of Agriculture and land
Reclamation. Economic Affairs Sectors.
34. Mohamed Hammadi (2007). Improving
nutritive value of a North African range grass
(Stipa tenacissima). Effect of dung ash and urea
treatment on digestion by goats Animal Feed
Science and Technology Volume 136, Issues 12, 15 July, Pages 1-10 .
35. NRC (1996). Nutrient Requirements of Sheep.
6th ed. Natl. Acad. Press, Washington, D.C.
36. Ojai, U.I., H.E. Etima and F.C. Okoye (2007).
Effects of urea and aqueous ammonia treatment
on the composition and nutritive value of maize
residues. Small Ruminant Research Volume 69,
Issues 1-3, May 2007, Pages 232-236.
37. Oltjen, R. R., E. E. Williams, Jr., L. L. Slyter,
and G. V. Richardson. (1969). Urea versus
biuret in a roughage diet for steers J. Anim. Sci.
29:816-821.
38. Pordomingo, A. J., J. D., Wallace A.S. Freeman,
and M.L. Galyean (1991). Supplemental corn
grain for steers grazing native rangeland during
summer.J.Anim.Sci.69:1678-1687.
39. Ørskov, E. R. (1992). Protein Nutrition in
Ruminants. 2nd ed. Academic Press, Inc., San
Diego CA.
40. Rock, D. W., J. K. Ward, and T. J. Klopfenstein
(1991). Escape protein for beef cows: I. Source
and level in corn plant diets J Anim Sci 69:
2282-2288.
41. Rusev, V. and V. Lazarov (1967). The milking
of ewes. Animal breeding Abst. 36, 2640.
42. Sahoo, B.M.L. Sarawat ,N.Haque and
M.Y.Khan (2002).Influence of chemical
treatment of wheat straw on carbon–nitrogen
and energy balance in sheep Small Ruminant
Research Volume 44, Issue 3, June, Pages 201206.
43. Sanson, D. W., D. C. Clanton, and .G Rush.
(1990). Intake and digestion f low-quality
meadow hay by steers and performance of cows
on native range when fed protein supplements
containing various levels of corn. J. Anm. Sci.
68:595-603.
44. S.A.S Institute (1990). S.A.S.user's guide. SAS
Inst.Inc.cary., N.C. USA.
45. Satter. L.d.. and L. L. Styler. (1974). Effect of
ammonia concentration on rumen microbial
protein production n vitro. Br. J. Nutr. 32:199208.
46. Sidwell G. M, Everson D O & Terrill C E
(1964). Lamb weight n some pure breeds and
crosses Journal of Animal Science 23:105-110.
47. Tuah A.K. and E.R. Ørskov (1989). The
degradation of untreated and treated maze cobs
and coca pod husks n the rumen. PROCEEDNG
177
editor@americanscience.org
Journal of American Science
2010;6(6)
OF THE FOURTH ANNUAL WORKSHOP
AFRICAN RESEARCH NETWORK FOR
AGRICULTURE BY-PRODUCTS (ARNAB).
48. Tyrrel H. F and P. W. Moe (1975). Effect of
intake on digestive efficiency. Journal of Dairy
Science 58(8):1151-1163.
49. Wanapat , M. F. Sundstøl and T. H. Garmo
(1985). A comparison of alkali treatment
methods to improve the nutritive value of straw.
I. Digestibility and metabolizability Animal
Feed Science and Technology Volume 12, Issue
4, July, Pages 295-309.
50. Woodford J. A, Jorgensen N. A and Barrington
G. P. (1986). Impact of dietary fiber and
physical form on performance of lactating dairy
cows. Journal of Dairy Science 69:1035-1047.
51. Wu.G, F.W.Bazer ,J.M.Wallace andT.E.Spncer
(2006) Board-Invited revw: Intrauterine growth
retardation : Implication for the animal Sciences
. J. Anim sci 84: 2316-2337.
52. Yilmza O ,H.Denkb and D . Bayram (2007) .
Effects of lambing season , sex and birth type
on growth performance in Norduz lambs. Small
Ruminant Research Volume 68, Issue 3, April,
Pages 336-339.
53. Zinn, R. A. E. G. Alvarez, M. F. Montano and J.
E. Ramirez (2000). Interaction of protein
nutrition and laidlomycin on feedlot growth
performance and digestive function in Holstein
steers Journal of Animal Science, Vol 78, Issue
7 1768-1778. ARC, 1980.
3/8/2010
http://www.americanscience.org
178
editor@americanscience.org
