NUTRITIVE VALUE FOR GOATS
OF ATRIPLEX SPECIES
GROWN WITH HYPERSALINE WATER
by
Susan Taft Wiley
A Thesis Submitted to the Faculty of the
DEPARTMENT OF ANIMAL SCIENCES
In Partial Fulfillment of the Requirements
For the Degree of
MASTER OF SCIENCE
WITH A MAJOR IN ANIMAL SCIENCE
In the Graduate College
THE UNIVERSITY OF ARIZONA
1982
STATEMENT BY AUTHOR
This thesis has been submitted in partial fulfillment of requirements for an advanced degree at The
University of Arizona and is deposited in the University
Library to be made available to borrowers under rules of
the Library.
Brief quotations from this thesis are allowable
without special permission, provided that accurate
acknowledgment of source is made. Requests for permission
for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of
the major department or the Dean of the Graduate College
when in his judgment the proposed use of the material is
in the interests of scholarship. In all other instances,
however, permission must be obtained from the author.
SIGNED:
Wday
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below:
,
7-
W. H. BROWN
Professor of Animal Science
a
Date
ACKNOWLEDGMENTS
The author wishes to express her appreciation to
• her major professor, Dr. W. H. Brown for his guidance,
constructive criticism and friendship. I wish to thank
Dr. R. S. Swingle for his guidance and editing assistance.
The author wishes to give special thanks to her
parents for their continued encouragement in this endeavor.
TABLE OF CONTENTS
Page
LIST OF TABLES vi
ABSTRACT
1
INTRODUCTION
4
4
5
7
8
9
LITERATURE REVIEW
Mineral Accumulation by Halophytes
Nutrition Composition of Atriplex
Grazing Studies -- Ruminant
Non-Ruminant Studies
Water Requirements
11
EXPERIMENTAL PROCEDURE Source of the Plant Material Acceptable Study Comparison of Alfalfa Hay to
A. lentiformis -- Trial 1 Comparison of A. lentiformis to
A. barclayana and the Effect of
Water Leaching on Their
Digestibility -- Trial 2 11
12
13
14
16
RESULTS AND DISCUSSION Raw Dietary Ingredient Analysis -- Acceptability Study Preliminary Acceptability Study Trial 1 Trial 2 General Discussion 16
16
18
22
34
CONCLUSIONS 36
LITERATURE REVIEW 38
iv
LIST OF TABLES
Page
Table
1.
2.
3.
Chemical and Gross Energy Composition of
Alfalfa Hay and A. lentiformis -- Trial 1 . . 17
Chemical Composition and Gross Energy of
Experimental Diets -- Trial 1
Intakes plus Apparent Digestibilities by
Goats Fed Diets Containing 25% A.
lentiformis plus Partial Digestion
Coefficients Calculated by Difference
for A. lentiformis -- Trial 1
19
20
4.
Nitrogen Balance Data a -- Trial 1
22
5.
Chemical and Gross Energy Composition
of Feed Ingredients -- Trial 2
23
6.
7.
8.
9.
10.
Chemical Composition and Gross Energy of
Experimental Diets a -- Trial 2
26
Intakes and Apparent Digestibilities by
Goats Fed Diets Containing 25%
Halophyte -- Trial 2
Analysis of Variance for Digestion -Trial 2
27
Partial Digestion Coefficients Calculated
by Difference for Halophytes Fed As 25%
of the Diet -- Trial 2
29
32
33
Nitrogen Balance Data a -- Trial 2
11. Analysis of Variance for Nitrogen Balance
Data -- Trial 2
30
ABSTRACT
Samples of Atriplex lentiformis and Atriplex
barclayana were used to determine potential uses for
ruminants. It was determined that diets containing more
than 25% halophyte with alfalfa hay would not be acceptable
by goats. Analyses of the dietary ingredients revealed that
the Atriplex species were high in ash as compared to alfalfa
hay (av. 30 vs 10%). Partial digestion coefficients, as
calculated by difference, indicated that the two Atriplex
species were more digestible than alfalfa hay with regard
to crude protein. All other nutrient parameters measured
yielded similar results, but less digestible for fiber and
leached materials. Leaching with fresh water decreased
mineral content of the two halophytes, but did not improve
acceptability of digestibility.
vi
INTRODUCTION
Halophytes are plants which grow naturally in alkaline or saline soils. These plants are distributed worldwide and are subjected to a loosely defined classification
system. Some halophytes may occur in terrestrial or marine
environments. The genus, Atriplex, with about 120 species,
includes annual and perennial herbs and shrubs most of which
are considered to be halophytes. Included in this group
are halophytes which may be obligatory in their requirement
for excess soil salinity throughout their life cycle
(Waisel 1972) or the salt tolerance may vary with different
phases of growth and development (Hayward 1956). Some
halophytes, particularly the genus Atriplex, are commonly
referred to as saltbush due to their ability to accumulate
salt on the leaf surface.
The distribution of Atriplex, a terrestrial halophyte,
appears to be controlled by edaphic conditions (Reimold and
Queen 1974).
Encroaching desertification, particularly in arid and
semi-arid regions of the world, has increased the need for
non-conventional forage production. Arid and semi-arid
climate zones place major constraints on maximizing
1
2
agricultural production. Halophyte plants, due to their
ability to withstand these severe environmental conditions,
offer agricultural practitioners in these regions a potential to increase present livestock production levels.
Various salt tolerant plants are currently being
investigated for potential domestic crop production due to
their ability to withstand drought, saline or alkaline soil
and soil nutrient imbalances. Some of the species in the
genus Atriplex appear to have potential for domestication,
primarily due to high field dry matter yields and protein
content that is comparable to alfalfa hay (Goodin and McKell
1970, Glenn, Fontes and Yensen 1982).
Recent interest in developing the agronomic potential
in arid and semi-arid regions of the world has centered on
the use of saline and hypersaline irrigation water. In
these areas, groundwater is a finite resource, while seawater
or other brackish water is often readily available. Seawater
or saline water contains 30-35 ppt total dissolved salts,
while hypersaline water contains 40 ppt (Glenn, Fontes, and
Yensen 1982). Halophytes, as previously indicated, may have
a potential as a suitable crop under these conditions with a
major thrust toward increasing livestock production in these
areas.
As previously stated, encroaching desertification and
decreasing groundwater stores has stimulated interest in the
3
potential uses of non-conventional high yielding forages
such as Atriplex. Crops suitable for livestock use that
can be cultivated with saline or other brackish water
would help alleviate existing livestock production problems
in arid and semi-arid regions of the world. Little information is available on the nutritional value of halophytes
for ruminants and no nutritional information is available
on halophytes grown with hypersaline irrigation water.
This study was undertaken to determine potential uses of
plants, such as Atriplex, may have for ruminants.
This study was conducted in two phases using the same
goats. The purpose of Trial 1 was to determine the acceptability and digestibility of Atriplex lentiformis as compared
to alfalfa hay. Trial 2 was conducted to compare the digestibility of two Atriplex species, A. lentiformis and A.
barclayana, and to determine whether leaching to reduce
mineral content would be beneficial in terms of improving
acceptability and digestibility.
LITERATURE REVIEW
Due to habitat and genetic differences among salttolerant plants with regard to nutrient composition and
acceptability by livestock, primarily in natural grazing
situations, the review of literature for this study will
center on information available concerning the genus
Atriplex.
Mineral Accumulation by Halophytes
Due to their ability to withstand high (>10 ppt total
dissolved salts) soil salinity levels halophytes are unique
in their metabolism and physiology. The leaf surface and
associated structures are the primary areas of salt or
mineral accumulation. These plants are particurlarly unique
in their selective absorption of chloride (Wood 1925). In
his study,. Wood noted that the salt content of the plant
varied seasonally with an increase in ash toward the end
of the dry season. It has been suggested that this high
ash content (>15% and mostly NaC1) contributes to the
relative unpalatability of these plants (Leigh and Mulham
1967, Goodin 1979, Glenn et al. 1982). Welch (1978) noted
in his study with A. canescens, that plant ash content
lacked a relationship to soil salinity levels though there
4
5
was a positive correlation when the halophyte was grown in
varying saline nutrient solutions (Ashby and Beadle 1957).
Ash content exceeded 20% when the halophytes were grown in
high saline nutrient solutions, which is an abnormally
high ash value when compared to glycophytes. Attempts to
wash some of the minerals from the leaf surface of A.
halimus proved unsuccessful (Mozafar and Goodin 1970).
Nutritient Composition of Atriplex
Halophyte plants belonging to the genus Atriplex,
vary in nutrient composition with seasonal variation and
stage of maturity (Chatterton, Goodin, McKell et al. 1971).
The leaves are considerably more nutritious than the stems
and contain the highest amounts of fat, protein, nitrogen
free extract, total digestible nutrients and the least
amount of ash as compared to the stems (Chatterton et al.
1971). According to NRC analyses (1964, 1968, 1982),
Atriplex nuttallii may vary in ash content from 12.0% to
22.0% (dry matter basis) during periods of vegetative
growth or dormancy, respectively. In general, crude
protein content in saltbush may vary seasonally from 4.0%
to 12.0% (NRC 1964, 1982). Lignin content in various
species of saltbush ranged from 10.0% to 14.0%, depending
upon the stage of dormancy. Calcium to phosphorus ratios
(14:1) appeared to remain constant throughout the life cycle
6
of the various Atriplex species reported by the NRC (1964,
1968). Extensive information on the nutritive value of
halophytes during the vegetative growth periods was unavailable. Consequently, due to the seasonal variation of
these plants, the stem to leaf ratio is important when considering the use of saltbush for reserve fodder or for
incorporation into livestock rations. Forage value is
highest during the cool season, even though most new
growth occurs during the warmer drier season, probably due
to the accumulation of excess salts on the leaf surface
during periods of drought. During late season, when other
annuals have reached maturity and are depleted of nutritional components, saltbush provides grazing livestock with
calcium, protein and carotenoids. Hence, saltbush is an
important browse (Chatterton et al. 1971). Immature saltbush is lower in crude fiber and higher in crude protein
than mature halophytes (Glenn et al. 1982). Four-wing
saltbush, A. canescens, has the greatest concentration of
protein and phosphorus in the upper portion of the twigs due
to new growth occuring near the tips, while cellulose is in
greater concentration in the lower portion of the twigs and
at the base. This portion of the shrub puts out the least
amount of growth and therefore contains more fiber (Cook,
Stoddart and Harris 1959).
7
Grazing Studies
--
Ruminant
In Australia, 4-5 million sheep are pastured on
Atriplex dominated areas (Gates and Muirhead 1967). In the
United States, A. canescens is a valuable forage on desert
grassland ranges, as it is one of the few sources of green
feed when other herbaceous plants are dormant.
Pasture stocking rates have been shown to affect
not only the viability of the Atriplex stands, but also
the amount of dietary intake of the halophyte by livestock.
In Australia, in November, A. vesicaria comprised 46% of the
forage eaten by sheep, although the saltbush made up 86% of
the pasture. In February, A. vesicaria made up 90% of the
diet, as the only other available feed was dead material
(6.4%) and D. australe (3.1%), a perennial herb (Leigh and
Mulham 1967). A. vesicaria, probably due to its unpalatable
nature, was only utilized as feed when other ground herbage
was limited such as in periods of prolonged drought. Peiper,
Cook and Harris (1959) in their study with 4-wing saltbush
and stocking rates, observed that dry matter intake decreased
with intense grazing. Increased selection of the less preferred species and of the more fibrous portions of these
secondary plants decreased the daily forage intake. However,
in some instances, digestible nutrient intake increased with
increasing utilization of these secondary species. This is
probably due to an increase in the percentage of the diet of
8
a particular nutrient and subsequent increased digestibility.
Thus, a change in sppcies consumption caused by stocking
rates will affect overall dry matter intake and digestibility of certain nutrient components. In several cases,
metabolizable energy and digestible protein were adequate
in light stocking but deficient under heavy rates, probably
due to the increased fiber component in the diet. Cook et
al. (1959) supported this when he reported that in harvesting saltbush, the shrubs exhibited higher protein values in
light harvest than in heavy intense harvest due to the new
growth exhibited on the tips of the twigs. It should be
further emphasized that saltbush stands require periodic
rests from grazing to maintain vigorous pasture areas
(Peiper and Donart 1978).
Non-Ruminant Studies
In a poultry study conducted by Schurg, Maiorino
and Reid (1982), A. lentiformis and A. barclayana were
compared. A basal stock diet was used which contained milo
and soybean meal. The halophytes were included in the diets
at levels of 5%, 10% and 15%, replacing milo. Diets containing up to 10% A. barclayana produced similar body weight
gain as the basal diet, but levels of 15% A. barclayana and
all levels of A. lentiformis produced lower body weight
gains than the basal diet. High mortality losses (83.8
9
and 94.4%) were reported for 10% and 15% A. lentiformis
diets, respectively.
Water Requirements
In any grazing situation, water is an important consideration. Halophytes with their high ash content accentuate the grazing animal's critical need for water. In
Australia, sheep grazing on a saltbush (A. vesicaria)-mixed
community drank 6-7 1/day during the summer months. When
placed on an Atriplex dominant pasture their water consumption doubled during a particularly dry year (12-14 1/day).
Water requirements for grazing animals are influenced by
several parameters, including animal breed or species,
ambient temperature and radiation load (MacFarlane, Morris
and Howard 1963, MacFarlane, Morris and Howard 1958,
MacFarlane, Dolling and Howard 1966). Type of vegetation
grazed may also be an important factor. For example, higher
water turnover rates were recorded for sheep on saltbush
than grassland pastures, though there was a variation from
year to year, depending on the amount of herbaceous plants
in the saltbush community (MacFarlane, Howard and Seibert
1967, Wilson, Leigh and Mulham 1969). The amount of water
consumed depends not only on the amount of saltbush in the
diet but also on the ambient temperature and the animal's
ability to rid their body of the accumulated heat load
(Wilson 1974).
10
Sheep and cattle can be grazed together during
periods of drought on Atriplex dominated pastures with little
competition between the two species of animals. This is due
to individual grazing behavior and plant preferences exhibited by the two different species of animals. According
to Graetz and Wilson (1980), cattle and sheep performed
similarly (within species) when grazing on a saltbush
(A. vesicaria) dominated pasture. The sheep did consume a
higher proportion of available grass than did the cattle.
In other related studies by the same researchers, cattle
required proportionally more water (up to 50%) than sheep
due to a lower salt tolerance, further exemplifying the
critical need for adequate water availability in saltbush
dominated pastures.
It is evident that Atriplex dominated pastures are
capable of maintaining grazing livestock on native ranges.
In view of diminishing pasturelands, encroaching desertification and increasing need to maximize livestock production
in arid and semi-arid regions of the world, plants such as
halophytes may be suitable for confinement production
practices. Salt tolerant plants are currently receiving a
great deal of attention in an effort to alleviate pressure
exerted on the agricultural community for increased production in these areas.
EXPERIMENTAL PROCEDURE
Source of the Plant Material
Aerial portions of A. lentiformis (Trials 1 and 2)
and A. barclayana (Trial 2) irrigated with waste water from
a shrimp aquaculture facility at Puerto Penasco, Sonora,
Mexico were used in this study. Seedlings were established
in a greenhouse on fresh water and conditioned to seawater
irrigation before transplanting into the field in April.
After the plants were established in field plots, they were
irrigated to a depth of 6-10 cm twice daily with waste water
which contained approximately 40 ppt total dissolved salts
(TDS). In comparison, seawater contains 30-35 ppt TDS.
After 200 days growth, the plants which averaged 1 m in
height were harvested by hand and placed on tarpaulins and
air-dried. A considerable amount of leaf shatter occured
with A. lentiformis during drying and most of the larger
stems were discarded. Thus, the A. lentiformis used in the
two feeding studies consisted mainly of leaves and smaller
stems which amounted to approximately two-thirds of the
original plant dry matter. The entire above ground portion
of A. barclayana was used. Leached material (Trial 2) was
prepared by placing approximatley 10 kg dried Atriplex into
11
12
a revolving drum mixer and rinsing with fresh running tap
water for 2-3 hours. Washed material was placed on screens
and air-dried.
Acceptability Study
A preliminary acceptability study was conducted
using eight Nubian wether goats, mean initial weight 11.55
kg to determine the maximum level of Atriplex which could
be used. Upon arrival at the University of Arizona experimental farm, the goats were placed in individual pens (1.2 x
4.8 m) and were castrated, wormed, and innoculated with
tetanus toxoid modified live vaccine. Daily feed allowances
were offered in equal portions at 0700 and 1600 hours.
Drinking water was available at all times. The pens were
cleaned daily and hoof care administered as necessary.
Goats were individually weighed bi-weekly. Daily management
of the goats remained the same throughout the study. The
goats were randomly allotted to two groups and assigned to
diets of either chopped alfalfa hay (IFN 1-00-0059) or 100%
A. lentiformis. Ten percent of a 50:50 molasses:water
mixture was added to the above and subsequent diets to
encourage intake and to decrease dustiness. The diet of
100% A. lentiformis met with complete refusal by the goats
and after 7 - 10 days the diet was changed to one of 75%
A. lentiformis and 25% alfalfa hay. This diet and a subsequent one containing 50% A. lentiformis and 50% alfalfa
13
hay met with similar results. It was finally determined
. that a diet of 25% A. lentiformis and 75% alfalfa hay would
be suitable for the digestion trials.
Comparison of Alfalfa Hay to
A. Lentiformis - Trial 1
The same eight Nubian wether goats (mean initial
weight 18.7 kg) from the acceptability study were kept in
their previously assigned groups according to dietary treatment. Diets containing 25% A. lentiformis were fed ad
libitum during a 21 day preliminary adjustment period prior
to a 7 day total collection period. The goats were kept in
individual pens for the first 20 days and in metabolism
crates the last 8 days of the trial. Feed intake was restricted on a per unit of body weight basis to the level of
the goat with the lowest intake. During Trial 1, feed
intake was restricted to 80% of maximum voluntary intake the
last 8 days of the trial. During the collection period,
total feces and urine from each goat were collected daily.
A 10% aliquot of the daily fecal excretion was dried for
48 hours at 50C in a forced-air oven. At the conclusion of
each collection period, daily aliquots for each goat were
pooled and ground through a 1 mm screen in a Wiley mill. A
portion of the ground composite was retained for analysis.
A 5% aliquot of the daily urine excretion was pooled on an
individual basis and refrigerated until analysis. Samples
14
of diet ingredients and mixed diets were taken during each
collection period and prepared for analysis in the same
manner as the fecal samples.
Final dry matter, nitrogen and ash were determined in
all samples using A.O.A.C. (1970) methods. Gross energy
was determined with an adiabatic bomb calorimeter and cell
wall constituents were determined as described by Goering
and Van Soest (1970). Digestibilities for diet components
were calculated in the usual manner. Partial digestion
coefficients for the halophyte portion of each diet was
calculated by difference using the determined coefficients
for alfalfa hay. Analysis of variance (Steel and Torrie
1960) was used for statistical evaluation of the data.
Comparison of A. lentiformis to
A. barclayana and the Effect of Water Leaching
on Their Digestibility -- Trial 2
In Trial 2, the two Atriplex species, A. lentiformis
and A. barclayana and the two preparations, untreated and
leached, were factorially arranged to give four experimental
treatments. Diets consisted of 25% of the various halophyte materials and 75% chopped alfalfa hay (IFN 1-100-059).
The diets were randomly assigned to four of the Nubian wether
goats used in Trial 1 (mean weight 31 kg) in a 4 x 4 latin
square digestion trial. Each period of the square consisted
of a 21 day preliminary adjustment period followed by a 7
day total collection period. Feed intake was ad libitum
15
for the first 18 days of each period and then restricted to
90% of maximum voluntary intake for the remainder of the
period. Water intake was measured for each goat during the
last three periods of the latin square. Digestion trial
procedures and analytical methods were the same as described
in Trial 1.
RESULTS AND DISCUSSION
Raw Dietary Ingredient Analysis -Acceptability Study
Chemical composition and gross energy of the dietary
ingredients are presented in Table 1. A. lentiformis was
much higher in ash and lower in organic matter (OM) than
alfalfa hay (27.7 vs 8.1%, 72.3 vs 91.9%, repectively).
Acid detergent fiber (ADF) (23.8 vs 37.8%)and gross energy
(GE) (3.48 vs 4.52 Meal/kg) were lower in A. lentiformis than
alfalfa hay, respectively. A. lentiformis and alfalfa hay
were similar in crude protein (CP), cell contents (CC),
neutral detergent fiber (NDF) and lignin content.
Preliminary Acceptability Study
During the preliminary acceptability study the goats
were given ample time (7-10 days) to consume diets containing
100%, 75% or 50% A. lentiformis. A. lentiformis was replaced
by chopped alfalfa hay as the halophyte portion of the diet
decreased. Intake was very erratic and some of the goats
made no attempt to sample the halophyte material. This
feeding behavior supports numerous grazing studies
(Chatterton et al. 1971, Nemati 1977) which have suggested
there are palatability problems with Atriplex species on
the range. Previous investigators found that Atriplex was
16
17
Table 1. Chemical and Gross Energy Composition of Alfalfa
Hay and A. lentiformis-- Trial 1.
Component a
Alfalfa Hay
A. lentiformis
91.9
72.3
8.1
27.7
Crude Protein, %
14.0
13.0
Cell Contents, %
52.6
55.5
Neutral Detergent Fiber, %
47.4
44.5
Acid Detergent Fiber, %
37.8
23.8
Permanganate Lignin, %
8.5
6.4
Gross Energy, Mcal/kg
4.52
3.48
Organic Matter, %
Ash, %
aDry matter basis
not readily consumed except during periods of drought where
little other feed was available (Leigh and Mulham 1967).
As estimated by esophageal fistulas, grazing sheep would
rarely consume more than 46% of the diet as A. vesicaria
(Leigh and Mulham 1976) when other feed was available. The
25% halophyte dietary level determined in this study supports
the relatively low grazing dietary intake . levels of 46%.
The goats were consistent in their consumption of the
offered diets at the 25% level.
18
Because of the results in this preliminary experiment, diets containing 25% Atriplex were used for the remainder of this study. Though the consumption of the 25%
halophyte diet was considered to be adequate for maintenance
(Table 3), the goats consumed less (P<.05) of the 25% A.
lentiformis diet than those goats on the alfalfa hay diet
(696 vs 769 g/day).
Trial 1
Chemical composition and GE values for the mixed
diets are presented in Table 2. The 25% A. lentiformis
diet contained more (P<.05) ash than the alfalfa hay diet
(13.3 vs 8.1%) and less OM (86.7 vs 91.9%) and ADF (P<.05)
(34.6 vs 43.4%) than did the alfalfa hay diet. The two
diets were similar with respect to CP, CC, NDF, lignin and
GE.
Apparent digestion coefficients are presented in
Table 3. The most striking difference between the digestibilities of the two diets are noted in CP and ADF. Crude
protein digestibility was higher (P<.05) for the lentiformis
diet than for the alfalfa hay diet (72.9 vs 64.1%) while
ADF digestibility was higher (P<.05) for the alfalfa hay
diet (56.5 vs 48.3%). Digestion coefficients for OM, CC,
NDF and GE were similar (P>.05) for both diets.
Partial digestion coefficients, calculated by difference for A. lentiformis are presented in Table 3.
19
Table 2.
Chemical Composition and Gross Energy of
Experimental Diets -- Trial 1.
Component a
Alfalfa Hay b
25%
A. lentiformis c
91.9
86.7
8.1
13.3
Crude Protein, %
13.2
13.9
Cell Contents, %
50.3
52.9
Neutral Detergent Fiber, %
49.7
47.1
Acid Detergent Fiber, %
43.4
34.6
Permanganate Lignin, %
9.9
10.4
Gross Energy, Mcal/kg
4.57
Organic Matter, %
Ash, %
4.23
aDry matter basis
b Chopped alfalfa hay plus 10% molasses
C25% A. lentiformis: 75% chopped alfalfa hay plus 10%
molasses
20
Table 3. Intakes plus Apparent Digestibilities by Goats
Fed Diets Containing 25% A. lentiformis plus
Partial Digestion Coefficients Calculated by
Difference for A. lentiformis -- Trial 1.
Alfalfa
25%
Item
A. lentiformis Hay
Diet
Diet
A. lentiformis
by Difference
Intake, g/day a
preliminary period
696
769
Intake, g/day a
collection period
712
769
Organic Matter
65.5
63.6
71.0
Cell Contents
74.3
73.2
77.7
Crude Protein
72.9
64.1
99.5
Neutral Detergent Fiber
53.7
53.8
53.3
Acid Detergent Fiber
48.3
56.5
23.4
Gross Energy
63.3
62.7
65.0
Apparent Digestion
Coefficientsb, %
aDry matter basis
b Apparent digestion coefficients for the entire diet.
Each value is the mean of four goats.
21
A. lentiformis digestibility was higher than alfalfa hay for
CP (99.5 vs 64.1%) and OM (71.0 vs 63.6%). Milthorpe (1970)
has suggested that unpalatability may be the result of
proteins being too readily digested, breaking down to
ammonia and causing digestive discomfort to the animal.
During this study, it was not observed that the goats were
experiencing digestive discomfort, though the calculated
digestion coefficients indicate that Atriplex was highly
digestible. Previous investigators have shown that some
halophytes contain relatively high protein values adding to
their value on the range during periods of drought
(Chatterton et al. 1971, Cook et al. 1959, Peiper and Donart
1978). Cell content digestibility was greater for the halophyte material (77.7 vs 73.2%) while ADF digestibility was
lower (P<.05, 23.4 vs 56.5%) as compared to alfalfa hay. The
other parameters measured were similar to the apparent digestion coefficients for alfalfa hay.
Nitrogen (N) balance data is presented in Table 4.
Although nitrogen intake for the two diets was similar,
fecal N was less (4.3 vs 5.8 g/day) and urinary N was higher
(10.2 vs 8.2 g/day) for the halophyte diet than for those
goats on the alfalfa hay diet. Whether expressed as g/day,
percentage of intake or percentage of absorbed, N-retention
was significantly less (P<.05) for those goats on the halophyte diet than for the goats on the alfalfa hay diet (1.2 vs
2.1 g/day; 7.1 vs 13.4%, and 9.9 vs 20.9%, respectively).
22
Table 4.
Nitrogen Balance Data a -- Trial 1.
Alfalfa Hay Diet
25% Halophyte Diet
16.0
15.7
Fecal
5.8
4.3
Urinary
8.2
10.2
2.1
1.2
% of Intake
13.4
7.1
% of Absorbed
20.9
9.9
N-intake g/day
Intake
N-excretion g/day
Retained g/day
a Each value is the mean of 4 goats.
Trial 2
Chemical composition and GE of the dietary ingredients are shown in Table 5. As indicated in Trial 1,
halophytes are higher in ash than alfalfa hay. A. lentiformis and A. barclayana, untreated and leached, contained
significantly (P<.05) more ash (av. 30.0 vs 9.9%) than
alfalfa hay. A. lentiformis untreated was higher in CP
(15.7 vs 9.4%), CC (58.4 vs 53.1%), lignin (11.6 vs 9.8%)
23
Table 5. Chemical and Gross Energy Composition of Feed
Ingredient-- Trial 2.
Component b
Organic
Matter, %
Alfalfa
Hay
A. barclayana
Untreated Leached
A. lentiformis
Untreated Leached
90.1
62.6
78.4
64.9
73.7
9.9
37.4
21.7
35.1
26.3
Crude
Protein, %
18.4
15.7
15.8
9.4
11.0
Cell
Contents, %
54.3
58.4
46.4
53.1
47.4
Neutral
Detergent
Fiber, %
45.7
41.6
53.6
47.9
52.6
Acid Detergent
Fiber, %
35.8
23.2
27.5
29.5
31.0
H2 SO4 Lignin,%
8.3
11.6
13.4
9.8
14.8
Gross Energy,
Meal/kg
4.5
3.1
3.9
2.9
3.3
Ash, %
a Each value is the mean of four observations.
b Dry matter basis
and GE (3.1 vs 2.9 Meal/kg) than A. barclayana untreated.
The two untreated halophytes were similar in ash (37.4 vs
.
35.1%) and OM (62.6 vs 64.9%). A. lentiformis untreated was
lower than A. barclayana untreated with regard to NDF
24
(41.6 vs 47.9%). Compared to the alfalfa hay, the untreated
halophytes contained more (P<.05) ash (9.9 vs av. 36.3%)
and lignin (8.3 vs av. 10.7%), but less (P<.05) CP (18.4 vs
av. 12.6%), ADF (35.8 vs ay. 26.4%) and GE (4.5 vs av. 3.0
Meal/kg).
The leaching process used in this study reduced the
ash content in the halophytes from 36.3% to approximately
24% and appeared to be more efficient for A. lentiformis.
Leaching A. lentiformis reduced the ash content by approximately 42% while the ash content in A. barclayana was reduced
only by 25%. This was in contrast to a previous experiment
(Mozafar and Goodin 1970) in which washing leaves and twigs
of A. halimus with distilled water for 48 hours did not
reduce their ash content. Mozafar and Goodin (1970) have
suggested that the quantity of salts removed from the leaves
of A. halimus would depend on the age of the leaves (mature
vs immature), rate of formation and bursting of vesiculated
hairs and the salinity of the growing medium. The vesiculated hairs, common to Atriplex, are believed to increase
transpiration and accumulate excess salts on the surface
of the superficial hairs (Wood 1925). Hence, in our study,
the greater efficiency of mineral leaching in A. lentiformis
may be due to field handling (resulting in the rupture of
the vesiculated hairs thereby depositing the salts on the
leaf surface) or to genetic differences as compared to A.
25
barclayana. In addition to the mineral loss there was also
a considerable loss of CC during the leaching process
resulting in higher ADF, NDF and GE values for the leached
as compared to the untreated materials.
Chemical composition of the experimental diets
(Table 6) was similar except that A. barclayana leached had
lower CC and NDF values than the other three diets.
Intake data are shown in Table 7. Ad libitum consumption of diets containing A. lentiformis was higher (P<.05)
than for diets containing A. barclayana (av. 1334 vs av.
1215 g/day). Leaching of the halophytes did not have a
beneficial effect on diet acceptability by the goats and
actually depressed it (av. 1225 vs av. 1325 g/day).
As would be expected, goats consuming the untreated
diets consumed more water than did those on the leached
diets (4881 vs 3916 ml/day). In field studies it has also
been noted that as saltbush in the diet increases water
consumption increases (Wilson 1974; MacFarlane et al. 1958,
1963, 1966). The high ash content increases the animal's
requirement for water in an effort to maintain electrolyte
balance(s) in the body and to flush the excretory system of
the excess salts taken in by the animal. This is essentially
counterproductive in areas where halophytes occur or are
being considered for domestication.
26
Table 6. Chemical Compositip and Gross Energy of
Experimental Diets -- Trial 2.
Component b
A. lentiformis
Untreated Leached
A. barclayana
Untreated Leached
Organic Matter, %
84.1
86.7
83.3
86.8
Ash, %
15.9
13.3
16.7
13.2
Crude Protein, %
16.6
16.1
16.4
14.9
Cell Contents, %
56.5
53.5
54.9
50.9
Neutral Detergent
Fiber, %
43.5
46.5
45.1
35.5
Acid Detergent
Fiber, %
31.8
33.5
34.4
35.9
H 2 SO 4' Lignin, %
9.6
10.5
8.4
10.2
Gross Energy,
Meal/kg
4.3
4.4
4.1
4.3
aDiets contained 25% halophyte and 75% chopped alfalfa hay
with 10% molasses added. Each value is the mean of four
observations.
b Dry matter basis
-
•
• 4
•
• E
•
27
tr)
cp
•
r-1
cil
t•-•
.
r-4
CD
co
cs)
.
lt)
•
CO
CS)
CO
CO
•
•di
CO
a)
In
•14
.
0
r-4
0
0
U)
t•-•
cc)
01
cr)
•
.
bD
cd
O
0
cd 4
O
cd
cd
H CD
cd
4-)
cd d
O
-0 CD
C
l
-P
O
•
cd
<
CO
C••
•
r-I
CD
0
0
CS)
r--1
0
C.-.
N
rH
r-1
•
•
-
+.)
4-)
coU)
:S
-H
CL)
E
O
Ci)
Cd
.
-7t4
.
ir)
•r-1
Ln
4-)N
In
cd
cr)
•
cf)
m
•
t--
.11
•
di
cs)
.
H
Cl
CO
C-•
Cl 0 1-1
CO
CS)
h.
11)
•di
CO
cf)
r-1
1-4
Cti
Cl
R
zi
R
O
+)
CD
„W
cd 0
1 -4
O cd
z
z
0
o.,-1
•,-1
+)
:8
O
b.0
.,-1
a
li
.......
›)
>1
cd
cd
0
0
'Ci
......0
..
a)
a)
cd
cd
ci
...
0
x
cd
cd
H
O
-P g
0
-H
-ri
-ri
'ti.0
a)
a)
PT-1
4-1
0
CD
0
9 -1
c.)
-r1
§
-
P
k
r-i
0
-
., '0
0
-1-)
tri
bi) bA
4:1
u)
0)
0 0
a)
-I-)
cd
M C.0 N
•
"II
IO
0
Lo
t•-•
0
o
-1-1
4-)
VI
ho
ci)
-1-1
'0
•zi•
4-)
En
a)
4 o
4-) -ri
,o
ca
P.(
P4
O
4
O
ei-i
0 CD
k
CD .1-1
-0 -P
0 0
-H 0)
bD
0
-r-I
"Ci
O
0
k
In
o
'0
k
C14
a)
CD
a)
p.,
P.
44
CD
SD4 4
4-)
a)
CD k
k 0
4 t1-1
U)
>1
CD
Cd
4-)'d
4-)
4
r-4 0
CO
t--
O
1--1
cd
Z 0
0 -i_4
k
0
4-1
4
0
k -H
0 c1-4
e1-1
9-1
..
a)
bs2.u)
-
LO • -ri
"Ci 0
N CD Eo
a.) c.)
k
Pi cd
0 = •
tH 0 .0
O 4)• (13 OU)
X ›'. CO cd -F-1 0
.7:5 -,-4 k H 0 4)0
CD E -0 ID E cil -ri
-
a) 4-)
cd
p
U) a) k ..C) 0 bA cd
-H 4 'ri 4 .r4
W 4 ) cd k cd TI k
CD
CD 4-)
O
.4) 0 -PU)
O 0
Q 4.) 1 1 4) 4) 0 •C)
.
-
-
4-)
0
.
0 H
0
-r--,
'o
zi
•
CO
4-) cd
cd ›
H
4
di 0
cd
X 41
CA
cd
H
ti-r
0
H 0
cd
E
P4
to ocn-
.,-1
kk
q
-e-f
cs, -,-1
k
0
(H
›.
cd
4
Z
cd
3 1 64
ki
I
"0
C--
.---•4)k
4-)k
-1-)
4-)
O
=
cd 0
-"H
be....)
.,••••
0 H
cd
cd
• ;-4
E-1
F-4
tr)
C-•
..--,
H
cd H
4-) N
▪
r--1
C.0
C!)o
r-1
1-1
1-1
-r4
.ri
cd
•1-1
(I)
b.D
4--)
0,4
r-i
CO
0
a)
ta
-ri r-1
cd
tsz
0 4
-P
cd
0 ti)
r-1
a) I:,
a)
• a)
O
4-)
CA
.z
cd
1-4
0
4)k
r-1
di CD
a)
E
b....9..
COCD
di
r-i
•
Cd
r-1
0
H
4-)
0
0
Cd
1:7)
-1-)
Cd
Cd
-1-1
k
-P
o
N 0 CO
1-1
c1-1
in
Cl•tti
CO
CO CO CO
c-
k C.)
PY-4
W
E
r-1
11.)
N
•T--1
r-1
O
CY)
-
-0
CH
0
C/)cil
cr)
w -0
r=4 ca
E$-4
-PC)0
C)
a) o
k
al ;. 1
-
H P. 0
W 1:3 cd
-H "ci CD k cd P40
c? cd
<4 ci-i
A
4 o "CS CD
28
Apparent digestion coefficients are presented in
Table 7. Analysis of variance for these data are presented
in Table 8. Digestibilities for OM (67.4%), NDF (54.6%),
ADF (50.2%) and GE (66.1%) were higher (P<.05) for diets
containing A. lentiformis untreated than for diets containing
A. barclayana untreated than for diets containing A.
barclayana untreated (64.2, 48.4, 46.0 and 61.9%, repectively). Digestibilities for CC and CP tended to be higher
(P>.05) for the A. lentiformis diets than for those containing A. barclayana. Though the leaching process aided in
decreasing the mineral content of the halophytes, it adversely
affected diet acceptability and digestibility by washing out
important nutrients such as CC. This detrimental effect
that the leaching process had on the two halophytes tested
was unexpected. It was felt that by decreasing the ash
content, feed intake and digestibility of major nutrients
would increase. But the opposite effect occurred probably
due to the loss of important constituents during washing.
Partial digestion coefficients, calculated by difference for the halophytes, along with the digestion coefficients for alfalfa hay determined in Trial 1 are shown
in Table 9. Since the halophytes comprised only 25% of the
diet, this method magnifies the differences observed among
diets. It clearly shows the superiority of A. lentiformis
in comparison to A. barclayana and that the leaching of
•
-
•
•
•
••
29
Tti
0
CD
r.1
*ts *CO
Co
CD
Tri
Tr'
ID CO CD N N CD
•
CD
.
1--1
CO
•
N
if)
•
Tri
N
Tri
CO
CO
di
H
N
1--41-1
cD
cm
v-1
C
H
cr)
CY3
0)
00
1-1
Co
I—ItC
C)
N
C.-
co
co
co
*
CI)
N
Tti
If)
CO
03)
1-1
CS)
CO
00
H
*
1-1 r-1 00
0
co
T• ti
1--1
Cq
0
Ct1
`7ti
di
(MN°
CD LI) CD 0 0 CO
Cr) N
N if) CD 0
If)if)
CY)
t—I
di
co
•
Cs
CO CD CD
CD
O
ts
VD
Cs
cr)
1-1
*
* * *
N
C.-
CO
f--I C
C
1--1
O
Tti
Tti
Tti N N
H 00
.
CD CO di 0 O
MC-COI—its
1-1 N N 11") O
CS)
r-1
CS)
Cs
C
o N CO CO N
-
cd
H
N
C.CD
CO 0
N
Cf;
* * *
*
Co
a)
Cf)
-
N
CY")
CO
ri
N 1-1
NW
H CO
1-1
CD
O 0
O -F4
4-)
7:3 Ct)
a) a)
rn tu)
ca
P"-1
cd
30
Table 9. Partial Digestion Coefficients Calculated by
Difference for Halophytes Fed As 25% of the
Diet -- Trial 2.
Partial
Digestion
Coefficients, %
Alfalfa
Haya
A. lentiformis
Untreated Leached
A. barclayana
Untreated Leached
Organic
Matter
63.6
78.8
62.1
65.8
55.4
Crude Protein
64.1
111.2
101.7
108.6
92.9
Cell Contents
73.2
82.8
66.9
78.6
60.9
Dry Matter
62.6
78.1
65.2
63.2
54.8
Neutral
Detergent
Fiber
53.8
57.1
52.0
32.4
42.2
Acid
Detergent
Fiber
56.5
31.3
22.1
14.6
20.5
Gross Energy
62.7
76.3
57.5
59.5
49.4
a Used to calculate partial digestion coefficients for
halophyte portion of the diet. Determined in an earlier
trial using goats at this station (Wiley et al. 1981).
these materials to remove salts had a detrimental effect on
their digestibilities. All calculated coefficients for
untreated A. lentiformis, with the exception of that for
ADF were higher than for those determined for alfalfa hay.
31
This is in agreement with the results of Trial 1. Except
for the fiber components, partial digestion coefficients
for A. barclayana were similar to those for alfalfa hay.
Nitrogen (N) balance data are presented in Table 10.
Analysis of variance for these data are presented in Table
11. Daily N intake was slightly higher for both A.
lentiformis diets than for the A. barclayana diets (28.6 vs
26.3 g/day), respectively, reflecting the differences in
protein content between the two halophyte species. Fecal N
was similar for the two halophytes (6.7 to 7.2 g/day) while
urinary N was higher when goats received the untreated diets
(16.3 vs 14.8 g/day). N retention ranged from 3.9 to 5.8
g/day for both species of saltbush. N retention expressed
as a percentage of intake was different for the four treatments. A. barclayana untreated and A. lentiformis leached
(20.6 and 19.0%, respectively) had the highest values. A.
barclayana leached and A. lentiformis untreated were 16.6%
and 15.0%, respectively. Percent N absorbed followed the
same pattern. The N retention figures obtained in Trial 2
are higher than those figures for Trial 1. This may be
related to the feed intake differences, as related to
percent of body weight (80.0% vs 90.0%) that existed between
the Trial 1 and 2, respectively.
32
Table 10. Nitrogen Balance Data a -- Trial 2.
A. lentiformis
Untreated Leached
A. barclayana
Untreated Leached
Nitrogen intake, g/day
Intake
28.8
28.4
27.6
24.9
6.8
7.2
6.7
7.1
17.5
15.6
15.1
13.9
4.5
5.5
5.8
3.9
% of Intake
15.0
19.0
20.6
16.6
% of Absorbed
19.6
25.9
27.3
23.0
Nitrogen excretion,
g/day
Fecal
Urinary
Nitrogen retention,
g/day
a Mean of 4 observations.
33
*
N
*
0
•
•
N
ri
N
*
cs)
N
•
CD
V
*
00
ri
00
t••••
VI
N
•
•
N
N
CNI
*
N
00
If)
*
i
*
ri
N
00
N
*
01
*
*
ri
C•
•
•cti
N
CD
•
Lt)
I—I
0
In
di
co
0
*
*
di
di
di
Lc)
(D
c
co
i
0)
o0
CD
LCD
0
N
N
CO
CO
*
Cn
*
01
Lf)
.
00
CD
0)
4-)
9-1
1-1
(.0
CY)
LCD
Cf)
Cr,
CO
w
4)
cd
O
N
r-1
r-1
O
• -
1
(:14
0
0
0)
C9
0
•cti
CD
.
0
0)
0
•
N
0
ri
CD
'II
N
.
00
N
di
0)
•
C
ce)
di
N
N
ri
CD
0
O
O
C•-•
ri
0
0
0
0
ri
*
*
CD
ri
N
CO
r
00
.
ri
N
Cf)
W
N
.
0
.
Cf)
r-I
r-I
r•-1
W CO
-I-) CD
CU W
c.)
cd
N
›.
Q
4)
0
-r-{
e
cf)
0k
1-1 El
cd
E4
ro
0
34
General Discussion
Results of this study indicate that there are
acceptability problems associated with these halophytes.
It was thought that this may be due to the high mineral
content of these plants, but the leaching process depressed
feed intake, probably by washing out many other valuable
nutrients. It appears that A. lentiformis was more readily
accepted than A. barclayana by goats.
This differs from
the investigations by Schurg et al. (1982) in which these
two species of saltbush were incorporated into poultry
rations. Poultry preferred A. barclayana over A. lentiformis.
Trial 2 indicates that A. barclayana was as least as digestible as alfalfa hay. Also, the leaching process decreased
digestibility of major nutrient components in both species
of halophytes. The differences between the two species in
their acceptability and digestibility by the goats may be
due to genetic differences or to plant parts.
The unpalatability of these and similar halophytes
may be related to the high protein digestibility as suggested
by Milthorpe (1970). The Atriplex used in this study contained approximately 15% CP and when calculated by difference, yielded digestion coefficients in excess of 95%.
Previous investigators (Chatterton et al. 1971, Cook et al.
1959 and Peiper and Donart 1978) have noted that some
species of saltbush contain relatively high amounts of
protein adding to their value on the range.
35
Although the digestibility data from Trial 1 and 2
was encouraging, it must be emphasized that the diets contained only 25% halophyte. Furthermore, physical assessment
of the goats after the completion of Trial 1 showed that
the goats on the 25% A. lentiformis diet lacked coat sheen
and, in general, did not appear to be as thrifty as the
goats on the alfalfa hay diet. This was not observed in
Trial 2.
Grazing studies have determined that Atriplex species
serve a useful and necessary role as reserve fodder during
periods of drought, although they are not a preferred species
(Chatterton et al. 1971, Gates and Muirhead 1967, Goodin and
McKell 1970 and Peiper and Donart 1978). Results of this
study suggest that if it is possible to cultivate Atriplex
species in regions of marginal agricultural production, the
forage could be used for ruminant production. Species
selected, stage of plant maturity, harvest intensity and
availability of drinking water are all important aspects
when considering the use of halophytes for animal production.
Palatability problems, possibly related to the high mineral
content would seem to be the greatest obstacle in using
these or similar halophytes in livestock rations.
CONCLUSIONS
On the basis of the results of the feeding and
digestibility trials reported in this thesis and the in-
formation available in the literature, the following conclusions were drawn.
1.
Atriplex lentiformis and Atriplex barclayana,
grown with hypersaline irrigation water, was
more digestible (except for fiber) than
alfalfa hay.
2. A. lentiformis was superior to A. barclayana in
acceptability, nutrient composition and
digestibility.
3.
Leaching with fresh water decreased mineral
content of the two halophytes tested, but did
not improve acceptability or digestibility.
4.
High ash content may limit extensive use in
livestock rations, particularly in areas where
drinking water is a limiting factor.
36
37
5. Further research is needed, especially,
in areas of animal growth production and
lactation, if halophytes are to be considered for widespread use.
LITERATURE REVIEW
A.O.A.C., 1970. Official Methods of Analysis (11th Ed.).
Association of Official Analytical Chemists,
Washington, D.C.
Ashby, W. C. and N. C. W. Beadle. 1957. Studies in
halophytes III. Salinity factors in the growth of
Australian saltbushes. Ecology 38 (2):344-352.
Chatterton, N. J., J. R. Goodin, C. M. McKell, R. V. Parker
and J. M. Rible. 1971. Monthly variation in the
chemical composition of desert saltbush. J. Range
Manage. 24:37-40.
Cook C. Wayne, L. A. Stoddart and Lorin E. Harris. 1959.
The chemical content in various portions of the
current growth of salt-desert shrubs and grasses
during winter. Ecology 40 (4): 644-651.
Gates, C. T. and W. Muirhead. 1967. Studies of the
tolerance of Atriplex species. 1. Environmental
characteristics and plant response of A. vesicaria,
A. nummularia and A. semibaccata. Austr. J. Exp.
Agric. Animal Husb. 1617:39-49.
Glenn, E. P., M. R. Fontes and N. P. Yensen 1982. Productivity of halophytes irrigated with hypersaline
seawater in the Sonoran desert. In: Biosaline
Research: A Look to the Future. H. San Pietro
Plenum Publ. Corp. pp. 491-494.
Goering, H. K. and P. J. Van Soest. 1970. Forage fiber
analyses (apparatus, reagents, procedures and some
applications). Agricultural Research Service, U. S.
Dept. of Agr., Agriculture Handboodk No. 379.
Goodin, J. R. 1979. Atriplex as a forage crop for arid
lands. In: G. Ritchie (Ed.) New Agricultural
Crops pp. 133-148. AAAS Selected Symposium 38.
38
39
Goodin, J. R. and C. M. McKell. 1970. Species for the
improvement of subtropical and temperate areas.
Atriplex spp. as a potential forage crop in
marginal agricultural areas. Proc. of XI International Grassland Congress, pp. 158.
Graetz, R. D. and Wilson A. D. 1980. Comparison of the
diets of sheep and cattle grazing a semi-arid
chenopod shrubland. Aust. Range. J. 2 (in press).
Hayward, H. E. 1956. Plant growth under saline conditions.
UNESCO. Arid Zone Research Utilization of Saline
Water 4:37-71.
Leigh, J. H. and W. E. Mulham. 1967. Selection of diet
by sheep grazing semi-arid pastures on the Riverine
Plain. 3. A bladder saltbush (Atriplex vesicaria) pigf ace (Disphyma australe) community. J. Exp. Agric.
Animal Husb. 7:421-425.
MacFarlane, W. V., B. Howard and B. D. Siebert. 1967. Water
metabolism of Merino and Border Leicester sheep
grazing saltbush. Aust. J. Agric. Res. 18:947-958.
MacFarlane, W. V., C. H. S. Dolling and B. Howard. 1966.
Distribution and turnover of water in Merino Sheep
selected for high wool production. Aust. J. Agric.
Res. 17:491-502.
MacFarlane, W. V., R. J. H. Morris and B. Howard. 1958.
Heat and water in tropical Merino sheep. Aust. J.
Agric. Res. 9:217-18.
MacFarlane, W. V., R. J. Morris and B. Howard. 1963.
Turnover and distribution of water in desert camels,
sheep, cattle and kangaroos. Nature (Lond.) 197,270.
Milthorpe, F. L. 1970. Biology of Atriplex. Studies of
the Australian Arid Zone. (CSIRO, Canberra 1970).
Mozafar, Ahmad and J. R. Goodin. 1970. Vesiculated hairs:
A mechanism for salt tolerance in Atriplex halimus
L. Plant Physiol. 45:62-65.
-
National Research Council of the National Academy of Sciences.
1964. Joint US - Canadian Tables of Feed Composition.
Nutritional Data for USA and Canadian Feeds. No.
1232. Washington, D.C.
40
National Research Council of the National Academy of
Sciences. 1968. Nutrient Requirements of Sheep.
Washington, D.C.
National Research Council of the National Academy of
Sciences. 1982. US - Canadian Tables of Feed
Composition. Nutritional Data for USA and Canadian
Feeds. Washington, D.C.
Nemati, Nasser. 1977. Comparative palatability of Atriplex
canescens. J. Range Manage. 30 (5):368-369.
Peiper, Rex, C. Wayne Cook and Lorin E. Harris. 1959.
Effect of intensity of grazing upon nutritive content
of the diet. J. Animal Sci. 18:1031-1037.
Pieper, Rex D. and Gary B. Donart. 1978. Response of
Fourwing saltbush to periods of protection. J.
Range Manage. 31 (4):314-315.
Reimold, Robert J. and William H. Queen (editors). 1974.
Ecology of Halophytes. Academic Press, New York.
pg. 237, 362, 366.
Schurg, W. A., P. M. Maiorino and B. L. Reid. 1982.
Utilization of Atriplex barclayana and lentiformis
by growing chicks and rabbits. J. An. Sci. 33
(Proceedings, Western Section).
Steel, R. G. D. and J. H. Torrie. 1960. Principles and
Procedures of Statistics. McGraw-Hill Book Co.,
Inc. New York.
Waisel, Yoav. 1972. Biology of Halophytes. Academic
Press, New York. pg. 42, 238, 295.
Welch, Bruce L. 1978. Relationships of soil salinity,
ash, and crude protein in Atriplex canescens. J.
Range Manage. 31(2):132-133.
Wilson, A. D. 1974. Water consumption and water turnover
of sheep grazing semi-arid pasture communities in
New South Wales. Aust. J. Agric. Res. 25:399-347.
Wilson, A. D., J. H. Leigh and W. E. Mulham. 1969. A
study of Merino sheep grazing a bladder saltbush
(Atriplex vesicaria) cotton bush (Kochia aphylla)
community on the Riverine Plain. Aust. J. Agric.
Res. 20:1123-1136.
41
Wood, J. G. 1925. The selective absorption of chloride
ions; and the absorption of water by the leaves
in the genus Atriplex. Aust. J. Exp. Biol. Med.
Sci. 2:45-53.