EVALUATION OF FOURWING
SALTBUSH AS A FORAGE FOR
SHEEP AND ANGORA GOATS
D. N. Ueckert
J. L. Petersen
J. E. Huston
M. W. Wagner
ABSTRACT
fourwing saltbush is an excellent protein source for range
livestock and big game animals (for example, see NunezHernandez 1989). However, the actual feeding value of
fourwing saltbush to livestock has not been quantified
relative to its effects on animal performance. We initiated
research in 1984 to evaluate fourwing saltbush as a
source of supplemental nutrients for sheep and Angora
goats in western Texas. Fourwing saltbush was selected
for study based on previous research in the region which
showed winter leaf retention, laboratory-determined nutritional values, and potential forage yields of western
Texas ecotypes were high (McFarland and others 1987;
Petersen and others 1987).
Western Texas accessions of fourwing saltbush
(Atri plex canescens) appeared to be unpalatable to
Angora kids during September-October but were readily
eaten by yearling ewes during winters when annual {orbs
were not available. Fourwing saltbush served as a source
of supplemental nutrients during winter for sheep, but
its feeding value was considerably overestimated by
laboratory-determined nutritional values. Results from
grazing and metabolism trials suggest plant secondary
metabolites in fourwing saltbush may interfere with nutrient utilization, or that protein nitrogen in the forage may
be rapidly hydrolyzed in the rumen, absorbed as ammonia, and excreted in the urine.
METHODS
INTRODUCTION
Plantings of western Texas ecotypes offourwing saltbush were established by direct seeding or transplanting
containerized seedlings during 1981-84 at the Texas A&M
University Agricultural Research and Extension Center
near San Angelo and on land owned by the University of
Texas System in Reagan and Crockett Counties. Stocking
rates in all grazing trials were set at light-to-moderate
levels to assure forage availability would not limit consumption. Salt and a mineral supplement containing
12 percent phosphorus and 12 percent calcium were provided ad libitum in all grazing trials.
The animals were fasted 15 hours prior to taking initial
and final weights. Data were subjected to analyses of
variance, and means were separated by Duncan's multiple
range test where appropriate.
Nutrient concentrations in rangeland forages are
often below those required to satisfy the nutritional
requirements of grazing livestock. As a result, concentrated supplemental feeds must often be provided to
attain acceptable levels of livestock performance. A
potential alternative to this practice involves the introduction of high-quality shrubs into the forage complex.
For example, plantings of oldman saltbush (A.triplex
nummularia) are currently being utilized in South Africa
to alleviate nutrient deficiencies in grasslands during dry
summers. Research has shown oldman saltbush pastures
to have a 3-month dry season carrying capacity of about
four to five sheep/acre (10 to 13/ha) (Barnard 1986). Similar interest in the use of shrubs as a means for improving
the quality of livestock diets has been evident in the western United States (Gade and Provenza 1986; Otsyina and
others 1984). Fourwing saltbush (Atriplex canescens)
has been identified as valuable source of supplemental
nutrients for livestock. It is readily consumed by cattle
(Shoop and others 1985; Soltero and Fierro 1981), and
when present, supplemental feed requirements tend to
decline (Gonzales 1972). It is generally concluded that
Angora Goat Studies
1984 Grazing Trial-Sixty weanling Angora kids were
utilized in a grazing trial September 4 through October 8,
1984, to evaluate fourwing saltbush pastures for Angora
kids. The kids were divided into 12 uniform groups of five
head each, and groups were randomly assigned to two
replications of each of six treatments: (1) dry (senescent)
grass; (2) dry grass+ 32 percent crude protein (CP)
concentrate; (3) fourwing saltbush; (4) fourwing saltbush
+ 32 percent CP concentrate; (5) fourwing saltbush-grassforb mixture; and (6) fourwing saltbush-grass-forb mixture+ 32 percent CP concentrate. The dry grass plots
supported a mixture ofkleingrass (Panicum coloratum),
buffalograss (Buchloe dactyloides), and red threeawn
(Aristida longiseta). The saltbush-grass-forb mixture
a
Paper presented at the Symposium on Cheatgrass Invasion, Shrub DieOff, and Other Aspects of Shrub Biology and Management, Las Vegas, NV,
April 5-7, 1989.
Authors are Range Ecologist, Research Associate, Range Animal Nutritionist, and Research Associate, respectively, Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center, 7887 N. Hwy. 87, San Angelo, TX 76901. M. W. Wagner is
currently Biologist II, Texas Parks and Wildlife Department, 4200 Smith
School Road, Austin, TX 78744.
300
This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
plots supported King Ranch bluestem (Bothriochloa ischaemum), Lehmann lovegrass (Eragrostis lehmanniana),
red threeawn, buffalograss, kochia (Kochia scoparia), and
desertholly perezia (Perezia nana). The concentrate feed
(65 percent cottonseed meal, 22 percent ground milo, 10
percent dehydrated alfalfa meal, 2 percent molasses, and
1 percent salt) was provided ad libitum.
through February 23, 1989. The ewes were divided into
uniform groups of10 head each, and the groups were
randomly assigned to five treatments: (1) WW-Spar
bluestem; (2) fourwing saltbush/WW-Spar bluestem
rotation; (3) fourwing saltbush-sideoats grama mixture;
(4) grass-fourwing saltbush mixture; and (5) seeded pasture (mixture ofkleingrass, WW-Spar bluestem, and Wilman lovegrass). Grasses in the grass-fourwing saltbush
mixture pastures included sand dropseed, slim tridens,
kleingrass, and silver bluestem. There were two replications of all treatments except the fourwing saltbushsideoats grama mixture and the seeded pasture.
Metabolism Trial-Eight yearling Angora nannies
were utilized in a metabolism trial April 22 through
May 11, 1985. Four were fed fresh, succulent spring
growth offourwing saltbush ad libitum and four were
fed fourwing saltbush ad libitum+ 0.66lb (300 g)/day
of the 32 percent CP concentrate described above. Fourwing saltbush was hand-harvested daily. The goats were
preconditioned on the experimental diets for 14 days prior
to initiation of the metabolism trial.
Daily intake of saltbush, concentrate, and water, and
daily output of feces and urine were recorded for each
goat. Nitrogen balances for the two treatments were
determined by standard metabolism trial procedures.
ANGORA STUDY RESULTS
1984 Grazing Trial-The weanling Angora kids
were observed to prefer grasses and forbs over fourwing
saltbush when a choice was available. Furthermore,
a low degree of utilization offourwing saltbush by the
weanling kids in saltbush monoculture plots suggested
intake may have been low where saltbush was the only
forage available. Weanling kids grazing dry grass and
those grazing fourwing saltbush lost about 3lb (-40
g/head/day) during the 34-day trial, while those grazing
the saltbush-grass-forb mixture gained 0.4lb (5 g/head/
day) (fig. 1). Kids receiving the 32 percent CP concentrate
in the grass plots and in the fourwing saltbush-grass-forb
plots gained 9 and 7.9lb (120 and 105 g/head/day), respectively, and their weight gains were significantly (P=0.05)
greater than those of kids receiving concentrate in the
fourwing saltbush plots (3.7lb) (49 g/head/day) (fig. 1).
Sheep Trials
1987 Grazing Trial-Forty-nine yearling Rambouillet
ewes were utilized in a grazing trial January 8 through
March 9, 1987. The ewes were divided into uniform
groups of seven head each, and the groups were randomly
assigned to four treatments: (1) "WW-Spar" bluestem
(Bothriochloa ischaemum var. ischaemum); (2) fourwing
saltbush/WW-Spar bluestem rotation (1-2 days on saltbush rotating with 1-2 days on bluestem); (3) fourwing
saltbush-sideoats grama (Bouteloua curtipendula) mixture; and (4) rangeland + 23 percent CP supplement fed
at 0.3 lb (136 g)/head/day.
There were two replications of all treatments except
the fourwing saltbush-sideoats grama mixture. The
23 percent CP supplement feed contained cottonseed
meal (45 percent), ground milo (40 percent), and salt
(15 percent). The native rangeland supported sand dropseed (Sporobolus cryptandrus), sideoats grama, silver
bluestem (Bothriochloa saccharoides), slim tridens (Tridens muticus), redseed plaintain (Plantago rhodosperma),
huisachedaisy (Amblyolepis setigera), and plains dozedaisy (Aphanostephus ramossissimus). Percentage of
fourwing saltbush forage utilized by sheep in each plot
was visually estimated at the end of the trial.
Metabolism Trial-The spring growth (leaves and
twigs) offourwing saltbush (16 percent crude protein;
62 percent dry matter digestibility) was readily eaten by
yearling Angoras in metabolism stalls. However, total
feed intake was significantly less in goats fed saltbush
10
8
g
c:
·n;
C!'
1988 Grazing Trial-Ninety yearling Rambouillet
ewes were utilized in a grazing trial January 12 through
March 14, 1988. The ewes were divided into uniform
grol.!ps of 10 head each, and the groups were randomly
assigned to five treatments: (1) WW-Spar bluestem;
(2) fourwing saltbush/WW-Spar bluestem rotation;
(3) fourwing saltbush-sideoats grama mixture; (4) seeded
pasture; and (5) seeded pasture+ 23 percent CP supplement (described above) fed at 0.3 lb (136 g)/head/day.
The seeded pasture was a mixture of kleingrass, WWSpar bluestem, and Wilman lovegrass (Eragrostis superba). There were two replications of all treatments
except the fourwing saltbush-sideoats grama mixture.
6
4
2
0
-2
-4
Grass
-Forage only
Saltbush
I>
I Forage+ 32% C.P.
Figure 1-Weight gains (I b) of weanling Angora kids
grazing dry (senescent) grasses, fourwing saltbush,
or a fourwing saltbush-grass-forb mixture (SGF)
alone or with 32 percent crude protein concentrate
ad libitum, September 4 through October 8, 1984.
Means followed by different lower case letters are
significantly different {P=0.05).
1989 Grazing Trial-Eighty yearling Rambouillet
ewes were utilized in a grazing trial December 20, 1988,
301
SGF
Table 1-Results1 from metabolism trial with yearling Angora nannies fed fresh fourwing saltbush alone or with 32 percent
crude protein concentrate during April 22 through May 11,
1985
Fourwing saltbush was readily browsed by the ewes in all
pastures where it was available. Ewes grazing WW-Spar
bluestem pastures lost 11lb (-81 glhead/day) during the
62-day trail (fig. 3).
Yearling ewes rotated between bluestem and fourwing
saltbush pastures lost 4.4lb (-32 glhead/day), which was
significantly (P=0.05) less weight loss than that of ewes
grazing only bluestem (fig. 3). By comparison, ewes grazing the seeded pastures lost only 0.1lb (-1 glhead/day),
Diet
Criterion
"
..
Weight change (lb)
Intake
Concentrate (g/kg·75)
Fourwing saltbush (g/kg· 75)
Total (g/kg·75 )
Water (g/kg· 75)
Dry matter digestibility
Fourwing saltbush (percent)
Total (percent)
Nitrogen intake (glhead/day)
Fecal nitrogen (glhead/day)
Urine nitrogen (glhead/day)
Nitrogen balance (glhead/day)
Fourwlng
saltbush
Fourwing
saltbush
+ concentrate
-2.5a
O.Sa
Oa
29a
29a
139 a
19 b
33a
52 b
192 a
62a
62a
Sa
2a
?a
-1 a
GOa
63a
23b
Sb
13 b
Sb
20~----------·------------------------~
. ··---. --- ------ -- -- ---·- _____j_4~:Lc::.
g
10i·--···---·····--·································----·
--··-···--·-·······-···--·---------···-·-
c:
"iij
~
1
Means within a row followed by similar lower case letters are not significantly different (P=O.OS).
5+------·------··--------------·--···--0
bluestem
alone, compared to those fed saltbush+ 32 percent CP
concentrate (table 1). Intake of saltbush was similar in
the two treatments. Angora yearlings fed only saltbush
had a negative nitrogen balance (-1 glhead/day), whereas
those fed saltbush+ concentrate retained 5 g nitrogen/
head/day (table 1). Goats fed saltbush alone lost about 88
percent of their daily nitrogen intake in the urine, compared to 57 percent for those fed saltbush+ concentrate.
BSR
R+P
Figure 2-Gains (lb) of yearling Rambouillet ewes
grazing WW-Spar blues tern, a WW-Spar bluestem/
fourwing saltbush rotation (BSR), or rangeland
(mixed grasses + annual forbs) +a 23 percent
crude protein supplement fed at 0.3 lb (136 g)/
head/day (R+P), January 8 through March 9, 1987.
Means followed by different lower case letters are
significantly different (P=O.OS).
SHEEP GRAZING RESULTS
Yearling ewes grazing WW-Spar bl uestem pastures
lost 3.2lb (-24 glhead/day) during the 60-day grazing
trial in 1987, compared to a gain of 5.8lb (44 glhead/day)
for those in the bluestem/saltbush rotation (fig. 2).
The bluestem was dormant during the first half of the
grazing trial, but a small quantity of new basal growth
was available for grazing during the second half of the
trial. Annual forbs (redseed plaintain, plains dozedaisy,
huisachedaisy) were abundant in the fourwing saltbush
pastures used in the bluestem/saltbush rotation, and
appeared to be preferred over saltbush by the sheep. Less
than 5 percent of the available fourwing saltbush browse
was utilized by sheep "rotated among the bluestem and
saltbush pastures. Ewes receiving the 23 percent CP
concenkate and grazing the rangeland where annual
forbs were also abundant gained 14.1lb (107 glhead/day)
(fig. 2). Forbs were rare in the fourwing saltbush-sideoats
grama mixture pasture and the sheep readily consumed
fourwing saltbush, utilizing about 40 percent of the available browse. Sheep grazing the saltbush-sideoats grama
pasture gained 10.2 ± 2.8 lb (77 ± 21 glhead/day) (mean±
SD) (n=10) (data not shown).
Growing conditions were very poor, and there were no
forbs in any of the pastures during the 1988 grazing trial.
10
5
g
0
-0.1 c
c:
'iij
~
-5
-10
-11.0 a
-15
bluestem
BSR
KBL
Figure 3-Gains (lb) of yearling Rambouillet ewes
grazing WW-Spar bluestem, a WW-Spar blue stem/
fourwing saltbush rotation (BSR), seeded pasture
(mixture of kleingrass, WW-Spar bluestem, and
Wilman lovegrass) (KBL), or seeded pasure +a
23 percent crude protein supplement provided
at 0.3 lb (136 g)/head/day (KBL+P), January
12 through March 14, 1988. Means followed
by different lower case letters are significantly
different (P=O.OS).
302
KBL + P
which was significantly less weight loss than that of
ewes in the bluestem/saltbush rotation. Ewes grazing
the seeded pastures and receiving 23 percent CP supplement gained 4.4lb (32 glhead/day) (fig. 3). Improved
performance of ewes on the seeded pastures compared
to that of those on the WW-Spar bluestem pastures was
probably related to cultural practices in that the seeded
pastures had been shredded twice during the previous
growing season whereas the bluestem pastures were
neither shredded nor grazed. The shredding appeared
to enhance growth late in the growing season, which in
turn improved nutritional quality during the winter
months. The poor performance of ewes in the bluestem/
saltbush rotation relative to those grazing the seeded
pasture was unexpected and the reason is unclear. Ewes
grazing the saltbush-sideoats grama pasture lost 2.1 ±
3.8lb (-15 ± 28 g/head/day) (n=10) (data not shown).
Growing conditions were also poor during the 65-day
grazing trial initiated in late December 1988; thus no
annual forbs were present in any of the treatment
pastures. Fourwing saltbush was readily consumed
by the ewes in pastures where it was available. Ewes
grazing WW-Spar bluestem lost 13.8lb (-96 g/head/day)
(fig. 4). Ewes rotated among bluestem and fourwing
saltbush pastures lost 2.3lb (-16 g/head/day), which was
significantly less weight loss than that of ewes grazing
only bluestem. Ewes grazing the mixture of grasses and
fourwing saltbush gained 7.6lb (53 g/head/day) during
the 65-day trial (fig. 4). Ewes grazing the fourwing
saltbush-sideoats grama pasture gained 5. 7 ± 2.8 lb
(40 ± 19 g/head/day) (n=10), and those grazing the
kleingrass-bluestem-lovegrass mixture gained 2.8 ±
3.7lb (19 ± 26 g/head/day) (n=10) (data not shown).
DISCUSSION
Laboratory analyses (Petersen and others 1987) suggested that the fourwing saltbush leaves should have
provided a diet of sufficient quality for growth of young
Angora goats and sheep. Fourwing saltbush appeared
to be unpalatable to Angora kids but relatively palatable
to yearling Angoras and ewes. The reason the shrub was
not consumed by Angora kids is unclear. The Angora kids
had never been exposed to palatable shrubs prior to the
grazing trial; thus they may have had insufficient time
to learn to browse during the 34-day trial. However, the
possibility exists also that saltbush forage contained sufficient concentrations of plant secondary metabolites to
deter feeding. Low palatability of some accessions of fourwing saltbush has been associated with high concentrations of saponins (Sanderson and others 1987). The
depressed weight gains of Angora kids receiving protein
concentrate and grazing saltbush, compared to weight
gains of kids receiving the concentrate and grazing dry
grasses or forbs, suggested secondary metabolites in the
saltbush interfered with nutrient utilization or reduced
feed intake in young goats. Results from our metabolism
trial with Angora yearlings fed succulent spring growth
of saltbush also suggested an interference with nutrient
utilization. However, it is possible that the protein nitrogen in new spring growth of saltbush may be rapidly
hydrolyzed in the rumen, absorbed as ammonia, and
excreted in the urine. Nitrogen retention was similar
in Angora goats fed diets containing 30 percent dried
fourwing saltbush leaves (harvested in June) and diets
containing 30 percent alfalfa hay in a New Mexico study
(Nunez-Hernandez and others 1989). The plant growth
stage and percentage offourwing saltbush in the diet
may influence nitrogen retention. Further research is
warranted to explain the apparent low value of the spring
and September-October forage of western Texas accessions offourwing saltbush for Angora goats and to determine the value of the shrub for goats during winter.
Weight changes of yearling ewes grazing in winterdormant grass-saltbush mixtures or rotations were generally superior to those of ewes grazing only dormant
grasses, as was expected. The ewes grazing dormant
grass-saltbush mixtures generally performed better
(lost less weight or gained more weight) than those in
1- or 2-day rotations among dormant grass and fourwing
saltbush pastures. However, the dormant grass-saltbush
mixtures or rotations did not consistently provide diets of
sufficient quality to meet the maintenance requirements
of the young ewes. Performance of ewes grazing dormant
grass-saltbush mixtures or rotations was significantly
lower than that of ewes grazing dormant grasses and
receiving protein supplement.
These data suggest that fourwing saltbush plantings
would be of value as a source of supplemental nutrients
during the winter for sheep. However, the feeding value
10
5
g
1::
0
-5
"ia
(!)
-10
-15
-20
blue stem
BSR
GSM
Figure 4-Gains (lb) of yearling Rambouillet ewes
grazing WW-Spar bluestem, a WW-Spar bluestem/fourwing saltbush rotation (BSR), or a grassfourwing saltbush mixture (GSM), December 20,
1988, through February 23, 1989. Means followed by different lower case letters are significantly different (P=0.05).
303
of the shrub to sheep is considerably less than is suggested by its laboratory-determined nutritional value,
probably because of plant secondary metabolites or other
inherent plant characteristics that interfere with nutrient
utilization, forage intake, or both. These findings suggest
that researchers and resource managers should be cautious in predicting the feeding value of plants to livestock
and wildlife from laboratory analyses.
Otsyina, R. M.; McKell, C. M.; Malechek, J. M.; Van Epps,
G. A. 1984. Potential of Atriplex and other chenopod
shrubs for increasing range productivity and fall and
winter grazing use. In: Tiedemann, A. R.; McArthur,
E. D.; Stutz, H. C.; Stevens, R.; Johnson, K., compilers.
Proceedings-symposium on the biology of Atriplex
and related chenopods; 1983 May 2-6; Provo, UT. Gen.
Tech. Rep. INT-172. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Forest and
Range Experiment Station: 215-219.
Petersen, J. L.; Ueckert, D. N.; Potter, R. L.; Huston, J. E.
1987. Ecotypic variation in selected fourwing saltbush
populations in western Texas. Journal of Range Management. 40(4): 361-366.
Sanderson, S. C.; Pendleton, R. L.; McArthur, E. D.;
Harper, K. T. 1987. Saponin effect on small mammal
forage preference in a planting of Atriplex canescens.
In: Provenza, F. D.; Flinders, J. T.; McArthur, E. D.,
compilers. Proceedings-symposium on plant-herbivore
interactions; 1985 August 7-9; Snowbird, UT. Gen.
Tech. Rep. INT-222. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Research
Station: 74-77.
Shoop, M. C.; Clark, R. C.; Laycock, W. A.; Hansen, R. M.
1985. Cattle diets on shortgrass ranges with different
amounts offourwing saltbush. Journal of Range Management. 38(5): 443-449.
Soltero, G. S.; Fierro, L. C. 1981. lmportancia del chamizo
(Atriplex canescens) en la dieta de bovinos en pastoreo
en un matorral desertico de Atriplex-Prosopis durante
la epoca de sequia. Chihuahua, Mexico: Rancho Experimentalla Campana; Pastizales. 12(1): 2-7.
REFERENCES
Barnard, S. A. 1986. Oldman saltbush in the winter region. Pretoria, South Africa: Department of Agriculture
and Water Supply; Farming in South Africa, Pastures
No. 140.4 p.
Gade, A. E.; Provenza, F. D. 1986. Nutrition of sheep
grazing crested wheatgrass versus crested wheatgrassshrub pastures during winter. Journal of Range Management. 39(6): 527-530.
Gonzales, M. H. 1972. Manipulating shrub-grass plant
communities in arid zones for increased animal production. In: McKell, C. M.; Blaisdell, J.P.; Goodin, J. R.,
tech. eds. Wildland shrubs-their biology and utilization: an international symposium; 1971 July; Logan,
UT. Gen. Tech. Rep. INT-1. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station: 429-434.
McFarland, M. L.; Ueckert, D. N .; Hartmann, S. 1987.
Revegetation of oil well reserve pits in west Texas.
Journal of Range Management. 40(2): 122-127.
Nunez-Hernandez, G.; Holechek, J. L.; Wallace, J.D.;
Galyean, M. L.; Tembo, A.; Valdez, R.; Cardenas, M.
1989. Influence of native shrubs on nutritional status
of goats: nitrogen retention. Journal ofRange Management. 42(3): 228-232.
304