Published 1986

23 Sulfur in Livestock Nutrition

R. D. GOODRICH AND J. E. GARRETT

University of Minnesota
St. Paul, Minnesota

Sulfur is essential for all animals because S-containing compounds that

have metabolic, structural, and regulatory functions are ubiquitous. Be-
cause S is not stored in the body, animal diets should contain a relatively
constant supply of S. Thus, the inorganic S contents of feeds offered to
ruminant animals and the S-containing amino acids and B-vitamins con-
tained in diets for nonruminants concerns animal nutritionists. Because
of microbial metabolism of S in the rumen, cattle, and sheep can utilize
inorganic as well as organic forms of S. Nonruminants must be supplied
with organic forms of S.
Interest in the S nutrition of ruminants has been stimulated by the
use of nonprotein nitrogen in diets for cattle and sheep-S is required by
bacteria and protozoa that digest feeds and for the synthesis of microbial
protein.

I. SULFUR-CONTAINING COMPOUNDS IN ANIMAL

TISSUES

A. Sulfur-containing Amino Acids

The S-containing amino acids include methionine, cysteine, cystine,

and taurine. Because the other S amino acids can be produced meta-
bolically from methionine (Fig. 23-1) and because methionine is not
produced by mammals from other S amino acids, methionine is the
dietary essential amino acid for nonruminants (Baker, 1977). However,
about half of the S amino acid requirement of nonruminants can be met
by cysteine. Taurine is a dietary essential amino acid for cats.
The S-containing amino acids are important components of many
proteins, enzymes, and several hormones. By virtue of their presence in
polypeptide chains they contribute to the primary structure of proteins.
Free sulfhydryl groups participate in hydrogen binding and in the for-
mation of disulfide bonds between cysteine molecules in polypeptide
chains. Hydrogen binding and covalent disulfide bonds contribute to the
essential configuration of protein molecules. The free hydrophobic
Copyright 1986 © American Society of Agronomy-Crop Science Society of America-Soil
Science Society of America, 677 South Segoe Road, Madison, WI 53711, USA. Sulfur in
Agriculture, Agronomy Monograph no. 27.
617
618 GOODRICH & GARRETT

Methionine
!
S-adenosylmethionine

l
S-adenosylhomocysteine

1
"---Homocysteine
l)erine
Cystathionine

l~moserine
Cysteine+---+ Cystine

! !
Taurine- Cysteic Acid
Fig. 23-1. Metabolism of S-containing amino acids by mammalian tissue.

thioether group of methionine in polypeptides may also contribute to the

tertiary structure of protein due to interaction with other sites on the
protein molecule.
Many enzymes contain S, and S plays important roles in their activ-
ities. Disulfide bonds are essential for enzyme structure and sulfhydryl
groups function as sites of hydrogen binding, for interaction of substrates
with active sites of enzymes and for binding of prosthetic groups of en-
zymes with substrates.

B. Sulfur-containing Hormones

Several peptide hormones contain S. Insulin contains disulfide bonds

between its two peptide chains, as well as within one of the peptide chains.
Glucagon and ACTH contain S amino acids. The internal ring structure
of oxytocin is formed by a disulfide bond between cysteine molecules.

C. Sulfur-containing B-Vitamins

Thiamine and biotin both contain S. Thiamine is a part of the coen-

zymne (thiamine pyrophosphate) that is involved in the decarboxylation
of a-ketoglutaric and pyruvic acids and in transketolase reactions. Biotin
functions in aspartic acid metabolism; in decarboxylation of oxaloacetic,
succinic, and oxalosuccinic acids; and in C0 2 fixation reactions in rumen
microorganisms and in mammalian tissue.
SULFUR IN LIVESTOCK NUTRITION 619

D. Other Sulfur-containing Compounds

Collagen, the major structural protein in animal tissues, contains S

amino acids. Chondroitin sulfates are present in bone, tendons, cartilage,
skin, and heart valves. Sulfated mucopolysaccharides also form the or-
ganic matrix that is calcified to form bone. OtherS-containing compounds
that are important in animal metabolism include hemoglobin, the cy-
tochromes, lipoic acid, glutathione, coenzyme A, fibrinogen, and sulfol-
ipids. Heparin and penicillin contain S.
The many diverse compounds that contain S and the highly essential
functions that these compounds perform, illustrate the importance of
providing proper S nutrition for all mammals. Animal performance can-
not be maintained at normal levels without adequate dietary S.

II. RUMINAL METABOLISM OF SULFUR

Ruminant animals, such as cattle and sheep, can use inorganic S to

meet their S requirements, because of metabolism by rumen microor-
ganisms. Rumen bacteria rapidly reduce inorganic S and incorporate the
reduced S into organic compounds. The organic S-containing compounds
that are produced by rumen bacteria are absorbed from the small intestine
as the bacteria are digested. Inorganic Sis converted into S amino acids
in the rumen and these amino acids appear in milk within a few hours
after consumption of inorganic S (Block et al., 1951; Hale & Garrigus,
1953; Anderson, 1956; Emery et al., 1957a,b; Bray, 1964).
The following points concerning S nutrition are well established:
1. Sulfate is reduced to HS- in the rumen prior to S incorporation
into organic molecules (Lewis, 1954).
2. The optimum pH for ruminal so~- reduction is 6.5 (Lewis, 1954).
3. Cysteine formation from so~- is more rapid than methionine for-
mation (Emery et al., 1957a).
4. High concentrate rations favor so~- reduction, because of increased
microbial activity in the rumen (Emery et al., 1957b) and greater
supply of H when high-energy diets are fed.
5. Many strains of rumen bacteria can reduce so~- (Emery et al.,
1957a).
6. Sulfide is absorbed from the rumen, duodenum, and intestine (Bray,
1969a,b).
7. Much of the absorbed Hs- is lost in urine (Bray, 1969a).
The general pathway for S amino acid synthesis from inorganic S is
shown in Fig. 23-2 (Lewis, 1954; Block et al., 1951; Roy & Trudinger,
1970).
· Assimilatory and dissimilatory pathways exist for the conversion of
so~- to HS-. Many bacteria use the assimilatory pathway, while dissi-
milatory reduction occurs in only a few bacterial species.
In the assimilatory pathway, the initial reaction involves SO~- and
620 GOODRICH & GARRETT

Serine
\. Cysteine

SO~..___.So~-...s2 -~tattionine.-...Methionine
\ / --._.HomoJysteine+-+Methionine
s2o~-
Fig. 23-2. Microbial incorporation of inorganic S into cysteine and methionine.

ATP, and results in the formation of adenenosine-5'-phosphosulfate (Hilz

& Lipman, 1955; Bandurski et al., 1960; Peck, 1960). Adenosine-5'-phos-
phosulfate (APS) is named active sulfate, and is then phosphorylated by
another ATP to form 3'-phosphoadenosine-5'-phosphosulfate (PAPS).
Reduction of so~- occurs as PAPS accepts two elections from a donor
protein (fraction C) and S03 is formed. The S03 is bound to a protein
(bound sulfite) where an additional six electrons are accepted to form
Hs-. Sulfite reductase participates in this reaction, but the exact process
is not fully understood. In this pathway, HS- may be transferred, via a
S transferase, directly to serine to produce cysteine. Free HS- is not
produced via this pathway.
Dissimilatory so~- reduction by the rumen bacteria Desulfotoma-
culum, occurs on a large scale and results in the formation of free HS-.
Bacteria that use the dissimilatory pathway require SO~- for growth and
the reduction of So~- is linked to energy yielding processes. In this path-
way, So~- initially reacts with ATP to form APS; APS-reductase then
aids in the conversion of APS to S03, AMP, and H+. Cytochrome C3
serves as the electron donor. Free S03 is reduced via sulfite reductase,
forming free HS-.

III. ABSORPTION AND EXCRETION OF SULFUR

Because rumen microorganisms metabolize both inorganic and or-

ganic forms of S, a variety of S-containing compounds are available for
absorption. Both so~- and Hs- are absorbed from the rumen and in-
testines (Bray, 1969a,b,c; Bird & Moir, 1971). Sulfur-containing amino
acids and B-vitamins are absorbed from the small intestine.
Fecal loss of consumed inorganic S is influenced by chemical form
of the S. Johnson et al. (1971) reported that about 64, 22, and 22% of
orally administered elemental S (S0}, so~- -S, and D-L-methionine-S ap-
peared in feces. Large S losses in urine occur following the consumption
of So~- -S, probably due to the absorption of so~- from the rumen and
to the rapid conversion of So~- to HS-, which is more readily absorbed
from the rumen than So~- (Kulwich et al., 1957; Johnson et al., 1970).
Sulfur losses may also occur because of the formation of volatile H 2S.
Sulfur in feces occurs as protein-S, organic-S, ester sulfate-S, free sulfate-
S, and sulfide-S.
SULFUR IN LIVESTOCK NUTRITION 621

IV. SULFUR REQUIREMENTS

A. Ruminants

Because S is required for the synthesis of S amino acids, it must be

present in adequate quantities if normal growth of rumen bacteria is to
occur (Kahlon et al., 1975a,b). Thus, bacterial populations and metabolic
activities are modified by a lack of S. Bull and Vandersall (1973) and
Spears et al. (1976) reported that 0.14 to 0.24% Sin substrate dry matter
is required for optimum in vitro digestibility. Consequences of S defi-
ciencies for rumen bacteria include lowered rumen bacteria numbers
(Gall et al., 1951; Whanger, 1968); reduced cellulose digestion (Martin
et al., 1964; Bryant, 197 3); reduced ability to metabolize lactate (Whanger
& Matrone, 1966, 1967); reduced protein synthesis (Hume & Bird, 1970;
Kahlon et al., 1975a,b); and reduced ability to synthesize riboflavin and
vitamin B12 •
Dietary S requirements of ruminants, as listed by the National Re-
search Council (1978, 1984a, 1985), range from 0.10 to 0.21% of diet dry
matter. Beef cattle require at least 0.10% S in their diets (Table 23-1 );
sheep have higher S requirements (0.14 to 0.26% S) than beef cattle; and
young dairy calves and lactating dairy cows require feeds that contain
0.21 and 0.20% S. Such amounts of S are generally present in diets for
ruminants. However, rations composed of corn (Zea mays L.) grain and
corn silage may not provide adequate S (Meiske et al., 1966). Several
grasses are inherently low in available S (Ely et al., 1978).
Sulfur requirements of ruminants are frequently expressed as N/S
ratios. Loosli (1952) reported that animal tissues contain an N/S ratio of
15: 1. Thus, many nutritionists have formulated diets to contain an N/S
ratio of 15:1. Goodrich and Meiske (1969) questioned the use of N/S
ratio in diet formulation. Depending on the digestibility and retention
of dietary Nand S, a variety ofN/S ratios may result in an N/S ratio of
15: 1 at the tissue level. If N is more available than S, dietary ratios of
< 15:1 are required. Conversely, if S is more available than N, dietary
Table 23-1. Sulfur requirements of ruminants.
Ruminant Sulfurt Reference+
%
Growing-finishing cattle 0.10 NRC (1984a)
Growing-finishing sheep 0.14-0.26 NRC (1985)
Dairy cattle NRC (1978)
Calf starter concentrate 0.21
Growing heifers 0.16
Dry pregnant cows 0.17
Lactating cows 0.20
Mature bulls 0.11
t Percentage of diet dry matter.
t National Research Council (NRC).
622 GOODRICH & GARRETT

Table 23-2. Sulfur amino acid requirements of pigs. t

Stage of growth Dietary protein:!: Sulfur amino acids:!:§
-------%-------
Starting
1 to 5 kg 27 0.76
5 to 10 kg 20 0.56
Growing
10 to 20 kg 18 0.51
20 to 35 kg 16 0.45
Finishing
35 to 60 kg 14 0.40
60 to 100 kg 13 0.30
Bred gilts and sows,
young and adult boars 12 0.23
Lactating gilts and sows 13 0.36
t National Research Council (1979).
:j: Concentrations in the as-fed diet.
§ Approximately 50% of the S amino acid requirement should be supplied as methionine.

ratios > 15:1 would be necessary. Thus, N/S ratio appears to have little
practical use and may actually be misleading. It is suggested that diets
for ruminants be formulated to provide quantities of S.

B. Nonruminants

Sulfur requirements of nonruminants are expressed as amounts of S

amino acids. Requirements for S-containing B-vitamins are given as sep-
arate requirements. For nonruminants, about half of the S amino acid
requirement may be supplied as cystine (Sasse & Baker, 1974b). The
percentage of the S amino acid requirement that can be met by cystine
is reduced if the diet contains so~-. Sasse and Baker (1974a) reported
that so~- is not a dietary essential; however, it may reduce the need for
cystine, but not for methionine.
Sulfur amino acid requirements of pigs range from 0.23 to 0.76%
(Table 23-2) of the as-fed diet (about 88% dry matter). The highest re-
quirements are for young pigs. Heavy finishing pigs and bred sows have
lowerS amino acid requirements than young growing pigs.
Sulfur amino acid requirements of chickens and turkeys are higher
than those for pigs (Tables 23-3 and 23-4). Highest requirements are for
young, rapidly growing birds.

V. INTERRELATIONSHIPS OF SULFUR WITH OTHER

MINERALS

A. Copper, Molybdenum, and Sulfur

Interrelationships among Cu, Mo, and S have been thoroughly doc-

umented and many researchers have attempted to explain the mecha-
SULFUR IN LIVESTOCK NUTRITION 623
Table 23-3. Sulfur amino acid requirements of chickens. t
Type of bird Dietary protein:j: Sulfur amino acids:j:§
--------%--------
Broilers
0 to 3 weeks 23 0.93
3 to 6 weeks 20 0.72
6 to 8 weeks 18 0.60
Replacement pullets
0 to 6 weeks 18 0.60
6 to 14 weeks 15 0.50
14 to 20 weeks 12 0.40
Laying hens 14.5 0.55
t National Research Council (1984b).
:j: Concentrations in the as-fed diet.
§ Approximately 50% of the S amino acid requirement should be supplied as methionine.

Table 23-4. Sulfur amino acid requirements of turkeys. t

Stage of growth Dietary protein:j: Sulfur amino acids:j:§
%
Starting
0 to 4 weeks 28 1.05
4 to 8 weeks 26 0.90
Growing
8 to 12 weeks 22 0.75
12 to 16 weeks 19 0.65
Finishing
16 to 20 weeks 16.5 0.55
20 to 24 weeks 14 0.45
t National Research Council (1984b).
:j: Concentrations in the as·fed diet.
§ Approximately 50% of the S amino acid requirement should be supplied as methionine.

nisms involved. Early Australian research showed that Mo inhibited Cu

storage in the liver of sheep (Dick & Bull, 1945), and that high concen-
trations of dietary so~- increased the severity of the effect of Mo on Cu
(Dick, 1952). These interrelationships are more pronounced in ruminants
than in nonruminants.
Goodrich et al. ( 1978) summarized results of many studies that ex-
amined Cu, Mo, and S interrelationships and reviewed reports by Dowdy
and Matrone (1968a,b), Dowdy et al. (1969), Huisingh et al. (1973), and
Dick et al. (1975), that explain the mechanisms by which these elements
interact. Either Mo or S may interfere with Cu metabolism, but the effect
on Cu metabolism of high levels of both is greater than high levels of
either individually. High dietary concentrations of inorganic so~- and
other inorganic S sources or organic S, if they are reduced to HS-, lower
blood and liver Cu, lower blood Mo, and increase fecal Mo. Dietary Mo
concentrations of 2 to 5 ppm are associated with reduced storage of liver
Cu and development of anemia. Concurrent high dietary concentrations
ofboth Sand Mo result in lowered Cu absorption, high fecal and urinary
Cu, lowered blood and liver Cu, and depletion of Cu stores.
624 GOODRICH & GARRETT

Formation of cupric sulfide (CuS), cupric molybdate, or cupric thiomo

lybdate in the digestive tract of ruminants may explain the above ob-
servations. Decreased absorption of Cu and resulting low blood and liver
Cu may be explained by formation ofunabsorbable CuS or cupric thiom-
olybdate. Symptoms of a Cu deficiency and at the same time high blood
concentrations of Cu may be explained by formation of absorbable, but
unavailable cupric molybdate. Cupric sulfide may accumulate in animal
tissues in the presence of high Mo, because Mo inhibits sulfide oxidase.

B. Sulfur and Selenium

An interaction between S and Se occurs because of similar orbital

structures of these elements, and because they form structural analogs.
Selenium may replace S in organic molecules, such as the selenoamino
acids (selenomethionine and selenocysteine). Seleno compounds may in-
terfere with the activity of enzymes (Shrift, 1958, 1967) because they
compete with the normalS-containing compounds for active sites. Also,
high dietary so~- increases the incidence of white muscle disease in lambs
due to its interference with the absorption of selenite (Muth et al., 1961;
Schubert et al., 1961; Hintz & Hogue, 1964; Hogue, 1970). Sulfate also
increases Se excretion in rats and may lessen toxic effects of excessive
intakes of Se (Muth, 1970). Whanger ( 1970) reported that So~-, S03,
HS-, cysteine, and methionine, have differing effects on uptake ofSe by
rumen microbes. The uptake ofSe compounds is inhibited to the greatest
degree by their S analogs. This may explain why S compounds do not
always interfere with Se metabolism (Underwood, 1971).

VI. SULFUR DEFICIENCY

A. Ruminants

Sulfur deficiencies in ruminants may occur under the following cir-

cumstances: (i) when nonprotein nitrogen sources are used to meet a large
percentage of an animal's nitrogen requirements; (ii) when low quality
proteins are fed; (iii) when diets that are low in protein content are offered;
or (iv) when certain forages with low S availabilities are fed. In these
instances, supplemental S must be fed to: (i) ensure proper ruminal diges-
tion; (ii) provide for normal incorporation of S into microbial protein;
(iii) maintain needed number of rumen microbes; and (iv) sustain mi-
crobial metabolism. Supplemental S may also aid in the detoxification
of cyanide (Ely et al., 1978; Tewes, 1981) that may occur in some forages
(i.e., white clover).
Sulfur deficiencies are accompanied by poor animal performance,
reduced milk production, decreased weight, and slow wool growth; an-
orexia; low dry matter digestibilities; profuse tearing and salivation; ema-
ciation; dullness; weakness; and death (Bouchard & Conrad, 1973a; Starks
SULFUR IN LIVESTOCK NUTRITION 625

et al., 1953; Thomas et al., 1951; Whanger, 1968). Partial responsibility

for these symptoms can be attributed to improper rumina! fermentation.
A supply of S must be provided to rumen microbes for adequate pro-
duction of S-containing compounds, such as microbial protein and B-
vitamins. Sulfur deficiency in the rumen gives rise to the following: (i)
decreased microbial numbers; (ii) a shift from gram positive to gram
negative bacteria; (iii) decreased fiber digestion; (iv) decreased concen-
trations of butyric and higher molecular weight organic acids; (v) de-
creased microbial protein production; and (vi) inefficient utilization of
dietary protein and nonprotein nitrogen (Kahlon et al., 197 Sa; Martin et
al., 1964; Spears et al., 1979; Thomas et al., 1951; Whanger & Matrone,
1967).
In addition, S deficient ruminant animals do not convert rumina!
lactic acid to propionic acid. Lactic acid accumulates because of decreased
numbers of rumen bacteria that use the acrylate pathway to produce
propionate from lactate. Consequently, blood and urine lactate levels
increase (Whanger, 1968). Other compounds that increase in S-deficient
animal's blood plasma are alanine, citrulline, cystine, serine, and total
nonessential amino acids. Glycine and tyrosine concentrations in plasma
decrease. Physical changes in S-deficient animals include smaller livers,
spleens, and testes; larger brain and adrenals; and decreased blood volume
(Chalupa et al., 1971).
Blood parameters that may be used to indicate S status are blood
lactate, blood urea-nitrogen, and serum sulfate (Goodrich et al., 1978;
Whiting et al., 1954). Total dietary S content generally provides sufficient
evidence on the adequacy ofS nutrition; butS analyses may be misleading
when forages that have low S availabilities (i.e., fescue Festuca arundi-
nacea) are fed.
B. Nonruminants

Practical swine diets are rarely S-deficient, but poultry diets may be.
Characteristics of S deficiency in nonruminants are usually those asso-
ciated with deficiency of S-containing organic compounds-S containing
amino acids and B-vitamins. A deficiency of S amino acids (methionine
and cysteine) is the most likely S deficiency. Symptoms of S amino acid
deficiency in poultry are decreased rate of gain, inefficient weight gain,
reduced egg production, and lighter egg weights. In swine, symptoms of
a S amino acid deficiency include slower growth rate, poor feed conver-
sion, and decreased nitrogen retention (Allee & Trotter, 1974; Bell et al.,
1950; Bomstein & Lipstein, 1964, 1965; Harms & Damron, 1969; Reid
& Weber, 1973; Trotter & Allee, 1974). Sulfur amino acid deficiencies
will more likely occur in younger than in older animals because require-
ments for S amino acids decrease with age (Baker, 1977).
Deficiencies of inorganic Shave been observed in nonruminants when
low so~- diets were fed. Symptoms include increased S amino acid re-
quirements, increased S amino acids excretion, weakening of the aorta,
626 GOODRICH & GARRETT

low urea synthesis, and reduced collagen metabolism (Brown et al., 1965;
Brown et al., 1971; Michels & Smith, 1965; Whittle & Smith, 1974).
Alleviation of S amino acid deficiency may be accomplished by sup-
plementing the diet with methionine or by selection of natural high pro-
tein feeds that provide necessary quantities of methionine. Sulfate-S may
be fed to correct a cysteine deficiency if methionine concentration in the
diet is adequate to meet the methionine requirement (about 50% of the
S amino acid requirement) and the so~- -S concentration in the diet is
<200 ppm (Baker, 1977).

VII. SULFUR TOXICITY

Toxicity of S to farm animals is influenced by chemical form and

method of administration. The production of H 2S from inorganic S by
microbes in the rumen and gastro-intestinal tract is primarily responsible
for inorganic S toxicity. Livestock are extremely sensitive to H 2S and
tolerant of S0 (National Research Council, 1980).

A. Ruminants

Sulfur toxicity is most likely when ammonium sulfate is used as a

major source of nonprotein nitrogen or when gypsum is used as a calcium
source. When large amounts of organic S-containing compounds are fed,
palitability of the diet is reduced. Most rations fed to ruminants have
little potential for S toxicity.
Symptoms of S toxicity in ruminants are reduced feed intake, lower
growth rates, inefficient feed conversion, diarrhea, constipation, muscle
twitching, depression, and death (Bird, 1972; Coghlin, 1944; Johnson et
al., 1968; L'Estrange et al., 1969, 1972; L'Estrange & Murphy, 1972; Luedke
et al., 1959). The minimum tolerable level of S in the diet has been
established at 0.4% by the National Research Council (1980). This is
higher than the levels for nonruminants, because ruminants have a greater
tolerance to H 2S.

B. Nonruminants

Sulfur toxicity in nonruminants may result from an excess ofS amino

acids in the diet. Of the S-containing amino acids, methionine is the most
toxic and requires monitoring since it is often added to practical diets.
Effects of S gases on swine are also of concern, since these gases are
liberated from liquid manure pits located under confinement pens.
Symptoms of a methionine toxicity are reduced feed intake; depressed
weight gain; reduced feed efficiency; decreased levels of hepatic ATP;
liver damage; darkened spleen; decreased kidney size; increased excretion
of adenylated compounds; and reduced packed cell volume, hemoglobin,
and total red blood cells (Harper et al., 1970; Katz et al., 1973; Katz &
SULFUR IN LIVESTOCK NUTRITION 627

Baker, 1975a,b; Wahlstrom & Libal, 1974). Modest excesses of methio-

nine may result in only reduced feed intake, whereas large excesses cause
metabolic disorders (Baker, 1977). Toxicity symptoms of inorganic S
containing compounds, such as H 2S and S0 2 are eye irritation, increased
nasal discharge, loss of sense of smell, difficult breathing, depressed growth,
scouring and in severe situations, death (Anderson & Strothers, 1978;
Embry et al., 1959; Leach et al., 1960; O'Donoghue, 1961; O'Donoghue
& Graesser, 1962; Patterson et al., 1979).
Amounts of methionine in swine diets are more critical than those
in poultry diets. As little as 0.2% supplemental D-L-methionine in swine
diets may cause growth depression, whereas poultry can tolerate up to
1% excess methionine (Baker, 1977). Much greater quantities of so~­
can be tolerated than either organic or gaseous S compounds. The min-
imum tolerable level for inorganic Sis between 0.2 and 0.3% (National
Research Council, 1980), whereas concentrations of 5 to 10 ppm of S0 2
and 28 to 477 ppm of H 2S may be deliterious.

VIII. SOURCES OF SULFUR

A. Feedstuffs

Sulfur contents of some common feedstuffs are presented in Table

23-5. Forages and cereal grains contain similar amounts of S (averaging
0.18 and 0.17%, respectively). High protein feeds listed in Table 23-5
contain an average of0.45% S. Sulfur in the form of methionine accounts
for 26, 24, and 48% of the S in forages, cereal grains, and high protein
feeds, respectively. Cystine-S accounts for 35, 41, and 42% of the S in
forages, cereal grains, and high protein feeds, respectively.
Sulfur requirements of ruminants are met by diets formulated using
most common feedstuffs. When supplementary protein needs are met by
urea or other nonprotein nitrogen compounds, additional S may be re-
quired to maintain adequate dietary concentrations of S. Rumen fer-
mentation and animal performance have been improved when S was
added to diets that contain large amounts of nonprotein nitrogen. Ani-
mals fed low quality forages, such as straw, corn stalks, and mature grass
hay may respond to S supplementation. The low availability ofS in spear
grass (Heteropagon contortus), forage sorghums, and fescue appears to be
the reason for animal performance responses when animals fed these
forages are fed additional S (Archer & Wheeler, 1978; Benson & Ely,
1982; Ely et al., 1978; Guardiola et al., 1980; Hunter & Siebert, 1980).
Many swine diets are formulated from corn and soybean (Glycine
max L.) meal. Other high protein feeds may be used to replace soybean
meal, when cost and availability favor them. Because these high protein
feeds contain a high percentage of S amino acids, supplementation with
S amino acids is generally not necessary. The availability of S amino
acids from high protein feeds is generally high (Baker, 1977).
628 GOODRICH & GARRETT

Table 23-5. Sulfur and S amino acid contents of common feeds. t

International
Feed+ feed no. Sulfur Methionine Cystine
%Dry matter
Forage
Alfalfa meal, dehy 1-00-023 0.24 0.29 0.31
Bromegrass 1·00-887 0.20
Clover: ladino white 1·01·378 0.28 0.30 0.40
Red 1·01-415 0.17
Com silage 3·02·912 0.13 0.18 0.16
Sorghum, sudan grass 2-04-485 0.11
Timothy hay 2-04-912 0.13
Cereal grains
Barley 4-00-549 0.17 0.17 0.24
Com 4·02-935 0.12 0.19 0.25
Oats 4-03·309 0.23 0.19 0.22
Sorghum 4-04-383 0.15 0.15 0.22
Wheat 4-05-211 0.18 0.20 0.31
High protein feeds
Animal origin
Blood meal 5·00·380 0.37 0.97 1.35
Fish meal
Anchovy 5·01·985 0.84 2.16 0.66
Herring 5-02-000 0.50 2.27 0.81
Menhaden 5-02-009 0.49 1.91 0.61
Meat meal 5-00-385 0.50 0.75 0.70
Meat and bone meal 5-00-388 0.27 0.70 0.53
Plant origin
Brewers grains 5-02-141 0.32 0.50 0.38
Com, distillers grains 5-28-235 0.46 0.43 0.26
Cottonseed meal 5·01-617 0.43 0.62 0.78
Linseed meal 5·02-045 0.46 0.64 0.67
Soybean meal 5·04-600 0.37 0.72 0.63
Sunflower meal 5-04-738 1.01 0.74
t National Research Council (1982).
:t: Forages Cereal grains
Alfalfa meal, dehy (Medicago sativa L.) Barley (Hordeum vulgare)
Bromegrass, (Bromus sp.) Corn (Zea mays identata)
Clover, ladino (Trifolium repens) Oats (Avena sativa)
Clover, red (Trifolium pratense) Sorghum (Sorghum bicolor)
Corn silage (Zea mays identata) Wheat (Triticum aestivum)
Fescue (Festuca arundinacea)
Sorghum, sudan grass (Sorghum bicolor sudanese)
Timothy hay (Phleum pratense)
High protein feeds, plant origin
Brewers grains (Hordeum vulgare)
Com, distillers grains (Zea mays identata)
Cottonseed meal (Gossypium spp.)
Linseed meal (Linum usitatissimum)
Soybean meal (Glycine max)
Sunflower meal (Helianthus annuus)

High requirements for S amino acids frequently dictate the addition

of supplemental S amino acids when typical poultry diets are fed. Usually
D-L-methionine is used to supplement poultry diets.
SULFUR IN LIVESTOCK NUTRITION 629
Table 23-6. Relative availabilities of S.
Reference
Sulfur source a b c d e g h
L- Methionine 100 100 100 100
D-L-Methionine 78 63 68
Calcium sulfate 70 94
Sodium sulfate 77 68 60 80 68 68 55 68
Ammonium sulfate 93
Potassium-magnesium sulfate 67
Sodium sulfide 43
Elemental sulfur 8 30 38 36
Lignin sulfonate 39
Molasses 59
a Loosli & Harris (1945). Based on retention of absorbed N.
b Hale & Garrigas (1953). Based on "S contents of wool.
c Albert et al. (1956). Based on weight gains.
d Johnson et al. (1971). Based on true retention of "S.
e Gil et al. (1973). Based on in vitro protein synthesis.
f Bouchard & Conrad (1973a, b). Based on true digestibilities of S.
g Kahlon et al. (1975a). Based on in vitro protein synthesis.
h Bull & Vandersall (1973). Based on true digestibilities of S.

B. Supplements

Relative availabilities to ruminants of several sources of supplemen-

tal S are shown in Table 23-6. Of the sources, L-methionine has the
highest relative S availability. Other organic S sources, D-L-methionine,
lignin sulfonate, and molasses have relative S availabilities ranging from
39 to 85%. Sulfate-S sources range from 55 to 94% as available as L-
methionine. Sodium sulfite and S0 are the least available supplemental
S sources, ranging from 8 to 43% as available as L-methionine. The
inability of inorganic S sources to be utilized as efficiently as £-methionine
may be due to their conversion to HS-, which is absorbed from the rumen
and lost in urine.
Organic sources of S are usually supplemented when nonruminants
require S supplementation. The preferred S source is D-L-methionine
since it is less toxic than L-methionine. Sulfate-S may be used in situa-
tions where methionine requirements have been met and additional S is
required to meet cystine requirements.

REFERENCES

Albert W.W., U.S. Garrigus, R.M. Forbes, and H.W. Norton. 1956. The sulfur requirements
ofgro_wing-f!lttening lambs in terms of methionine, sodium sulfate and elemental sulfur.
J. Amm. Set 15:559.
Allee, G.L., and R.M. Trotter. 1974. Sulfur amino acid requirement of the finishing pig. J.
Anim. Sci. 39:974.
Anderson, C.M. 1956. The metabolism of sulphur in the rumen of the sheep. N.Z. J. Sci.
Tech. 37A:379.
630 GOODRICH & GARRETT
Anderson, D.M., and S.C. Strothers. 1978. Effects of saline water high in sulfates, chlorides
and nitrates on the performance of young weaning pigs. J. Anim. Sci. 47:900.
Archer, K.A., and J.L. Wheeler. 1978. Response to salt and sulphur by cattle grazing sorghum.
Proc. Aust. Soc. Anim. Prod. 12: 172.
Baker, D.H. 1977. Sulfur in nonruminant nutrition. National Feed Ingredients Assoc., Des
Moines, IA.
Bandurski, R.S., L.G. Wilson, and T. Asahi. 1960. Yeast sulfate reductase. J. Am. Chern.
Soc. 82:3218.
Bell, J.M., H.H. Williams, J.K. Loosli, and L.A. Maynard. 1950. The effect of methionine
supplementation of a soybean oil meal-purified ration for growing pigs. J. Nutr. 40:551.
Benson, M.E., and D.G. Ely. 1982. Supplementation of tall fescue hay diets with distillers
dried grains with solubles, sulfur, and/or starch (lambs). Ken. Agric. Exp. Stn. Prog.
Rep.
Bird, P.R. 1972. Sulphur metabolism and excretion studies in ruminants: X. Sulphide
toxicity in sheep. Aust. J. Bioi. Sci. 25:1087.
Bird, P.R. and R.J. Moir. 1971. Sulphur metabolism and excretion studies in ruminants.
I. The absorption of sulphate in sheep after intraruminal or intraduodenal infusions
of sodium sulphate. Aust. J. Bioi. Sci. 24:1319.
Block, R.J., J.A. Stekol, and J.K. Loosli. 1951. Synthesis of sulfur amino acids from inorganic
sulfate by ruminants. II. Synthesis of cystme and methionine from sodium sulfate by
the goat and by the microorganisms of the rumen of the ewe. Arch. Biochem. Biophys.
33:353.
Bomstein, S., and B. Lipstein. 1964. Methionine supplementation of practical broiler ra-
tions. I. The value of added methionine in diets of varying fishmeallevels. Br. Poult.
Sci. 5:167.
Bomstein, S., and B. Lipstein. 1965. Methionine supplementation of practical broiler ra-
tions. III. The value of added methionine in broiler finisher rations. Br. Poult. Sci.
7:273.
Bouchard, R., and H.R. Conrad. 1973a. Sulfur requirement oflactating dairy cows. I. Sulfur
balance and dietary supplementation. J. Dairy Sci. 56:1276.
Bouchard, R., and H.R. Conrad. 1973b. Sulfur requirement of lactating dairy cows. II.
Utilization of sulfates, molasses, and lignin-sulfonate. J. Dairy Sci. 56:1429.
Bray, A. C. 1964. The recycling and excretion of sulphur in sheep. Proc. Aust. Soc. Anim.
Prod. 5:336.
Bray, A. C. 1969a. Sulphur metabolism in sheep. I. Preliminary investigations on the move-
ment of sulphur in the sheep's body. Aust. J. Agric. Res. 20:725.
Bray, A.C. 1969b. Sulphur metabolism in sheep. II. The absorption of inorganic sulphate
and inorganic sulphide from the sheep's rumen. Aust. J. Agric. Res. 20:739.
Bray, A. C. 1969c. Sulphur metabolism in sheep. III. The movement of blood inorganic
sulphate across the rumen wall of sheep. Aust. J. Agric. Res. 20:749.
Brown, R.G., G.M. Button, and J.T. Smith. 1965. Changes in collagen metabolism caused
by feeding diets low in inorganic sulfur. J. Nutr. 87:228.
Brown, R.G., A. Macris-Hagerty, E. Liddy, and M.L. De Jesus. 1971. Urea metabolism in
sulfate deprived and sulfate-supplemented rats. J. Anim. Sci. 32:1164.
Bryant, M.P., 1973. Nutritional requirements of the predominant rumen cellulolytic bac-
teria. Proc. Fed. Am. Soc. Exp. Bioi. 32:1809.
Bull, L.S., and J.H. Vandersall. 1973. Sulfur source for in vitro cellulose digestion and in
vivo ration utilization, nitrogen metabolism and sulfur balance. J. Dairy Sci. 56:106.
Chalupa, W., R.R. Oltjen, L.L. Slyter, and D.A. Dinius. 1971. Sulfur deficiency and tolerance
in bull calves. J. Anim. Sci. 33:278.
Coghlin, C.L. 1944. Hydrogen sulfide poisoning in cattle. Can. J. Comp. Med. 8:111.
Dick, A.T. 1952. The effect of diet and of molybdenum on copper metabolism in sheep.
Aust. Vet. J. 28:30.
Dick, A. T., and L.S. Bull. 1945. Some preliminary observations on the effect of molybdenum
on copper metabolism in herbivorous animals. Aust. Vet. J. 21:70.
Dick, A.T., D.W. Dewey, and J.M. Gawthome. 1975. Thiomolybdates and the copper-
molybdenum-sulphur interaction in ruminants nutrition. J. Agric. Sci. 85:567.
Dowdy, R.P., G.A. Kunz, and H.E. Sauberlich. 1969. Effects of a copper-molybdenum
compound upon copper metabolism in the rat. J. Nutr. 99:491.
Dowdy, R.P., and G. Matrone. 1968a. Copper-molybdenum interaction in sheep and chicks.
J. Nutr. 5:191.
SULFUR IN LIVESTOCK NUTRITION 631
Dowdy, R.P., and G. Matrone. 1968b. A copper-molybdenum complex: its effects and
movements in the piglet and sheep. J. Nutr. 95:197.
Ely, D.G., J.W. Spears, and L.P. Bush. 1978. Sulfur supplementation to Kentucky 31 fescue
fed to lambs. Ken. Agric. Exp. Stn. Prog. Rep. 14.
Embry, L.B., M.A. Holscher, R.C. Wahstrom, C.W. Carlson, L.M. Krista, and O.E. Olson.
1959. Salinity and livestock water quality. S. Dakota Agric. Exp. Stn. Bull. 481.
Emery, R.S., C.K. Smith, and L. Faito. 1957a. Utilization of inorganic sulfate by rumen
microorganisms. II. The ability of single strains of rumen bacteria to utilize inorganic
sulfate. Appl. Microbiol. 5:363.
Emery, R.S., C.K. Smith, and C.F. Huffman. 1957b. Utilization of inorganic sulfate by
rumen microorganisms. I. Incorporation of inorganic sulfate into amino acids. Appl.
Microbiol. 5:360.
Gall, L.S., W.E. Thomas, J.K. Loosli, and C.N. Huhtanen. 1951. The effect of purified diets
upon rumen flora. J. Nutr. 44:113.
Gil, L.A., R.L. Shirley, and J.E. Moore. 1973. Effect of methionine hydroxy analog on
bacterial protein synthesis from urea and glucose, starch or cellulose by rumen mi-
crobes, in vitro. J. Anim. Sci. 37:159.
Goodrich, R.D., T.S. Kahlon, D.E. Pamp, and D.P. Cooper. 1978. Sulfur in ruminant
nutrition. National Feed Ingredients Assoc., Des Moines, lA.
Goodrich, R.D., and J.C. Meiske. 1969. Non-protein nitrogen in beef cattle rations. p. 77.
In Proc. 13th Annual Minnesota Nutritional Conf. University of Minnesota.
Guardiola, C.M., G.C Fahey, Jr., J.W. Spears, and U.S. Garrigus. 1980. Effect of sulfur
supplementation on in vitro cellulose digestion and on nutrient utilization and nitrogen
metabolism of lambs fed low quality fescue hay. Can. J. Anim. Sci. 60:337.
Hale, W.H., and U.S. Garrigus. 1953. Synthesis of cystine in wool from elemental sulfur
and sulfate sulfur. J. Anim. Sci. 12:492.
Harms, R.H., and B.L. Damron. 1969. Protein and sulfur amino acid requirement of the
laying hen as influenced by dietary formulation. Poult. Sci. 48:144.
Harper, A.E., N.L. Benevenga, and R.M. Wahlhueter. 1970. Effects of ingestion of dispro-
portionate amounts of amino acids. Physiol. Rev. 50:428.
Hilz, H., and F. Lipmann. 1955. The enzymatic activity of sulfate. Proc. Nat!. Acad. Sci.
USA 41:880.
Hintz, H.F., and D.E. Hogue. 1964. Effect of selenium, sulfur and sulfur amino acids on
nutritional muscular dystrophy in lamb. J. Nutr. 82:495.
Hogue, D.E. 1970. Selenium. J. Dairy Sci. 53:1135.
Huisingh, J., G.G. Gomez, and G. Matrone. 1973. Interactions of copper molybenum and
sulfate in ruminant nutrition. Proc. Fed. Am. Soc. Exp. Bioi. 32:1921.
Hume, I.D., and P.R. Bird. 1970. Synthesis of microbial protein in the rumen. IV. The
influence of the level and form of dietary sulphur. Aust. J. Agric. Res. 21:315.
Hunter, R.A., and B.D. Siebert. 1980. The utilization of spear grass (Heteropagon contortus).
IV. The nature and flow of digesta in cattle fed spear grass alone and with protein or
nitrogen or sulfur. Aust. J. Agric. Res. 31:1037.
Johnson, W.H., R.D. Goodrich, and J.C. Meiske. 1970. Appearance in the blood plasma
and excretion of3 5S from three chemical forms of sulfur by lambs. J. Anim. Sci. 31:1003.
Johnson, W.H., R.D. Goodrich, and J.C. Meiske. 1971. Metabolism of radioactive sulfur
from elemental sulfur, sodium sulfate and methionine by lambs. J. Anim. Sci. 32:778.
Johnson, W.H., J.C. Meiske, and R.D. Goodrich. 1968. Influence of high levels of two forms
of sulfate on lambs. J. Anim. Sci. 27:1166.
Kahlon, T.S., J.C. Meiske and R.D. Goodrich. 1975a. Sulfur metabolism in ruminants. I.
In vitro availability of various chemical forms of sulfur. J. Anim. Sci. 41: 1147.
Kahlon, T.S., J.C. Meiske, and R.D. Goodrich. 1975b. Sulfur metabolism in ruminants. II.
In vivo availability of various chemical forms of sulfur. J. Anim. Sci. 41:1154.
Katz, R.S., and D.H. Baker. 197 Sa. Methionine toxicity in the chick: nutritional and met-
abolic implications. J. Nutr. 105:1168.
Katz, R.S., and D.H. Baker. 1975b. Toxicity of various organic sulfur compounds for chicks
fed crystalline amino acid diets containing threonine and glycine at their minimal
dietary requirements for maximal growth. J. Anim. Sci. 41:1355.
Katz, R.S., D.H. Baker, C.E. Sasse, A.H. Jensen, and B.G. Harmon. 1973. Efficacy of
supplemental lysine, methionine and rolled oats for weanling pigs fed a low-protein
com-soybean meal diet. J. Anim. Sci. 37:1165.
632 GOODRICH & GARRETT
Kulwich, R., L. Struglia, and P.B. Pearson. 1957. The metabolic fate of 35 sulfur in sheep.
J. Nutr. 61:113.
Leach, R.M., T.R. Zeigler, and L.C. Norris. 1960. The effect of dietary sulphate on the
growth rate of chicks fed a purified diet. Poult. Sci. 39: 15 77.
L'Estrange, J.L., J.J. Clarke, and D.M. McAleese. 1969. Studies on high intake of various
sulphate salts and sulphuric acid in sheep. I. Effects on voluntary feed intake, diges-
tibility and acid base balance. Ir. J. Agric. Res. 8:133.
L'Estrange, J.L., and F. Murphy. 1972. Effect of dietary mineral acids on voluntary intake,
digestion, mineral metabolism and acid-base balance of sheep. Br. J. Nutr. 28:1.
L'Estrange, J.L., P.K. Upton, and D.M. McAleese. 1972. A comparison between different
levels of sodium sulphate and sodium chloride. Ir. J. Agric. Res. 11:127.
Lewis, D. 1954. The reduction of sulphate in the rumen of the sheep. Biochem. J. 56:391.
Loosli, J.K. 1952. Meeting the sulfur requirements of ruminants. Feed Age 2:44.
Loosli, J.K., and L.E. Harris. 1945. Methionine increases the value of urea for lambs. J.
Anim. Sci. 4:435.
Luedke, A.J., J. W. Bratzler, and H. W. Dunne. 1959. Sodium metabisulfite and sulfur dioxide
gas (silage perservative) poisoning in cattle. Am. J. Vet. Res. 20:690.
Martin, J.E., L.R. Arrington, J.E. Moore, C.B. Ammerman, G.K. Davis, and R.L. Shirley.
1964. Effect of magnesium and sulfur upon cellulose digestion of purified rations by
cattle and sheep. J. Nutr. 83:60.
Meiske, J.C., R.D. Goodrich, A.L. Harvey, and O.E. Kolari. 1966. The value of added sulfur
to linseed meal or com-urea supplements for finishing steers. Minn. Beef Cattle Feeders
Day Rep., p. 9.
Michels, F. G., and J.T. Smith. 1965. A comparison of the utilization of organic sulfur by
the rat. J. Nutr. 87:217.
Muth, O.H. 1970. Selenium-responsive disease of sheep. J. Am. Vet. Med. Assoc. 157:1507.
Muth, O.H., J.R. Schubert, and J.E. Oldfield. 1961. White muscle disease (myopathy) in
lambs and calves. VII. Etiology and prophylaxis. Am. J. Vet. Res. 22:465.
National Research Council. 1978. Nutrient requirements of domestic animals: Nutrient
requirements of dairy cattle, 5th ed. National Research Council, National Academy of
Sciences, National Academy Press, Washington, DC.
National Research Council. 1979. Nutrient requirements of domestic animals: Nutrient
requirements of swine, 8th ed. National Research Council, National Academy of Sci-
ences, National Academy Press, Washington, DC.
National Research Council. 1980. Mineral tolerance of domestic animals. National Research
Council, National Academy of Sciences, National Academy Press, Washington, DC.
National Research Council. 1982. United States-Canadian tables of feed composition, 3rd
ed. National Research Council, National Academy of Sciences, National Academy
Press, Washington, DC.
National Research Council. 1984a. Nutrient requirements of domestic animals: Nutrient
requirements of beef cattle, 6th ed. National Research Council, National Academy of
Sciences, National Academy Press, Washington, DC.
National Research Council. 1984b. Nutrient requirements of domestic animals: Nutrient
requirements of poultry. 8th ed. National Research Council, National Academy of
Sciences, National Academy Press, Washington, DC.
National Research Council. 1985. Nutrient requirements of domestic animals: Nutrient
requirements of sheep, 6th ed. National Research Council, National Academy of Sci-
ences, National Academy Press, Washington, DC.
O'Donoghue, J.G. 1961. Hydrogen sulfide poisoning in swine. Can. J. Comp. Med. Vet.
Sci. 25:217.
O'Donoghue, J.G., and F.E. Grasesser. 1962. Effects of sulfur dioxide on guinea pigs and
swine. Can. J. Comp. Med. Vet. Sci. 26:255.
Patterson, P.W., R.C. Wahlstrom, G.W. Libal, and O.E. Olson. 1979. Effects of sulfate in
water on swine reproduction and young pig performance. J. Anim. Sci. 49:664.
Peck, H.D., Jr. 1960. Evidence for oxidative phosphorylation during the reduction of sulfate
with hydrogen by Desulfovibrio desulfuricans. J. Bioi. Chern. 235:2734.
Reid, B.L., and C.W. Weber. 1973. Dietary protein and sulfur amino acid levels for laying
hens during heat stress. Poult. Sci. 52:1335.
Roy, A.B., and P.A. Trudinger. 1970. The biochemistry of inorganic compounds of sulfur.
Cambridge University Press, Cambridge.
SULFUR IN LIVESTOCK NUTRITION 633
Sasse, C.E., and D.H. Baker. 1974a. Factors affecting sulfate-sulfur utilization by the young
chick. Poult. Sci. 53:562.
Sasse, C.E., and D.H. Baker. 1974b. Sulfur utilization by the chick with emphasis on the
effect of inorganic sulfate on the cystine-methionine interrelationship. J. Nutr. 104:244.
Schubert, J.R., O.H. Muth, J.E. Oldfield, and L.F. Remmert. 1961. Experimental results
with selenium in white muscle disease of lambs and calves. Proc. Fed. Am. Soc. Exp.
Bioi. 20:689.
Shrift, A. 1958. Biological activities of selenium compounds. Bot. Rev. 24:550.
Shrift, A. 1967. Microbial research with selenium. p. 241-271. In O.H. Muth (ed.) Sym-
posium: selenium in biomedicine. AVI Publishing Co., Westport, CT.
Spears, J.W., D.G. Ely, and L.P. Bush. 1979. Influence of supplemental sulfur on in vitro
and in vivo microbial fermentation of Kentucky 31 fall fescue. J. Anim. Sci. 47:552.
Spears, J.W., D.G. Ely, L.P. Bush, and R.C. Buckner. 1976. Sulfur supplementation and in
vitro digestion offorage cellulose by rumen microorganisms. J. Anim. Sci. 43:513.
Starks, P.B., W.H. Hale, U.S. Garrigus, and R.M. Forbes. 1953. The utilization of feed
nitrogen by lambs as affected by elemental sulfur. J. Anim. Sci. 12:480.
Tewes, 0.0. 1981. Supplementation of cassava/urea based rations with elemental sulphur
for sheep and goats: effect on growth, rumina!, serum and urinary thiocyanate con-
centrations. Nutr. Rep. Int. 24:1263.
Thomas, W.E., J.K. Loosli, H.H. Williams, and L.A. Maynard. 1951. The utilization of
inorganic sulfates and urea nitrogen by lambs. J. Nutr. 43:515.
Trotter, R.M., and G.L. Allee. 1974. Sulfur amino acid requirement of the growing pig. J.
Anim. Sci. 39:984.
Underwood, E.J. 1971. Trace elements in human and animal nutrition, 3rd ed. Academic
Press, New York.
Wahlstrom, R.C., and G.W. Libal. 1974. Gain, feed efficiency, and carcass characteristics
of swine fed supplemental lysine and methionine in corn-soybean meal diets during
the growing and finishing periods. J. Anim. Sci. 38:1261.
Whanger, P.D. 1968. Sulphur in ruminant nutrition. Metabolism and importance. Sulphur
Inst. J. 4:9.
Whanger, P.D. 1970. Sulphur-selenium relationships in animal nutrition. Sulphur Inst. J.
6:6.
Whanger, P.D., and G. Matrone. 1966. Effect of dietary sulfur upon the production and
absorption of lactate in sheep. Biochem. Biophys. Acta. 124:273.
Whanger, P.D., and G. Matrone. 1967. Metabolism of lactic, succinic and acrylic acids by
rumen microorganisms from sheep fed sulfur-adequate and sulfur-deficient diets.
Biochem. Biophys. Acta. 136:27.
Whiting, F., S.B. S1en, L.M. Bezeau, and R.D. Clark. 1954. The sulphur requirements of
mature range ewes. Can. J. Agric. Sci. 34:261.
Whittle, B., and J.T. Smith. 1974. Effect of dietary sulfur on taurine excretion by the rat.
J. Nutr. 104:666.