WHOLE AND PROCESSED COTTONSEED WITH ADDED FIBER ON RUMEN VARIABLES, MILK PRODUCTION AND COMPOSITION pdf

WHOLE AND PROCESSED COTTONSEED WITH ADDED
FIBER ON RUMEN VARIABLES, MILK
PRODUCTION AND COMPOSITION
by
BENJAMIN FINIS SULLIVAN, B.S.
A THESIS
IN
ANIMAL NUTRITION
Submitted to the Graduate Faculty
of Texas Tech University in
Partial Fulfillment of
the Requirements for
the Degree of
MASTER OF SCIENCE
Approved
August,
1984
/ V
// •
ACKNOWLEDGMENTS
I would like to express my deep appreciation to Professor
C. Reed Richardson for his guidance and support of this thesis and
to the members of my committee. Professors Mark Hellman, Max Miller
and John Anderson, for their suggestions and advice.
I would also like to dedicate this thesis to my wife, Karita,
whose love, support and sacrifice allowed me to pursue this endeavor
and to whom I will always be grateful.
11
TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS ii

LIST OF TABLES iv
I. INTRODUCTION 1
II.
LITERATURE REVIEW 3
Effects of Whole Cottonseed 3
Effects of Added Dietary Fat 8
Cottonseed Meal 16
III.
EFFICACY OF WHOLE AND PROCESSED COTTONSEED ON
DIGESTIBILITY, RUMEN VARIABLES AND THE PRODUCTION
OF MILK AND ITS COMPONENTS 20
Summary 20
Introduction 21
Materials and Methods 22
Results and Discussion 29
LITERATURE CITED 40
111
LIST OF TABLES
Table Page
1. Composition of Diets—Exp. 1 23
2.
Nutrient Composition of Feed Ingredients—Exp. 1 24
3. Composition of Diets—Exp. 2 26
4.
Nutrient Composition of Feed Ingredients—Exp. 2 27
5. Composition of Seed Pellets 28
6. Milk and Butterfat Production of All Cows—Exp. 1 30
7.
Milk and Butterfat Production of Cows Supplying Data to
All Three Periods—Exp. 1 30

8. Milk and Butterfat Production of Cows in First
Lactation—Exp. 1 31
9. Dry Matter Intake of Hay, Total Diets and Digestible
Energy—Exp. 1 32
10.
Milk Production and Composition, Average Weight Gain,
Dry Matter Intake and Feed Efficiency—Exp. 2 34
11.
Apparent Digestibilities, Rumen VFA and pH—Exp. 2 35
12.
Mean Fatty Acid Composition of Milk Fat—Exp. 2 37
IV
CHAPTER I
INTRODUCTION
Cotton is one of the world's most important agricultural,
nonfood commodities accounting for more than 49.5% of the total
fiber production (natural and man-made) in 1980 (1982 World
Almanac).
Gossypium hirustum (produces medium-staple fibers) is one of the
two most economically important species of cotton cultivated in the
United States. In west Texas G. hirustimi has been used as a dry-land
crop in areas where reduced water tables and(or) high fuel costs
have prevented economical irrigation.
Upon harvesting, cotton must be processed through a cotton gin
to separate the cotton fibers from the seed, leaves, stems and dirt.
Whole cottonseed
(WCS),
as it comes from the gin, may be processed
further to produce a number of eonomically important products.
Cot-

tonseed oil, extracted from the seed by either solvent or mechanical
processing, is used in several food products including margarine,
shortening, cooking and salad
oils.
The two remaining products after
oil extraction, cottonseed meal
(CSM),.
and hulls
(CSH),
are used as
protein and fiber sources, respectively, in ruminant feeds. Linters,
the short cellulosic fibers adhering to the seed after ginning, can
be removed by treating the seed with acid to produce delinted cotton-
seed
(DLCS),
used for planting. The linters are used as mattress
and upholstery stuffing, in the production of coarse cotton yarns
and upon purification, linters form the base for cellulose deriva-
tives for the manufacture of explosives, paints, plastics and film.
Whole cottonseed, without further processing, is fed by many
dairymen throughout the Southwest as a source of protein, fat, fiber
and phosphorous. Economic pressures and the benefit in production
many dairymen associate with WCS feeding has created a renewed inter-
est in the feeding value of whole cottonseed. However, problems of
freight cost, handling, and storage associated with WCS, because of
its bulky, fibrous nature, could be alleviated by pelleting if the
cost of production and(or) effects on livestock production do not
prohibit its use.
CHAPTER II
LITERATURE REVIEW

Effects of Whole Cottonseed
Milk Components
The effects of feeding WCS on the production of milk and its
components have been quite variable. In a recent study by Anderson
et
_al.
(1984) cows were fed rations containing 10% WCS, 5% extruded
soybean
(ESB),
or 12% whole sunflower seed
(WSS),
dry matter (DM)
basis.
Cows receiving WCS produced more (P<.05) milk, 4% fat-cor-
rected milk (FCM) and protein than cows fed whole sunflower seed.
Milk fat percent and fat production were higher (P<.05) for the WCS
diet compared to the ESB or WSS diets. But when WCS was fed at
18.5%,
DM basis, replacing an isonitrogenous amount of a corn silage based
ration,
milk production, percentages of milk fat and protein were
unaffected (Hawkins et al.,
1982).
In a fifteen week experiment
(Hansen, 1980) Holstein cows received rations with 7% ESB or WCS
fed at 15% or 30%. The WCS treatments increased percent milk fat,
but decreased milk production, percent solids-not-fat, (SNF) and
protein. A related study (Hansen, 1980) involving 55 commercial
dairy herds fed various levels of WCS resulted in no difference in
fat,

protein or SNF content of the milk.
Anderson e^
aJ^.
(1979) fed WCS in two experiments. In the first
experiment, when WCS replaced 1.9 kg of the concentrate in an alfalfa
hay (ad
libitum),
corn silage and concentrate diet, cows fed WCS
produced more (P<.05) milk, fat, FCM and SNF than controls. There
3
were no differences (P>.05) in the percentages of SNF or fat, but
percent protein was lower (P<.05) for the WCS diet. In experiment
two diets were: (1) control; (2) 20% replacement of concentrate
with WCS; and (3) control diet but isocaloric to diet two. Corn
silage was fed at 9.1 kg/hd/d and alfalfa ad libitum. There were
no differences (P>.05) in FCM production or percent composition of
milk fat or protein among treatments. Cows on rations two and three
produced more (P<.05) milk and SNF than controls and had a higher
percentage of SNF in their milk. In three experiments conducted
in Hawaii (Stanley ^ aJ^.,
1969),
where restricted fiber intake and
a warm climate appear to affect low solids and fat content in milk,
five pounds of WCS replaced six pounds of concentrate in isocaloric
diets.
Cows fed WCS in the three experiments had higher (P<.05)
fat production and percent composition of fat than controls. In
the third, conducted at a commercial dairy, lower (P<.05) milk yields
occurred in cows on the WCS diet.
Moody (1968) replaced part of a control diet with 2.27 kg WCS,

1.13 kg CSM, acidulated soap-stock from cottonseed replacing 4% milo
in the concentrate, 5% CSH, or acidulated soap-stock and .5% cotton-
seed hulls. There were no differences in milk yield, SNF or protein
due to treatment. Percent fat was highest for the WCS diet followed
by the CSM diet. When WCS replaced a CSM and corn mixture in the
concentrate on an equal weight basis, cows produced more milk
(P<.05),
FCM (P<.01) and percent fat (P<.01) (Ramsey and Miles,
1953).
The
replacement of two lb of a barley, wheat bran and CSM control ration
by two lb of WCS resulted in an average decrease of .12 lb milk,
.06%
serum solids and an increase of .21% fat (Davis and Harland,
1946).
When two lb of WCS replaced 2 lb of CSM in a basal ration,
cows fed CSM produced, on the average, more milk and fat than cows
on whole cottonseed (Lush and Gelpi,
1932).
Moody and Barnes (1966) studied the effects of WCS and crude
cottonseed oil against a control while varying alfalfa hay levels
at either 1.25 kg/100 lb body weight or 2 kg/100 lb body weight.
There were no significant differences in milk production, SNF or
protein among treatments. Cows fed WCS and alfalfa hay at either
rate produced significantly more milk fat. In limited fiber rations
(Moody and Cook,
1961),
alfalfa hay was fed at one lb/100 lb body
wt,
1.5 lb/100 lb body wt, or ad libitum. Whole cottonseed was fed

at 22% of a grain concentrate. Cows fed hay at one lb/100 lb body
wt had significantly higher percent fat and FCM production than cows
on the other rations.
Feed Consumption, Digestibilities, and Weight Gain
Dry matter intake of cows fed WCS at 1.9 kg/hd/d (Anderson
^
aJ^.
,
1979) was higher (P<.05) than of cows fed a control diet
in experiment one. Results of DM or digestible energy intake were
not different (P>.05) in experiment two. A lack of significant dif-
ference in DM intake is in agreement with Smith et^ a^. (1981) and
Hawkins et_ jl.
(1982).
Dry matter intakes of cows receiving 10%
WCS were lower (P<.05) than cows offered 5% ESB, but higher (P<.05)
than cows fed 12% whole sunflower seed (Anderson et jl.,
1984).
Cows fed WCS to replace CSM in rations where Johnson or Sudan grass
hay and sorghum silage were offered ad libitum consumed less (P<.05)
silage but more (P>.05) hay (Ramsey and Miles,
1953).
These results
are in agreement with Lush and Gelpi
(1932).
Hawkins et al. (1982)
reported less (P<.10) total feed consumption of a corn silage based
ration with WCS fed at
18.5%.
Substitution of WCS in a basal diet increased (P<.05) digesti-

bilities of nitrogen (N), energy and ether extract (EE) (Smith et^
al., 1981),
but did not produce significant effects in digestibility
of DM (Smith et^
al.,
1981 and Anderson et^
al^.,
1984) or crude and
acid-detergent fiber (ADF) nor on net Ca, P, or Mg absorption (Smith
et al.,
1981).
Keele and Roffer (1982) reported no effect on total
organic matter (OM) digestibility, increased apparent ruminal and
total digestibility of N and decreased apparent OM digestibility.
Changes in body weight gains reported by several workers were
not significantly affected by WCS feeding (Ramsey and Miles, 1953;
Moody and Barnes, 1966; Moody, 1968; Anderson et_
al^.
,
1979; Hawkins
e^
al.,
1982).
Weight changes reported by Anderson ^ al. (1984)
were not different (P>.05) but there were tendencies towards greater
weight gain in cows fed ESB or whole sunflower seed. Body weight
gains were significantly lower in cows fed WCS and offered hay ad
libitum compared to cows receiving hay at restricted levels (Moody
and Cook,
1961).

Volatile Fatty Acids And Free Fatty Acids
The three major rumen volatile fatty acids
(VFA),
acetic,
pro-
pionic,
and butyric, were not altered (P>.05) in cows fed WCS com-
pared to a control and energy equivalent ration. Whole cottonseed
feeding, however, did result in tendencies toward higher acetic and
lower propionic acid concentrations (Anderson et al.,
1979).
Moody
and Barnes (1966) reported nonsignificant increases in total VFA
on high roughage rations and higher acetic:propionic ratios from
cows fed WCS vs cottonseed oil and control diets.
Whole cottonseed fed at varying levels in a feeding study with
55 commercial dairy herds and a digestibility study (Smith £t al^.,
1981) resulted in significantly altered levels of milk free fatty
acids
(FFA).
Although WCS contains 15% oleic (C18:l) and 62% lin-
oleic (C18:2) by weight of the total lipid content of WCS, results
showed up to a fourfold increase of C18:l yields and no effect on
C18:2 yields in the milk. Yields of the short chain fatty acids
(FA),
C6:0 to
C12:0,
and C6:0 to
C14:0,
were depressed in the di-

gestibility and feeding study, respectively, when V7CS was fed. The
percent by weight of short chain fatty acids decreased with subse-
quent increases of stearic (C18:0) and C18:l fatty acids as feeding
levels of WCS increased in the diets. Net increases of percent and
yield of milk fat resulting from transfer of WCS fat as de novo syn-
thesis of fatty acids was reduced by as much as 50%. These results
are supported by Keele and Roffler
(1982),
who reported increased
duodenal flow rates of palmitic, C18:0 and C18:l FA over other FA
in cows fed whole cottonseed. The increased duodenal flow rates
of
C16:0,
C18:0 and C18:l and increased milk yields of C18:0 and
C18:l indicate high rimien lipolysis and biohydrogenation of CIS:2
(Smith et al., 1981; Keele and Roffler,
1982).
8
Effects of Added Dietary Fat
Fat,
because of its high energy density, may be added to dairy
rations in attempts to better balance rations for high producing
cows,
restricted in energy and(or) fiber. Research has been con-
ducted in recent years to determine more extensively the effects
additional dietary fat have on the production and composition of
milk.
Milk Yields and Milk Components
The use of a concentrate containing 5% unprotected fat to in-
crease DM EE from 3.2% to 8.3% resulted in increased (P<.05) milk

yields in second lactation cows considered to have a high genetic
level of production. Milk production of second lactation
cows,
with
a low genetic level for production, was increased (P<.10) on the high
fat concentrate. There was not a response in first lactation cows
due to treatment (Mattias et_ al.,
1982).
Feeding an animal-vegetable
fat blend in a high fat diet (6% fat vs 3% fat, DM) resulted in an
increase (P<.05) in milk yield and a subsequent decrease (P<.01)
in milk fat percent in high producing
cows.
In low producing
cows,
milk production was not altered significantly but percent milk fat
was depressed
(P<.01).
Production of 3.5% FCM was not different
(P<.05) between groups (Heinrichs ^
jJ^.
,
1981).
Palmquist and Con-
rad (1980) reported decreased (P<.01) production of milk, FCM, fat
and protein in cows fed 10% tallow in a grain concentrate fed at 50%
DM compared to cows receiving 10% hydrolyzed fat in grain fed at 50%
and 33% DM or grain fed at 33% containing 10% tallow. Palmquist and
Conrad (1978) conducted two trials using hydrolyzed animal fat. In
trial one hydrolyzed fat, at two levels, was compared to a control

and ground raw soybeans in diets ranging from 2.9 to 10.8% in total
diet EE (DM). Milk yield, fat and protein were not different
(P>.05).
In trial two, hydrolyzed fat was fed in high fat diets of 5.9 and
6.8% total dietary EE compared to low fat diets with 3.3 and 2.9%
ether extract. Cows receiving the two high fat diets produced more
(P<.05) percent and yield of milk fat. Cows on the 6.8% EE diet
produced more (P<.05) FCM than cows on the low fat diets. Milk and
protein production were not affected
(P>.05).
Rations containing
5.2%
fat produced significant increases in percent milk fat, slight
increases in 4% FCM and no increase in milk yield compared to a ration
containing 2.7% fat (Byers et al.,
1949).
A protected tallow supplement (60% formalin treated soybean meal
and 40% tallow) was fed at 0, 15 and 30% (Smith ^
al^.
,
1978) to
Holstein cows during the first 15 weeks of lactation. The protected
fat supplement resulting in a decrease (P>.05) in milk production,
and an increase (P<.05) in 4% FCM, percent and yield of milk fat and
a decrease (P<.05) in percent and yield of SNF compared to controls.
These results became greater as fat levels increased. A significant
decrease in SNF was reported by Souleimani et^ al. (1982) from feeding
a hydrogenated vegetable fat supplement. The feeding of formaldehyde
treated safflower or soybean oils resulted in an increase in the total
solids (TS) content of the milk. Unprotected safflower oil and

pro-
tected hydrogenated soybean oil depressed milk total solids. Protect-
ed, unsaturated soybean oil and protected coconut oil increased
10
(P<.05) percent milk fat and protein (Astrup £t al.,
1976).
Mattos
and Palmquist (1974) reported increases of milk yield
(P<.01),
per-
cent (P<.05) and yield (P<.001) of milk fat and a decrease (P<.05)
in milk crude protein in cows supplemented with 3.6 kg of either
unprotected or formaldehyde-protected full-fat soyflour.
Digestibility, DM Intake And Body Weight Change
Palmquist and Conrad (1978) reported trends towards increased
digestibility of DM, energy, ADF and calcium (Ca) due to fat feeding
in trial one. Digestibility of EE was increased (P<.05) in diets
containing fat. Nitrogen digestibility was increased on medium fat
(P>.05) and on high fat diets
(P<.05).
Magnesium digestibility was
higher (P<.05) for the medium fat diet consisting of raw ground soy-
beans over the high fat and control diets. In trial two, digesti-
bility of DM, energy and magnesium was not affected (P>.05) by
treatment. Digestibility was higher for ADF (P>.05) and EE (P<.05)
in high fat diets but lower (P>.05) for calcium. Diets containing
tallow or hydrolyzed fat (Palmquist and Conrad, 1980) had higher
(P>.05) digestibility coefficients for EE and ADF over the control
diet.
Energy, N and DM digestibility was lower (P>.05) in one ration

with grain fed at 33% containing 10% hydrolyzed fat compared to the
control diet. Unprotected full-fat soyflour, in a study by Mattos
and Palmquist
(1974),
increased (P<.05) DM digestibility compared
to control and protected soyflour diets. Digestibilities were higher
for EE (P<.05) and ADF (P>.05) from diets containing high fat levels.
11
Nitrogen digestibility was lower (P<.05) on the protected soyflour
diet.
Heinrichs et al. (1981) reported no difference (P>.05) in DM,
crude protein, ADF or Ca intakes associated with feeding diets con-
taining 3 or 6% fat. Dry matter intake and body weight were not
affected
(P>.
05)
from supplementation with oleic acid, Crisco or
a fat high in C18:l trans fatty acid (Sulner and Shultz,
1980).
These results are in agreement with Palmquist and Conrad (1978)
using ground, raw soybeans and hydrolyzed animal fat in Jerseys,
Palmquist and Conrad (1980) feeding an animal-vegetable fat blend
and Souleimani et al^. (1982) feeding a hydrolyzed vegetable fat.
In a second trial (Palmquist and Conrad, 1978) DM intake was not
altered (P>.05) but cows fed a high fat, high protein diet did have
lower (P<.05) body weight changes than cows on a low fat, high
pro-
tein diet. Smith et al. (1978) found depressed (P<.05) DM intake
in cows fed a high fat (protected tallow) supplement without any
change (P>.05) in body weight. Mattias et al. (1982) fed a concen-

trate diet containing 5% animal fat and reported no significant
changes in body weight. Inclusion of WSS at 10, 20 and 30% as a
source of dietary fat to Holstein heifers did not affect (P>.05)
body weight gains but did suppress (P<.05) DM consumption resulting
in improved (P<.05) feed efficiency (Park and Rafalowski,
1983).
VFA And FFA Production
Studies have been conducted on the effects of feeding fat, in
various forms in order to better understand events which lead to
12
depressed milk fat synthesis in dairy cattle.
Van Soest (1963) discussed three theories to explain depression
of milk fat concentration: 1) deficiency of rumen acetic acid;
2) deficiency of beta-hydroxybutyric acid; and 3) a decline in blood
lipids required for milk fat synthesis resulting from a glucogenic
response during high propionate production on high concentrate diets,
suppressing tissue fat mobilization. A deficiency of rumen acetic
acid caused by feeding ground roughage or high concentrate diets
was substantiated by cited work which described a decrease in the
Reichert-Mersial number of the milk fat from cows receiving restricted
roughage or high concentrate diets and a return to near normal fat
composition as a result of feeding acetic acid or acetate salts.
Brown
et^
_al^.
(1962) found decreased (P<.05) molar percent of rumen
acetate in cows fed a low roughage diet. However, Bauman et al.
(1971) reporting decreases in percent milk fat and molar ratio of
acetate:propionate attributed these findings to an increase in
pro-

pionate production rather than a decrease in acetate. This is in
agreement with McCullough
(1966).
The increase in rumen propionate
concentrations leads to increased lactate and glucose production,
stimulating insulin production, resulting in a reduction in the re-
lease rate of adipose free fatty acids. Milk fat synthesis is de-
pressed due to a decrease in availability of preformed long chain
FA to the mammary gland (Christie,
19
79).
Dietary fat interferes with microbial activity, affecting VFA
production (Astrup et^ al•,
1976).
Several workers have reported
a decrease (P<.05) of the acetate:propionate ratio in cows fed an
13
unprotected, unsaturated fat as a result of decreased (P<.05)
ace-
tate concentrations (Mattos and Palmquist, 1974; Palmquist and Con-
rad, 1978; Seiner and Shultz, 1981) and increased propionate (Palm-
quist and Conrad, 1978; Seiner and Shultz,
1981).
This does not
agree with Brown et al. (1962) who, although he reported a depres-
sion in acetate levels (P>.05) associated with tallow and cottonseed
oil feeding, found increases in valerate and higher acids for tallow
(P>.05) and cottonseed oil (P<.05) in cows on low roughage diets.
Acetate:propionate ratios have not been affected (P>.05) when hydro-
genated fats (Palmquist and Conrad, 1978; Seiner and Shultz, 1981)

and protected oils (Astrup ^
^1.,
1976) or fat (Mattos and Palmquist,
1974) have been fed. Palmquist and Conrad (1980) found differences
(P<.05) in rumen propionate concentrations to be associated with
dietary fiber level and not from feeding either tallow or hydrogen-
ated vegetable oil.
Milk fat depression occurs from shifts in rumen acetate:propion-
ate ratios inducing a glucogenic response from adipose tissue, causing
it to: 1) compete with the mammary gland for lipogenic substrate,
thereby reducing availability of acetate to the mammary gland; 2)
absorb and esterify increased amounts of long chain FA; and 3) de-
crease mobilization of adipose long chain FA to the mammary gland
for milk fat synthesis (Palmquist and Jenkins,
1980).
The decreased
mobilization of adipose FA would, however, have a minimal effect,
as less than 10% of milk FA are from adipose tissue. Approximately
50%
of milk FA are from de novo synthesis in the mammary gland
uti-
lizing acetate and beta-hydroxybuterate and
40-45%
contributed by
14
dietary sources (Mattos and Palmquist,
1978).
Palmquist and Jenkins (1980) summarized factors affecting rumen
effects on fat sjoithesis. Fatty acids in conventional diets are
mostly esterified and usually rapidly hydrolyzed by rumen lipolytic

bacteria. The biohydrogenation of unsaturated FA is dependent on a
free carboxyl to obligate lypolysis as the initial step, which, al-
though rapid, may be the rate limiting step depending on whether the
FA precursor is esterified. Increases of unsaturated FA concentra-
tions in the milk, particularly
C18:2,
can occur as a result of de-
creased populations of lipolytic and biohydrogenating organisms from
high grain-low roughage diets. A source of long chain fatty acids
includes rumen protozoa and bacteria, both capable of de novo syn-
thesis of long chain FA, utilizing precursors with odd or even chain
carbons or containing branched chains. Modification of FA chain
length occurring by alpha and beta oxidation. De novo synthesis
may be inhibited by dietary fatty acids, absorbed in cellular lipids
of rumen microorganisms and occurring as membrane phospholipid and
unesterified fatty acid. Data supporting the theory of fat as an
inhibitory agent affecting rumen microbial activity on fiber diges-
tibility include inhibition of rumen bacteria in pure culture by
FA (Hartfoot, 1978; Maczulak, 1979) and binding of FA to microbial
cells (Nieman, 1954; Henderson, 1973; Maxcy and
Dill,
1976) reduced
by adding fiber (Hartfoot £t^ al.,
1974),
reducing inhibition in pure
cultures (Maczulak,
1979).
Unsaturated
fats,
particularly polyun-

saturates,
inhibit microbial growth (Palmquist and Jenkins, 1980)
and are more toxic to rumen microbes than saturated fats (Galbraith
15
and Miller, 1973; Henderson, 1973; Maczulak,
1979).
Dietary
unes-
terified FA, particularly lineoleate, may also inhibit rimien biohy-
drogenation (Moore
etal.,
1969).
Mattos and Palmquist (1974) reported decreases (P<.05) of milk
C6:0 to C16:0 FFA with increases (P<.05) of C4:0 and all C18 FFA
from cows fed protected or unprotected fat. Free fatty acid concen-
trations of C18:0 and C18:l were lower (P<.05) on the protected fat
supplement compared to the unprotected supplement. The authors sug-
gested less ruminal biohydrogenation of the protected supplement.
Decreases (P<.05) of C8 to C14 FA and increases (P<.05) of C4 and C16
to C18:l FA resulted in cows fed a 15% protected tallow supplement
(Smith et
al.
,
1978),
an additional significant decrease and increase
in C6 and C18:2 respectively from the 30% tallow diets. The decrease
of the short chain FFA is possibly explained by the increased mammary
gland uptake of long chain FA inhibiting de novo synthesis of short
chain FA in the mammary gland by feedback inhibition of the long
chain acyl-CoA carboxylase (Mattos and Palmquist,

1974).
The in-
creased yields of milk butyric acid may be due to a partial or com-
plete independence of the malonyl CoA synthetic pathway (Mattos and
Palmquist,
1974);
or decreased utilization as a precursor for FFA
chain elongation resulting from suppressed mammary de novo FA syn-
thesis (Mattos and Palmquist, 1974; Smith et al.,
1978).
Similar
results have been reported for cottonseed oil and tallow (Brown et^
al., 1962),
ground raw soybeans and hydrolyzed fat (Palmquist and
Conrad,
1978),
a supplement high in linoleate (Young et^ al•>
1978),
oleic acid and hydrolyzed vegetable fat (Seiner and Shultz,
1980).
16
Feeding diets containing low levels of lipid result in higher
proportions of FA synthesized de novo in the mammary gland with re-
sultant lower yields of C18 FA and as much as 50% of palmitic acid.
Alteration of milk FA composition from dietary fats may occur as a
result of one or more fatty acids: 1) being absorbed and transported
to the mammary gland, where it is esterified unaltered and appearing
at a higher rate in the milk; 2) altered by rumen hydrogenation,
appearing in the mammary gland in hydrogenated form after eventual
esterification; 3) becoming desaturated before esterification, ap-

pearing in the milk as a fatty acid unrelated to the dietary fatty
acid; 4) occurring in large enough amounts to affect de novo FA syn-
thesis by inhibiting mammary gland uptake of FA, inhibiting one of
the enz3niies involved in FA synthesis; or 5) affecting rumen VFA meta-
bolism, reducing the availability of low molecular weight substrates
required for FA synthesis (Christie,
1979).
Origins of C4-C14 FA
are entirely endogenous, all C18 FA are exogenous, and C16 and C16:l
FA may have contributions from both endogenous and exogenous sources
(Smith et al., 1978; Christie,
1979).
Cottonseed Meal
Gossypol,
1,1'6,6',7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-
dimethyl(2,2'-binapthalene)-8,8'-dicarboxaldehyde, is a naturally
occurring substance in cottonseed
meal.
A yellow pigment, located
in the intercellular structures called pigment glands distributed
throughout the cotyledons and periphery of the axial tissue in glanded
varieties of cottonseed (Martinez et al.,
1970)
,
gossypol inhibits
17
feeding patterns of deleterious insects on cotton plants (Bottger
et al.,
1964).
Gossypol has gained a substantial amount of interest

because it is a toxic substance to monogastric animals (Gallup,
1928),
particularly young poultry and swine (Church,
1977).
Symptoms of gossypol toxicity summarized by Lindsey et al. (1980)
include:
1) anorexia; 2) decreased hemoglobin due to the formation
of gossypol-iron complex which interferes with either iron absorption
or utilization after absorption resulting in a decrease of available
iron to the liver (Brahman and Bressani,
1975);
3) hypoproteinemia as
a result of extensive liver degeneration; 4) decreased hematocrit
(Brahman and Bressani,
1975);
and 5) dyspnea. Gossypol is naturally
detoxified in monogastrics by accumulation of free gossypol in the
liver (Albrect et^ al., 1970) where it is metabolized and excreted
in the bile (Lindsey et a]^.
,
1980) and in ruminants through perma-
nent binding with soluble proteins in the rumen (Reiser and Fu,
1962).
Detoxification of gossypol by treatment with ferrous sulfate
has alleviated symptoms of toxicity in
rats,
poor performance in
growing-finishing
pigs,
accumulation of gossypol in the liver of

pigs fed CSM (Rincon et al., 1980) and increase DM intake and daily
gain in calves fed WCS (Cummins and Hawkins,
1982).
Lindsey et al.
(1980) reported high levels of total, free and bound gossypol in the
liver of lactating cows fed either solvent extracted (Sol CSM) or
screw press CSM (SPCSM) indicating insufficient detoxification of
gossypol in the rumen. Cows fed the Sol CSM had the highest levels,
consumption of gossypol in this group reaching 54.5 mg/kg/d. Feeding
either Sol CSM or SPCSM decreased hemoglobin due to hemolysis of
18
extravascular erythrocytes, decreased hematocrit and increases in
temperature and respiratory rate during hot weather. The necropsy
of one cow that died during hot weather revealed severe fatty degen-
eration of hepatocytes. Hollon el^ al. (1958) showed the tolerance
of free gossypol ingestion in ruminants to be associated with age
and corresponding functional development of the rumen. They found
a high correlation between free gossypol consumption greater than
140 mg/cwt/d and death within 48 d in calves fed CSM as the primary
protein source. Symptoms described were erratic appetite, one to
two wk, and abdominal pain and dyspnea one to two days prior to
death;
bright red blood slow to coagulate; hydrothorax and hydroper-
eritoneum; and fatty degeneration of liver tissue. Serum transam-
inases increased corresponding to increased levels of gossypol due
to cellular destruction of primary hepatic and heart muscle cells
decreasing the concentration of liver transaminases (Brahman and
Bressani,
1975).
Commercial extraction of the oil from cottonseed, whether by

solvent or pressure methods, involves using heat and moisture (Mar-
tinez et al., 1970; Church, 1977) which can decrease the nutritional
value of CSM by formation of an insoluble gossypol-protein complex
(Smith et^ al^. , 1959) resistant to in vitro digestion of trypsin and
pepsin (Sherrod and Tillman,
1962).
This complex is formed by bind-
ing of lysine (Baliga and Lyman, 1957; Martinez ^ al., 1964)
epsi-
lon-amino groups with two reactive carbonyl groups of gossypol
(Lyman
et^ _al.,
1959) decreasing the availability of lysine and other
amino acids (Jones and Smith, 1977 a,b), resulting in poor growth
19
rates in rats (Smith £^
al ,
1959; Lyman e^ al., 1959; Jones and
Smith,
1977a) and significantly lower digestibility of cottonseed
protein in sheep (Sherrod and Tillman,
1962).
Craig and Broderick
(1981) reported only minimal losses of lysine availability in SPCSM
and Sol CSM autoclaved less than sixty min. The authors suggested
that more severe heat treatment, greater than what normally occurs
during oil extraction, must occur before any substantial availability
of lysine is realized. Other workers (Wong et al., 1972; Finlay
et al^., 1973; Meisner ^ ^., 1978) have described a reaction of
gossypol with the epsilon-amino groups of two lysine residues of

pepsinogen to form a zymogen which completely inhibits the conver-
sion of pepsinogen to its active form, pepsin.
Moore (1914) and McCandlish (1921) reported trends towards de-
creased milk yields and percent fat x>7hen CSM replaced linseed meal
(LSM) and(or) wheat bran and an overall increase in percent and yield
of milk fat, without any influence on milk yields, when CSM replaced
cracked corn (McCandlish,
1921).
Milk and butterfat were increased
in cows fed CSM (up to 11 lb) compared to LSM without affecting herd
health (Huffman and Moore,
1930).
Cottonseed meal fed as the only
concentrate (Miller and Wise, 1944) depressed percent fat, TS and
SNF after four mo on the treatment. When placed on pasture, several
cows on the CSM treatment displayed anorexia, decreased milk produc-
tion and abortions. Lindsey
et^ £l^.
(1980) found no effect on milk
production, percent fat or TS in cows fed either SPCSM or Sol CSM
compared to soybean
meal.
CHAPTER III
EFFICACY OF WHOLE AND PROCESSED COTTONSEED ON
DIGESTIBILITY, RUMEN VARIABLES AND THE
PRODUCTION OF MILK AND ITS COMPONENTS
Summary
Four,
first lactation, Holstein cows were used in a 4 X 4 Latin
square design, lactation and digestion study. Whole "fuzzy" cotton-

seed
(WCS),
pelleted whole cottonseed
(PCS),
cottonseed meal (CSM)
or pelleted delinted cottonseed (PDLCS) were used in isonitrogenous,
isofibrous diets fed at 3.5% of body weight per cow per day. Animals
were adjusted to treatment for 10 d followed by 7 d total collection
of feces for determination of dry matter digestibility. Feed refu-
sals were weighed and sampled for subsequent analysis. Rumen fluid
samples were analyzed for pH and volatile fatty acids. Milk samples
obtained during collection periods were analyzed for butterfat (BF),
total solids (TS), solids-not-fat
(SNF),
protein, and free fatty
acids
(FFA).
Treatment means for milk production (kg), BF (%), milk
protein (%) and dry matter digestibility (%) were:
20.85,
2.93,
3.42,
70.74;
19.48,
2.03, 3.61,
69.52;
20.18,
2.18, 3.39,
71.07;
20.13,

2.71, 3.41, 72.20 for the WCS, PCS, CSM and PDLCS diets, re-
spectively. A production study was conducted utilizing 83 lactating
Holstein and Jersey cows to determine the effects of feeding WCS,
PCS and CSM on milk production, BF and alfalfa hay consumption.
Animals were allotted to a 3 X 3 Latin square design according to
breed, stage of lactation and number of previous lactations. Diets
20
21
were formulated to be isonitrogenous with treatments replacing ap-
proximately 20% of a commercial supplement (dry matter basis) and
alfalfa hay offered ad libitum. Treatment means for milk production
(kg),
BF (%) and hay consumption (kg/hd/d) were:
23.26,
3.63, 6.55;
23.12,
3.65, 7.34;
23.14,
3.56, 7.82 for the WCS, PCS and CSM diets,
respectively.
Introduction
A combination of increasing feed costs and economic pressures
have developed a greater interest in the potential use of by-products
as a feed source for livestock producers. Whole cottonseed, a by-
product of the cotton industry, has been fed by dairymen in the South-
west for years. Considered a protein feed (NRC, 1982) WCS also
pro-
vides a source of energy, fat, fiber and phosphorous. Its use,
however, is dependent upon availability and the cost of other
pro-

tein and energy sources.
Feeding WCS has increased (P<.05) the production of milk, fat-
corrected milk (FCM) (Ramsey and Miles, 1953; Anderson ^
al.,
1984),
fat,
solids-not-fat (SNF) (Anderson et al., 1979) and protein (Ander-
son et al.,
1984).
Hawkins et al. (1982) reported no effect on milk
production or percent milk fat and protein when WCS, fed 18.5% dry
matter (DM) basis, replaced an isonitrogenous amount of a basal ra-
tion.
In a study reported by Hansen
(1980),
cows fed WCS produced
less milk and decreased percent SNF and protein, but treatment in-
creased percent fat. Increased fat tests have been shown when cows