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VERSITY OF KENTUCKY AGRICULTURAL EXPERIMENT STATION PROGRESS REPORT 150 `
/

 PROGRAM FOR l965 ANNUAL LIVESTOCK FIELD DAY
LEXINGTON PRINCETON I
July I4, l965 July I6, l965 I l
Morning Morning g
Chairman ··· C. Frank Buck Chairman ·· Paul P. Appel
Coldstream Farm ·· Conducted tours Livestock Farm West Kentucky
showing beef, sheep and swine Substation. Conducted tours -
research will start at regular showing beef and swine
intervals, beginning at 9 a.m. research will start at regular I
(EST). Last tour starts at intervals beginning at 9 a.m. l
IO a.m. (CST). Last tour starts at
IO a .m .
Noon Noon 4
Lunch Lunch ’
Courtesy of G. W. Gardner, Bluegrass Courtesy of Farmers Elevators, Inc. I
Stockyards, Lexington and Field Packing Com-
pany, Owensboro
Afternoon y
Chairman ·' W. P. Garrigus
l:l5 Address ·· "Livestock and C. B. Cox, Vice President, .
Meat Trends" Armour and Company

 KENTUCKY
ANIMAL SCIENCE RESEARCH REPORTS
  1965
PROGRESS REPORT 150
July 1965
_ UNIVERSITY OF KENTUCKY
AGRICULTURAL EXPERIMENT STATION

 
 CONTENTS
‘ Page
BEEF CATTLE SECTION
Sources of Nitrogen for Supplementing Ground Ear Corn Rations . . 7
V Supplementation of Corn - Corn Silage Rations for Feedlot
Cattle .................... 8
- Tylosin for Beef Steers on Pasture ............ 9
Measurement and Selection of Economically Important Traits
in Beef Cattle - 1965 ............... 12
ANIMAL NUTRITION SECTION
Concentrations of Pantothenic Acid, Niacin, Folic Acid and —
Vitamin Blz in Ruminal Fluid of Steers Fed Different
Levels and Forms of Hay and Grain .......... 15
B- Vitamin Synthesis In Vitro: Effect of Source of Rumen
Microorganisms and Substrate ............ 16
‘ Utilization of Glucose and Starch by Wethers When Given
Orally or Into the Abomasum ............. 18
Starch Digestion in Steers as Influenced by Dietary Level ..... 20
Non-protein Nitrogen Sources for In Vitro Starch Digestion
by Rumen Microorganisms ............. 22
Conversion of Zein to Microbial Protein in Lambs Fed Two ‘
Cellulose: Starch Ratios .............. 23
Influence of Dietary Nitrate on Pre-intestinal Destruction
of Vitamin A by Steers .............. 24
Carotenoid Balance of Vitamin A Depleted Sheep ........ 25
Volatile Fatty Acid Concentrations in Ruminal Fluid of
· Steers Fed Neomycin and Bacitracin ____,,,,,, 27
Amino Acid Composition and Biological Value of Ruminal Fluid
Proteins From Steers Fed Roughage or Concentrate Levels . . 29
(Continued on ncxt page)

 Page
(ANIMAL NUTRITION continued)
Distribution of Radioactivity in Lambs Receiving C14 — Labeled `
Carotene ................... 30
SHEEP SECTION l ·
Three Levels of Protein for Early - Weaned Lambs Sired by
Either Hampshire or Southdown Rams ......... 33 t
GENETICS SECTION
Effectiveness of Different Oral Progestogens in Synchronizing I
Estrus and Ovulation in Ewes ............ 34 _
Effect of Short- Time Exposure to Continuous Light on Ovulation ,
Rate and Fertility of Ewes ............. 35
Selective Breeding for Earlier Lambing in a Purebred Flock
of Southdown Sheep ................ 36
Semen Traits of Yearling Southdown Rams During July ...... 37
Maintenance of Induced Corpora Lutea in Anestrous Ewes by ·
Hysterectomy .................. 39
MEATS SECTION
Relationship of Retail Yield and Edible Portion to Meatiness .
Characteristics of Kentucky Spring Lambs ........ 41
The Effect of Muscle Quality on Quick—Aged, Dry-Cured Hams . . . 43
The Effects of Pancreatic Lipase and Papain on Quick-Aged,
Dry-Cured Hams ................. 45
Partial Pumping of Hams ............... 47 `
The Effects of Texture and Color of Muscle on Beef Rib _ A
Desirability .................. 49 ·
Quality Comparisons and Chemical Composition of the Loineye (
From Three Different Weight Groups of Hampshire Barrow
and Gilt Littermates ............... 52
(Continued on next page)

 Page
SWINE SECTION
_ Effect of Sulfonamide Supplementation of Feed on the Performance
of Pigs .................... 55
_\ Protein Supplements for Growing-Finishing Pigs on Concrete . . . 57
Progress Report on Artificial Insemination of Swine ....... 58
The Use of Corn Silage and Rye Pasture for Bred Sows ....... 59
Antibiotics for Early Weaned Pigs ............. 61

 
 7
- BEEF CATTLE SECTION
SOURCE OF NITROGEN FOR SUPPLEMENTING GROUND EAR CORN RATIONS
N. W. Bradley, J. Ralph Overfield, C. O. Little and G. E. Mitchell, Jr.
University of Kentucky
. Two previous experiments showed that a simple ration of ground ear corn,
. distillers dried grains with solubles (DDG/ S), ground limestone, salt and vitamin A
was excellent for fattening yearling steers in drylot. Replacing one—half of the DDG/ S
with urea resulted in a depressed rate of gain one year and had no effect the next year.
Additions of trace minerals, alfalfa meal, molasses or a complex supplement contain-
ing B vitamins, lysine, and increased levels of calcium and phosphorus did not improve
steer performance.
Because of the variable results with additions of urea, 120 steers were used
in replicated lots of 10 steers each to test each of the following treatments:
1. Ground ear corn + DDG/S
2. Ground ear corn + DDG/S + urea
3. Ground ear corn + soybean meal (SBM)
4. Ground ear corn + SBM + urea
5. Ground ear corn + corn gluten meal (CGM)
6. Ground ear corn + CGM + urea
The urea in treatment 2 replaced one-half of the nitrogen in the DDG/S in
treatment 1. Rations used in the other treatments were formulated to contain nitrogen
equivalent to that in rations 1 and 2. Ration ingredients for all six rations are given
in Table 1.
All lots of steers were fed their respective rations for a 133-day feeding period.
Results of the feedlot trial are given in Table 2. Statistical analysis of the data reveal-
ed the following:
1. DDG/S gave a highly significant increase in rate of gain over corn gluten
meal, corn gluten meal + urea and soybean meal + urea. DDG/S also increased average
daily gain 0. 19 lb. over soybean meal. This value approached significance at the 5
percent level.
2. DDG/S + Urea gave a highly significant increase in rate of gain over corn
gluten meal and corn gluten meal + urea, also a significant increase in rate of gain over
soybean meal + urea.
3. Soybean meal gave a highly significant increase in rate of gain over corn
gluten meal, also a significant increase in rate of gain over corn gluten meal + urea
and soybean meal + urea.
In this experiment DDG/S was the best of the supplements used, and corn gluten
meal was the least desirable in respect to rate of gain and feed efficiency. Interest-
ingly enough, replacing one—half of the protein in DDG/S or CGM did not significantly
depress rate of gain. However, when urea replaced one—half of the protein in soybean
meal, rate of gain was significantly depressed. These results confirm a previous
conclusion that substituting urea and corn for a part of natural protein supplements
sometimes, but not always, depresses performance. Obviously, this area of ruminant
nutrition needs further research to define more clearly conditions under which depressed
performance can be expected when urea is used in beef cattle rations.

 8 .
Table 1. —Ration Ingredients (lb/ ton)
 
Ingredients 1 2 3 4 5 6
 
Ground shelled corn 1 , 291 1, 423 1, 430 1, 498 1, 418 1, 492
Ground corn cobs 323 356 358 375 355 373
DDG/S 359 179 --- —-— --— -——
SBOM —-- —-- 186 85 ~·—- --— .
Urea -—- 18 --— 15 —-— 15. 3
Corn gluten meal —-- —-- —-- —-— 201 93 _
Ground limestone 7.2 7.2 7.2 7.2 7.2 7.2
Salt 20 20 20 20 20 20
Vitamin A, I.U. 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000
  ,
Table 2. —Steer Performance
 
Corn
DDG SBM Gluten .
+ + Corn + .
DDG Urea SBM Urea Gluten Urea
 
Days on Expt. 133 133 133 133 133 133
No. steers 20 20 20 20 19 19
Initial Wt 741 743 742 742 744 737 A
Final Wt 1074 1062 1050 1021 1008 1011 _
Total gain 333 319 308 279 264 274
A.D.G. 2.51 2.40 2.32 2.10 1.98 2.06 ,
Feed/Hd/day 22.2 21.6 21.5 20.5 19.6 19.7
Feed/cwt gain 887 899 930 977 1078 1047
Carcass Gradea 11.6 11.0 11.0 10.7 10.8 10.5
2/ 10 = average good, 11 = high good, 12 = low choice.
SUPPLEMENTATION OF CORN—CORN SILAGE RATIONS FOR FEEDLOT CATTLE
J. T. Thompson, J. R. Overfield, N. W. Bradley and C. O. Little I
University of Kentucky
The potential of high corn yields in certain areas of Kentucky and the demand 9,
for fed cattle in the state have increased the interest in practical feedlot rations for
beef cattle. Reports from this station have included work with ground ear corn rations
and various protein supplements. The results have verified that urea can be used
efficiently for supplementing ear corn rations; however, only limited information is
available on the effectiveness of urea supplements in silage rations. This experiment
was conducted to obtain information on the feedlot performance of yearling steers fed
different levels of corn silage and corn supplemented with soybean meal or urea.

 9 .
Fifty yearling steers averaging 757 lb each were allotted to 5 groups of 10
and placed on the following rations:
Lots 1 and 2 - Ground shelled corn and supplement fed at 1. 5%
body weight, corn silage ad lib.
Lots 3 and 4 - Ground shelled corn and supplement fed at 1. 0%
- body weight, corn silage ad lib.
Lot 5 - Ground shelled corn and supplement fed at 0. 5% body weight,
corn silage ad lib.
Lots 1 and 3 received a soybean meal supplement, and lots 2, 4 and 5 received
a urea supplement. Composition of the supplements is given in Table 1. Before
feeding, the supplements were mixed with the ground shelled corn portion of the ration,
and this corn-supplement mixture was fed as a top dressing on the silage. All steers
were implanted with 24 mg diethylstilbestrol at the beginning of the 125-day feeding
period. At the end of the feeding period, the steers were slaughtered and various
carcass measurements made.
The results of this experiment are summarized in Table 2. With both supple-
ments, a reduction in the level of shelled corn in the ration from 1. 5% to 1. 0% of body
weight and an increase in corn silage intake gave decreased rates of gain. These
decreases were 0. 19 lb per day with soybean meal supplement and 0. 17 lb daily with
urea supplement. Further reduction of corn intake to 0. 5% of body weight with urea
supplement decreased gain an additional 0. 06 lb per day. These differences in rate
of gain were accompanied by changes in dry feed intake. Feed required per 100 lb gain
was not affected by corn-corn silage changes with the soybean meal supplement; how-
ever, with the urea supplement, less feed was required when corn was decreased and
silage was increased. At each level of corn-corn silage feeding that a comparison
could be made, the steers fed soybean meal gained at a faster rate and required less
feed than the urea—fed steers.
The economy of these rations is shown by the feed cost figures. The feed costs
per unit of gain for steers on the same silage levels were slightly larger with the urea
supplement than with the soybean meal supplement in this experiment; however, this
could change with changes in prices of soybean meal and urea. It should be pointed out
that the rations which gave the fastest rate of gain were not necessarily the most eco-
nomical. As the level of corn silage in the rations was increased the cost of gains was
reduced. There were little differences in the various carcass measurements. Although
only a small number of animals was involved in this experiment, the results suggest
that urea can be efficiently utilized in corn silage rations and high quality beef can be
produced economically with corn silage.
TYLOSIN FOR BEEF STEERS ON PASTURE
D. B. Herd, N. W. Bradley, D. E. McKechnie and G. E. Mitchell, Jr.
University of Kentucky
Results of two years' work at this station suggest that administration of the
antibiotic tylosin in a sustained release bolus may improve gains of grazing steers.
Preliminary investigations indicated that the effective life of the boluses being used
was approximately 40 days; however, in the first year's work, treated steers gained

 10
Table 1. —Composition of Soybean Meal and Urea Supplements Mixed with Ground
Shelled Corn and Fed with Corn Silage.
 
Soybean meal Urea .
Supplement Supplement .
 
Soybean meal (44%) 85. 0 --
Urea (262 equiv.) -— 33.0 ‘
Ground shelled corn —— 34.0
Dicalcium phosphate 8. 5 20. 0
Limestone 6. 0 12. 0
Trace mineral premixa 0. 5 1. 0
Vitamin Ab + +
2/ Composition of trace mineral premix in parts per thousand: manganese, 90; zinc,
80; iron, 30; copper, 5.5; iodine, 1. 8; and cobalt, 1.0.
9/ Vitamin A was included to provide 20, 000 I. U. per steer daily.
Table 2. —Feed—lot Results and Carcass Data from Steers Fed Soybean Meal or Urea
Supplements with Different Levels of Corn and Corn Silage (125-day Feeding
Experiment)
Supplement Soybean Meal Urea
Level of Corn as % Bd Wt 1. 5% 1. 0% 1. 5% 1. 0% 0.5%
Initial wt, lb 757 757 757 757 757
Final wt, lb 1056 1031 1041 1020 1012
Total gain, lb 299 274 284 263 255 ·
ADG, lb 2.39 2.20 2.27 2.10 2.04
Ration intake, lb /hd /day
Corn silage (wet) 23. 9 32. 5 24. 6 32. 3 37. 7 _.
Corn silage (air dry wt) 8.0 10.8 8.2 10.7 12.6
Shelled corn 12.0 7.3 12.8 8.1 3.7
Supplemental 1 . 55 1. 63 0. 77 0. 84 0. 76
Total air dry feed 21.5 19.7 21.7 19.6 17.0
Feed/cwt gain 901 900 958 938 833
Feed cost/cwt gainb 19. 87 17. 77 20. 57 18. 14 13. 87 ·
Dressing % 63. 9 64. 9 64. 9 64. 8 62. 9
Carcass gradec 13.1 12.5 12.3 12.6 12.4
Rib eye, sq in. 11.65 12.83 11.88 12.95 11.93
Fat over rib eye, cm 1.63 1.61 1.90 1.49 1.57
Selling price/cwt 24. 47 24. 73 24. 49 24. 84 23. 78
 
2/ Supplements were thoroughly mixed with the ground shelled corn before feeding.
LY Feed costs calculated from the following: corn silage, $8. 00 per ton; ground
shelled corn, 52. 00 per ton; soybean meal supplement, 86. 80 per ton; and urea
supplement, 97. 20 per ton.
9/ Grade on scale of 12 = low choice, 13 = average choice. ,
g/ Price per cwt of live weight on grade—yield basis.

 11
faster during the first two weeks after bolusing, but not from 14 to 42 days, suggesting
a shorter—than-expected bolus life. The following year, bolusing at 14-day intervals .
was compared with 42-day intervals. Both treatments gave a substantial increase in
gain over control animals, but the differences were not statistically significant. The
V 42-day bolus treatment was slightly more effective in increasing gains than the 14-day
bolus treatment, suggesting that the boluses were effective for at least 42 days.
The following experiment was conducted to obtain additional information concern-
ing the influence of tylosin boluses on the gains of grazing steers.
Fifty-one 550—pound yearling Angus steers were randomly allotted to a control
group and a group receiving single tylosin boluses at the beginning of the experiment
2 and at 42-day intervals thereafter.
The boluses weighed 64 j O. 5 grams and contained 6 grams of tylosin activity
as tylosin phosphate.
Each steer was implanted with 24 mg of stilbestrol. All steers grazed together
on bluegrass—white clover pastures for 168 days beginning May 19, 1964. Weights
were taken every 14 days. The steers were held off feed overnight before each period
weight and off feed and water before initial and final weights were taken. Rumen
samples were taken by stomach tube 1, 2, 4 and 6 weeks after the start of the experi-
ment for determination of the tylosin activity present in ruminal fluid.
Performance of the steers is summarized in Table 1. The use of tylosin
boluses gave a small but nonsignificant increase in average daily gain. Once again, it
appeared that the bolus release rate was not uniform over the 42-day periods. It can
be seen in Table 2 that the tylosin—treated steers consistently gained faster than did
the control steers during the first 2 weeks after each bolus, but gained slower during
the second and third 2-week periods. This large difference in gain during different
periods after bolusing suggests that the tylosin was not being released at a uniform rate.
This was further supported by a limited number of rumen assays which showed that
the level of tylosin present in the ruminal fluid decreased progressively with time after
bolusing and was essentially gone by the end of 4 weeks. This latter evidence was
obtained during the first 42-day period only.
Under these conditions, where the tylosin was not uniformly released through-
out the bolusing period, it was not possible to evaluate the growth—promoting properties
of the antibiotic. Some other method of administration or an improved bolus with a
more uniform release rate is needed before a fair analysis of the value of tylosin for
grazing steers can be made.

 12
Table 1. —Effect of Antibiotics on Grazing Steer PerformanceE/
 
Control TylosinP./
 
Number of steers 25 26 l
Initial weight, lb 542 549 V
Final weight, lb 770 789 ·
Total gain, lb 228 240
Total ADG, lb 1 . 36 1. 43
 
§/ All steers were implanted with 24 mg of stilbestrol at the beginning of the
experiment.
ti/ Tylosin boluses (one bolus per steer) were administered at the beginning of the
experiment and repeated at 42-day intervals.
Table 2. —Average Daily Gain of Steers at Different Times After Bolusing
 
Time After Bolusing
 
0-14 days 14-28 days 28-42 days
(:2/ 1**;/ c&/ TW c2/ Tl9/
First bolus, lb 3.37 3.95 2.74 2.39 .21 .14
Second bolus, lb 1.69 2.14 .79 .30 1.27 1.30 i
Third bolus, lb 1.67 2.01 4.06 3.65 .59 .51
Fourth bolus, lb 1.00 1.87 -.70 -.61 -.41 -.48
Average of the
four boluses, lb 1.93 2.49 1.72 1.43 0.42 0.37 .
 
2/ Control. I
pj Tylosin at 42-day intervals.
MEASUREMENT AND SELECTION OF ECONOMICALLY
IMPORTANT TRAITS IN BEEF CATTLE — 1964
N. W. Bradley, J. Ralph Overfield, J. D. Kemp and J. T. Thompson
University of Kentucky
The objectives of this long-range breeding project are to use rate of gain, ·
efficiency of gain, conformation and carcass characteristics in an overall selection
experiment and, also, to develop a method of estimating a bull's transmitting ability
for carcass characteristics as well as rate of gain and conformation.

 13
The herd of Hereford cattle being used in this project has increased steadily
to a total of 349 head of varying ages. During the first three months of 1965, 93
calves were born. At present 176 cows and heifers are being bred to calve during
_ January, February and March of 1966.
A postweaning performance test has been completed with 20 selected bulls
from the 1963 calf crop. Three of these bulls were kept for progeny testing during
the 1964-65 breeding season. The other 17 bulls were slaughtered to obtain carcass
measurements. A summary of the performance data is given in Table 1, and a
‘ summary of the carcass measurements is given in Table 2. The data are summarized
according to the sire of the bulls. Progeny test data for these two sires (SP 194 and
A HP RS 15) may be found in the 1963 Kentucky Animal Science Research Reports. Bulls
sired by HP RS 15 gained 0. 18 lb per head daily more than did the sons of SP 194.
The progeny of HP RS 15 had an increase in fat thickness over the rib of 0. 08 inch,
an increase in dressing percent of 1. 3, an increase in yield grade of 0. 5 and an
increase of almost 4% in the fat content of the rib.
Growth rate of calves sired by the first three herd sires selected for use in
this project has been disappointing. Seven additional herd sires have been obtained.
Preliminary growth data from calves sired by these bulls seems to be much improved.
Complete results will be reported as they are collected and compiled.
Table 1. —Preweaning and Postweaning Performance of Bulls by Two Different Sires
 
Sire
Item SP 194 HP RS 15
 
Preweaning
Number 8 12
Age, days 221 234
Weaning Wt, lb 424 431
ADG, lb 1. 56 1. 59
Adj. ADG, lb 1.68 1.68
Type§/ 11.5 12.2
Index 106 110
Postweaning
Number 8 12
Age in days 432 433
Final wt. , lb 789 815
ADG, lb 2.15 2. 33
Wt./Day of age, lb 1-. 83 1. 88
Type9~/ 12.0 12. 4
1¤deXE/ 115 ll9
Feed/cwt gain 816 813
 
E/ 11 = high good, 12 = low choice, 13 = average choice.
h/ (Wt /day of age x 40) + (Type x 5) - 18 = Postweaning index.

 14
Table 2. —Carcass Data of Bulls by Two Different Sires
 
Sire
Item SP 194 HP RS 15
 
Number 7 10
Wt at slaughter, lb 889 913
Cold carcass wt, lb 509 536
Dressing % 57. 3 58.6
Hide wt, lb 75.6 77.5
Conformation2/ 12.1 13. 2
Marbling scorepj 3. 9 3. 9 —
Ribeye area, sq in. 12. 3 12. 1
Fat thickness, in. 0. 34 0. 42
Kidney fat % 2 2 _
Quality§ 10. 0 10.1
Yield grade9/ 1 . 7 2. 2
Carcass grad/e§/ 10.0 10.1
Color of fatg 2 2
Color of leanS/ 6.0 7.3
Wt. of rib, lb 22.0 22. 8
% fat 26. 7 30 . 6
% lean 57. 9 54. 5 .
% bone 15. 4 15. 9
W—B shear force, lb 16.1 16. 5
PalatabilityE./ V
flavor 7. 56 7. 47
juiceness 7. 45 7. 33
tenderness 7. 37 7. 19
overall satisfaction 7. 46 7. 37 V
2/ 10 = average good, 11 = high good, 12 = low choice, 13 = average choice. · _
W 3 Z traces, 4 = slight-
9/ The lower the yield grade the greater the estimated percent lean cuts.
g/ 2 : creamy white. y
9/ The higher the number the darker the lean.
£/ 1" cores roasted at 3250 to an internal temperature of 1600 in an electric oven.
££/ Average of 3 scores. The higher the number the more desirable.

 15
ANIMAL NUTRITION SECTION i
CONCENTRATIONS OF PANTOTHENIC ACID, NIACIN, FOLIC ACID AND VITAMIN
B12 IN RUMINAL FLUID OF STEERS FED DIFFERENT LEVELS AND FORMS OF .
HAY AND GRAIN
A B. W. Hayes, CG. E. Mitchell, Jr. , C. O. Little and N. W. Bradley
University of Kentucky
It has been well established that changes in the level of concentrates in the
» ration and different types of feed processing produce major changes in the microbial
activity in the rumen. Investigation concerning the possible effects of such changes
on microbial B-vitamin synthesis, which occurs in the rumen, has been limited.
Results reported last year in the Kentucky Animal Science Research Reports showed
that ration effects on levels of thiamine and riboflavin in ruminal fluid from steers
were significant (P <. 05) but that levels of biotin were not significantly (P). 05)
affected by the various rations studied. The present report is a continuation of that
study to include pantothenic acid, niacin, folic acid and vitamin B12.
Procedure
Samples of ruminal fluid from 48 yearling Angus steers, weighing approxi-
mately 397 kg (875 lb) were assayed microbiologically for the 4 B-vitamins. All
steers were fed a groimd ear corn and soybean meal ration for I4 days before 8 steers
were assigned to each of the following treatments:
I. Flaked corn IV. Ground corn and long hay
II. Ground corn V. Flaked corn and ground hay
III. Flaked corn and long hay VI. Ground corn and ground hay
Corn was self-fed and alfalfa hay was fed at the rate of 1. 8 kg (4 lb) per head per day.
In rations III and IV, corn and hay were fed separately, while in rations V and VI the
corn and hay were combined in a complete mixture. Soybean meal, vitamins A and D,
and minerals were mixed with the corn at appropriate levels to balance the rations
according to NRC requirements. Rations were adjusted at frequent intervals to equal-
ize intake of these components and to regulate ground hay intake. Ruminal samples
were taken via stomach tube on the first and 56th days of the experiment.
Results and Discussion
Initial and average vitamin concentrations at 56 days (mcg/ 100 ml ruminal
fluid) are presented in Table 1. The largest concentrations of all 4 B-vitamins were
foimd in ruminal fluid of steers fed the all-concentrate rations (I and II). Pantothenic
acid and niacin values for steers receiving ground corn (II) were significantly greater
than those for steers receiving flaked corn (I), and these values were significantly
greater than the values for steers receiving hay. Ruminal fluid from steers fed
ground corn and either ground or long hay (IV and VI) contained significantly more
niacin than ruminal fluid from steers fed flaked corn and ground hay (V).
Folic acid values for steers receiving the all-concentrate rations (I and II)
were significantly greater than the values for steers receiving the other rations.
Vitamin B12 data show that steers maintained on flaked corn (I), ground corn
(I I) or ground corn and long hay (IV) had significantly more vitamin B12 in their
ruminal fluid than steers fed ground hay and either flaked or ground corn (V and VI).

 16
These data further demonstrate that ration changes can produce wide fluctu-
ations in the levels of B-vitamins in ruminal fluid. Further research is needed to
determine the practical implications of these findings. ·
Table 1. —B-vitamin Levels in Ruminal Fluid of Steers (mcg/ 100 ml ruminal fluid)
 
Igzmil Concentration after 56 Days on Respective Ration
n . I II III IV V VI
centration
Pantothenic 71 246b 354a 65 77 115 112
acid
Niacin 146 649b 8503 222°· d 375C 141d 324C b
Folic acid 7.6 18.63 18.03 8.0 8.3 9.1b d 14.% d
vitamin B12 8.0 6.43,C 8.8a 4.8b·°·d 5.83»° 2.2 · 2.1 t
 
3· b» C· d Means in the same line, excluding initial concentration, that have different
superscript letters are significantly different (P( . 05). »
B-VITAMIN SYNTHESIS IN VITRO; EFFECT OF SOURCE OF RUMEN MICRO-
ORGANISMS AND SUBSTRATE
B. W. Hayes, G. E. Mitchell, Jr., C. O. Little, G. D. Potter and
C. R. Acord
University of Kentucky ‘
Cellulose-digesting microorganisms are prevalent in the rumen when high
roughage rations are fed to beef cattle and when the major component of the ration is —
grain there is an increase in ruminal amololytic activity. Thus, it seems possible
that some of the differences in ruminal B-vitamin synthesis when animals are fed
different rations may be due to the presence of different microbial populations in the
rumen. The present E vitro study was designed to furnish information on this subject.
Procedure I
Washed cell suspensions were prepared from ruminal fluid obtained from each
of three steers that were fed daily rations shown in Table 1. Microbial cells from
two volumes of ruminal fluid were suspended in one volume of a basal medium buffered
with phosphate and bicarbonate. Series of flasks containing 150-ml aliquots of washed
cell suspensions from each steer were incubated in 250-ml Erlenmeyer flasks with
finely ground substrates given in Table 2. Amounts of substrate in each flask per 150
ml of the washed cell suspension were based on a ratio of the amounts of hay, corn and
soybean meal in each steer's ration to an assumed ruminal ingesta volume of 75 liters.
Each flask was fitted with a two-hole rubber stopper and glass tubing so that carbon
dioxide could be bubbled through the mixture during incubation to provide anaerobiosis
and agitation. Flasks were incubated in a constant temperature water bath at 390C. .
After an 8-hour incubation period, contents in each flask were centrifuged at 20, 000
X G. The resulting supernatant was assayed for individual B-vitamins by standard
microbiological techniques.

 17
Table 1. —Steer Rations (kg/ steer/ day) »
 
‘ Alfalfa Ground Soybean
Hay Shelled Corn Meal
 
Steer 1 6. 80 -— —-
Steer 2 1.36 6.63 0.68
` Steer 3 —— 6. 63 0. 68
 
Table 2. —Substrates for Washed Ruminal Microorganisms (g/150 ml)
 
Alfalfa Shelled Soybean
Substrate Hay Corn Meal
 
Control -— —- -—
Hay 13. 5 —- --
Mixed 2. 7 7. 2 0. 9
Concentrate -- 7. 2 0. 9
 
Results and Discussion
Results of this study are presented in Table 3. When microorganisms from
the steer receiving the hay ration were used, apparent synthesis of riboflavin, niacin,
folio acid, pantothenic acid and vitamin B12 was less as hay was removed from the
substrate. Thiamine synthesis was greatest when the substrate was a mixture of hay,
corn and soybean meal.
Microorganisms from the steer fed the mixed ration synthesized more ribo-
flavin, niacin and pantothenic acid on the hay or mixed substrates than on the
concentrate substrate. The mixed substrate favored the greatest synthesis of thiamine,
folic acid and vitamin B12, while the smallest amounts of these vitamins were synthe-
sized when hay was the substrate.
Feeding the all—concentrate ration resulted in a rumen microbial population
which synthesized less of all vitamins studied in the hay substrate than on either the
concentrate or the mixed substrate. There was little difference between the concentrate
and mixed substrates in promoting B-vitamin synthesis by these microorganisms.
Summary
With some exceptions, B-vitamin synthesis was greater when the E vitro
substrates corresponded to rations of steers from which ruminal microorganisms
were obtained. In general, larger amounts of B-vitamins were synthesized by micro-
organisms obtained from steers receiving the all-concentrate and mixed rations than
by microorganisms from the steer receiving the hay ration.

 18
Table 3. —-Influence of Source of Ruminal Microorganisms and Substrate on &Vitro _
Synthesis of B-vitaminsa
 
Meg/100 M1. Washed Cell Suspension .
Final Ribo- Thia— Folic Pant.
Substrate pH flavin mine Niacin Acid Acid B12
 
Microorganisms obtained from steer fed hay
Control 6.65 52 1.9 30 2.3 0.9 0.5
Hayb 5.40 880 2.5 150 8.7 5.0 1.0
Mixedc 5.70 380 3.8 120 4.7 1.5 0.8
Concentrated 6.10 200 2. 5 80 3. 5 1.0 0. 6 `
Microorganisms obtained from steer fed mixed ration
Control 6.70 80 1.2 70 2.3 1.0 1.0 A
Hayb 5.50 310 2.5 240 6.0 2.5 1.5
Mixedc 4.90 300 6.2 280 9.7 3.0 2.3
Concentrated 5. 25 180 3. 8 150 7. 0 1. 1 1. 8
Microorganisms obtained from steer fed all concentrate ration
Control 6.70 140 2.5 150 16.3 2.0 1.4 1
Hayb 5.70 320 3.8 320 20.3 3.0 1.6 `
Mixedc 4.50 380 5.0 840 23.2 5.5 2.1
Concentrated 5. 30 360 6. 2 840 23.0 5. 5 2. 5
V
&Aliquots of 150 milliliters of washed cell suspensions were adjusted to pH 6. 9 and
incubated with appropriate substrates in 250—milliliter Erlenmeyer flasks at 39OC
for 8 hours.
b13.5 grams hay.
CMixture of 2. 7 grams hay, 7. 2 grams corn and 0. 9 gram soybean meal. »
dMixture of 7. 2 grams corn and 0. 9 gram soybean meal.
UTILIZATION OF GLUCOSE AND STARCH BY WETHERS WHEN GIVEN ORALLY
OR INTO THE ABOMASUM
C. O. Little, G. E. Mitchell, Jr. and J. W. McAtee
Much of the carbohydrate material fed to ruminants is digested in the rumen
and converted by microbial activity to short chain fatty acids. These acids form the
major source of energy for tissue metabolism. This is in contrast to non—ruminants
in which glucose plays a major role in energy metabolism. Because of the microbial
conversion of carbohydrates into fatty acids in the rumen, it is generally believed
that insignificant quantities of hexose sugars are actually absorbed from the ruminant
digestive tract. Blood and tissue carbohydrates presu