xt7gf18scv7z https://exploreuk.uky.edu/dips/xt7gf18scv7z/data/mets.xml   Kentucky Agricultural Experiment Station. 1969 journals 181 English Lexington : Agricultural Experiment Station, University of Kentucky Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Progress report (Kentucky Agricultural Experiment Station) n.181 text Progress report (Kentucky Agricultural Experiment Station) n.181 1969 2014 true xt7gf18scv7z section xt7gf18scv7z • » •   E;.
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  UNIVERSITY OF KENTUCKY * AGRICULTURAL EXPERIMENT STATION Progress Report I8I
I I I »   .;»r  

 PROGRAMS FOR I969 ANIMAL SCIENCES FIELD DAYS
JuIy I6, I969 - University CoIdstream Farm, Lexington -
JuIy I8, I969 — Western Kentucky Substation Farm, Princeton
- Conducted tours of beet, sheep, and swine research at regular ‘
intervaIs beginning at 9:00 a.m.
- Lunch provided by BIuegrass Stockyards, Lexington, and Field
Packing Company and Owensboro Milling Company, Owensboro
· Address ·· "Livestock Potential of Kentucky" · Charles E.
Barnhart, Dean and Director, CoIIege of AgricuIture, University
ot Kentucky

 KENTUCKY I
ANIMAL SCIENCES RESEARCH REPORTS
1969
*7
Progress Report 181
July 1969
UNIVERSITY OF KENTUCKY -
AGRICULTURAL EXPERIMENT STATION

 CONTENTS
ANIMAL FOODS Page
Effect of Castration and Slaughter Weight on Lamb Carcass
Characteristics ............................... 5
Performance and Carcass Characteristics of Rams and Wethers
Slaughtered at Different Weights ...................... 8
Effects of Rate of Gain, Slaughter Weight and Castration on Selected
Chemical, Histological and Organoleptic Characteristics of
Ovine Muscle and Adipose Tissue ..................... 9
Physical, Chemical and Histological Properties of Low, Medium and
High Quality Hams at Various Intervals During Curing and Aging .... 12
Hardening Ice—cream by Immersion in Liquid Nitrogen ............ 14
ANIMAL NUTRITION
Effect of Dietary Calcium and Phosphorus Level on Performance,
Carcass Characteristics and Bone Mineralization of Swine ........ 15
Copper, Molybdenum and Sulfate Interrelationships in Swine ,,,_,,,,_ 15
Effects of Continuous Feeding of 2, 2-Dichlorovinyl Dimethyl Phosphate
(DDVP) on Performance of Growing-Finishing Pigs ........... I6
Effects of Aureomycin and Copper Sulfate on Performance of Growing-
Finishing Pigs ............................... 1'7
Effects of Spectinomycin on Performance of Growing—Finishing Pigs ,,_,, 17
Effects of Carbadox on the Performance of Growing-Finishing Pigs ____, 18
Growth and Digestibility Studies with Qpague-2 and Normal Corn for
Growing Pigs ................................ 19
Effects of Dietary Protein and Fat on Intramuscular Fat and Backfat
Thickness of Swine ............................. 20
Effect of Protein Level on Performance and Carcass Characteristics
of Growing—Finishing Swine ........................ 20
Comparison of Corn and Wheat in Diets for Growing—Finishing Swine ,,,, 23
Effect of Dietary Ascorbic Acid on Performance of Growing-Finishing
Swine .................................... 23
Effect of Evaporative Cooling on the Performance of Finishing Swine ,,,,, 24
Bluegrass-ladino Clover and Sorghum—sudan Hybrid for Grazing
Steer Calves ................................ 24
Creep Feeding Spring and Fall Calves ..................... 25
Energy and Protein Supplements for Wintering Yearling Stocker Steers . . . 26
Effect of Limited Water Intake on Feed Consumption and Nutrient
Digestibility ................................. 27
Feedlot Performance of Steers Fed Two Levels of Urea ............ 29
Nitrogen Sources for Feedlot Steers Fed Ground Ear Corn Rations ...... 30
(2)

 ’ ANIMAL NUTRITION (continued) Page
Level of Feed Intake and Molasses Additions to Urea Rations for
Feedlot Steers ............................... 32 _
Soybean Meal and Urea in Steer Finishing Rations ............... 32
Soybean Meal, Urea and No Supplementary Nitrogen Comparisons for
Steers Fed Corn Silage . ; ......................... 34
Feeding Behavior of Steers Fed Soybean Meal and Urea Supplemented
Diets .................................... 35
Nitrogen in the Digestive Tract of Steers Fed Soybean Meal or Urea ..... 36
Amino Acids in Plasma of Steers Fed Different Nitrogen Sources ....... 37
Digestion of Cellulose Infused into the Abomasum of Steers .......... 39
l Rumen Stimulatory Properties of Proline ................... 40
Various Physical Measurements as Indicators of Fat in Cows ........ 41
Turnover of Vitamin A Stores in Mature Beef Steers ............. 42
Liver Vitamin A Turnover in Mature Rams .................. 42
Influence of Corn Oil on Pre—intestinal Disappearance of Vitamin A
in Sheep ................................... 43
Plasma and Urinary Components in Vitamin A—Deficient Ewes ........ 43
Amylase Activity in the Pancreatic Secretions of Sheep Following I
Glucose Infusions ............................. 45
Digestion of Cellulose Infused into the Cecum of Lambs ............ 46
Digestion of Cellulose and Mixtures of Corn Oil and Cellulose Infused
into the Cecum of Wethers ......................... 46
Oral and Abomasal Administration of Lysine to Wethers ........... 47
Amino Acids in Plasma of Early Weaned Lambs ............... 48 _
Grass Hays for Pregnant and Lactating Ewes ................. 48
Roughage Levels in Rations for Early-weaned Lambs ............ 49
Factors Affecting Rumen Microbial Activity in Young Lambs ......... 50
Urea or Heated Soybean Meal for Young Lambs ................ 52
Urea for Lambs From Birth to Market ..................... 53 I
Amino Acids in Equine Cecal Contents, Cecal Bacteria and Serum ...... 55
Hepatic Utilization of Glucose and Volatile Fatty Acids in the Equine ..... 56
Liquid Supplements for Lactating Dairy Cows ................. 57
Synthesis and Physiological Requirements of Amino Acid for Lactating ·
Cows .................................... 59
Development of Methods for Relating Forage Properties to Intake and
Digestibility ................................ 59
Bioassay, Isolation, Identification of Toxic Factor(s) in Tall Fescue and
Vasoactive Mycotoxins Associated with Tall Fescue ........... 59
(3)

 GENETICS AND PHYSIOLOGY Page
Synchronization of Estrus of Gilts with Aimax, PMS and HCG ........ 61
Effect of 2, 2-Dichlorovinyl Dimethyl Phosphate (DDVP) on Reproductive `
Performance of Swine ........................... 62
When Should Dairy Heifers Be Bred for First and Second Calves? ...... 63
Molecular, Ionic, and Cellular Migrations in Freezing Solutions and
Their Effects on Sperm Survival ..................... 64
Effect of Sire on Certain Carcass Traits of Young Bulls ........... 65
Effect of Sire, Sex and Sire X Sex Interactions on Beef Cattle Performance
and Carcass Traits ............................ 67
Seasonal Variation in Free Amino Acid Concentration in Seminal
Plasma of Rams .............................. 70
Motility of Ram Spermatozoa After Storage in Glycerol or Propylene
Glycol Dilutors at 40 and -40OC ...................... 71
Effect of Vaginal Sponges and PMS on Reproductive Performance in
Spring-bred Yearling and Aged Crossbred Ewes ............. 72
Relationship Between Gestation Length and Number of Lambs Born ..... 73
Use of Hormones to Stimulate Breeding Activity in Anestrous Yearling
Ewes .................................... 73
Semen Characteristics of Southdown Rams Fed a Chlorohydrin
(3 —Chloro-I, 2-Propanediol) ........................ 75
Sources of Variation in Semen Characteristics of Yearling Southdown
Rams .................................... 76
Influence of the Photoperiod on Ovulation, Fertility and Embryo
Survival Rates in Ewes .......................... 77
(4)

 ..5-
ANIMAL FOODS SECTION
EFFECT OF CASTRATION AND SLAUGHTER WEIGHT .
ON LAMB CARCASS CHARACTERISTICS
James D. Kemp, J. D. Crouse, Winston Deweese and W. G. Moody
The relationship of castration to carcass composition and meat quality has been eluci-
dated only partially. This is particularly true as it applied to lambs slaughtered at different
weights. This study, therefore, was designed to study the effects of castration and slaughter
weight on lamb carcass characteristics.
Thirty crossbred ram lambs and 30 similar wether lambs (castrated before 10 days of
age) were placed on feed in dry lot at 18 kg and assigned in equal numbers to slaughter
weights of 36, 45 and 54 kg. Lambs were slaughtered, and the carcasses were chilled 48
hours, graded, weighed, measured, and cut into wholesale cuts, retail cuts and edible
portions. One leg from each carcass was dissected into fat, lean and bone. Total carcass
composition was calculated.
Live animal and carcass weights are given in Table 1. Although live weights were
similar for rams and wethers in each weight group the carcass weights were greater for
wethers, indicating higher dressing percents (50. 0 vs 48.4) for wethers. Testicles (lamb
fries) weigh about 3/4 of 1% of live weight. If they were included in dressing percentage the
difference between rams and wethers would be reduced. Since the wholesale price per pound
of lamb fries is approximately twice that of carcasses, the value of ram carcasses plus fries
is approximately equal to the value of wether carcasses from lambs of equal weight. A
Age at slaughter was significantly (P< . 01) less for rams. This resulted in signifi-
cantly (P< . 01) more carcass weight per day of age for rams despite the fact that wethers
had heavier carcasses. Carcass grades were similar for rams and wethers, but grades were
higher for heavier carcasses although all graded prime or choice.
Carcass measurements dealing with fatness including width behind shoulders, fat
thickness over eye muscle, over spinous process and over ribs were significantly greater
for wethers than for rams.
There were only minor differences in percent wholesale cuts owing to sex. There _
were, however, some significant differences owing to weight. Percent leg, shank and kidney
decreased (P< . 01), and percent breast and flank and kidney fat increased (P< . 01) with an
increase in weight. There were major differences in percent retail cuts owing to both weight
and sex (Table 2). As weight increased, percent retail cuts decreased (P< . 01), owing to
extra fat trim in heavier carcasses. Percent retail cuts from rams was significantly
(P< . O1) greater than for wethers. This was also related to fatness as shown by the fat trim
for the different groups. I
Percent edible portion and percent bone followed the same pattern as did percent
retail cuts. As fatness increased owing to either weight or sex, the percent of edible meat
decreased. Fat trim was in inverse relationship to edible portion and bone. When expressed
as actual weight rather than percent the differences were much greater for fat trim than for
bone.
Dissection of the leg revealed that there was a significant (P< .01) increase in _
percent fat and corresponding decrease in lean and bone as weight increased. Legs from
rams had a significantly higher percent lean and bone and lower percent fat than did wethers.
These same trends followed when total carcass composition was calculated.
Conclusions
Wethers had higher dressing percentages than did rams, but the differences were
reduced when testicle weights were included. Value of ram carcasses plus testicles was

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similar to value of wether carcasses. Rams had more carcass weight per day of age. Wether _
carcasses were fatter as denoted by measurements, more fat trim, lower retail and edible
portion yields and more fat in legs. Heavier carcasses in both sex groups were fatter and
had lower yields of retail cuts and edible portion and higher yields of fat trim. The increase
in fatness and decrease in retail yield and edible portion was greater in wethers than in rams
as carcass weight increased. Castration had no effect on carcass grade.
PERFORMANCE AND CARCASS CHARACTERISTICS OF RAMS
AND WETHERS SLAUGHTERED AT DIFFERENT WEIGHTS
W. P. Deweese, H. A. Glimp, J. D. Kemp and D. G. Ely
Although a trend has developed toward marketing lambs at heavier weights, some
research data suggest a high positive relationship between weight of lamb and amount of fat.
The following experiment was designed to compare the performance of rams versus wethers
slaughtered at different weights and to correlate performance with loin—eye area, percent fat
in the rack, and the fat thickness over the 12th rib.
Sixty Hampshire-sired crossbred lambs (30 rams and 30 wethers) were weaned at 18. 1
kg (40 lb) and fed a high concentrate pelleted ration in pens of five lambs each. Lambs were
assigned to slaughter groups with one-third slaughtered at live weights of 36. 2, 45.3, and
54.4 kg (80, 100, and 120 lb). They were weighed weekly until they reached slaughter weight.
They were then slaughtered and carcass measurements were taken. Average daily gain and
feed consumption were measured for every 9. 1 kg increment from 18. 1 kg to slaughter.
Rams consistently gained faster on less feed than did wethers for each 9. 1 kg incre-
ment. Rams gained a maximum of 0.415 kg per head daily from 36. 2 to 45. 3 kg, while
wethers gained a maximum of 0. 352 kg for the 36. 2 to 45. 3 growth period. Loin-eye areas
for rams and wethers were, respectively: 13. 50 sq cm, 12. 85 sq cm (36.2 kg lambs);
14. 18 sq cm (45.3 kg lambs); and 17. 83 sq cm, 15. 29 sq cm (54.4 kg lambs). Wethers had
greater fat thickness over the 12th rib at all three slaughter weights than did rams.
Table 1 . — Average Daily Gain and Feed Consumption at Different Weights
.)_ Average Daily Gain (kg) Feed? Gain (kg)
Welbht (kg) Rams Wethers Rams Wethers
Birth 18. 1
18.1 -27.2 0.321 0.279 3.71 4.26
27.2 -36.2 .402 .348 4.98 5.76
36.2 -45.3 .415 .352 5.67 6.43
45.3 - 54.4 .338 .315 7.57 8.13
 
Table 2. — Fat Measurements in Ram and Wether Carcasses
 
_ _ _ Percent Fat in Rack Backfat Thickness (mm)
Slaughter Wt’ kg Rams Wethers Rams Wethers
36.2 10.57 15.31 3.9 5.0
45.3 16.15 19.65 4.9 7.9
54.4 18.38 28.61 6.9 11.0
 

 -9..
EFFECTS OF RATE OF GAIN, SLAUGHTER WEIGHT AND CASTRATION
ON SELECTED CHEMICAL, HISTOLOGICAL AND ORGANOLEPTIC
CHARACTERISTICS OF OVINE MUSCLE AND ADIPOSE TISSUE
Doris Tichenor, James D. Kemp, W. G. Moody, J. D. Fox and Winston Deweese
The amount of lamb consumed in the United States has declined in recent years, al-
though total annual meat consumption has risen steadily. Efforts to improve consumer
acceptance of lamb have centered around identifying the desirable lamb carcass and improving
the quality factors which lead to eating satisfaction. Ways of increasing the yield of edible
meat have also been sought.
The objectives of this study were: (1) to examine the effects of slaughter weight and
rate of gain upon lamb fatty acid composition, muscle fiber size, shrinkage during cooking,
and palatability; and (2) to determine whether there are significant differences between rams
and wethers with respect to these characteristics.
Two experiments involving 132 lambs were conducted during a 2-year period.
Experiment I included 72 wethers randomly divided into 3 groups, to be slaughtered at light
(36 kg), medium (45 kg), and heavy (54 kg) weights. Experiment II included 30 rams and 30
wethers with each sex equally divided into light, medium and heavy slaughter weight groups.
Within each weight, the lambs were sorted equally as fast and slow gamers on the basis of
average daily gain from 27 kg to slaughter. The animals were slaughtered as they reached
the desired weights, and samples were taken for the planned analyses.
Myristic, palmitic, stearic, oleic, linoleic and linolenic acids were determined in
perinephric and subcutaneous adipose tissue by gas -liquid chromatography. Histological
measurements of muscle fiber diameter, intramuscular fat cell size, and relative abundance
of intramuscular fat were made on longissimus dorsi and semitendinosus muscles. A rack
from each lamb was roasted and cooking losses, palatability, and shear values were
determined. The data were subjected to analysis of variance and simple correlation analysis.
Results and Discussion
— Levels of myristic and oleic acids in perinephric adipose tissue decreased and levels
of palmitic acid increased with increasing weight of the animals (Table 1) . The perinephric
fat of slow—gaining heavy wethers contained higher levels of stearic acid than that of
comparable fast—gaining wethers. Stearic acid generally increased as oleic acid decreased.
The fatty acid composition of subcutaneous adipose tissue was not affected by slaughter weight .
or rate of gain.
Table 1. — Average Weight Percents of Six Fatty Acids in Perinephric Adipose .
Tissue§/
Slaughter Weight
Fatty Acid Experiment I Experiment II
Light Med Heavy Light Med Heavy
(Percent)
Myristic 3.0 2.8 2.8 3.3X 2.9Xy 2.7y
Palmitic 19. 3X 20. 2XY 21. 2Y 19.6 19. 8 20. 9
Stearic 27.4 28.0 27.6 27.8 27.7 28.3
Oleic 42.35 40.7SI` 40.5 38.8 36.9 37.2
Linoleic 6.0 6.3 6.0 7.6 8.3 8.2
Linolenic 2.1 1.9 1.9 2.8 2.7 2.6
 
*2-./Within each category, means on the same line having different superscripts
differ significantly; s and 1; are used for P< . 05 and x and y are used for
P< . 01. Sets of means without superscripts are not significantly different.

 ...1Q..
Both perinephric and subcutaneous fat of rams contained less stearic acid and more
linoleic and linolenic acids than comparable fat of wethers (Table 2). The ram fat contained -
a higher proportion of unsaturated 18-carbon fatty acids.
Table 2. — Average Weight Percents of Six Fatty Acids in Subcutaneous
and Perinephric Adipose Tissue of Rams and Wethers?
 
Subcutaneous Perinephric _
Fatty Acid Rams Wethers Rams Wethers
(Percent)
Myristic 5.3 5.2 3.0 2.9
Palmitic 23 . 25./ 24. 3H/ 19. 5 20. 5
stsaric 16. 2§/ 17. 9E/ 26. 99 29.1X/
oieic 42. 7§/ 41.41-4/ 38.2 / 37.1 /
Lmoisic 9. 2*i/ 7. 9X/ 8. 8’£ 7. all
Limiemc 3.4 9. 5 2. 99 2. 5X/
Total unsaturated 55. 2 52. 8 A 50. 0 46. 8
 
2/ See footnote al/, Table 1
Muscle fibers of the semitendinosus were larger in heavy lambs than in the lightweight
animals (Table 3) . The average L dorsi fiber diameter was also greater in the heavy lambs
(Exp. II), the increase being largely attributable to the rams. Average fat cell diameter was
larger in the L dorsi than in the semitendinosus (Table 3), and the L dorsi fat cell size was
larger in heavy animals than in medium and lightweight animals.
Table 3. — Average Fiber and Fat Cell Diameters (microns) of semitendinosus and L dorsi
muscles?
Slaughter Weight
Experiment I Experiment Il ‘
Item Light Medium Heavy Light Medium Heavy
(Microns)
Fiber diameter,
semitendinosus 37. 9°£/ 44. 0X/ 42. 7X/ 38. 05/ 39. 8-5;/ 43 . 81;/
Fiber diameter,
L dorsi 38.1 39.0 39.9 34.6 38.5 40.3
Fat cell diameter,
semitendinosus 55. 3 50. 7 60. 9
Fat cell diameter, / /
L dorsi 54.55/ 54.5§ 65.21;
 
2/ See footnote 2;/ , Table 1.
Total shrinkage losses were highly variable among animals, but the percentage of
shrinkage loss as drippings increased with increasing weight (Table 4) . Roasts from slow-
gaining lambs had more weight loss from drippings than those from fast gainers, and roasts
from wethers had more than those from rams.

 -11..
Table 4. — Weight of Drippings from Roasted I?acks as a Percent of
Total Weight Loss During Cooking?.
Item Experiment I Experiment II
Slaughter weight
Light 23. 5*5/ 18. 5%/
Medium 30. TL? 23 . 6X/
Heavy 41. 7E 33. 1%./
Rate of gain
Fast 29. 7’.€/ 23. 5>i/
sihw 94. 9X/ 25. 7X
Sex /
Rams 21. 5’i
Wethers 28. 6X/ 5
?‘-/ Within each category, means in the same column havin different
8
superscripts differ significantly (P< . 01) .
Flavor and juiciness of roasted li dorsi muscles were not affected by slaughter weight,
rate of gain or sex. The flavor of all roasts was considered acceptable, and meat from the `
heavy lambs was as well-liked as that from the younger, lightweight lambs. Meat from rams
and wethers was equally desirable in flavor and juiciness.
Tenderness of roasted racks from wethers increased with increasing weight (Table 5).
Roasts from wethers had a higher average tenderness score than roasts from rams, but all
were acceptable. Warner—Bratzler shear values were negatively correlated with tenderness
(F< . 01).
Table 5. — Average Palatability Panel Scores for Tenderness of Roast
Lambiv E
Item Experiment I Experiment II
Slaughter weight / I
Light 7.1§ 7.1
Medium 7. 6E/ 6 . 9
Heavy 7. 91;/ 7. 5
Rate of gain
Fast 7. 5 5. 9%/
Slow 7. 5 7. 5X/
Sex
Rams 6 . 9X./
wethers 7. 5X/
 
zi/Scores were assigned on a 10-point rating scale where 10 = excellent
and 1 = very poor.
`Q/ Within each category, means in the same column having different
superscripts differ significantly; gand 1; are used for P< .05 and x
and y are used for P( . 01. Sets of means without superscripts are
~ not significantly different.

 -12-
General acceptability scores were highly correlated with flavor, juiciness and
tenderness, but tenderness appeared to be the most important determinant of acceptability.
Positive correlations (P< . 01) were obtained between tenderness and percent weight
lost from drippings, indicating that loins containing larger amounts of fat were more tender.
Fiber diameters of the semitendinosus and L dorsi muscles were unrelated to
sensory tenderness.
PHYSICAL, CHEMICAL AND HISTOLOGICAL PROPERTIES OF LOW, MEDIUM
AND HIGH QUALITY HAMS AT VARIOUS INTERVALS DURING
CURING AND AGING
W. G. Moody, J. D. Fox, James D. Kemp and W. R. Henning
Much work has been done comparing pale, soft, exudative (PSE) pork with normal
pork. Only a small amount of work, however, has been reported comparing dry—cured hams .
from fresh hams of varying quality groups. This study was designed, therefore, to compare
certain physical, chemical and histological properties of dry-cured hams at various intervals
during curing and aging.
Thirty pairs (60 total) of fresh hams were equally divided into three groups of low,
medium and high quality hams based on the Wisconsin pork quality standards. All hams
were cured at 20 to 40 C for 2 days per lb, using 10 lb of curing mixture per 100 lb of fresh
hams. An additional period of 30 days was provided for salt equalization. Hams were then
smoked in a conventional smoker until brown. Aging was accomplished in a controlled
temperature and humidity room at 750 F and 65%, respectively. The biceps femoris muscle
of each right ham was sampled fresh, after salt equalization and after 2 and 4 months' aging
for physical, chemical, and histological observations. The left hams were used as controls
and weighed at designated intervals to determine shrinkage. At the end of the 4 months'
aging period the left ham of each group was cut and scored for aroma and soundness. In
addition, a palatability test and Warner—Bratzler shear analysis were determined on the
same muscle of each left ham.
Results of the histological studies are shown in Table I. The percent red fibers per
bundle was slightly less, but fiber size was slightly larger in the low quality group. The
difference in size and numbers of red fibers per muscle bundle seemed to be directly related
to capillary numbers and total blood supplying the muscle. Both intrafiber and intrafasci—
cular fat were evaluated microscopically, using low magnification. In general, the low
quality hams possessed less intramuscular fat than the high quality hams. The number of
fibers per bundle was determined by counting both red and white fibers in each of five  
secondary bundles which contained less than 70 total fibers. Selecting relatively small
bundles helped reduce the counting error.
The pH of the fresh muscle was not significantly different among groups. However,
a slightly lower pH was observed in the low quality group (Table 2) . Expressible juice was
determined by the filter paper press method, and the low quality group had a significantly
(P< 0. 01) higher percent expressible juice than did hams in group 3 when fresh and after
salt equalization. There were no significant differences after aging 2 and 4 months. These
data reveal the extremely poor water—binding ability of PSE muscle. There was no signifi-
cant difference in moisture or salt content among groups. High quality hams contained more
ether extractable fat and myoglobin on a fresh basis than did hams of either medium or low
quality.
Results of the palatability and shrinkage data are shown in Tables 3 and 4 respectively.
Hams with low quality scores (I) were rated significantly lower (P< 0. OI) in flavor and
overall satisfaction by the taste panel. There was no significant difference in tenderness
among groups as noted by either the panel or the WB shear. However the low quality groups
tended to be slightly more tender. The low quality hams shrank significantly (P< O. Ol) more
during curing and aging than the high quality group.

 -13..
Table 1. — Histological Determinations
 
Variables Group 1.%/ Group 2ki/ Group 39/
Red fibers, % 39. 8 44. 0 43. 5
Fiber No. /bundle, Sec. g/ 47. 0 49. 0 50. 0
Fiber size, p. 75 72 73
lntrafiber fat9/ slight slight small
Interfascicular fat9/ traces small moderate
%/ Group 1 — Low quality hams (PSE). Muscles extremely pale, soft and watery.
]l/ Group 2 - Medium quality hams. Muscles pale, moderately soft and moderately watery.
9/ Group 3 - High quality hams. Muscles uniformly grayish pink, moderately firm and
1 moderately dry.
*1/ Fiber numbers per bundle determined on 5 secondary bundles with less than 70 total fibers.
9/ Relative amounts of intramuscular fat as determined by ocular grid at low magnification.
63X.
Table 2. — Selected Fresh Ham Variables
  N
Variable Group 1 Group 2 Group 3
pH?~./ 5.63 5.69 5. 83
Expressible j7ice}£/ 10. 92 10. 02 9. 14
Moisture, %% 72. 91 71. 34 71.10
. Ether extract, 7;%/ 5. 68 5. 93 7. 79
Myoglobin2h.9/ 0. 51 . 55 . 71
V 2/Taken on biceps femoris muscle.
E./Reported as square inches of expressible juice on No. 2 filter paper when a 2 gm sample
was subjected to 50 lb pressure for 5 minutes.
§;P< 0. 05
z _ P< 0.01 j
Table 3. — Palatability Data
 
7 Quality Tenderness
1 Groups Panel? W-BL; Flavor?) Saltinessy 08%/
1 7.08 13.12 4.80 6.29 4.95
2 7.17 13.84 6.11 6.42 6.05
3 6.91 17.02 6.58 6.69 6.54
 
E/Based on 9-point hedonic scale.
1 `Q/W—B = Warner-Bratzler shear, lb force to shear one—inch cores
9/os = Overall satisfaction

 -14-
Table 4. — Percent Shrinkage of Hams by Periods
 
Quality Out of Out of Out of Aging periods
Groups Cure Salt Eq Smoke 1 Mo 2 Mo 3 Mo 4 Mo
1 5.53 11.87 12.43 20.0 23.2 26.0 28.3
2 4.07 10.92 11.57 18.6 21.64 24.4 26.6
3 3.36 9.47 10.20 16.5 19.77 22.4 24.2
  -
Summary
PSE muscle selected from the biceps femoris of low quality hams had slightly fewer
but larger red fibers per muscle bundle than similar muscle fibers from high quality hams.
Similarly, the low quality hams contained less microscopic and ether extractable fat than
high quality hams. The pH was slightly lower and the expressible juice much higher in the
low quality group. Additionally, low quality hams were slightly more tender but less flavor-
ful, and shrank significantly more than high quality hams during curing and aging.
HARDENING ICE -CREAM BY
IMMERSION IN LIQUID NITROGEN
A. W. Rudnick, I. J. Ross* and J. D. Fox
Exposing ice-cream to liquid nitrogen for hardening could have several advantages,
both physically and economically. The experiments were undertaken to learn if the rapidity
of hardening of ice-cream would have any effect on body and texture of the product when
served at normal temperatures. in
Ice-cream made by both batch and continuous process was hardened by submerging
round 1/2 gallon containers of the product in liquid nitrogen. Thermocouples were placed at
the outside carton surface, inside carton surface, mass average** and center. Time of
immersion varied from the period required to reach -28. 9 C at mass average to the time
required for the center to approach -195. 6 C (3 to 50 minutes). Control samples were
hardened in high velocity air at -28. 9 C j 1. 1 C. All samples were stored at the latter
temperature for varying periods of time.
After tempering the samples at -15OC for 24 hours, samples were given to expert ¤
judges for evaluation of body and texture. No body and texture differences were noted '
between controls and nitrogen-hardened samples. Samples stored for 6 months showed no
evidence of shrinkage. Based on this study, the hardening process of ice-cream production
can be speeded up drastically without damage to ice-cream quality. A proviso of economic
feasibility must be made.
*Department of Agricultural Engineering.
**Mass average = two-thirds the radius from the center.

 ..15-
ANIMAL NUTRITION SECTION
I EFFECT OF DIETARY CALCIUM AND PHOSPHORUS LEVEL ON PERFORMANCE,
CARCASS CHARACTERISTICS AND BONE MINERALIZATION OF SWINE
G. L. Cromwell, V. W. Hays and J. R. Overfield
- Two factorial experiments involving 224 SPF Yorkshire pigs were conducted to evaluate
dietary calcium and phosphorus levels in corn-soybean meal diets for pigs from 18. 6 to 95. 6
. kg bodyweight. In experiment I, phosphorus levels of 0. 50, 0. 63 or 0. 75% and calcium levels
of 0. 65 or 0. 75% were fed to a mean weight of 46 kg, after which phosphorus levels were
reduced to 0.4, 0. 5 and 0. 6% and calcium levels to 0. 5 and 0. 6%, respectively. An additional
~ phosphorus level of 0. 38% fed to 46 kg bodyweight followed by 0. 3% was used in experiment II.
Dicalcium phosphate and calcium carbonate were used to adjust dietary calcium and phosphorus
levels.
No significant (P < . 05) differences in gains, feed/ gains, metacarpal ash or turbinate
ash were detected among pigs fed the three higher phosphorus levels or the two calcium levels
. in either experiment. In experiment II, pigs fed 0.38% phosphorus gained significantly
(P ( . 01) slower (683 wg 783 gm/day), required more feed per unit gain (3.46 xg 3. 15) and
8 had a lower ash content in the metacarpals (49. 2 E 52. 3%) and turbinates (31. 7 xg 40. 6%) than
those fed the three higher phosphorus levels. Carcasses of barrows fed the low pho