xt7sxk84kq5j https://exploreuk.uky.edu/dips/xt7sxk84kq5j/data/mets.xml   Kentucky Agricultural Experiment Station. 1971 journals 196 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.196 text Progress report (Kentucky Agricultural Experiment Station) n.196 1971 2014 true xt7sxk84kq5j section xt7sxk84kq5j KENTUCKY A
A   1971 A A

_ July 21, I97I - CoIdstream Farm, Lexington
Juiy 23, I97I · Western Kentucky Substation Farm, Princeton
9:00 · II:3O a .m . - Visit research areas on the Farm . The Following are some of the topics °
to be discussed:
Beet CattIe Dairy
Beet CattIe Breeding Research. Greater Protits For Kentucky Dairymen .
Nitrogen Suppiements tor Individual Stalls For CaIves . _
Finishing Steers. Modern Milking Management. `
Identification Systems. Mastitis Controi Programs.
Cow Herd Management. Protein LeveIs tor Dairy Cows.
Types ot Beet Cattie.
Growing-Grazing-and Finishing
Program .
Swine Horses
Practicai Swine Nutrition. Formulating Horse Rations.
Siotted FIoors For Hogs. Management Practices with Horses.
Managing the Gestating Sow. Current Research in Horse Nutrition.
Managing the Feeder Pig. Horse Parasite Control.
Advances in Sheep Production.
Three Lamb Crops in Two Years.
Early Weaning Lambs .
Protein Suppiements.
I2:OO Noon — Barbecue Iunch.
(July ZT , Lexington-provided by Rurai EIectric Cooperative)
(July 23, Princeton-·provided by Southern States Cooperative
and EvansviIIe Producers)
I:OO p.m. · Address by Dr. W. P. FIatt, Director, Georgia Agricultural Experiment Station,
Athens, Ga .

Histological Changes in the Circulatory System Within the Pampiniform Plexus and
Testis of Heat—Stressed Rams ............................ ·. . . 5
Semen Characteristics in the Ram Following Temporary Occlusion of the Blood
I Supply to the Testes .......................,............ 6
Histology of the Reproductive Tract of Southdown Rams Fed the Chlorohydrin
(3-Chloro—1, 2—Propanediol) ................................ 8
M One—Day Vs 14-Day Flushing Effects on Reproduction in Gilts ................ 9
Estrus Synchronization of Gilts Fed Aimax .......................... 10
Effects of Chlormadinone Acetate (Estrostat) on Breeding Efficiency of Beef Heifers .... 11
Effects of PMS Dosages on Bovine Ova Production, Recovery and Fertilization ....... 12
Relationship Between Fertilized Ova and Backfat, Serum Lipid Levels and
Endometrial Fat in Beef Cows ............................... 13
Plasma Amino Acid Patterns and Nitrogen Constituents in Yearling Bulls and Heifers _
with Different Rates of Growth ............................... 14
Phenotypic Response and Time Trends to Date of Birth Selection in Southdown Sheep .... 15
Effects of Population Structure on Response to Selection, Using Tribolium Castaneum . . . 15
Genetic Correlations Between Semen and Growth Traits Measured on Yearling .
Southdown Rams ...................................... 16
The Mode of Inheritance of "White Heifer Disease" ...................... 17
Effect of Dietary Protein and Energy Levels on Carcass and Palatability Characteristics
of Swine .......................................... 19
Properties of Ham and Loin Muscles as Affected by Pork Quality, Cutability and
Anatomical Location .................................... 21
Relationship of Fresh Ham Traits to Cured Ham Quality ................... 23
Effects of Castration on Ovine Neutral Lipid and Phospholipid Deposition .......... 28
Effect of Storage Temperature on Shelf Life of Fresh Pork Sausage ............. 29
Effect of Teat Dip on the Characteristics of Staphylococci Isolated from the A
Bovine Udder ....................................... 30
Recycling Animal Waste Through Poultry I. Dried Rumen Residue .............. 32
Recycling Animal Waste Through Poultry II. Dried Poultry Manure ............. 34
Equine Cecal Bacterial Growth as Measured By 358 ......... . ........... 35
Role of the Cecum in Protein Nutrition of the Equine ..................... 35
Studies on Equine Cecal Bacteria ............................... 36
Nutrient Digestion and Indicator Retention Before and After Fistulation in Horses ...... 36
. . Effects of Estimated Net Energy and Protein Content of Feed on Milk Yield and
Composition During the Early Stage of Lactation ..................... 38

Oral or Abomasal Supplements of Methionine or Methionine Hydroxy Analogue
for Lactating Cows ..................................... 39
` Absorption Measured by Arterial—Venous Difference of Sugars, Volatile Fatty Acids
and Amino Acids in Calves Fed Milk or Hay and Concentrate .............. 40
A Portal Blood Flow in Holstein Calves and Steers as Affected by Position, Activity,
Weight, Feeding and Diet ................................. 40
Absorption of Sugars, Volatile Fatty Acids, and Amino Acids, Measured by
Arterial—Venous Difference in Steers on Two Maturity Alfalfa Hays ........... 40
Creep Feeding Spring Calves on Kentucky Bluegrass - Ladino Clover or Fescue —
Ladino Clover Pasture .................................. 40
Effects of Blighted Corn Silage on Beef Cattle ......................... 43
Preformed Protein Sources of Different Solubility in Steer Rations ............. 43
Preformed Protein Source in All—Concentrate and Minimum Roughage Rations
for Finishing Steers .................................... 45
Supplemental Nitrogen Sources for Growing Steer Calves ................... 47
Comparative Efficacy of the High CIS and High TRANS Isomers of Diethylstilbestrol if
for Steers ......................................... 48
Chromic Oxide and Crude Protein Excretion in Steers as Influenced by
Water Restriction ..................................... 50
Placental and Mammary Transfer of Vitamin A in Beef Cows ................. 50
Ruminal Destruction of Vitamin E Administered with Ethoxyquin or Sodium Nitrate ..... 51
Pre-Intestinal Disappearance of Vitamin D2 in Ruminants .................. 52
Feedlot Performance and Carcass Characteristics of Steers Fed Tapazole ......... 54
Pattern of Digesta Passage and Ruminoreticular Motility in Sheep Fed Hay
E1 Libitum ......................................... 55
Digestibility and Passage Rate of Alfalfa Hay in Wethers Treated with Histamine
and Formic Acid ...................................... 57
14C—Leucine Incorporation by Liver and Muscles of Insulin-Treated Sheep ......... 58
Ruminal Histamine in Wethers with Acute Indigestion ..................... 58
Cellulose Digestion in Sheep Fed an Extract of Aspergillus Orygae ............. 59
Absorption of Amino Acids in Sheep Fed Alfalfa ........................ 59
Absorption of Leucine Infused into the Abomasum of Sheep .................. 60
Biliary Excretion of Injected Vitamin A in Sheep - Effect of Replacing Collected Bile .... 60
Entero—Hepatic Recycling of Vitamin A in Sheep ....................... 61
Diurnal Variations in Amino Acid Absorption in Sheep .................... 61
Evaluation of Heat, Formaldehyde and Tannic Acid Treated Soybean Meal for Lambs .... 62
Urea and Heated Soybean Meal Supplementation to Lamb Rations ............... 63
Effect of Opaque—2 Corn and Protein Level on the Nitrogen Utilization of
Early Weaned Lambs .......................... ' .......... 64
Apparent Excesses of Amino Acids in Whole Egg Protein ................... 66
Effect of Soybean Meal, Lysine and Methionine Supplementation to Opaque—2 and
Normal Corn on Performance of Young Pigs ....................... 67
Effect of Blighted Corn on the Performance of Growing—Finishing Pigs ........... 68

Effect of Dietary Protein and Fat Levels on Carcass Measurements and Eating
Quality of Pork ....................................... 68
Effect of Protein Level on Intramuscular Fat in Swine ..................... 69
Effect of Dietary Fat, Cholesterol and Ascorbic Acid on Performance and Plasma
Cholesterol Levels in Swine ................................ 69
Effect of Added Thiocyanate and Iodine to Corn-Soybean Meal Diets on Performance
and Thyroid Status of Pigs ................................. 70
M Effects of Iodine Levels, Protein Sources and Goitrogens on Performance and
p Thyroid Status of Pigs ................................... 70
Reproductive and Progeny Performance of Protein Restricted Gilts ............. 71
Avoidance and Water Maze Learning Ability of Swine ..................... 71
Effect of Copper and Vitamin E on Response of Pigs Fed Corn and Wheat Base Diets .... 72
Effects of Neomycin, Terramycin, Carbadox and Oleandomycin on Performance of
Growing-Finishing Swine ................................. 72
Effect of Arsanilic Acid and Vitamin E on Performance of Growing-Finishing Swine .... 73 V

R. S. Sand and R. H. Dutt
Blood flow in ram testes has been shown by use of a 133—Xenon washout technique to double
initially and then to decline to approximately one—half control values by the fifth and seventh days of heat
stress. Blood flow changes were similar with both whole body heat stress and with local application of
heat to the scrotum, which suggests that a mechanism responsible for regulating testis blood flow rate
is located in or near the testes. The role of the pampiniform plexus in regulating blood flow was studied.
Histological sections of the circulatory system were prepared from the pampiniform plexus, testis and
a portion of the spermatic artery anterior to the pampiniform plexus from control rams and from rams
. ( after 7 days of heat stress (320C, 62 to 72% relative humidity).
No significant changes were detected in the venous vessels at any location sampled. Exposing the
rams to heat for 1 week significantly increased thickness of arterial walls (Table 1). The arterial wall
was significantly (P < . 05) thicker anterior to the pampiniform plexus (21%) and at the top of the pampini-
form plexus (22%). The increase (62%) in arterial wall thickness in the middle of the pampiniform plexus
was highly (P < . 01) significant. The treatment had no significant effect on arterial wall thickness at the
base of the pampiniform plexus nor at the testis locations.
Table 1. —Mean Arterial Wall Thickness (microns) by Location for Treated and A
  Control Rams
Anterior ‘
Group Spermatic Pam iniform Plexus Testis
Arter To Middle Base Middle Distal
Control 178b 171 125 098 095 076
Treated 216C 209C 202d 121 109 089
due to
treatment +21 +22 +6 2 +23 +1 5 +1 7
%/Difference among locations highly significant (P< . 01).
E/Mean of 8 observations (2 sections from each testis from 2 rams).
H/Sinificantly (P< . 05) thicker than controls.
— Significantly (P< .01) thicker than controls.
Diameter of the spermatic artery in the middle of the pampiniform plexus was significantly
(P . 05) decreased by 28%. The decrease in arterial diameter suggests that this location may be
the site of blood flow regulation to the testis. It should be pointed out that the arterial diameter was
decreased from 4 to 28% at locations in the pampiniform plexus and increased from 14 to 16% in the
testis from the treated rams (Table 2). Thus, there is no evidence to suggest that changes in the blood
vessels within the testis were responsible for the decreased blood flow.
In the treated rams the mean cross—section area of the artery in the middle of the pampiniform
plexus was 0. 14 mm2 compared with 0. 27 mm2. Exposure to heat stress reduced the area of the lumen
of the artery in this region to 52% of that for control rams.
Changes induced in arterial wall thickness and lumen diameter in the mid—region of the pampini-
form plexus by heat stressing indicate that the pampiniform plexus acts as a biological thermostat to
control blood flow to the testes. Furthermore, results of this study suggest that the reduced blood
flow may be responsible for spermatogenic impairment in heat—stressed rams.

Table 2. -—Mean Arterial Diameter (microns) by Location for Treated and
Control Rams
_ Group Spermatic Pampiniform Plexus Testis
Artery Top Middle Base Middle Distal
Control 434b 568 589 459 389 269
Treated 391 535 426C 440 453 307
due to ‘
treatment — 1 0 - 6 - 28 -4 +1 6 +14
%/Differences among locations highly significant (P < . 01).
-6/Mean of 8 observations (2 sections from each testis from 2 rams).
- Significantly (P <. 05) smaller than controls.
R. S. Sand and R. H. Dutt
The volume of blood flow through the testes of rams has been shown to be affected by local and
whole body heat stress. It appears that spermatogenic disruption in rams which accompanies heat
stress may be the result of decreased blood flow through the testis. The study in this report according- P
ly was carried out to determine the effects of altering the blood flow to the testes of rams on subsequent
semen characteristics.
Complete cessation of blood flow through the testes of rams by occlusion for 30 minutes or 1
hour had no significant effect on semen volume. Percent motile sperm cells, concentration, and percent
morphologically abnormal sperm cells were all significantly affected by the treatment. Concentration of
sperm cells was significantly (P <. 05) reduced in the treated rams (Table 1). Mean concentration of Y
sperm cells for the 12 weeks of the study was 1. 9 and 1. 7 million/mm3 for the 30-minute and 1-hour
occlusion groups, respectively, compared with 4.0 million/mm3 for control rams. The difference
between occlusion for 30 minutes and for 1 hour was significant (P<. 05). Differences among weeks
were also significant (P <. Ol). The treatment by week interaction was significant (P 4. 01), which can
be accounted for by the nearly uniform start and finish concentrations and the wide divergence of the
treatment means during the middle of the 12-week experimental period.
Percent motile sperm cells was significantly (P<. 01) reduced by interruption of blood flow to the
testis for short intervals. Occlusion of blood to the testis for 30 minutes and 1 hour decreased motile
cells by 32 and 48%, respectively (Table 2). The variance in percent motile cells among weeks was
highly significant (P <. O1) as a result of time changes. The difference in percent motile cells among
rams within treatments was significant (P <. 01).
Percent morphologically abnormal cells was significantly (P<. 05) increased 139 and 140% by
occluding blood flow for 30 minutes and 1 hour, respectively (Table 3). Variation among weeks was
highly significant (P <. 01), and the treatment by week interaction was significant (P<. 05). The increase
in percent morphologically abnormal sperm cells following treatment shows that temporary interruption
of blood flow to the testes interfered with maturation of the sperm cells. The decrease in sperm cell
numbers and in percent abnormal cells from treated rams throughout the experiment shows that the
treatments affected all stages of sperm cell development.
The detrimental effect on spermatogenesis was more severe following blood flow occlusion for 1
hour than for the 30-minute period. The similar effects of heat stress and blood occlusion on semen

characteristics lead to the conclusion that impairment of spermatogenic activity following heat stress
may be caused by the reduced blood flow to the heated testis.
Table 1. —Mean Sperm Cell Concentration in Ram Semen
Following Temporary Occlusion of Blood Flow
to the Testes
Weeka . . ~
After Duration of Blood Flow Occlusion
Treatment 30 minuteb 1 hourb Controlc
1 2. sssd 4.06 3.94
2 1. 40 2. 78 4. 09
_ _ 3 0. 70 1. 17 4. 10
4 1. 31 O. 80 3. 65
5 1. 16 0. 84 4. 02
6 1. 24 0. 52 3. 41
7 1 . 30 1 . 15 4. 33
8 1. 58 1 . 12 4. 53
9 1. 64 1. 10 3. 81
` 10 3 . 68 1 . 38 4. 3 6
11 3. 20 2. 49 4. 10
12 3. 26 3. 03 3. 82 _
Mean 1.92** 1.726 4.01
I E Differences among weeks are highly significant
b/(P< . 01) .
E/Mean of 2 observations from 2 rams. V
H/Mean of 2 observations from 4 rams. 3
E/Sperm cell concentration in millions/mm .
— Significantly (P< . 05) lower than controls.
Table 2. —Percent Motile Spermatozoa in Semen from Rams
Following Occlusion of the Spermatic Artery
Vigil; Duration of Blood Flow Occlusion
‘ Treatment 30 minuteb 1 hourb Controlc
1 60 38 57
2 35 27 69
/ 3 18 5 61 V
4 20 18 60
5 47 17 60
6 32 17 55
7 32 32 64
8 47 30 65
9 40 25 55
10 60 30 60
11 65 55 65
12 63 53 57
Mean 43d 33d* 8 63
%/I Difference among weeks are highly significant (P<. O1).
E/Mean of 2 observations per week from 2 rams.
H/Mean of 2 observations per week from 4 rams.
-5/Highly significant (P<. 01) lower than controls.
— Significantly (P <. 05) lower than 30-minute rams.

Table 3. —-Percent Morphologically Abnormal Spermatoz oa
in Semen from Rams Following Temporary
Occlusion of Blood Flow to the Testis
. a
Vl;/$21; Duration of Blood Flow Occlusion
Treatment 30 minuteb 1 hourb Controlsc
1 37. 6 31. 1 17. 3
2 46. 0 44. 9 8. 7
3 18. 2 24. 6 7. 5
4 27. 4 26.0 8. 9
5 26. 4 20. 6 10. 9
6 20. 4 33. 1 12. 4
7 28. 5 25. 1 7. 7 `
8 28. 1 21. 1 9. 1
9 30. 2 25. 1 15. 2
10 17. 2 21. 5 9. 5
11 11. 2 17. 1 9. 8
12 16. 1 18. 5 11. 1
Mean 25. ed 25. 7d 10. 7
%/Z Difference among weeks was highly significant (P<. 01).
E/Mean of 2 observations from 2 rams.
H/Mean of 2 observations from 4 rams.
— Significantly (P<. 05) greater than controls.
Jack L. Kreider and R. H. Dutt
The chlorohydrin (3—chloro-1, 2—propanediol) produces reversible infertility in rams when fed
daily. However, until now the action of this compotmd on the ram reproductive tract was not known.
The present study was conducted to determine the effects of this compound on the reproductive tract of
the ram and to obtain information concerning the site of action on sperm cells.
Two mature Southdown rams of proven fertility were fed the chlorohydrin (3-chloro-1, 2- ·
propanediol) in gelatin capsules at the rate of 62. 5 mg/kg of body weight for 10 days. On the twelfth
day after beginning the 10-day treatment period, both rams were slaughtered and their reproductive
tracts were removed by dissection for laboratory study. Tissue samples of the accessory glands,
testes and epididymides of each ram were fixed in a solution of 90% ethyl alcohol, 5% glacial acetic \
acid and 5% formalin. After fixation, samples were embedded in paraffin and sectioned with a micro-
tome at a thickness of 6 microns. The sections were mounted on slides and stained with hemotoxylin
and eosin for detailed microscopic study.
Gross examination of the reproductive tracts of both rams showed necrosis of the caput epi-
didymis as evidenced by a greenish discoloration of the area. The corpus and cauda epididymis, as
well as the accessory glands, appeared to be grossly normal.
Examination of the histological sections of the caput epididymis of treated rams showed severe
disorganization of the tubular epithelium. There was also evidence of acute disruption of the stere-
ocilia which border the epididymal epithelium. No apparent differences were observed between histo-
logical sections of the accessoryglands of chlorohydrin—treated rams and a control. lt is significant to
note however, that the chlorohydrin treatment had a definite effect on the histology of the testes.
Seininifcrous tubules showed disorganization of the germinal elements and the lumen was completely

The dosage of chlorohydrin us ed in this study was two and one—half times larger than that us ed in
a previous study in which, from semen studies, there was no evidence of disruption of spermatogenic
activity. In the earlier study motility of sperm cells in treated rams decreased and fertility was blocked.
. When results of the two studies are considered, it is concluded that at low levels the chlorohydrin blocks
fertility by acting at the epididymal level, whereas at higher levels it has a detrimental effect on the
seminiferous tubules and spermatogenic activity.
C. P. Moore, R. H. Dutt, V. W. Hays and G. L. Cromwell
  Increasing the energy level or "flushing" gilts before breeding is a common recommendation and
generally accepted practice for increasing litter size. The present study was conducted to determine the
effect of increasing the energy level only during the period of greatest follicular growth, i. e. , during the
first day of heat, on ovulation rate and litter size. Results will be compared with those following the
usual 14-day flushing period and in unflushed control gilts.
In March, 36 gilts weighing approximately 245 lb each were randomly assigned at estrus to one of
the following flushing treatments; (1) control —— 5. 0 lb of feed daily; (2) 1-day flushing -- 5.0 lb of feed
daily, except for a 24-hr period of Q libitum feed intake during estrus; and (3) 14-day flush —— 5.0 lb of _
feed daily, except for a 2—week period ad libitum feed intake starting on day 7 of the cycle. In June, 30
additional gilts were randomly allotted to the same treatments. All gilts were bred at the subsequent
estrus and slaughtered on the 28th day of gestation.
Flushing for 1 day (14. 8) or 14 days (15.4) significantly increased the average ovulation rate over
controls (13. 7). However, there was no significant difference between the two flushing treatments ‘
(Table 1). There was no significant difference in the average ovulation rate between the early spring bred
gilts (14. 9) and the summer bred gilts (14.4); however, there were significantly (P<. 01) more live
embryos per litter in the early spring bred gilts (13. 4 vs 11. 0).
Table 1. —Average Ovulation Rate in Gilts after 1- or 14-Day Flush
Season Control 1-day flush 14-day flush Average
V Spring 13.7 14.6 15.0 14.4
Summer 13.8 15.1 15.8 14.9
Average 13.7 14.8** 15.4** 14.6
**Significantly (P<. O1) higher than controls.
Average live embryos per litter at 28 days gestation for control, 1-day flushing and 14-day
flushing were 11. 2, 11. 9 and 13. 0, respectively (Table 2). Flushing increased live embryos (1 day,
6.3%; 14 days, 16. 1%) per litter over controls. The increase resulting from the 14-day treatment
was significant (P<. 05). There was no significant difference in litter size between the two flushing
treatments. Average weight of embryos was not significantly affected by treatment (control, 1.40 vs
treated, 1.33 g) or season (early spring, 1. 31 vs summer, 1.40 g). There was no significant inter-
action between flushing and season in the traits studied.

Table 2. —Live Embryos per litter at 28 Days Gestation
Season Control 1-day flush 14-day flush Average
Spring 12. 0 12. 8 14.4 13. 1**
Summer 10.4 11.0 11.6 11.0
Average 11.2 11.9 13.0* 12.0
*Significantly (P< . 05) larger than controls.
**Significantly (P< .01) larger than summer.
D. L. Hammell, G. L. Cromwell, V. W. Hays and R. H. Dutt
An experiment involving 54 gilts was conducted to evaluate the efficiency of methallibure (AIMAX)
for synchronizing estrus in gilts. _
Crossbred gilts averaging 249 days of age at breeding were fed AIMAX at a level of 125 mg per day
for 20 days (Table 1). Following withdrawal of AIMAX from the diet, all gilts exhibited estrus within 10
days, with an average of 6.46 days. Forty-eight (89%) gilts were synchronized within a 5-day period,
from 4 to 8 days following AIMAX withdrawal. Most of the gilts were given two natural services at 24-
hour intervals, beginning at the onset of estrus. Of the 54 gilts bred, 31 (57.4%) farrowed an average of
8.4 total pigs and 7. 5 live pigs per litter. Gestation length varied from 111 to 117 days, with an average
of 113. 8 days.
Table 1. —Estrus Synchronization of Gilts with A1MAXa
Number of gilts 54
Following AIMAX withdrawal,
Number showing estrus on:
day 1 1
day 2 O
day 3 0 `
day 4 3
day 5 4
day 6 25
day 7 9
day 8 · 7
day 9 3
day 10 2
Number of gilts showing estrus 54
Number of gilts bred 54
Av days to estrus 6.46
Number of pigs farrowed 31
Farrowing rate 57.4
Gestation length — days
range 111-117
average 113. 8
Av number of pigs/litter
born 8. 4
born live 7. 5
E Fed at a level of 125 mg/gilt/day for 20 days.

N. W. Bradley, J. A. Boling and D. R. Lovell
The preweaning and postweaning growth data and observations of estrus during the growing phase
of this study were presented in the 1970 Kentucky Animal Sciences Research Report (Ky. Agr. Exp. Sta.
Prog. Rpt. 188, p. 33).
At the termination of the 196-day postweaning growth phase of this study, the 45 heifers were
turned to pasture as a group. While grazing they were offered ground ear corn free choice from a self-
· V feeder. Four fertile bulls were turned with the heifers 23 days after the heifers were turned to pasture.
The bulls remained with the heifers for 89 days. During this time the heifers were observed for
estrus, and dates of breeding were recorded. The heifers were slaughtered 21 days after the bulls were
removed from the pasture. Carcass measurements were made at slaughter, and the ovaries and uterus
V examined. Crown—rump measurements were recorded on the isolated embryo from pregnant heifers.
The reproductive performance data are presented in Table 1. All heifers in group 3 (Estrostat at
O, 98 days in growing phase) were pregnant at slaughter. Six heifers in group 2 (Estrostat at 0, 70 and
140 days in growing phase) were not pregnant at slaughter. The heifers in this group returned to estrus ,
later during the breeding phase of the study than those in group 3, which possibly resulted in the lower
conception rate. Examination of the reproductive tracts at slaughter revealed no gross abnormalities in
the one open heifer in the control group and the six open heifers in group 2.
Table 1. —Effects of Estrostat on Reproductive Performance of ·
Group 1 Group 2 Group 3
Number of heifers 14 16 15
Avg age of first estrus,
days 403 495 447
Number pregnant 13 10 15
Avg estrus cycles during
breeding phase before
· conceptionb 1. 5 2. 0 1. 8
Avg days to first estrus I
after last Estrostat
injection ——- 115 109
Avg estrus interval, days -—- 19 21
Mean crown—rump length
of fetus, mm 148. 7 46.1 125. 5
E Group 1 = Control heifers
Group 2 = 250 mg Estrostat injected at 0, 70, 140 days of
growing phase.
Group 3 = 250 mg Estrostat injected at 0, 98 days of growing
— One heifer was not observed in estrus but was pregnant at
slaughter. Average includes only pregnant heifers.
Carcass data of the heifers are presented in Table 2. Carcass grade, dressing percentage or
marbling score were not significantly (P <. 05) affected by injection with Estrostat.

Table 2. —Carcass Data of Heifers at the Termination of Breeding
Group 1 Group 2 Group 3
— Estrostat at Estrostat at
Control 0, 70, 140 days 0, 98 days
Number of heifers 14 16 15
Dressing % 63.4 63. 8 63. 2
Marbling scorea 6. 6 5. 8 5. 8
Carcass gradeb 13. 3 14.0 14. 2
%/Slightly abundant = 5, moderate = 6, modest = 7. P
— Low choice = 12, avg. choice = 13, high choice = 14.
J. W. McGaugh and Durward Olds
Superovulation has been tried by many workers, and varying successes have been reported. Al-
though many types of hormone preparations and dose rates have been used it is difficult to decide, on
basis of the literature, which dose rate will produce the desired results. The present study was designed
to determine the response and variability of cows to different doses of PMS (pregnant mare‘s serum
Four groups of 10 cows were given one, two, three, or four thousand international units (IU) of
PMS on day 16 of the estrous cycle (heat = day 0). On day 19, 10 to 15 mg of estradiol benzoate or
diethylstilbesterol were given. At the ensuing estrus, the cows were bred and injected with 2000 IU of
HCG. All cows were slaughtered for ovum recovery 3 to 7 days after breeding.
In total, the 40 cows produced 410 ovulation points (10. 3 per cow) and 211 ova were recovered
(51. 5%), of which 82 were fertilized (38. 9%). On the average, each 1000 IU of PMS resulted in 5. 82
ovulation points, 2. 67 ova recovered, and 1. 14 fertilized ova recovered. The number of ova ovulated,
ova recovered and fertilized ova recovered from the oviducts and uterine horns and the number of cows
producing them within each group is listed in Table 1. While the effects of dosage were linear, there
was considerable variation among cows (not associated with age or weight of the cows), and it seemed
that the fertilization rate was higher for 3000 IU (63. 3%) than for the other dosages. Ovum recovery
was more efficient (64. 2%) when all ova were in the oviducts as compared with when they were in the .
uterus (34_ 2C{)_
Each additional 1000 IU of PMS increased the ovarian length by 9. 67 mm, width by 8. 04 mm,
thickness by 4.42 mm, and weight by 17. 87 g. Each ovarian variable was increased significantly as the
interval from PMS to heat increased. The ovarian length seemed to be the most reliable predictor of
ovulation point numbers and each centimeter resulted in 2.4 ovulation points.
Unless our evaluation of cleavage stages was occasionally in error, the cleavage rate in this study
was about 33 hours per cleavage which is somewhat slower than might be expected in untreated cows as
reported in the literature. From this study, a dosage of 3000 IU of PMS injected on day 16, 10 mg of
estrogen injected on day 19, and 2000 IU of HCG injected at estrus appeared to produce the largest
percentage of fertilized ova.

Table 1. Number of Ova Recovered and Fertilized Ova Recovered from the
Oviducts and Horns and the Number of Cows Producing Them Within
Each Group after Receiving Various Doses of PMS
1000 2000 3000 4000 Overall
Ovulation points 22 65 128 195 410
Number of cows
. ovulating 8 9 10 10 37
Number of ova
recovered 13 39 66 93 211
Number of Ova From:
Oviducts 9 21 47 46 123
Uterine horns 4 18 19 47 88
Number of cows from
which ova were
recovered 6 7 9 10 32 `
Number of fertilized
ova - total 6 3 42 31 82
Oviducts 5 1 34 16 56 ·
Uterine horns 1 2 8 15 26
Number of cows from
which the ova were
recovered 3 2 8 7 20
B. V. Able, R. H. Dutt, F. A. Thrift and N. W. Bradley
The following study was initiated to determine if the amount of backfat in beef cows influences
serum lipid level and endometrial fat content, and to determine if these traits are related to fertility.
Forty—eight subfertile cows and 8 heifers were used in the study. The experimental cows were checked
twice daily for a 60-day period with an aproned bull to detect estrus and to establish whether they were
cycling normally. At the onset of the second estrus period, each cow was bred naturally and slaughtered
3 days later. The reproductive tracts were removed and ova were recovered by flushing the oviducts and
uterine horns. Backfat measurements were made with a Bronson Model 12 Sonoray at a point 5 cm in
front of the hip bones in the center of the back. Serum lipid levels were determined by a turbidity method
on blood samples. Fat content of the endometrium was determined by an ether extract method.
Backfat measurements of cows ranged from O. 25 to 3. 30 cm with a mean of 1. 71 cm (Table 1).
For heifers mean backfat measurement, 0.48 cm was significantly less (P<. 01) than that of cows and
ranged from 0. 25 to 0. 76 cm. The cows that had fertilized ova had less backfat than the cows with
unfertilized ova (1. 30 vs 1. 83 cm), but the difference was not significant.
The cows had a significantly (P4. 01) higher concentration of lipids (396. 2 mg/100 ml) than the
heifers (328. 7 mg/100 ml). The serum lipid levels of cows with fertilized ova were higher than that of
cows with Lmfertilized ova (384. 5 vs 357. 1 mg/100 ml), but the difference was not significant.
Endometrial fat content of the cows ranged from 0.33 to 3. 1U} and for heifers, from 1. 3 to 2. 6',}Q