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 Front Cover
 Table of Contents
 Introduction
 Review of literature
 Experimental procedure
 Experimental results
 Summary, conclusions, and...
 Literature cited






Group Title: Bulletin - University of Florida. Agricultural Experiment Stations ; No. 669
Title: Spring lamb production in Florida
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00027200/00001
 Material Information
Title: Spring lamb production in Florida
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 20 p. : ill., chart ; 23 cm.
Language: English
Creator: Loggins, P. E
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1964
 Subjects
Subject: Lambs -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 20.
Statement of Responsibility: P.E. Loggins ... et al..
General Note: Cover title.
 Record Information
Bibliographic ID: UF00027200
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000929052
oclc - 18353754
notis - AEN9820

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 3
        Page 4
    Experimental procedure
        Page 5
        Page 6
    Experimental results
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
    Summary, conclusions, and recommendations
        Page 19
    Literature cited
        Page 20
Full Text
Bulletin 669


Spring Lamb Production in Florida



P. E. Loggins, M. Koger, A. C. Warnick, and T. J. Cunha







AGRICULTURAL EXPERIMENT STATIONS
University of Florida, Gainesville
J. R. Beckenbach, Director


March 1964





















CONTENTS
Page


INTRODUCTION ........ ........ .......... ....... ..... ........


REVIEW OF LITERATURE .. ...... ..... ........ ..... 3


EXPERIMENTAL PROCEDURE .......................................-- ........- .... 5

General Flock M anagem ent .. ................................... ... ....... 5
Breeding Program s .. ..... .. ..... ........ ...... ... ... ...... 5
Observations Made for Early Lambs .............-.............. .........- 7


EXPERIMENTAL RESULTS ......... ..-... ........... .....7....-.......-...... -....... 7
Reproductive Perform ance ......................................-.... ......- 7
Lambing Performance .. .......... ........................ -... ..... ......-- 10
Crossbred Lam bs ......- .... .. .............. ......... ..--. -- ...-... ...-... 13
H em oglobin D ata ....-.. -.. -.. ...... .. ... .........- ......... .... 16
General M anagem ent ........ -............................ ... .. ....... .... 16
W ool D ata ....... .. ......... ...-.......- .- ...- 17


SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS ................. ............ 19


LITERATURE CITED ...








SPRING LAMB PRODUCTION IN

FLORIDA

P. E. LOGGINS, M. KOGER, A. C. WARNICK, AND T. J. CUNHA

INTRODUCTION
The principal source of income from a sheep enterprise in
Florida is the sale of good quality lambs. Lamb sales represent
approximately 70 percent of the total return from sheep produc-
tion in the United States. Wool production is an important
secondary source of income for the sheep producer.
The classification of slaughter lambs on a market is milk fed
(spring) lambs, hot house lambs, and straight lambs. Market-
ing practices to date have established sectional patterns through-
out the country for the most valuable marketing dates. There-
fore, climatic conditions affect the marketing of lambs along with
the production practices.
The number of sheep in Florida is low (1960 census, 6,500
head), and excellent quality lambs are not yet being produced.
A six-year study from 1956 through 1962 on spring lamb pro-
duction has been conducted at the Florida Agricultural Experi-
ment Station at Gainesville. This publication is a report of the
results from this experiment.

REVIEW OF LITERATURE
Research workers have established the fact that sheep ex-
hibit seasonal polyestrous reproduction cycles. The work re-
ported by Hafez (5)2 showed that the breeding season begins in
late summer, and that breeds originating in the northern lati-
tude tend to have a later and a shorter breeding season. Russell
(7) observed differences in the onset of estrus within a breed.
DeBaca et al. (2) working with purebred Hampshire, Romney,
and Southdown sheep, observed that the average first estrus of
the breeding season varied as much as 30 days and that the mean
onset of estrus occurred in the order listed for the three breeds.
Further studies with ewes resulting from the mating of Hamp-
shire, Border Leicester, Romney, and Cheviot rams to crossbred
ewes showed that the Hampshire backcross ewes would breed
earlier in the season. Crossbreeding studies reviewed by Rae
SAssistant Animal Husbandman, Animal Geneticist, Animal Physiolo-
gist, and Animal Nutritionist and Head, Animal Science Department.
Numbers in parentheses refer to Literature Cited.








SPRING LAMB PRODUCTION IN

FLORIDA

P. E. LOGGINS, M. KOGER, A. C. WARNICK, AND T. J. CUNHA

INTRODUCTION
The principal source of income from a sheep enterprise in
Florida is the sale of good quality lambs. Lamb sales represent
approximately 70 percent of the total return from sheep produc-
tion in the United States. Wool production is an important
secondary source of income for the sheep producer.
The classification of slaughter lambs on a market is milk fed
(spring) lambs, hot house lambs, and straight lambs. Market-
ing practices to date have established sectional patterns through-
out the country for the most valuable marketing dates. There-
fore, climatic conditions affect the marketing of lambs along with
the production practices.
The number of sheep in Florida is low (1960 census, 6,500
head), and excellent quality lambs are not yet being produced.
A six-year study from 1956 through 1962 on spring lamb pro-
duction has been conducted at the Florida Agricultural Experi-
ment Station at Gainesville. This publication is a report of the
results from this experiment.

REVIEW OF LITERATURE
Research workers have established the fact that sheep ex-
hibit seasonal polyestrous reproduction cycles. The work re-
ported by Hafez (5)2 showed that the breeding season begins in
late summer, and that breeds originating in the northern lati-
tude tend to have a later and a shorter breeding season. Russell
(7) observed differences in the onset of estrus within a breed.
DeBaca et al. (2) working with purebred Hampshire, Romney,
and Southdown sheep, observed that the average first estrus of
the breeding season varied as much as 30 days and that the mean
onset of estrus occurred in the order listed for the three breeds.
Further studies with ewes resulting from the mating of Hamp-
shire, Border Leicester, Romney, and Cheviot rams to crossbred
ewes showed that the Hampshire backcross ewes would breed
earlier in the season. Crossbreeding studies reviewed by Rae
SAssistant Animal Husbandman, Animal Geneticist, Animal Physiolo-
gist, and Animal Nutritionist and Head, Animal Science Department.
Numbers in parentheses refer to Literature Cited.






Florida Agricultural Experiment Stations


(6) showed that (a) the lambs produced from the heaviest
breeds of rams-Suffolk, Oxford, Hampshire, Border Leicester,
Columbia, and Lincoln-have generally shown faster growth
rate and heavier market weights, and (b) the grade, quality, and
dressing percentage was generally higher for lambs sired by
Southdown rams. Carter et al. (1) from a seven-year study in
Virginia reported that adjusted daily gain (birth to slaughter)
of lambs sired by Columbia, Hampshire, Southdown, Dorset, Cor-
riedale, Hampshire x Southdown, and Shropshire rams mated to
grade native and western ewes were 0.65, 0.62, 0.59, 0.59, 0.59,
0.58, and 0.57 pounds, respectively.
Crossing of Columbia rams on Florida Native ewes (White-
hurst et al. 8) produced crossbred ewes that were superior to
either parent in number of lambs born and in weight of lamb at
weaning.
Climatic factors have been shown to be an important factor
in the reproduction phenomena of both the ram and ewe. Green
(4) reported that the level of fertility in rams is seasonal. Dutt
and Bush (3) reported that ewes placed in a controlled tempera-
ture of 450 to 480 F. from May 26 through October 8 had an
eight-week earlier average date of first estrus than the control
ewes which were kept at 880 F. Semen from treated rams
(450 to 480F) during the summer period was more fertile than
from the control rams.


O>I -> g
ttif


Figure 1.-The 1962 Florida Native ewe and lamb crop
the lot area used in the experimental study.


located in






Spring Lamb Production in Florida


EXPERIMENTAL PROCEDURE

General Flock Management
The experiments were conducted at the Florida Agricultural
Experiment Station farm located at Gainesville. The experi-
mental flock was housed in a pole type barn and allowed access
to permanent and temporary type pasture. The permanent pas-
tures were Coastal bermudagrass, pangolagrass, and bahiagrass.
Starr millet and Floriland oats were used as temporary winter
or summer pastures. Supplemental feeding was provided the
ewe flock when pasture conditions were inadequate. Trace min-
eralized salt and bonemeal, fed free choice, were provided at all
times. The nutritional level provided these sheep was calcu-
lated to meet all their needs. The pasture soil types were Blich-
ton fine sand and Blichton fine sandy loam. The average yearly
rainfall during the experimental period was 57.88 inches, with
monthly average maximum and minimum temperatures (F) as
follows:
Max. Min. Max. Min. Max. Min.
January 66 41 May 88 63 September 89 70
February 72 46 June 90 68 October 84 63
March 74 49 July 92 72 November 77 54
April 81 55 August 92 71 December 68 43

Three groups of ewes selected for this six-year study were
obtained from Tennessee, Texas, and Florida. The 30 original
Hampshire ewes and two Hampshire rams came from Lewis-
burg and Dyersburg, Tennessee. The 30 original Rambouillet
ewes and two Rambouillet rams came from Sonora, Texas. The
Hampshire ewes and rams were purebreds. The grade Rambouil-
lets were selected from a good commercial flock. The 30 original
Florida Native ewes and two Native rams were selected from
four different locations (Gainesville, Ocala, Palatka, and Lake
Wales) within the state. Yearling ewes and rams were pur-
chased for this study.

Breeding Programs
The three groups of ewes were assembled for the study in
the spring of 1956 and were exposed to rams of the same breed-
ing as yearlings for the 1957 lamb crop. A straightbreeding
program was also followed for the 1958, 1961 and 1962 lamb
crops. Various crossbred and Hampshire lambs were produced


















*A x "FT -'.







crossed with Florida Native ewes; Florida Native rams were
... .,. .^', ; .. :.. ;.
.:A :..: ., ;,, ,'. f..- .. ,,' . i f .,. ,. ,.

Figure 2.--The 1962 Rambouillet ewe and lamb crop grazing Coastal
bermudagrass pasture in vicinity of the pole-type barn used in this study.

in 1959 and 1960. Hampshire, Rambouillet, and Florida Native
ewes were mated to Hampshire rams; Rambouillet rams were
crossed with Florida Native ewes; Florida Native rams were
crossed on Rambouillet ewes.
Rams were placed with the ewes on July 1 each breeding sea-
son. A 90-day breeding season was used for the 1957-58-59 lamb
crop, while a 75-day breeding season was used for lambs born
in 1960, 1961, and 1962. The ewes were sheared during the last
week in April or the first week in May in the 1957-60 phase of
the study. The ewes were sheared during the last week of
March in 1961 and 1962.
Vasectomized rams were used (a) to determine date of estrus
prior to the breeding season beginning on April 15 of each year
and (b) as a means of determining breeding dates during the
breeding season. The vasectomized rams were turned in with
the ewes each morning for approximately 40 minutes. A ewe
was considered in estrus if she stood for mounting by the ram,
after which she was removed so the rams would check the en-
tire flock.
The fertility of the rams was checked every 14 days, and those
found to be low in semen quality were replaced by reserve rams
kept under cool conditions. Semen collections were made from
June 15 to October 15, using an artificial vagina, and the semen
was rated on the basis of volume, motility, and concentration
of sperm.






Spring Lamb Production in Florida


Observations Made for Early Lambs
Data were collected on date of first estrus and subsequent
estrus periods, date of lambing, birth weight, number of ewes
lambing, and the number of lambs dropped. The number of
lambs that died during the first 24 hours after birth and to
weaning or market date was recorded. May 19th and 20th were
used as the final date for weight and slaughter grade data for
the six lamb crops produced. Their average age on this date
was 142 days. All lambs were graded by the same committee of
three members in the Animal Science Department. The lambs
were weaned on May 20th in the 1957-58-59 lamb crops. The
1960-61-62 lamb crops were weaned on March 15, March 9, and
February 23, respectively. The six lamb crops were creep fed
beginning two weeks after the first lamb was born. Periodic
weights were obtained on the lambs and ewes at 14 or 28 day
intervals during the experiment. Hemoglobin levels were de-
termined on ewe groups every 28 days for 42 months after the
study was initiated. The hemoglobin levels were measured to
use as an indicator of internal parasite infections.


EXPERIMENTAL RESULTS

Reproductive Performance
The yearly performance of the breed groups is presented
in Tables 1, 2, 3, and 4. The averages for the various traits
measured are reported on unadjusted data.


--
F. 3 Th' 957 Ha' psh re lamb cop at maket date May 20th
Figure 3.--The 1957 Hampshire lamb crop at market date, May 20th.






Florida Agricultural Experiment Stations


The late breeding performance of the Hampshire flock and
their low productivity resulted in their being dropped from the
study following the 1960 lamb crop.

TABLE 1.-YEARLY SUMMARY OF THE HAMPSHIRE EWE
FLOCK BREEDING PERFORMANCE.
1957 1958 1959 1960
Number of ewes 26 24 17 11
Number in heat by July 1 2 0 0 0
Date of first estrus
Average July 29 Aug. 1 July 23 July 19
Range (days) 121 40 52 35
Average estrus periods per ewe 2.4 2.3 1.4 1.2
Average lambing date Jan. 4 Jan. 6 Dec. 20 Dec. 24


w


- 'A U -... l '.,- -. rIIa
f. Now,
do &aF-


Figure 4.-The 1957 Rambouillet lamb crop at market date, May 20th.

TABLE 2.-YEARLY SUMMARY OF THE RAMBOUILLET EWE
FLOCK BREEDING PERFORMANCE.


1957 1958* 1959 1960 1961


1962


Number of ewes 30 28 35 29 47 45
Number in heat by
July 1 10 3 10 5 0 0
Date of first estrus
Average July 2 July 19 July 12 July 14 July 29 July20
Range (days) 37 68 87 86 48 72
Average estrus
periods per ewe 1.6 3.1 1.4 1.6 1.3 1.3
Average lambing date Dec. 19 Feb. 2 Dec. 11 Dec. 21 Dec. 30 Dec. 17

The Rambouillet rams had low semen quality, which accounts for some of the high
percentages Of ewes returning to estrus.


FrX
Vol'.






Spring Lamb Production in Florida


TABLE 3.-YEARLY SUMMARY OF THE FLORIDA NATIVE
EWE FLOCK BREEDING PERFORMANCE.

1957* 1958 1959 1960 1961 1962


Number of ewes
Number in heat by
July 1
Date of first estrus
Average
Range (days)


33 32 35 41 39 45

- 0 6 0 0 0

- July 23 July 17 July 23 July 31 July 25
- 39 88 55 34 28


Average estrus
periods per ewe 1.1 1.5 1.1 1.1 1.0
Average lambing date Jan. 1 Dec. 21 Dec. 21 Dec. 18 Dec. 30 Dec. 17

The Florida Native flock was not assembled early enough to obtain data on the 1957
breeding season.

The breeding performance of the ewe flocks studied to date
shows that the average date for first estrus occurs late in July.
An earlier breeding season would be more desirable so that lambs
could be marketed before May when hot weather begins. Fur-
ther research is needed on selection and breeding to develop an
early lambing flock. The Rambouillet ewes were slightly earlier


i- e 15 -X Ni lab



.Figure -The 197 Florida Native lamb.
Figure 5.-The 1957 Florida Native lamb


crop at market date, May 20th.







Florida Agricultural Experiment Stations


in showing first estrus than the Florida Native ewes, while the
Native ewes lambed slightly earlier. The difference in lambing
dates is primarily due to the greater fertility of the Native
ewes. There was considerably less variation in date of first
estrus in the Florida Natives compared to the Rambouillet ewes.
The Natives consistently showed first estrus at approximately
the same dates each year.

TABLE 4.-SUMMARY OF BREEDING PERFORMANCE OF THE HAMPSHIRE,
RAMBOUILLET AND FLORIDA NATIVE FLOCKS FOR ALL YEARS (UN-
WEIGHTED MEAN).

Hampshire* Rambouillet** Florida Native**
Number of ewes 78 214 225
Number in heat by
July 1 2 28 6
Date of first estrus
Average July 26 July 16 July 24
Range (days) 62 66 49
Average estrus
periods per ewe 1.8 1.7 1.2
Average lambing date Dec. 29 Dec. 29 Dec. 23

Based on four lamb crop only.
** Based on six lamb crops.


Lambing Performance
The yearly lambing performance of the breed groups is pre-
sented in Tables 5, 6, 7, and 8.
The yearly performance of the Hampshire ewe flock, as
shown in Table 5, failed to maintain a level of production ade-
quate to replace and maintain the breeding ewe flock. Further
study of these data show a low lambing percentage and a higher
death loss of lambs from birth to the marketing date of May
20th used in this study. The average weight and live slaughter
grade scores are below the recommended level for profitable
sheep production.
The percentage of lambs raised, as shown in Table 6, needs
to be improved through further studies. The low level of 62
percent of lambs raised from the 1962 lamb crop was attributed
to a dietary deficiency of vitamin A. Night blindness occurred,
and liver analysis of lambs showed vitamin A levels below nor-
mal. The 1960 lambs were weaned on March 15; 1961 lambs
on March 9; and the 1962 lambs on February 23 at an average








Spring Lamb Production in Florida


TABLE 5.-YEARLY LAMBING PERFORMANCE OF
THE HAMPSHIRE EWE FLOCK.

1957 1958 1959 1960


Number of ewes
Number of ewes lambing
Percent of ewes lambing
Number of lambs dropped
Percent of lambs dropped
Average lamb birth wt. (Ib)
Percent lamb crop living 24 hrs. after birth
Percent lamb crop raised to May 20th
Average lamb weight (lb on May 20th)
Average live slaughter grade score-
May 20th*


9.4 11.2 10.1 11.4


Grades were determined to a third of the grade using the following scale for federal
grades of slaughter lambs: Grades 6-8 Utility, 9-11 Good, 12-14 Choice and 15-17 Prime.
Grades reported in the following Tables, 6, 7, 8, 9, and 10 follow the same procedure.



TABLE 6.-YEARLY LAMBING PERFORMANCE OF THE
RAMBOUILLET EWE FLOCK.


1957 1958 1959 1960 1961 1962


Number of ewes
Number of ewes lambing
Percent of ewes lambing
Number of lambs dropped
Percent of lambs dropped
Average lamb birth
wt. (lb)
Percent lamb crop living
24 hrs. after birth
Percent lamb crop raised
to May 20th
Average lamb weight
(lb)-May 20th
Average live slaughter
grade score-May 20th


7.6 7.4 7.0 7.0 7.1 6.4

87 79 103 83 87 84

85 71 97 80 85 62

64 59 55 61 70 74


10.9 8.8 10.0 12.5 14.2


7.9







Florida Agricultural Experiment Stations


TABLE 7.-YEARLY LAMBING PERFORMANCE OF THE
FLORIDA NATIVE FLOCK.

1957 1958 1959 1960 1961 1962


Number of ewes
Number of ewes lambing
Percent of ewes lambing
Number of lambs dropped
Percent of lambs dropped
Average lamb birth
wt. (lb)
Percent lamb crop living
24 hrs. after birth
Percent lamb crop raised
to May 20th
Average lamb weight
(lb)-May 20th
Average live slaughter
grade score-May 20th


6.8 7.0 7.2 6.4 6.6 6.5

94 91 103 94 108 111

81 91 97 81 108 111

50 61 56 55 64 67


5.7


7.9 7.8 9.0 11.5 13.2


TABLE 8.-SUMMARY OF LAMB PERFORMANCE OF THE HAMPSHIRE, RAM-


BOUILLET, AND FLORIDA NATIVE FLOCK
MEAN).


FOR ALL YEARS UNWEIGHTEDD


Hampshire Rambouillet Florida Native


Number of ewes
Number of ewes lambing
Percent of ewes lambing
Number of lambs dropped
Percent of lambs dropped
Average lamb birth wt. (Ib)
Percent lamb crop living
24 hrs. after birth
Percent lamb crop raised
to May 20th
Average lamb weight (Ib)
on May 20th
Average live slaughter
grade score-May 20th


214
182
85
204
95
7.1


10.5 10.7


225
209
93
243
108
6.8

100

95

59






Spring Lamb Production in Florida


age of 70 days. Weights and live slaughter grade scores, as
shown in Table 6, were improved for the three years of early
weaning when compared to the three previous years. How-
ever, the average weights for the lambs produced in the six-year
study were below a profitable level.
The data collected on the six lamb crops from the Florida
Native ewe flock are shown in Table 7. Lambing percentage
was higher in Florida Native flock as compared to the Hampshire
and Rambouillet flocks. The percentage of lamb crop raised
from birth to the May 20 date in the Florida Native lambs was
higher. The Florida Native lambs were weaned and handled
in the same manner as previously described for the Rambouillet
lambs. Weights and live slaughter grade scores for the early
weaned lambs in 1960 to 1962 were improved over the previous
three years, when weaning in the flocks occurred on the May
20 date. The yearly average weight for the Florida Native
lambs was below that for the Hampshire and Rambouillet lambs
handled in the same manner. However, the improvement made
in weight and slaughter grade plus the higher lambing percent-
age and livability makes these sheep important in future studies
on sheep production in Florida.

Crossbred Lambs
A crossbreeding study was initiated with the 1959 and 1960
lamb crops. Rambouillet and Florida Native ewes were crossed
with Hampshire rams. Rambouillet rams were crossed with Flor-
ida Native ewes, and Florida Native rams were crossed with
Rambouillet ewes. The Hampshire flock was straightbred. Eight
ewes were randomly selected from each breed group for the
crossbreeding phase of this study. The performance of the
straightbred lambs and the crossbred lambs is summarized in
Table 9.
The weight and market grade of lambs produced from Hamp-
shire rams crossed with Rambouillet and Florida Native ewes
were improved as shown in Table 9. The cross of Rambouillet
rams on Florida Native ewes did not increase the quality or
weight of the lamb. Florida Native rams crossed with Ram-
bouillet ewes produced lambs which were not superior to their
parent stock. Crossbreeding studies were dropped after two
years in order to increase selection pressure in the straightbred
breed groups. It was concluded from these limited data, and
other observations, that more progress could be made by straight-







14 Florida Agricultural Experiment Stations

TABLE 9.-A SUMMARY COMPARISON OF THE 1959-60 CROSSBRED LAMBS
TO THE STRAIGHTBRED LAMBS UNWEIGHTEDD MEANS).

May 20


No. No. No.
No. Lambs Lambs lambs
Ewes Born Lost mar-
keted


Breeding


Aver-
age
weight


Average
live
grade
score


Hampshire
Rambouillet
Florida Native
Hampshire ram x
Rambouillet ewes
Hampshire ram x
Florida Native ewes
Rambouillet ram x
Florida Native ewes
Florida Native ram x
Rambouillet ewes


1.5 15 3 12 71 11.3

16 18 3 15 63 11.0

16 20 5 15 58 9.5

16 20 2 18 59 9.2


Figure 6.-The 1962 ewe and lamb crop grazing oat pasture.







Spring Lamb Production in Florida


breeding programs and critical selection in the replacement ewe
lambs.
The data collected from the previous lamb crops suggest a
need for changes in our management. One of the changes made
was earlier weaning of the lambs. The 1957-58-59 lamb crops
were weaned on May 20. The 1960-61-62 lamb crops were weaned
on March 15, March 9, and February 23, respectively. The re-
sults of this change are shown in Table 10.

TABLE 10.-THE EFFECT OF AGE AT WEANING ON THE PERFORMANCE
OF STRAIGHTBRED LAMB CROPS UNWEIGHTEDD MEANS).

Avg. weaning Avg. wt. Avg. market
age (days) May 20 grade score

Hampshire lamb crop
1957 135 57 9.4
1958 134 74 11.2
1959 150 64 10.1
Early weaned
1960 81 69 11.4
Rambouillet lamb crop
1957 151 64 7.9
1958* 106 49 10.9
1959 159 55 8.8
Early weaned
1960 84 61 10.0
1961 70 70 12.5
1962 69 74 14.2
Florida Native lamb crop
1957 138 51 5.7
1958 150 61 7.9
1959 150 56 7.8
Early weaned
1960 87 55 9.0
1961 70 64 11.5
1962 69 67 13.2

Rambouillet lambing date late due to low fertility in rams.

The two early weaned lamb crops produced the last three
years of the study were heavier than the three previous years,
as shown in Table 10. Market grade was also improved in the
earlier weaned lambs.
This system of management tends to decrease the cost of
handling the ewe flock. The control of internal parasites in
the lamb is also improved due to less contamination of pastures
when the ewes and lambs are maintained on the same pasture.
Earlier weaning and dry lot production of lambs are means by
which sheep production may become more profitable.






Florida Agricultural Experiment Stations


Hemoglobin Data
Observations were made on weight changes and hemoglobin
levels of the ewe flocks every 28 days for 42 months. Hemoglo-
bin levels were used as an aid in determining parasite infections
in the flocks. Weight changes served as a guide for supplemen-
tal feeding of the ewes to meet the nutritional requirements for
lamb production.
The hemoglobin levels, as shown in Figure 7, followed a sea-
sonal pattern with significantly higher levels occurring in the
November and December period each year. Significant differ-
ences were found also for years and breeds. Florida Native
ewes had a higher hemoglobin level than Hampshire or Ram-
bouillet ewes.


II


,0








---- Hampshire
7 ............. Rambouillet
Florida Native


Sept. Dec. April Aug. Dec. Mar July Nov. Mar.
19 1956 1957 1957 1958 1958 1958 1959

Figure 7.-Hemoglobin levels of Native, Hampshire, and
Rambouillet breeding ewes. 1956-1959.

General Management

This six-year study of lamb production in Florida has dem-
onstrated the need for improved internal parasite control if
sheep production is to be profitable in this area. The manage-
ment program to control the internal parasites during this study
was through the use of anthelmintics and pasture rotation. The
following anthelmintics have been used: phenothiazine regu-







Spring Lamb Production in Florida 17

lar particle size, phenothiazine finely ground (less than 3 mi-
crons), piperazine, "cunic" (copper and nicotine sulfate), "Dylox"
(Chemazro Electrical Corp.), "Rulene" (Dow Chemical Corp.),
and pilot studies with other compounds. These anthelmintics
were administered at recommended levels, and treatment periods
varied from 21 days to 56 days in length. The pasture rotation
program was improved after the first four years of the study.
The sheep flock was maintained as two groups during the last two
years of the study and rotated between 10 pasture plots. Six
of the pastures were permanent grass pastures, Coastal ber-
mudagrass, and bahiagrass. Four were maintained as tempo-
rary pastures with oats and millet used for the seasonal crops.
The groups were rotated to a new pasture with the longest in-
terval possible between pastures. Three weeks was the shortest
interval.
Death losses due to internal parasites were higher during
the first four years of the study even with recommended drench-
ing programs being followed. The continued use of anthelmin-
tics and improved pasture rotation have reduced the losses due
to parasites, but adequate and practical control programs have
not been developed to date.
The volume, motility, and concentration of the semen studies
showed a definite seasonal and breed difference. The three
breeds studied were lower in semen and quality during August.
There was a gradual improvement in semen quality in Septem-
ber and by October sperm production was back to normal. The
Florida Native rams were less affected by the seasonal changes
and were never found to be sterile during the periods checked.
Some Rambouillet and Hampshire rams were affected to the de-
gree of temporary sterility. Extra rams were rotated from a
cooled room (70 F) to help assure fertility of rams used for
breeding the ewes. Semen quality was improved by moving the
low fertility rams to the cooled room for two weeks. The rota-
tion program of alternating a cooled ram every two weeks im-
proved ram performance during the breeding season.

Wool Data
Wool production is an important source of income in lamb
production. Little emphasis was placed on wool during this
study, although data were collected on the grease wool yield,
wool grade, and market price received for the wool. The yearly
wool clip was graded by the same panel of the Animal Science







Florida Agricultural Experiment Stations


Department. The sheep flock was sheared during the last week
in April during the first four years and the last week in March
during the last two years of the study. The wool data are sum-
marized in Table 11.
The grease wool yields as shown in Table 11 are lower than
the national averages for Hampshire and Rambouillet breed-
ing. These lower yields can be partially explained by the lack
of total body size obtained in these ewes during this study.
The Florida Native ewes had a heavier fleece than the average
for the state and were larger in body size. The prices received
for the wool are not in sequence with the grade. This can be
explained by the interest of the woolen mills in lower grading
wool for blending today's improved woolen apparels.

TABLE 11.-GREASE WOOL PRODUCTION ON HAMPSHIRE, RAMBOUILLET
AND FLORIDA NATIVE EWES (1957-1962).

Price
Received
Number Avg. Fleece per Lb.
Ewes Wt. (Lbs.) Average Grade (Cents)

Hampshire
1957 26 4.3 1 Blood 50's 51
1958 24 5.9 1 Blood 50's 44
1959 17 4.1 1. Blood 50's 42
1960 11 4.6 14 Blood 50's 48
Rambouillet
1957 30 7.0 Fine wool 64's 65
1958 28 8.3 Fine wool 64's 46
1959 35 6.2 Fine wool 64's 45
1960 29 6.5 Fine wool 64's 49
1961 47 6.8 Fine wool 64's 43
1962 45 7.1 Fine wool 64's 45
Florida Native
1957 33 3.3 Low 1/ Blood 46's 51
1958 32 4.5 Low 1/ Blood 46's 41
1959 35 4.7 Low 1/ Blood 46's 42
1960 41 4.3 Low 14 Blood 46's 48
1961 39 4.1 Low 1/ Blood 46's 37
1962 45 4.3 Low 1/ Blood 46's 45







Spring Laimb Prodactioi in Florida


SUMMARY. CONCLUSIONS, AND
RECOMMENDATIONS

1. Hampshire, Rambouillet, and Florida Native breeding
flocks were used in straight and crossbreeding programs during
a six-year (1957-1962) study on producing early lambs in
Florida.
2. The high percentage of death losses in the Hampshire
replacement ewe flock resulted in their being dropped from the
study after four years.
3. The Florida Native ewes had the highest percentage of
lambs raised to market date (May 20).
4. The Rambouillet ewe flock was superior to the Hampshire
flock in reproduction performance.
5. The average date of first estrus occurred late in July in
all breeding groups. The Florida Native ewes show less varia-
tion in date of first estrus and lambed slightly earlier.
6. The Hampshire and Rambouillet lambs were heavier and
graded higher than Florida Native lambs.
7. The limited study on lambs produced from the cross-
breeding phase of this study shows further work needed to de-
termine its value.
8. Early weaning of lambs (69 to 84 days of age) during
the last three years of the study increased market weight of
lambs.
9. The cost of production on lambs produced during this
study were below profitable levels due mainly to the light weight
lambs at market date, May 20.
10. Hemoglobin levels were significantly higher in Florida
Native ewes than in other breeds studied.
11. Semen quality of Rambouillet and Hampshire rams was
found to be lower during the breeding season than for the Flor-
ida Native rams. Cooling of the ram during the breeding season
(July 1 to September 15) improved semen quality.
12. The need for further work on reproduction phenomena,
growth rate of lambs, internal parasite control, and other man-
agement practices is evident from these results. Additional in-
formation on these aspects of production and perhaps others is







Florida Agricultural Experiment Stations


needed before sheep can be profitably raised on a large scale in
Florida. It is suggested that those interested in sheep produc-
tion in this state investigate the problems involved before be-
ginning such an enterprise. A visit to the Florida Agricultural
Experiment Station Sheep Unit at Gainesville would be helpful
and is highly recommended to those interested.


LITERATURE CITED

1. Carter, R. C., C. M. Kincaid, J. A. Gaines, and G. W. Litton. Breeds
of rams for spring lamb production. Va. Agri. Expt. Sta. Bul. 492.
1958.
2. DeBaca, R. C., A. C. Warnick, G. H. Hirchcock, and R. Bogart. Factors
associated with the onset of estrus in ewes. Oregon Agr. Expt. Sta.
Bul. 29. 1954.
3. Dutt, R. H., and L. F. Bush. The effect of low environmental tempera-
ture on initiation of the breeding season and fertility in sheep. J.
Animal Sci. 14: 885. 1955.
4. Green, W. W. Seasonal trends of sperm cell types in sheep. Proc.
Amer. Soc. Ani. Prod. 33: 207. 1940.
5. Hafez, E. S. E. Studies on the breeding season and reproduction of
the ewe. J. Agr. Sci. 42:189. 1952.
6. Rae, A. L. Crossbreeding of sheep. II. Crossbreeding for lamb and
mutton production. Ani. Breed. Abst. 20: 287-299. 1952.
7. Russell, S. F. Inheritance of characters in sheep. Okla. Agr. Expt.
Sta. Bul. 126. 1919.
8. Whitehurst, V. E., R. M. Crown, R. W. Phillips, and D. A. Spencer.
Productivity of Columbia sheep in Florida and their use for crossing
with native sheep. Fla. Agr. Expt. Sta. Bul. 429. 1947.




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