الجمعية المصرية للأغنام والماعزوالحيوانات الصحراوية
EGYPTIAN ASSOCIATION OF SHEEP, GOATS & DESERT ANIMALS
1ST INTERNATIONAL CONFERENCE ON
ENHANCEMENT OF SMALL RUMINANT PRODUCTION
المؤتمر الدولى الأول لتنمية المجترات الصغيرة
7-9 فبراير 2006
SHEEP CROSS BREEDING AND REPRODUCTIVE MANAGEMENT AS TOOLS TO ENHANCE FLOCK PRODUCTIVITY
By
Dr TALAAT HARB M REFAAT
Eng ABDULLAH TALAAT REFAAT
(7-9 FEB, 2006)
Sheep Cross Breeding and Reproductive Management Dr Talaat Refaat
1. والماعز لألغنام المصرية الجمعيةالصحراوية والحيوانات
EGYPTIAN ASSOCIATION OF SHEEP, GOATS & DESERT
ANIMALS
1ST
INTERNATIONAL CONFERENCE ON
ENHANCEMENT OF SMALL RUMINANT PRODUCTION
الصغيرة المجترات لتنمية األول الدولى المؤتمر
7-9فبراير2006
SHEEP CROSS BREEDING AND REPRODUCTIVE
MANAGEMENT AS TOOLS TO ENHANCE FLOCK
PRODUCTIVITY
By
Dr TALAAT HARB M REFAAT
Eng ABDULLAH TALAAT REFAAT
(7-9 FEB, 2006)
2. 2
1. GETTING STARTED :
Our project has started on 20/8/1998 with 20 Barki ewes from American
University of Cairo (AUC), Khartoum branch, which is located near our
farm at South of Tahreer, Sadat city. AUC has long experience in animal
production, especially with Barki breed.
At the same time we brought two Barki rams from Animal Production
Research Institute (APRI), Borg Al-Arab station. One of the main
objectives of this station is to keep the pure original characteristics of
Barki breed, since it has the best carcass specification in Egypt.
On 17/7/1999 we brought 80 Osimi ewes from Abu-Kabeer Sharkiya,
with the help of an experienced staff member of APRI. He made a good
job in selecting the ewes. Simultaneously we brought two Finn rams from
APRI, Sakha Station.
2. BUSINESS STRATEGY :
2.1. WHY BUSINESS STRATEGY:
Since animal production was not our original career, and there was
no previous experience in this area, we preferred to follow a scientific
approach in tackling any subject concerning animal production rather
than to follow a traditional disciplinary approach.
“A Systems Approach to research and development is now generally
recognized as being the most appropriate for gaining knowledge of
and designing technology for the improvement of agricultural
performance and for the subsequent putting into practice of the
knowledge and technology. A Systems Approach, unlike the more
traditional disciplinary approach considers the effects that changes in
one component or subcomponent of a whole farm or environment may
have on other components.” “1”.
It is stated in “ Production Systems in the Near East Region ,A
Training Manual for Characterization & Analysis” produced by the
FOA Regional Office for the Near East page 7 :
A properly applied systems approach should:
Begin with no preconceptions about the nature of the system ;
3. 3
Be geared towards improvement of the system ;
Examine the interactions and relationships between the internal
and external factors affecting production goals and levels of
performance and , from these , attempt to identify constraints to
better performance ;
Interactions must be adequately understood and constraints
correctly identified ;
Involve the farmers and their families in the process at all
stages ; and
Evaluate “solutions” for their effects on productivity, equity,
stability and sustainability.
Systems research means researchers must be open to problems at
farm and household level as well as to working with farmers and
willing to learn from rural wisdom and indigenous knowledge.
Therefore, setting a strategy “2, 3 &4”for our project was a must at
least for the following reasons:
To formulate the Mission Statement for the project.
To formulate the Vision Statement for the project.
To set the Goals & Objectives for the project.
To devise an appropriate organization capable for the
achievement of these Goals and Objectives.
To allocate new resources to the organization in stages “4&6”.
To comply with the imposed requirements set by new
customers.
To reposition the project relative to the similar competitors
organization especially in the frame of the new changes.
To form a basis for making action decision-now! Since
immediate action decision is a must regarding the new changes
in marketplace.
MISSION STATEMENT :
The MISSION of our project is:
To encourage and enable
All farm manager at the three
4. 4
Managerial levels
To improve
The decision making process
For all types of decisions
Strategic, tactical & technical.
VISSION STATEMENT :
The VISSION of our project is:
Quantitative Approaches, DSS, TQM, HRM,
Advanced S/W & H/W
& different Methodologies
Become
Common tools that
All farm managers can use
To help them
To achieve their objectives
3. GOALS AND OBJECTIVES:
GOALS of our project are:
G0, G1, ..., G4.
G0 is a temporary goal especially during the building stage. The other
four goals are permanent goals.
In the frame of the characteristics of the current situation of the farm;
the mission and the vision statements; and environment of the farm / our
project have five goals:
GOAL # 0
To establish
Mission statement, vision statement, goals, policies,
Procedures & adequate organization;
Objectives, scope of work“2, 3 ,4 &5”,
And
Job analysis and description
For the required manpower.
5. 5
GOAL # 1
To facilitate collection, keeping,
Updating for all information related
To animal production, cross breeding, reproductive management,
nutrition,.etc. On different media, and
To avail these information to all farm candidates.
GOAL # 2
To establish
Systems assurance function, product
Assurance function, and process assurance
In the meantime
To build and to improve:
i a quality control system
To all parts of the project
ii a training system
To all involving candidates.
GOAL # 3
To assist projects, managers
To perform
The four key stages of the project:
Initiation, establishment, implementation,
And project completion.
GOAL # 4
To perform
Professional system studies,
Feasibility studies
In the meantime
To devise systematic means for
Attaining objectives
6. 6
4. CROSSBREEDING:
4.1. INTRODUCTION:
Genetics and animal selection is of extreme importance. Consumer
preferences, the individual sheep producer’s selection criteria, and suitability
to a production management scheme need to be evaluated.
Unhealthy sheep cannot be profitable and as such lend to a poorly managed
program. It should be understood that both individual animals as well as
whole flock preventative health care programs are needed.
As these factors are portrayed, it is important to understand that no one
management tool can be emphasized over another. Quality assurance requires
that all facets must be understood and managed. It is important that the
producer utilize all available information resources:
nutritionists, feed salesmen, animal science faculty of universities, animal
production research institutes and practicing local veterinarians. This will
allow the formation of a complete sheep management program. “7”
4.2. GENETICS AND SELECTION:
BREEDS:
There are many recognized breeds of sheep world wide. Each breed has
strengths and weaknesses, and your choice of breed or breed combination
should be matched to the goals of your sheep enterprise (meat/carcass quality,
fine wool, milk production, reproductive efficiency, show lambs, colored
fleece, etc.). Breeds should also be chosen based on their adaptability to your
environment, their mature size, and the availability of quality breeding stock
in your region. “7”.
BREEDING CONCEPTS:
Selection is the process that increases the frequency of desirable genes, which
leads to the genetic improvement of your flock. You must decide what trait(s)
are important to your specific sheep enterprise, and have some method to
measure the trait(s). You can then compare the sheep in your flock and select
those that are superior in terms of the desired trait(s) to be the parents of the
next generation.
Develop a system that works for your flock. It can be as simple or complex as
You want to make it. Numbering systems commonly include a code for
The order in which the lamb was born, and the year in which it was born (ex.
9801, or 98-1 might signify the first lamb born in your flock in 1998). Tags
7. 7
May be colored coded to represent year of birth or sire line. Lambs can be
tagged within the first week of life.
Breed associations can assign registration numbers to individual sheep within
purebred, registered flocks. Many breed associations will also help provide
genetic evaluation information on your sheep. Ear tattoos are a permanent
method of sheep identification, but may not be as convenient to read as ear
tags. Paint brands are commonly used for short-term identification until an ear
tag or tattoo can be applied.
In order to make accurate selection decisions, you need to obtain or develop a
record-keeping system. Utilize those production records in combination with
visual evaluation to make your selection decisions. Keeping records is just the
first step. The important step is actually using those records to make selection
and culling decisions to improve the overall genetic make-up of your
flock.”7”
To understand selection, there are some basic genetic concepts that need to be
explained. The phenotype (physical appearance) of a sheep is the result of the
interaction of two factors, genotype (genetics) and environment (climate,
health, feeding & management system). Keep in mind that parents cannot pass
“environment” on to their offspring, but they do pass their genes on to their
offspring. To make improvement, we must separate genotype from
environment, and select those individuals that are genetically superior.
Performance records help us compare the traits of lambs of similar breed, age,
sex, birth type, and management system. Heritability is defined as the portion
of variation due to genetics. Growth, carcass, and fleece traits tend to be
moderately or highly heritable, so significant progress through selection is
possible. Most reproductive traits are low in heritability, which means it is
much more difficult to make genetic progress by selecting for these traits.
Traits that are low in heritability can be improved more by changing your
management system (i.e. reproductive traits can be improved more by altering
your feeding and health programs than through genetic selection).
The steps for developing a successful selection program are:
1. Determine the goals for your sheep enterprise.
2. Select a breed or breeds that are suited for your goals.
3. Determine which traits are most important for meeting your goals.
4. Identify and keep records on all your sheep.
5. Evaluate your ewe flock based on the important traits to determine where
improvement is needed.
8. 8
6. Choose rams that are superior in the traits that your ewe flock needs
improvement.
7. Select replacement ewes that are above your flock average for the important
traits.
The fewer traits you select, the more rapid the progress that can be made. This
is due to the fact that it is harder to find individuals that are superior in many
traits, than it is to find individuals that are superior in a few traits. This is also
related to the correlation between traits. Sometimes the correlation is good,
and sometimes it isn’t. For example, if you select for increased weaning
weight, you will also tend to increase 90-day weight and 120-day weight,
which may be positive.
However, selecting for increased weaning weight may also increase lamb
birth weights. If lamb birth weights are increased too much, it could lead to an
increase in difficult births, which is obviously not desirable.
Since rams have a much greater influence on the genetics of each lamb crop it
is critical to place the most selection emphasis on your rams. The rams and
ewes in your flock each contribute 50% of the genetics of the next generation;
however, since there are often many more ewes in a flock than rams, the
genetic influence of each individual ram is far greater than that of each
individual ewe.
The ram’s importance is compounded if you keep replacements out of him. A
poor quality ram is the most expensive sheep you’ll ever own!
Good rams are key for any breeding program
MATING SYSTEMS:
Purebreeding is the mating of rams of a particular breed to ewes of the same
breed. Breeders of registered sheep must use a purebreeding system. Sheep
producers who sell breeding stock (especially rams) to other producers
generally use a purebreeding system. Some commercial producers use a
purebreeding system in cases where a particular breed is best suited to their
management system and environment.
There are two basic types of purebreeding systems; outbreeding (the mating of
individuals less closely related than the average of the breed), and inbreeding
(the mating of individuals more closely related than the average of the breed).
Most purebred producers utilize outbreeding; however, inbreeding can be a
useful tool to detect the presence of genetic recessive defects in
9. 9
certain bloodlines. The elite seedstock producers also utilize inbreeding
because they may not be able to find unrelated rams that are superior to their
own rams.
Crossbreeding is the mating of rams of one breed to ewes of a different breed.
Crossbreeding is a common practice for commercial sheep producers because
it allows the producer to take advantage of the desirable traits of more than
one breed. For example, many large commercial producers maintain a fine-
wool flock of ewes (to take advantage of the wool quality and hardiness of
those breeds), and mate them to a meat-type ram (to take advantage of the
growth and carcass quality of those breeds). Some breeds may be included in
a crossbreeding system to improve prolificacy or out-of-season breeding.
Systematic crossbreeding involves the mating of rams and ewes of specific
breed types to produce offspring of a specified type. Many of these systems
rely on purebred flocks to supply replacement rams, and in some cases
replacement ewes. The two advantages to systematic crossbreeding are to take
advantage of complimentary breeds, and heterosis (hybrid vigor).
Heterosis is defined as the superiority of the crossbred individual relative to
the average of the purebreds used in the cross. In general, crossbreds tend to
be more vigorous, more fertile, and faster growing than the average of the
purebreds used in the cross. The effects of heterosis tend to be large for traits
that are low in heritability (such as reproductive traits), and small for traits
that are higher in heritability.
Suffolk rams are often used as terminal sires in crossbreeding programs
as they provide growth and muscle which compliments the wool quality
of many white faced breeds.
In general, unless you are selling breeding stock, you should probably be
taking advantage of a crossbreeding system. A crossbreeding system is not
just mating rams and ewes of several different breeds. Rather, a crossbreeding
system specifically targets two or three breeds that compliment each other’s
strengths and weaknesses to best fit your production goals. “7”
5. REPRODUCTIVE MANAGEMENT:
5.1. INTRODUCTION:
Reproductive rate is defined as the number of live lambs born per ewe
exposed for breeding. Optimal reproductive rates are essential to profitable
sheep production. “8”
10. 10
PUBERTY:
Puberty is when ewe first exhibits estrus (heat). Puberty is influenced by
age, breed, genetic selection, body size, nutrition, and season of birth. Most
ewe lambs reach puberty between 5 and 12 months of age. Ewe lambs will
tend to reach puberty their first fall. For this reason, spring-born ewe lambs
tend to exhibit puberty earlier than fall-born ewe lambs. Lambs born early in
the season reach puberty earlier than those born late in the season, due to
their increased age and body weight. High levels of feed pre- and post-
weaning reduce the age at puberty. Single lambs cycle at a younger age than
twin and triplet-born ewe lambs, due to their size advantage. Ewe lambs
from fine-wool, coarse wool, and late-maturing medium-wool breeds reach
puberty later than many of the meat (Suffolk, Dorset, etc.) and hair sheep
(Katahdin, St. Croix, and Barbados Blackbelly) breeds. Finnsheep and
Romanov ewe lambs and their crosses reach puberty at an early age.
Crossbred ewe lambs cycle at a younger age than purebred ewe lambs. “8”
5.2. THE ESTRUS CYCLE
In sheep, the length of the estrus cycle ranges from 13 to 19 days and
averages 17 days. The phases of the estrous cycle are proestrus, estrus,
metestrus, and diestrus. Estrus is the period of time when the ewe is
receptive to the ram and will stand for mating. It lasts approximately 24 to
36 hours. Ovulation (release of eggs by the ovary) occurs in mid to late-
estrus. Metaestrus begins with the cessation of estrus and lasts for about 3
days. Primarily it is the period of the formation of corpus luteum (CL). The
corpus luteum produces progesterone and maintains pregnancy in the ewe.
Diestrus is the period of the estrus cycle when the CL is fully functional.
Proestrus begins with the regression of the CL and drop in progesterone and
extends to the start of estrus. Rapid follicular growth is occurring during this
period. It usually extends from day 4 to day 13-15 of the cycle. Anestrous
refers to a state where the normal cycle stops. “8”
Estrous cycles are usually affected by the seasons. The number of hours
daily that light enters the eye of the animal affects the brain, which governs
the release of certain precursors and hormones. Most sheep are seasonally
polyestrus and short-day breeders. They will begin to exhibit estrus when
length of day begins decreasing. They will come into heat every 16 to 17
days until they are bred or return to anestrus. Thus, the most natural time for
sheep to breed in the U.S. and Canada is the fall (Oct-Nov). Some sheep
11. 11
breeds are less seasonal. They breed almost year-round or have an extended
breeding season. The less seasonal breeds include Dorset, Rambouillet,
Merino, Finnsheep, Romanov, and hair sheep. The most seasonal breeds are
the British long wool and meat breeds. The closer the flock is located to the
equator, the longer the breeding season and the less complete and shorter
will be the seasonal anestrus. “8”.
The signs of estrus in the ewe are much less pronounced than in the cow or
doe and can usually not be detected unless a ram is present. When mature
ewes are in heat, they will seek out the ram and stand still for him to mount
them. Sometimes they wag their tails vigorously. They may nuzzle the ram
around the belly or scrotum and even try to mount the ram. Young ewes
rarely exhibit these behaviors. There is evidence to suggest that rams and
ewes prefer to mate with their own breed, but when there is no alternative
ewes will mate with almost any breed of ram. “8”.
PRE-BREEDING:
Prior to breeding, ewes should be treated for internal parasites and have their
hooves trimmed. If there is a history or risk of abortions in the flock, ewes
should be vaccinated prior to breeding. It goes without saying that only
healthy, reproductively sound ewes should be exposed to rams for breeding.
The udder of every ewe should be examined. Those with hard lumps,
abscesses, or unresolved should be culled. Ewes that prolapsed should not be
kept for breeding, because there is a high probability for reoccurance. Ewes
that did not raise a lamb should be culled. Ewes that are in poor body
condition due to age and/or missing teeth should be culled. Ewes with
chronic hoof problems (e.g. foot rot) should be culled. “8”.
GESTATION:
The average gestation length in sheep varies from 144 to 151 days. The
average is 147 days. Individual pregnancies may vary from 138 to 159 days.
There are breed differences in gestation length. The earlier maturing breeds
(e.g. Finnsheep) tend to have shorter pregnancies than the late maturing
breeds (e.g. Rambouillet). Ewes carrying multiple births tend to have shorter
gestations. “8”.
The period of early gestation most critical to success during the lambing
season is the first 30 days after fertilization. The first 21 to 30 days after
breeding is when embryonic implantation occurs. This first 30 days is when
most embryonic mortality occurs. Thus, anything that can be done to reduce
12. 12
embryonic mortality and should result in more lambs born. Shearing,
vaccinating, working ewes, pronounced changes in feeding practices should
be avoided during the first 30 days of gestation. Ultrasonic pregnancy
scanning can be done on ewes from 35 to 60 days after breeding, depending
on equipment used and operator skill. Nutrition during early gestation is
quite simple. Ewes need only slightly above maintenance levels of nutrition
for the first 15 weeks of pregnancy.
Late gestation (last 4 to 6 weeks) is a critical period for ewe reproduction.
This is when the majority of fetal growth is occurring, placing increasing
nutritional demands on the ewe. Ewes consuming inadequate diets are prone
to pregnancy toxemia and milk fever. Nutrition in late-pregnancy affects the
size and vigor of lambs and the milk producing ability of the ewe. “8”.
5.3. PARTURITION:
There are three stages to parturition (lambing): 1) dilation of the cervix;
2) expulsion of the fetus(es); and 3) expulsion of the placenta. Stage one
usually takes 3 to 4 hours. The birth of a lamb usually occurs within an hour
of less from the rupture of the first water bag. A ewe lambing for the first
time or with multiple births may take longer. If labor takes over an hour for
mature ewes and over 2 hours for ewe lambs, assistance may be required.
The placenta is passed 2 to 3 hours after delivery is finished. In multiple
births, there are separate afterbirths for each lamb. After the lamb is born,
the ewe will lick and nuzzle it to begin the bonding process. “8”.
BREEDING EWE LAMBS:
Ewe lambs should not be bred until they achieve approximately 70 percent
of their mature size (weight). At the same time, care should be taken not to
overfeed replacement ewe lambs. Research has shown that overfeeding pre-
pubertal females (2 to 4 months of age) has a detrimental effect on
mammary development (they deposit excess fat in their udders) and affects
subsequent milk producing ability. Replacement ewe lambs should be fed
separately than market lambs or ram lambs being fed for market.
Pregnant and lactating ewe lambs should be kept separate from mature ewes.
Ewe lambs require extra nutrition because they are still growing. They will
not compete well at the feed bunk with mature ewes and will not gain weight
properly. Ewe lambs that are forced to run with the ewe flock will lose
weight in late gestation and lactation. Single-births are common with ewes
13. 13
lambs, but twins and triplets are not uncommon with the more prolific
breeds. Even when management and nutrition are practices, more lambing
problems will be encountered with ewes lambing for the first time at 12 to
14 months of age. “8”.
While breeding ewe lambs increases their lifetime productivity, it may not
be economically advantageous for all producers. Intensively managed sheep
operations usually benefit from breeding ewe lambs. “8”.
Hormonal Control “8”
A common method of inducing estrus in non-cycling ewes is progesterone-
based therapies. Progesterone prevents the ewe from returning to estrus and
ovulating. It is produced by the corpus luteum (CL) of the ovary following
ovulation and sustains pregnancy. When progesterones are introduced
artificially, they fool the body into thinking it is pregnant and the animal will
not ovulate or come into estrous (heat). When the progesterone source is
totally removed, the body realizes it is no longer pregnant and will ovulate
within a very predictable period. Progestins refer to the synthetic compounds
with the properties of progesterone. These substances mimic the function of
the CL. Progestogens (synthetic analogs of progesterone) can be provided by
feeding (MGA), implants under the skin (Synchro-Mate B®), sponges (or
pessaries) inserted into the vagina, or plastic delivery devices inserted into
the vagina (CIDR).
Intravaginal sponges (or pessaries) have been the traditional method of
inducing and/or synchronizing estrus in ewes. They contain progestagens
that are effective at lower doses than natural progesterone. Two types of
sponges are Chronogest (FGA) and Veramix® (MAP). Intravaginal sponges
are usually inserted over periods of 9 to 19 days and are used in conjunction
with PMSG, injected at the time of sponge removal or 48 hours prior to
sponge removal. Intravaginal sponges have high retention rates (>90%) and
females usually exhibit estrus 24 to 48 hours after removal. Responses to
intravaginal sponges have varied according to breed, protocol, co-treatment,
management, and mating system.
CIDR™ (controlled internal drug release) devices are made of progesterone-
impregnated medical silicone elastomers and were developed in New
Zealand. Protocols for the use of CIDR™ devices is usually identical to
protocols for intravaginal sponges. Research has shown that CIDR™
devices and intravaginal sponges yield similar results.
14. 14
Synchro-mate-B® is a cattle implant that contains 6 mg of the synthetic
progestagen norgestomet. One-third or one-half of the Synchro-mate-B®
implant is typically used in ewes. Implantation periods range from 9 to 14
days. Two days before the end of the implantation period, injections of
PMSG and /or PGF2a are usually given.
Melengesterol acetate (MGA®) is an orally active, synthetic progestagen
developed and used to suppress estrus in feed lot heifers. The use of this
product requires the feeding of a supplement containing MGA® once or
twice daily for a duration of 8 to 14 days. Protocols usually include co-
treatments with PMSG, P.G. 600® or Ralgro® (zeranol). Ralgro® is a
commercially available growth promotant for cattle and sheep with estrogen-
like effects on LH and FSH concentrations. P.G. 600® is the only veterinary
grade source of PMSG readily available in the U.S. Estrus responses to
MGA feeding vary, but are usually higher with co-treatment.
Prostaglandin-based protocols are only applicable to cycling ewes and are
restricted to use during the breeding season. The two commonly used
products are Lutalyse™ (PGF2a) and Estrumate® (cloprostenol).
Prostaglandins cause regression of the CL, telling the body than no
pregnancy exists. The ewe will ovulate within a very predictable time. When
a single treatment of prostaglandin is given to a flock of cycling ewes, 60 to
70 percent of the flock will exhibit a synchronized estrus beginning 30 to 48
hours later. A double injection system (11 days apart) is most common in
sheep.
Melatonin treatments have been shown to be an effective method of
inducing estrus in non-cycling ewes. Melatonin is called the "hormone of
darkness," because it is released by the pineal gland during the night.
Treatment with melatonin therefore mimics the short days of fall and
induces estrus after a minimum of approximately 35 days of treatment.
Light Control
Controlled lighting can be used to initiate estrus. Short-day breeders like
sheep may be programmed to cycle if they are maintained in a light-tight
building where the photoperiod is reduced gradually over an 8 to 12 week
period. Rams should be exposed to the same light regiment to obtain high
fertility. Light control is usually impractical for most producers.
15. 15
Ram Effect
The "ram effect" is when non-cycling ewes are stimulated to ovulate by the
sudden introduction of a ram or "teaser." Rams produce a chemical
substance called a pheromone, the smell of which stimulates the onset of
estrus. When ewes and rams are in constant contact (sight or smell), the
pheromones are much less effective at inducing estrus. Ewes that are not
cycling when a ram (or teaser) is introduced will ovulate in 3 to 4 days. This
first ovulation will be a "silent" heat, which cannot be detected by the ram.
Following this silent heat, there will be two normal estrus peaks, with some
ewes cycling around day 18 and the remainder around day 25. Ewes that do
not conceive at either of these times may return to heat in another 17 days. It
is expected that 60 to 70 percent of the ewes will conceive at the first normal
estrus. Of the remaining ewes, 60 to 70 percent should conceive at the
second estrus.
Although recommendations vary, rams should be isolated from ewes for at
least 6 weeks in order for the ram effect to work. Ewes must have no contact
with rams by either sight or smell, which means that they must be separated
by distance. The ram effect is not as effective with ewe lambs. The ram
effect is most effective during the transitional period when ewes have not
begun to cycle, but are almost ready to. Breed of ram can affect ewes'
response to the ram effect, with the less-seasonal breeds being more
effective at bringing non-cycling ewes into estrus.
The great value of the ram effect is the synchronization of estrus activity
which will result in large numbers of ewes ovulating, conceiving, and
lambing in a relatively short period of time. To be effective, it is important
to have adequate numbers of young, healthy rams. Teaser (vasectomized)
rams or testosterone-treated weathers can also stimulate the ram effect.
6. PROGRESS REPORT:
6.1. BREEDING:
Consumer preferences, our selection criteria, and suitability to a
production management scheme were evaluated. During initiation phase we
concluded to follow two directions:
First: Pure breeding since a particular breed is best suited to our
consumer preferences and environment, it is Barki breed.
16. 16
Second: Crossbreeding, Fenn rams to Osimi ewes. It allows us to take
advantage of the both desirable traits of the two breeds. In general,
crossbreds tend to be more vigorous, more fertile, and faster growing
than the average of the purebreds used in the cross.
Crossbred ewes tend to have an advantage over purebred ewes in
reproductive traits.
6.2. IMPORTANT TRAITS MEETING OUR GOALS:
Meat/carcass quality,
Reproductive efficiency, and,
Adaptability to our environment (climate, health, feeding &
management system).
WHY FINNSHEEP:
The Finnsheep is an ancient breed, native to Finland, also known by
the names of Finnish Landrace or Finn. It is one of several North
European short-tailed Landrace breeds. “9”
NewZealand Finn animals have a long lean carcasses. A proportion of
Finn genes within a composite ewe breed will generally decrease
fatness in lamb carcas, a desirable trait. “9”
Gestation
The average gestation length in sheep varies from 144 to 151 days.
The average is 147 days. Individual pregnancies may vary from 138 to
159 days. There are breed differences in gestation length. The earlier
maturing breeds (e.g. Finnsheep) tend to have shorter pregnancies
than the late maturing breeds (e.g. Rambouillet). Ewes carrying
multiple births tend to have shorter gestations. “8”.
In “9” it is stated that 11 good reasons for changing to New Zealand
Finnsheep (High fertility; Fast lamb growth; Long, lean carcasses;
Fine, lustrous wool; Good mothering ability ;Facial eczema
resistance; Easy lambing ;Early sexual maturity; Highly intelligent;
Profitability ;Constitution.)
6.3. RECORDKEEPING SYSTEM:
17. 17
Measuring traits and comparing animals requires an identification and
recordkeeping system. We selected the most common method of
individual sheep identification which is ear tags.
Record keeping systems commonly start with the birth of the lamb.
Lamb ID, birth date, birth type (single, twin, triplet), sire, and dam are
recorded along with other information critical to our sheep enterprise
(other items that may be found in production records include: birth
weight, weaning weight, post-weaning weight, average daily gain,
medication records, fleece traits, information on difficult births,
comments about the dam’s disposition or mothering ability, comments
about the lamb’s physical appearance, and more). Keeping records is
just the first step. The important step is actually using those records to
make selection and culling decisions to improve the overall genetic
make-up of your flock.
In order to make accurate selection decisions, you need to utilize those
production records in combination with visual evaluation to make your
selection decisions.
With our own numbering system, we developed a system that works for
our flock.
But actually after implementation our system needs to be modified by
adding codes and colors that can facilitates measuring of traits and
comparing animals.
6.4. OVERCOMMING DIFFICULTIES IN GOALS
ACHIEVEMENT:
Satisfactory results were not obtained under natural breeding
conditions.
We were about to end our project several times, since the project
expenditure was much greater than the project income. Thousands of
pounds were lost.
In spite of the money losses , it was obvious that we achieved a
technical contribution in purebreeding, crossbreeding as well as
reproductive management regarding the pre selected target traits.
Therefore it was not easy to end our project. We decided to discuss ,
analyze, and solve our problem.
Through a seminar held by our EASGADA we concluded that the
reasons for our money losses were : the high nutrition cost for the
flock and the low rate in lamb reproduction.
18. 18
The solution was to transfer from the natural breeding to artificial
manipulating of the reproductive cycle of sheep.
We applied progesterone-based therapies through sponges inserted
into the vagina , then hormonal Control When the progesterone source
is totally removed, the body realizes it is no longer pregnant and will
ovulate within a very predictable period.
Appendices 1&2 show the obtained results after overcoming
problems.
REFERENCES
1- FAO (Food Agriculture Organization Of The United Nations)
“Production Systems in the Near East Region, A Training Manual for
Characterization & Analysis”, Cairo, 2002.
2 -William G.F. Cornish with Board of Directors of the Saudi Computer
Society (SCS), “Strategic Plan for SCS”, Riyadh, KSA, 1993
3 - Talaat Harb M Refaat, “Information & Computer Systems Department
Business Plan”, United Projects for Maintenance & Operation Company
(UPMOC), Riyadh, KSA, 1993.
4- Talaat Harb M Refaat, “Job Description for UPMOC”, Technical
Report, Riyadh, KSA, 1992.
5 - William H., Roetzheim, “Structured Computer Project Management”,
Prentice Hall, New Jersey, 1988.
6 - FAO, “Food and Agriculture Organization of UN - Vacancy
Announcements”, Rome, 1993.
7- S.R.R. Haskell, J.M. Geske, and D.J. Resch,“ Sheep care and
management” , University of Minnesota Extension Service,
8- Susan Schoenian, Sheep & Goat Specialist, “Reproduction in the Ewe”,
Western Maryland Research & Education Center, Maryland Cooperative
Extension, Date of last revision: 19-Aug-2005
9- The New Zealand Sheep breeders' Association “The New Zealand
Fennsheep”
10- Marlon Knights, Todd Hoehn, Deborah Marsh, Paul Lewis, Joy
Pate,Alison Dixon and Keith Inskeep, “Reproductive management in the
ewe flock by induction OR synchronization OF ESTRUS” West Virginia,
Agricultural and Forestry Experiment Station, Morgantown.
11- David L. Thomas, “Breeding Ewe Lambs or Getting the Most out of
Ewe Lambs”, Department of Animal Sciences University of Wisconsin-
Madison.