REPRODUCTION IN
SHEEP AND GOATS
Ethiopia sheep and goat productivity improvement program
Outline
1. Introduction
2. Anatomy & Physiology of
reproduction
3. Reproductive performance
4. Management of reproduction
5. Examination of reproductive
soundness
1. Introduction


Reproduction – process producing
offspring.
Small ruminant productivity result of
interactions between:
 reproductive efficiency,
 growth rate,
 yield and
 quality of desired products
Introduction …

Reproductive rate (or reproductive efficiency)
can be defined as the number of offspring
raised & marketed per ewe or doe joined with
ram or buck

Reproduction is necessary for:
 Replacements;
 Expand flock size for meat, milk, skin & fiber
production
 Excess animals for sale
2. Anatomy & Physiology of reproduction

The male reproductive
system consists of
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testicles which produce
sperm and sex hormones,
a duct system for sperm
transport,
accessory sex glandsproduce semen
the penis, or male organ of
copulation, which deposits
semen in the female.
Structure of the male reproductive tract
Function





Testes produce the male gametes (spermatozoa) and secrete
the male sex hormone.
The scrotum is a muscular sac containing the testes and
plays a major role in temperature regulation(3 to 5oC below
body temperature )
Epididymis: located in the testes, and is a place where sperm
is stored and mature to a stage capable of fertilization.
Vas deferens: The vas deferens is the duct that rises from the
tail of the epididymis into the abdomen of urethra at the neck
of the bladder
Penis: The final part of the male reproductive tract and its
function is to deposit semen into the vaginal tract of the
female
Single versus split scrotum
Split scrotum.
Partially split scrotum.
Normal Scrotum
Female Reproductive tract of small ruminants

Female reproductive
tract:
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
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Vulva
Vagina (copulatory organ)
Cervix
Uterus (Body & horn)
Oviduct (fallopian tube)
Ovary
Structure of the female reproductive tract
Function

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

Ovaries; produce ova (egg), and secrete female
reproductive hormone (Progesterone and
estrogen)
Oviduct; Transport ova from ovary and Sperm from
uterus. It is site of Fertilization
Uterus; Has two horns and body, Provide proper
environment for the development of the
fetus
Cervix; transport sperm, block bacterial envision
during pregnancy
Vagina; site of semen deposition during natural
mating
Normal reproductive events
Puberty (sexual maturity)
st
 Age at 1 lambing/kidding
 Heat periods (estrus) and ovulation
 Mating and fertilization
 Gestation period
 Parturition
 Lactation

Puberty & age at 1st lambing/kidding

Puberty is the time when reproductive organs
become functional i.e.
 when a ewe/doe first exhibits estrus (heat).
 It is complete separation of prepuce and the penis
occurs
 motile spermatozoa production commences

Animals should attain a minimum body weight (2/3
of mature body weight) before they are mated to
avoid growth retardation
Puberty & age at 1st lambing/kidding

puberty occurs at :
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
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about 8 months (vary between 5 & 12 months) in sheep;
at about 7 months (vary between 3 to 12 months) in goats
Age at which puberty is attained determined by:
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Species, genotype or breed
nutrition
season, health and other environmental factors (e.g.
climate)
presence/absence of a sexually mature male
Puberty Cont’d…

As a result, large variations occur b/n
and within breeds and the age at first
lambing may also vary

Thus faster growing animals will reach puberty
earlier than slow growing

In both males and females, puberty generally
occurs when animals reach 45–60% of the
mature weight for the breed
Puberty in Menz sheep in the Ethiopian highlands

Ewe lambs attain puberty (first oestrus) at:
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Menz rams reach puberty at:
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350 days (11-12 months) of age;
16.9 kg mean weight (56% of mature weight)
an average age of 288 days (9-10 months),
19.3 kg of body weight, and
21.5 cm scrotal circumference
Onset of puberty was earlier with higher weaning
weight

poor nutrition can delay puberty by one season
Estrus and ovulation

Estrus, or heat, is defined as the time
when the female is receptive to male

Sheep and goats in the tropics tend to
experience estrus cycles throughout the
year:

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In sheep the cycle occurs every 14 to 19 days with a
mean of 16 days
In goats the cycle takes about 19 days to complete,
varying between 17 and 21 days
Sign of estrus:
Sheep
Goats
Restlessness
Restlessness
Frequent urination
Frequent urination
Going off feed
Going off feed
Decreased milk production
Seeking out the ram and standing to
be mounted by him or other ewes
Rapid tail movement
Occasionally mounting other does
Raised tail in the presence of the ram
Constant tail wagging from side to
side termed as tail flagging
Constant vocalization/bleating
Standing still when being mounted by Standing still when mounted by
ram
buck
Sign of estrus…
Sign of estrus…
The surest sign of heat is ‘standing heat’
Estrus detection techniques

Using a teaser ram or buck.

Tying an apron made of leather or canvas around the body of a ram/or
buck to prevent mating.

Using a teaser with a marking harness: When a ram/buck with a
marking harness mounts a female in estrus, some of the marking
pigment will be transferred to the rump of the female


In goats, tail flagging can be stimulated by placing one’s hand on the loin
and pressing down slightly. This mimics the pressure of the buck during
mounting.
Some producers in southern Ethiopia have indicated that a ewe in estrus
will stand immobile when pressed by hand in expectation of being
mounted.
Estrus detection techniques….
The estrus doe
don’t escape
from buck.
Buck is checking
the estrus does
through smell.
Estrus detection techniques…
The buck can detect does that A ram wearing a
are in heat but can not breed crayon marking
harness.
them. Apron can be made
Apron tied around body
from canvas, skins and
of buck
hides. Must be kept clean!!
Monthly distribution of lambing activity in
Menz sheep under natural mating
Timing of mating and lambing/kidding

Lambing/kidding during dry season

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Lambing/kidding during short rains

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(mating during August/Sept) is unproductive.
(mating Oct/Nov) is best for overall productivity.
Lambing/kidding during main rains

(mating Feb/March) is the second best option.
Ovulation

Ovulation rate – the no of eggs released at ovulation

Multiple births are due to the release of more than one
ovum at ovulation

It is determined by genetic factors, breed, body condition
of the dam

A well fed mature dam is more likely to produce twins
than a poorly fed dam

This has led to the practice of “steaming up”: feeding ewes/does
particularly well for 1 to 2 months before mating
Methods of mating
Several methods of mating:
1. Random mating: one or more males are left permanently
with the females.

Mating and lambing/kidding take place all year round

Maximum reproductive potential of animals can be
exploited

There is no rotation of rams:
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Difficult to organize selective breeding
Same ram stays for more than 2 years, which can lead to
Inbreeding.
Mating methods…
2. Organized mating: ewes/does put to the ram/buck
at regular intervals (every 7-9 months) for a
predetermined period of time (40-45 days on
average).

There is usually one ram/buck to every 25-30 ewes/does.
3. Controlled mating: a group of ewes (25-30) is left
with one ram for a predetermined period (40-45
days on average)
How can mating be controlled?

Separating males from females. This can be done by:


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Use of protective materials (apron) that can prevent
rams/bucks from serving females:

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This method does not need separation of males from females
Penis string as practiced by the Afar:
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keeping males in the shelter, or
grazing away from females
Can sometimes cause injury
Castration: castrating unwanted ram/buck
Selecting for body width and strong legs
Many small ruminants have a sharp “v”
shaped chest.
This leaves little space for rumen and fetuses
in the does and ewes.
A wide, nice chest area is needed.
Animals will be able to hold much more food,
will digest the food better and the offspring
will grow faster.
Legs should come straight down from the body
so they can support the weight of the animal.
Selecting for correct body shape
Gestation

Average gestation length in sheep/goat varies from
144 to 155 days, the average being 150 days.

There are breed differences in gestation length.
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Small and dwarf breeds have short gestation periods
Earlier maturing breeds tend to have shorter pregnancies than the late
maturing breeds
Ewes carrying multiple births tend to have shorter
gestations.
Final 2 months of gestation is critical – provide
supplementary feeding
Lactation

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Ewe/doe with good milk yield
Adequate feeding
All available high quality feeds must be
reserved primarily for ewes/does at the
end of gestation and at the start of
lactation
Intersex goats

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Occasionally, intersex (or pseudohermaphrodite) goats are born with
a mixture of male & female sexual
organs
The dominant gene for polledness is
linked to the gene for intersex
 Polled males x polled females =
high chance of intersex offspring
Intersex (hermaphrodite) goat
3. Measurements of reproductive performance
3.1 Age at puberty; Delayed age at puberty reduce life time
productivity of ewe/doe
3.2 Age at first lambing: usually 12-24 months. It is late in
animals in harsh environments
3.3 Post-partum interval (PPI): Time b/n parturition and onset
of the next cyclic ovarian activity (av. 83.5 days).

Affected by: Nutrition
 Suckling
 Parity
 breed
3.4 Parturition Interval (lambing/kidding interval): ~8mths

Requires excellent management
3.5 Fertility is number of ewes lambing or does kidding divided
by the number of ewes/does mated.
Measurement….
3.6 Litter size: number of lambs /kids born at a
time.
 Range 1.08 – 1.75, Av~ 1.38
 It is combination of ovulation rate and
embryo survival.
3.7 Annual Reproductive Rate (ARR):
 is the number of lambs or kids weaned per
ewe or doe of reproductive age per year.
 best estimator of reproduction & production
of sheep/goats.
Ways of assessing reproductive rate
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Fertility=number of ewes lambing or does kidding
divided by the number of ewes/does
mated.
Prolificacy = litter size = number of lambs born
alive/number of ewes lambing
Fecundity = Fertility x prolificacy = number of
lambs born alive/ewes available for
mating
Lambing rate = number of lambs born/ewes
available for mating
Weaning rate = number of lambs weaned/ewes
available for mating
Causes of poor reproductive
performance in sheep
Reproduction rate is influenced
by:

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Litter size
Young mortality
Interval between parturitions
Litter size:

Menz sheep = <10%

Washera = 17-25%

Horro = 35%
Parturition interval:

Indigenous sheep and goat breeds are able to
lamb at 8-9 month intervals!!!
Effect of birth weight on lamb
mortality in Menz sheep
4. Management of reproduction

Nutrition
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Early pregnancy: the goal of feeding should be to maintain BCS
Mid-Pregnancy: goal is slight increment in body weight
Late Pregnancy: goal is to increase nutrient intake to support fetal
growth
Season of lambing (lambing in short & long rain
seasons)
The male or ram/buck effect and estrus
synchronization
Use of exogenous hormones to synchronize breeding
during mating season

This will increase ovulation rate and subsequent multiple
births
5. Examination of reproductive soundness
Physical Examination includes:-
1.
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health history.
physical soundness, particularly of feet and legs.
Free from hereditary disease.
Smooth hair coat (evidence of malnutrition
and chronic infection)
Body condition score
Shape and size of testicle, scrotum, examination of sheath and Penis
Scrotal circumference and diameter:-
2.

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Measured at the widest part (use flexible measuring tape)
Ram with large testicle produce more semen
Large size breed 30-31cm
Breed
Menz
Horro
Age
6 months 9 months puberty
14-15
19.7-20.1 23-23.5
13.5-14.5 20-20.5
23-24
Measuring scrotal size
Examination of reproductive soundness...
3.
Semen evaluation:
Collection and evaluation of an ejaculate
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Motility
Morphological abnormality
Viability
Test of libido:
4.
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Determine ram/buck desire to mate ewe/doe
Males are exposed to oestrus females, and their
breeding activity is recorded over a period of two
weeks or more.

When should a ram/rbuck start
breeding?


at 7 to 8 months of age provided he has an acceptable size for
his breed and has BCS of at least 3.
what is the optimum life of a
breeding ram/buck?

A Ram/buck could start breeding The optimal
breeding age is over 7 months and up to 5
years
Examination of reproductive soundness...
Check width of udder and udder attachment
A doe with faulty udder
full udder, a strong
rear udder attachment,
large teat pointing
straight down
Points for Discussion

How do farmers/pastoralist identify does/ewes
that are in heat?

What advisory services shall farmers
/pastoralists get from extension agents on
sheep/goat reproduction?

Discuss other experiences you had with
reproduction of goats/sheep!!
Thank
you!!!