Age at Puberty and First Service

1. Age at Puberty and First Service
Zamzam University
Faculty of Agriculture
Animal Husbandry

2. • Definition of Puberty
• Puberty is the time when the reproductive
organs of animals become functional.
• In males, puberty is defined as the age at which
first ejaculation takes place (8- 12 months).
• In females, puberty can be defined as the time at
which the first functional estrus takes place and
the earliest age at which reproduction can occur

3. • Female sheep and goats may reach puberty at
6 to 10 and 5 to 8 months of age respectively.
But puberty does not necessarily mean the
time for breeding.
• The females should not be permitted for
mating before 10-12 months of age, depending
on the body weight of about 50- 70% body
weight of mature female.
• The age at which first mating takes place is
known as age at first service (it is the actual
mating to produce offspring).

4. • The age of puberty varies according to:
• 1. Breed- usually smaller breeds reach earlier their
age of puberty than larger breeds
• 2. Nutrition- poor nutrition will delay and good will
enhance the occurrence of puberty probably
related with the growth and development of the
body and reproductive organs.
• 3. Health- good health condition enhances the
occurrence of puberty
• 4. Presence and absence of sexually mature males-
the sight, sound and smell of males induce sexual
maturity in females

5. Importance of pregnancy testing
• Methods of pregnancy testing
• In previous days non-return rate (NRR) was
used to test pregnancy in small ruminants.
Female animals that are not returning to
estrus after first mating (service) during the
period of 60-90 days are termed as non-return
animals (“pregnant” animals”).

6. 2. Clinical methods
• In this method, uterus is palpated through rectal wall
to detect the uterine enlargement occurring during
pregnancy.
• Used for pregnancy diagnosis of large animals (cow,
mare, and buffalo)
• It is impractical for ewes and does because the size of
rectum in ewes and does is too narrow to insert
hand.
• Radiographic (X-ray)
• It is based on the identification of the fetal skeleton
on an X-ray, i.e. when the skeleton is displayed or
seen on an X-ray plate, the animal will be considered
as pregnant.

7. • Ultrasonic fetal pulse detection
• The instruments are placed outside of the
ewe/doe near the front of the right teat and
ultrasound waves are beamed toward the
uterus.
• Laboratory methods
• It rely on the determination of hormones
produced by the maternal tissues and fetus.
Hormones are determined from the blood, milk
and urine of the dam.
• The hormones that are commonly use

8. Artificial Insemination (AI) in Sheep
and Goats
• Artificial insemination is a process whereby
the sperm from a male is collected and used
to inseminate a female artificially (or by man).
In AI, sperm may be used fresh or can be
frozen and stored for long periods in liquid
nitrogen at -196 oC

9. Advantages Artificial Insemination
Reduces transmission of reproductive diseases,
because semen collection and preparation for AI
is carried out under most hygienic conditions
It increases the use of outstanding sires: rapid
improvement of the flock can be achieved
because semen that may be ejaculated in one
mating can be used for many inseminations

10. • It is cheaper to import/transport semen than live
males- reduces investment in large number of
males and reduces risks of illness or death of
male animals.
• • Reduces cost of feeding and management of
more males, because few males are sufficient for
many females in AI.
• • It is cheaper to import semen than importing a
live animal- Extensive dissemination of superior
genotypes can be achieved, because every
farmer can afford to buy semen than live animal

11. • Disadvantages
• The disadvantages are few, if properly done
• Requires extra equipment and well trained
personnel for proper service
• Detection of heat may be a difficult task when
animals are kept in fenced pasture with out an
attendant
• It requires frequent handling of the ewes or does
and dedication of time during the breeding
season
• It results in a lower conception rate, thus
requiring a second, or third insemination

12. Embryo transfer (ET)
• Embryo transfer (ET) is one of the recent
advances in manipulating reproduction in
females and it can be defined as the removal
of an embryo from a donor female (usually
superior genetic merit) and its placement in
the uterus of a recipient female (possibly with
inferior genetic merit).

13. Procedures of ET
• 1. Super-ovulation
• A female animal (donor) is induced to super-
ovulate.
• 2. Insemination
• Following super ovulating treatment, the donor
should be closely observed for signs of estrus.
Then it can be inseminated two to three times at
12-hours interval to ensure fertilization of all ova.

14. • Embryo recovery (collection)
• This can be carried out six days after
insemination. It can be either surgical or non-
surgical.
• 3.1. Surgical recovery
• In this method, the abdomen of the donor female
is opened by surgery. Then the oviduct or uterine
horns are flushed to collect the embryos. Because
of the adhesion effect (damage), the animal may
not be used for repeated recovery (collection). It
has also more risk to the health and life of the
animal.

15. 3.2. Non-surgical recovery
• In the non-surgical method, a catheter (plastic
tube) is passed into the uterus through the
cervix. It is desirable because there is less risk to
the life and health of the donor.
• Hence, it is used in repeated recovery attempts
to reduce incidence of reproductive tract
damage

16. • 4. Embryo storage
• The collected embryo can be kept for 20-30 hrs at
ambient temperature, but loose their viability after
42-72 hrs. Therefore, it is important to preserve the
embryos, by freezing at the temperature of liquid
nitrogen (-196 o C) if someone wants to keep for
long time.
• 5. Embryo transfer
• The embryo can be transferred non-surgically using
the same technique as is used in AI (injecting into
the uterus through the cervix with a pipette).
• They are deposited into the uterus through cervix of
the recipient female, when she is in estrus. This
provides favorable environmental condition for the
embryos.

17. Market Classes and Marketing of Live
Animals
• Market Classes (Grades)
• With market classes/grades it is simply mean type of
animals produced or raised for marketing. The market
classes of animals or type of animals are listed below
• 1. Feeder lambs/kids
• These are animals that grow on milk of the dams and
grass alone. Producers that grow young animals on
milk and grass alone and sell them at or after weaning
are termed as feeder lamb/kid producers. Growing
animals on the milk of the dams and gazing are the
cheapest form of feeding animals.

18. • Finishers
• Feeder lambs/kids are then fattened to produce
high quality finishers at the age of 12 – 18 months.
• The finishers are mostly produced by commercial
fatteners, because the system may not be feasible
to farmers, due to additional labour, feed and
facility requirements (farmers may not afford to
feed expensive feeds). Secondly farmers may be in
an urgent need of money, so they may prefer to
sell their animals at early stage of growth when
animals attain certain age or body weight

19. • Slaughter Animals
• Farmers may produce cull animals like
rams/bucks, castrates and old or sterile
ewes/does. Slaughter animals may be also
produced by specialized fatteners who buy
matured animals and fatten them for some
time, usually for 3 months.
• Pure–bred Breeding Stock
• These are animals with superior genetic make-
up and used as breeding stock. The breed type
could be for wool, milk or meat production

20. Marketing of Live Animals
• Animals can be marketed through different ways
• 1. Direct dealing between a seller and a buyer
(direct negotiation)
• Animals may be sold at a farm/village level or local
market to consumers, middle- men (dealers),
fatteners (in case of feeder lambs/kids), processing
plants (in case of finishers) or exporters (in case of
finishers and breeding stock). This system of
marketing gives an opportunity to the buyer to look
into the individual animals and to come up with
immediate decision (to buyer or not to buy)

21. Order buyers
• Processing plants, fatteners, hotel owners and
exporters may buy animals through order or through
an agreement between the producers and themselves.
• The producers may make an agreement with the buyer
to deliver/supply animals regularly. It favors the
producers either to produce more animals or to limit
the number of animals based on the demands of the
buyers.
• Moreover, the producer is assured about the sale of the
animals and would not worry about the market
situation.
• The producers receive fixed prices through out the year
without price reduction by the buyers because of an
agreement.

22. Marketing through a commission firm
(Commercial Service Companies)
• There are companies/firms taking animals
from the producer on the body weight basis
and sell them for other producers, processing
plants, fatteners and exporters.
• They do not buy animals by themselves,
because they do not want to have a risk of
death of animals during transporting and the
loss that may incurred with death of animals.

23. • The firms may have facilities to transport
animals to distant places.
• They are mostly from big cities who may know
processing plants, fatteners and exporters better
than the producers. So they can easily dispose
animals and for the services they provide, they
charge a commission (fee).
• Marketing through commission firms will not
work for pure-bred breeding stock because they
do not know the history of animals.

24. Auction sale
• Animals may be sold on per head basis or on
small groups. The small group of animals gives
the opportunity for the buyer to closely observe
the animals and decide to bid or not to bid.
• The initial price may be suggested by the owner
and then the buyers (auctioneers) are asked to
propose a bid. Because of the competition
between buyers, normally animals are sold to
the highest bidders.