Breeding management
of sheep
The reproductive activity of sheep is
stimulated by variations in the length.
In northern hemisphere where day length varies with the season of the year
oestrus takes place mostly from July to
October as opposed to the tropics where there is only little variation in the length
of day and the oestrus eycle resources through the yea. Ewes come on hest (oestrus) at regular intervals of about
18-21 days if not bred (Oestrus eycle). The oestrus period (the only period the
female can accept the male) last for about 3 days or 72 hours.
Age at puberty
Sheep attain puberty at 5-6 months
sexual organ of rams already functional at this time. However rams should not be used
before age 11/2 years while ewe lamb could be bred at 9-12 months. It is good
practice to replace breeding rams with newly selected ones after each breeding
season.
Easy handling
Handling is easier animals can be
caught and flock management is improved because it allows for certain
management practices such as isolation of rams outside breeding season and
weaning to be carried out. Other management practices such as identification
docking and castration can be done easily.
Feeding of
supplements is easier
This is because animal of the same age
physiological state such as yearlings gestation fattening weaning can be kept
in the same group. This improves performance since each animal receives
supplement meant to meet its particular production requirement.
Provision of housing leads to overall
improvement in the performance of the animals. Sheep housing can vary from a
low mud-wall building with thatched roof to a prick or concrete wall with
corrugated iron sheets roofing. Also corruaged iron walled building could be
used. Such housing should be located on a well-drained soil. It should be well
ventilated to avoid dampness. The floor can be of cement or rammed earth it
should be easy to clean and should be covered with good bedding material such
as straw or wood shavings which can be changed from time to time.
The building may be divided into pens.
Floor space requirements for lambs and adult sheep are about 0.4 and 1.7m2
respectively in addition floor space should be provided for feed and water troughs. There should be more
pens per building or more than one building with separate for males females and
weaner.
A store and a hay could form part of the
building. Alternatively the hay barn could be a separate structure. A run
(enclosure) made of chain link wire waist-high may be construed in front of the
pens. Divided into at least two sections for males and females if housed in
different pens in a single building. Water supply can be from a well tap and
bore hole or river. It should be clean and in sufficient quantity.
Feed and water troughs should be
provided in every pen, either built-in or moveable type. A rectangular feed
trough measuring 4 x 0.3 x 0.15m is adequate for 10 adult sheep. Simple feed
troughs could be made by cutting a drum lengthwise into two halves. If cut
drums used the edges should be made blunt to avoid injuries to the animals.
Large plastic basins are better as water troughs a age unlike metal drums they
do not corrode.
A foot-bath is required for the
prevention and treatment of foot-rot, a very common problem with sheep on wet
grounds. The most common types is the walk-through type which is a shallow long
receptacle. Where a small number of sheep is involved a bucket of basin may be
used.
A dip is an essential structure in a
sheep farm. The walk-in short-swim type is the most common. In this type the
animal enters the vats are best made with concrete.
A vat measuring 6 x 1.2 x 0.75m has a
capacity of about 2000 litres. It is necessary to put a roof over the vat to
prevent rain from diluting the chemical. In small-sized flocks a 200-liter drum
opened at one end can be used. The animals are immersed, one at a time in the
dipping solution contained in the drum for about 30 seconds. A knapsack sprayer
can also used.
Handling sheep
Handling in sheep management could
simply be defined as a way in which the husbandman drag, push or carry the
animal to where they will be fed, administered drug for research purpose for
observation and study of their behavior. Good handling of small ruminant will
prevent the animal from being injured and
guarantee the safety of the handler. If sheep are to be caught and
handled for any reason they should be confined to a small corral or shed
appropriate way to handle sheep are:
1.
Husbandman
or attend and must know how to relate with the animals since animal communicate
in one way or the other e.g. if a ram use its leg to scratch the ground continuously
it simply means it is ready to attack anybody.
2.
Sheep
may best be caught around the neck by the hind leg or by the rear flank.
They should be carried by allowing the
hind leg to fold towards the front while using the other hand to hold the remaining
leg. Never should they be caught by the wool.
3.
The
young animal should be carried close to
the chest depending on the age weight and body conformation.
Generally
what matter most is the good relationship with the animals as this will
facilitate good handing.
Breeding management
of sheep
The reproductive activity of sheep is
stimulated by variations in the length.
In northern hemisphere where day length varies with the season of the year
oestrus takes place mostly from July to
October as opposed to the tropics where there is only little variation in the
length of day and the oestrus eycle resources
through the yea. Ewes come on
hest (oestrus) at regular intervals of about 18-21 days if not bred
(Oestrus eycle). The oestrus period (the only period the female can accept the
male) last for about 3 days or 72 hours.
Age at puberty
Sheep attain puberty at 5-6 months
sexual organ of rams already functional at
this time. However rams should not be used before age 11/2 years while
ewe lamb could be bred at 9-12 months. It is good practice to replace breeding
rams with newly selected ones after each breeding season. A minimum of 6 rams
should be in a flock of 100 ewes feeding of breeding rams should be improved 6
weeks before the breeding season
Estrous cycle
The estrous cycle in the ewe is 16-17
days with estrous duration being 20-42 hours i.e. approximate 1-2 days average
being 30 hours. Ovulation occurs in the ewe from about 24-30 hours after the
onest of estrous after 16-17 days. There are no visible signs of heat in the
sheep except the acceptance of the ram or teaser with an apron. This is the
only external detection of heat in ewes. In flock mating, rams should be left
in flock for 6-8 weeks to ensure (3 estrous cycles) that all ewes are bred.
After that they are withdrawn. Rams should be joined with ewes 2 weeks after
lambing. The ewes will still be nursing their lambs at this stage but this does
not prevent them from getting pregnant. Batch lambing could be ensured by
synchronization using progrestogne virginal sponges. Ewes lambing within 2-3
weeks interval would be synchronized. This consists of inserting the
progrestogen in-plants into their vaginal for 12 days. Introduction of rams
to treated flock 2 days before sponge
removal would enhance ovulation. Mating does not begin until sponge removal.
Estrous normally spread over 4 days
following sponge removal. Non-pregnant ewes would return to estrous 16-21 days
following sponge removal. Gestation period in ewes would return to estrous 16-21 days following
sponge removal. Gestation period in ewes is about 5 months i.e. 152 days.
Repeat breeder ewes those weaning poor weight lambs and old ewes above 7 years
should be culled.
Signs of oestrus
-
Uneasiness
-
Frequent
urination
-
Tail
shaking/
-
Swollen
Vulva with a little mucus discharge.
-
Sometimes
the females could be seen mounting other animals themselves
-
Bellowing
Mating methods
There
are two main mating methods in sheep
Natural service
This involves the natural copulation
of the ram to ewe. In Nigeria where most females and males are kept together
there is no restriction to mating, where females are kept separately from males
careful observation particularly in the early morning should be carried out to
notice females on heat so as to breed them.
Artificial
Insemination
This has recently been given more
attention but is rarely practiced in Nigeria because.
-
There
are no enough semen banks
-
Fack
of chemicals large semen preservation e.g. solid nitrogen.
-
Lack
of enough proven males.
-
No
adequate technical known-how.
Management of
breeding ewes
The management of breeding females is
divided to three main phases.
Dry period (period
between weaning to gestation)
This usually last about three months.
The ewe is least productive at this period. It is a time the dam recovers from
the stress of the previous pregnancy and lactation. It is also a time when the dam prepares for the nest
pregnancy period; ewe should be given a higher plane of nutrition. Flushing
results in a higher lambing percentage. For mating the ratio of ram to ewes is
1:20-40. Hand service (isolating females on heat and introducing them to males)
can increase the number of females to 50 under intensive management.
Pregnancy (gestation)
period.
This refers to the period between
successful mating to parturition) in sheep. This period is about five months.
Foctal development in the first three months of pregnancy is normally slow
hence to make appreciable increases in feed supply. In the last four to six weeks prior to parturition and
quality of the feed given should be increase. This is done in order to meet the
nutrient requirement of the foctus as well as the dam. This enhanced feeding at
period (just before parturition) is called steaming up. Steaming up ensures the
following.
-
Greater
development of udder tissues and high milk yielding potential for the dam.
-
Law
ewe and lamb mortality
-
Higher
live weight gain in the young thus heavier adult stock.
-
Water
and minerals should be provided ad lib.
Signs of lambing
-
Uneasiness
i.e. restlessness
-
The
animals is constantly standing up. Sitting down and smelling the ground.
Udder enlargement.
There is a significant change in the size of the udder close to
Estrous cycle
The estrous cycle in the ewe is 16-17
days with estrous duration being 20-42 hours i.e. approximate 1-2 days average
being 30 hours. Ovulation occurs in the ewe from about 24-30 hours after the
onset of estrous after 16-17 days. There
are no visible signs of heat in the sheep except the acceptance of the ram or
teaser with an apron. This is the only external detection of heat in ewes. In
flock mating rams should be left in flock for 6-8 weeks to ensure (3 estrous cycles) that all
ewes are bred. After that they are withdrawn. Rams should be joined with ewes 2
weeks after lambing. The ewes will still be nursing their lambs at this stage
but this does not prevent them from getting pregnant. Batch lambing could be
ensured by synchronization using progrestogne virginal sponges. Ewes lambing
within 2-3 weeks interval would be synchronized. This consists of inserting the
progrestogen in-plants into their vaginal for 12 days. Introduction of rams
to treated flock 2 days before sponge
removal would enhance ovulation. Mating does not begin until sponge removal.
Estrous normally spread over 4 days
following sponge removal. Non-pregnant ewes would return to estrous 16-21 days
following sponge removal. Gestation period in ewes would
return to estrous 16-21 days following sponge removal. Gestation period in ewes
is about 5 months i.e. 152 days. Repeat breeder ewes those weaning poor weight lambs
and old ewes above 7 years should be culled.
Signs of oestrus
-
Uneasiness
-
Frequent
urination
-
Tail
shaking/
-
Swollen
Vulva with a little mucus discharge.
-
Sometimes
the females could be seen mounting other animals themselves
-
Bellowing
Mating methods
There
are two main mating methods in sheep
Natural service
This involves the natural copulation
of the ram to ewe. In Nigeria where most females and males are kept together
there is no restriction to mating, where females are kept separately from males
careful observation particularly in the early morning should be carried out to
notice females on heat so as to breed them.
Artificial
Insemination
This has recently been given more
attention but is rarely practiced in Nigeria because.
-
There
are no enough semen banks
-
Fack
of chemicals large semen preservation e.g. solid nitrogen.
-
Lack
of enough proven males.
-
No
adequate technical known-how.
Management of
breeding ewes
The management of breeding females is
divided to three main phases.
Dry period (period
between weaning to gestation)
This usually last about three months.
The ewe is least productive at this period. It is a time the dam recovers from
the stress of the previous pregnancy and lactation. It is also a time when the dam prepares for the nest
pregnancy period; ewe should be given a higher plane of nutrition. Flushing results
in a higher lambing percentage. For mating the ratio of ram to ewes is 1:20-40.
Hand service (isolating females on heat and introducing them to males) can
increase the number of females to 50 under intensive management.
Pregnancy (gestation)
period.
This refers to the period between
successful mating to parturition) in sheep. This period is about five months. Foctal
development in the first three months of pregnancy is normally slow hence to
make appreciable increases in feed supply. In the last four to six weeks prior to parturition and quality
of the feed given should be increase. This is done in order to meet the
nutrient requirement of the foctus as well as the dam. This enhanced feeding at
period (just before parturition) is called steaming up. Steaming up ensures the
following.
-
Greater
development of udder tissues and high milk yielding potential for the dam.
-
Law
ewe and lamb mortality
-
Higher
live weight gain in the young thus heavier adult stock.
-
Water
and minerals should be provided ad lib.
Signs of lambing
-
Uneasiness
i.e. restlessness
-
The
animals is constantly standing up. Sitting down and smelling the ground.
Udder enlargement.
There is a significant change in the size of the udder close to the female appears not to show any interest
grazing and lags behind the flock.
The
vulva appears slightly swollen with some mucus discharge.
When
the female is in the process of parturition it should be allowed privacy
assistance should only be given when there are obvious signs of difficulty at
which time a veterinarian should be invited.
Lactation period
Feeding of the lactating is aimed at
increased milk production to meet the need of the offspring. Normally the feed
requirement of a lactating female is greater than during pregnancy.
Management of lambs
The dam should be allowed to suckle
lamb immediately after birth. This is because at this time dam’s milk contains
colostrums. Colostrums contains antibodies which help to confer initial
immunity to the lamb it also stimulates the alimentary system. Colostrums production
ceases around the third or fourth day after parturition. It is important to
check the teat of the female to ensure that milk is available for the lamb. If
the dam’s milk supply is law the lamb may haw to the had wh
Weaning blow the age of 3 month is not
advisable for tropical sheep and goats. Weaning nibble at solid food such as
leaves. Grasses at 2-3 weeks of age. Where a dam dies immediately after
parturition artificial colostrums should
be provided. Artificial colostrums in made up of:
-
0.6
litre of cow’s milk
-
1
teaspoon cod liver oil
-
1 teaspoon cod liver oil
-
125mg
of broad spectrum antibiotics
Normally
a quarter (1/4) to 1litre of artificial colostrums is given per day for four
days.
Management of Ram
Management of ram is very crucial to
breeding and indeed the entire production of a sheep farm. If poorly cared for
ram attain puberty at a prolonged age. Normally a well managed ram in terms of
adequate feeding watering and health care attain puberty at about 6 months of
age if under intensive management
system. The ram could be older if under the extensive system. Rams must be fed
good nixture of grasses and legumes in addition to which concentrates may be
given at about 300 to 500gm per head per day. The hooves must be adequately
trimmed to prevent overgrowth and foot rot. They must be regularly disinfected
(every quarter) to prevent external parasites. Ram for breeding is kept in a separate pen or paddock usually very close to
the ewe to stimulate sexual desire. At puberty sperm production of the ram is usually
of low quality hence more mature and older rams must be used for mating. There is
the tendency to over-use the ram in an extensive system of production. However,
the acceptable mating ratio of ram to
ewe is between 1:20 and 1:3. Excess rams on the farm not required for mating are often castrated. Castrated
sums are called weather.
Management of buck
The buck is the male goat.. it must
attain the age of about 12 to 18 months of age
before it is used for mating. Even though it reaches puberty earlier
than 12 months it is not advisable to use for mating. Buck should be penned
separately to prevent indiscriminate mating. It must be fed good quality grass
and legumes and given concentrate at about 300 to 50gm of concentrate on daily
basis. A good buck can be used breeding for a period of 4 to 6 years effectively. The mating ratio is
similar to what obtains in sheep. Bucks that
are not being used for mating are usually castrated. Castrated bucks are called
bullocks and fattened for meat.
Management of a
female sheep or ewe
A female sheep is called “ewe” it
comes to puberty at about the age of 6 to 12 months depending on adequate
feeding and healthcare. When nutrition is poor sheep comes to puberty as late
as about 20 months. Attainment of puberty has been shown to be related to the
body weight of the animal and breed. Large breeds have been shown to reach
puberty much later than small breeds. The moment a ewe is selected for breeding
it must be separated and not allowed to run with rams to avoid indiscriminate mating.
Apart from nutrition the reproductive life of sheep is also influenced by
photoperiod or day-length or season particularly in the temperate region. In
the tropics and where there is adequate feeding this effect do not show as
there exist little variation in day length period throughout the year.
Conception rate in ewe can be increased by improving the quality of feed given
to the animal which subsequently encourages ovulation. This process is called
flushing. It may require putting the female animal on a lush green pasture with
quality concentrate a month beore mating. A female sheep comes to oestrus or
heat from 6 months of age and thereafter heat re-occurs at every 15 to 17 days.
Ewe must not be allowed for mating at the first oestrus. Oestrus lasts 20 to 42
hours in sheep. The heat signs are similar to what you have learnt for cattle.
Management Of Pregnant Eve
After mating, the ewe must be
separated from the flock and kept in individual pen or monitored to ensure
safety to prevent abortion. The ram must not be allowed to run with the females
again if on pasture. They must be grazed on separate paddock or the prepuce of the penis tied to the scrotum to prevent
aggressive mating from the males. Ewes must be well fed with good grass-legume mixtures with
minerals as supplements in form of block multinutrients if available.
Concentrates
at about 200 to 600g per day may be given toward the latter part of pregnancy
(6 to 8 weeks) to provide extra nutrients for the developing foetus.
The gestation period of a ewe 140 to
150 days (21 to 22 weeks). On the average the gestation period in sheep is
about 5 months. With this it is possible for an ewe to give birth at least once
a year or thrice in two years. The act of giving birth in sheep is called “lambing”.
Lambing
Lambing is defined act of giving birth
in sheep in sheep. Ewes demonstrate essentially the same characteristics when
giving birth. Towards the end of pregnancy the udder of the animal swells and
becomes larger. The ewe becomes restless bleats and there is a hollow
appearance on the flank region of the loin. Some watery discharge that is
opaque and yellowish is observed from
the vulva and the animal choose a secluded place to give birth. Parturition process is completed within
two hours. The animal could be assisted if in distress or invite a veterinarian
especially if the foetus position is
abnormal. The normal position is when the lamb or kid comes out with head
rested on the fore leg coming out first from the vagina. The dam cleans up the
lamb or kid by licking the mucus from the body and stimulates the lungs to
respire in some cases. The young animal after some time begin to show signs of
hunger and thereafter sucks the dam.