Feed usually represents the single largest cost in all types of sheep
production. A ewe's nutritional needs are not static. What and
how much to feed a ewe depends upon many factors, including the
ewe's age, weight, and body condition, along with her stage and
level of production. Climate, exercise, and disease can also have an effect
on her nutritional requirements.
A wide variety of feedstuffs can meet the nutritional needs of
ewes during their different production stages. There is no one
perfect feeding program. The choice of feeding program will depend
upon geographic region, when lambs are born, and the cost and
availability of feedstuffs.
Life cycle feeding of ewes
Feeding the ewe so she is gaining weight about 2 weeks before
breeding is called flushing. Flushing may increase lambing percentage
by increasing the number of eggs that the ewe ovulates. Flushing
works best on thin ewes (BCS < 2.0). Ewes that are already in good body
condition (BCS > 3) usually do not respond well to flushing.
Flushing has more effect early in the breeding season. Flushing
may also be beneficial late in the breeding season. Mature ewes
respond better to flushing than yearlings. You can flush ewes
by feeding them 0.5 to 1 lb. of grain per day or by moving them
to a better quality pasture. If flushing is continued through the breeding
season, it may enhance embryo survival during early pregnancy.
Ewes should not be bred on pastures that contain a high percentage
of legumes. Clovers (especially red clover), alfalfa, and birdsfoot
trefoil may delay estrus. Fescue grasses, as well as barley
grain and oat grain also contain compounds with estrogenic activity.
Estrogenic compounds are present in varying concentrations in
most all legume plants during the entire growing season, though
not when the plants are mature and dry.
Early to mid gestation is a critical period in the ewe's production cycle because placental development
occurs from day 30 to day 90 of gestation. Placental size or weight
affects nutrient transfer between the ewe and the her fetuses.
Underdeveloped placentas result in lower birth weights regardless
of late gestation nutrition. While the ewe's nutritional requirements during this period are not significantly above maintenance requirements, 21 days of severe underfeeding
or 80 days of moderate underfeeding can affect placental development.
Good nutrition during late gestation will help to ensure a successful lambing season. Knowing how much to feed ewes during late gestation can be difficult
because it depends upon the number of fetuses the ewe is carrying.
Underfeeding will result in the birth of small lambs. Small
lambs are less resistant to cold stress and will have slower
pre-weaning growth. Most of the ewe's mammary development occurs
during late gestation. Underfeeding will reduce the yield and
quality of milk, including colostrum. Overfeeding can result in oversized fetuses. Big lambs increase lambing problems and have
a higher mortality rate.
The nutrients that are important during late gestation are energy,
protein, calcium, selenium, and vitamin E. The amount of energy
required depends upon the number of fetuses the ewe is carrying. Cold stress increases nutritional requirements, especially if ewes are kept outside.
Winter lambing ewes usually cannot consume enough forage to
meet their energy needs. More energy is required two weeks before
lambing versus six weeks before lambing. Ewes carrying singles
do not need to receive grain as early as those carrying multiple
Pregnancy toxemia (ketosis or twin lamb disease) is a common disease in late gestation. It is caused by
an inadequate intake of energy during late gestation, as fetuses
make 70 percent of their growth during this period. As the ewe breaks down her
body fat to meet her increasing nutritional needs, toxic ketone
bodies are produced.
The ewes that are most prone to pregnancy toxemia are fat ewes,
thin ewes, old ewes, timid ewes, and ewes carrying multiple
births. Treatment is aimed at increasing blood glucose level. In
advanced cases, a caesarian section may be necessary.
Milk fever is different in sheep as compared to dairy cattle
in that symptoms occur pre-lambing. Simply states, milk fever is low blood
calcium (hypocalcemia). It is caused by either inadequate intake of calcium
(usually) or the inability to mobilize calcium reserves. The clinical
signs of milk fever are very similar to pregnancy toxemia. Differential
diagnosis is based on the affected ewe's response to calcium
Vaginal prolapses tend to occur more frequently in fat ewes
or ewe lambs carrying multiple fetuses. There is simply not
enough room for everything. . Preventing ewes from becoming overfat and limiting
intake are two ways to reduce vaginal prolapses.
Lactation places the greatest nutritional demand on ewes. How
much you feed a ewe will depend upon how many lambs she is nursing,
her size and condition, her age, and the time of the year the
lambs are born. Ideally, ewes should be separated into production
groups and fed according to the number of lambs they are nursing.
A general rule of thumb for concentrate feeding of lactating
ewes is 1 pound of grain for each lamb nursing the ewe. On pasture, ewes rearing triplets should be given access to more forage. Supplemental feeding may be advisable.
Protein and energy are both critical nutrients for milk production.
If either nutrient is fed below the requirement, milk yields
and lamb gain will be reduced. After the first 60 days of lactation,
you should reduce the amount of feed you are feeding because
all it will accomplish is making the ewes fat.
Most ewes will lose weight during lactation. Weight loss during
lactation affects protein requirements. The more weight ewes
lose, the higher their protein requirement will be.
Lactating ewes require a lot of water if they are expected to
milk well. It is estimated that lactating ewes require 100 percent
more water than non-lactating ewes. Ewes should have a free-choice
supply of fresh, clean water at all times. Heated water bowls
should be used during the winter to encourage water consumption.
Water bowls should be checked and cleaned on a daily basis.
Weaning often takes place at a time when ewes are still
producing a lot of milk. In this is the case, grain should be
reduced 1 to 2 weeks prior to weaning. For the last week or
so prior to weaning, no grain should be fed to the ewes. For
the last several days before weaning, ewes should be fed a low
quality grass hay or straw. After the lambs have been weaned,
the ewes should be maintained in dry lot and fed low quality
grass hay or straw until their udders start to dry up and recede.
It is not necessary to remove water from ewes at weaning. It
can also be dangerous during hot weather. Do not turn ewes onto
pasture immediately after weaning. Spring grass is high in protein,
water, and other nutrients which promote milk production.
The overriding concern at weaning time for ewes is to prevent
mastitis. Ewes need to be watched closely during the weaning
period for mastitis. Ewes with spoiled udders have decreased
or no future production value.
In annual lambing systems, maintenance is the longest period in
the ewe's production year. Maintenance means the ewe only needs
to maintain her body weight or have slow growth to recover the
weight (condition) she lost during lactation. A wide variety
of low-cost feedstuffs can meet the maintenance requirements
of ewes. Pasture or grass hay is all most sheep need to maintain
themselves. Pet sheep or wethers raised for wool should always be fed at a maintenance
Body condition scoring
Body condition scoring is a valuable management tool that can
be used to evaluate the feeding program and the need for changes.
Since there is a wide variation in weight, body condition is
usually better indicator of condition than weighing.
A body condition score estimates condition of fat and muscle.
Both the vertical bone protrusion (spinous process) and horizontal
protrusion (transverse process) of the loin are felt and used
to access body condition scoring. It is a subjective score.
The exact score is not as important as the relative scores and
differences between scores.
The system most widely used in the US uses a scale of 1 to
5, with 1 being an emaciated sheep, 3 being a sheep in average
condition, and 5 being an obese sheep. Half scores are commonly
used. On average, 1 condition score is equal to about 13 percent
of the live weight of a ewe at a moderate condition score of
3 to 3.5.
Most sheep have body condition scores between 2 and 4. A ewe's
body condition score will change throughout her production cycle.
The three most important times to body condition score ewes
are prior to breeding, late gestation, and weaning.
Body condition scoring
Source: Body condition scoring of sheep, Oregon
State University, 1994.
|Spinous processes are sharp and prominent.
Transverse processes are sharp; one can pass fingers under
ends. It is possible to feel between each process.
Loin muscle is shallow with no fat cover.
|Spinous processes are sharp and prominent.
Transverse processes are smooth and slightly rounded. It
is possible to pass fingers under the ends of the transverse
processes with a little pressure.
Loin muscle has little fat cover, but is full.
|Spinous processes are smooth.
Transverse processes are smooth and well covered, and firm
pressure is needed to feel over the ends.
Loin muscle is full with some fat cover.
|Spinous processes can be detected only with
pressure as a hard line.
Transverse processes cannot be felt.
Loin muscle is full with thick fat cover.
|Spinous processes cannot be detected.
Transverse processes cannot be detected.
Loin muscle is very full with very thick fat cover.
Generally, the better the body condition score is at mating, the
higher the ovulation rate will be. However, ewes with body scores
over 4 tend to have a higher incidence of being barren. Ewes that
have a body condition score of less than 3 at mating will respond
better to flushing. Ewes with body condition scores of 3 and 4
at lambing tend to lose fewer lambs and wean more pounds of lambs
than ewes with body condition scores of 2.5 or less.