A Decade of Pasture Lambing
at
Tamarack Lamb & Wool
Presented at the Great Lakes International Grazing Conference
February 12th & 13th 2001
Janet W McNally
Why Pasture Lambing
Through the 80's the Tamarack flock was lambed first on an accelerated
lambing schedule, and later, due to limited barn space, once per
year fall lambing schedule. This was my first introduction to
lambing on pasture. No longer was my flock size limited by the
size of the barn or my ability to clean lambing jugs and haul
pails of feed. Later, when I contemplated the logistics of using
Artificial Insemination in our breeding program, I made a shift
to spring lambing to improve the AI results. Once I had a taste
of the great economy and labor savings of lambing on pasture in
the spring, I never looked back. For the first time there was
enough money left to fuel flock expansion, and later to provide
some family income.
Most Midwestern farm flocks are limited in size to the barn on
the property. Roller coaster lamb prices make the investment in
new more capacious low labor lambing barns to accommodate a more
efficient sized flock difficult. In most cases the forage resources
of the farm greatly exceed the size of the barn and go underutilized.
Meanwhile the future of lamb prices is possibly more precarious
than ever. Currently the US lamb industry is protected by tariff's
that limit the flow of Australian and New Zealand lamb into the
country. In just two years this may change. If imports are not
controlled, and the currency exchange rate remains favorable to
importation, US producers may be facing lamb prices in the 45
to 65 cent range rather than the current 65 to 95 cent range.
Smaller margins make running larger numbers of sheep essential
just to keep flock income the same. With the average cost to produce
a pound of lamb in the Midwest around 65 cents a pound, Midwestern
producers will not only need to become more labor efficient, but
will need to find ways to cut expenses if they wish to stay in
business.
Pasture lambing can do this.
Prolific
Sheep
Over the past 50 years all research into the economics of sheep
production have had the same resounding results. The more lambs
a ewe raises, the more profitable she will be. The forces behind
this are simple, the more lambs sold, the less overhead costs
must be born by each lamb.
Looking at how to best utilize our seasonal forage
supply I came to recognize that while we had a huge
abundance of high quality grass in the spring, we were
faced with poor quality forage through the winter.
High quality stored forages suitable for lactating
ewes are many times higher in price due to demand by
dairy farmers. Stored feed is a major cost to the sheep
enterprise. It makes perfect sense to drop the lambs
in the spring, just ahead of the flush, grow them on
the high quality pasture, and market them in the fall,
in a sense de stocking the farm when the forage supply
gets tight and the quality drops.
One important note about using prolific breeds. Lambs born as
twins and triplets will be smaller at weaning. The total litter
weight is restricted by the milk supply of the dam. While the
obvious conclusion is that we need heavy milking dams, it is also
important to understand the value of retaining ownership of the
lamb to as close as slaughter as possible. If market conditions
and your forage curve dictate that you should be selling your
lambs early, in the late summer (Aug, Sept) then there is less
of a benefit to prolific breeds as there is when the lambs are
retained longer (thus allowing for compensatory growth after weaning).
In essence a prolific flock means we over winter as few sheep
as possible while having a literal explosion of lambs in the spring
flush.
The
Nitty Gritty
Pasture lambing is the lambing of ewes on pasture where ewes and
newborns are not jugged (put into a pen) and ewes are able to
forage for their own feed. For pasture lambing to go smoothly
with minimal mismothering, it is essential to provide an environment
that encourages ewes that have just lambed to stay put on their
lambing bed for one to three days. The factors that help encourage
good distribution of lambing ewes throughout the paddock and that
avoid congregating or overcrowding are 1) good quantity of palatable
green feed underfoot 2) lambing while it is still cool and wet
enough to reduce or eliminate much need to walk to water, 3) removing
of young inexperienced ewes from the drop bunch, 4) minimize disturbances
in the lambing paddock such as dogs or supplementary feed, 5)
lamb when flies or excessive heat are not a problem, 6) control
disturbance by predators 7) manage to have ewes lamb as closely
in time as possible.
Ultra
sound scanning
Ewes behave differently at lambing depending upon how many lambs
they give birth to. Ewes birthing triplets for instance are more
inclined to stay put for a long time on their lambing bed than
ewes with a single. In fact the later group are inclined to pack
up their newborns and go tour the paddock sometimes only hours
after birth. Anyone who has tried to ready one vs three toddlers
for a trip to town understand this perfectly. It is considerably
more difficult to organize three than it is one. Ovine mothers
are faced with the same difficulty. Unfortunately those single
bearing ewes (who are often also first time mothers ) tour the
paddock, investigating and sometimes luring other newborns away
from their birth spot. A triplet bearing ewe, who has just had
a lamb lured away by a less experienced single bearing ewe is
faced with the dilemma of trying to gather the strayed lamb while
caring for the two left in the nest. Pretty soon her litter is
scattered across the paddock.
I have found that ultrasound scanning for fetal number prior to
lambing, and then sorting ewes according to the number in utero
prior to lambing, to be an immensely helpful tool to managing
the afore mentioned problem. By moving the single bearing ewes
to a distant location, the amount of interference is greatly reduced.
This also allows the triplet drop bunch to be located where feed
might be better, or where observation, or predator control is
easier. I begin our pasture lambing management with ultrasound
scanning the flock. On the day lambing is to begin, the ewes are
sorted into three groups, the single, twin, and triplet group.
The single group is moved to a distant location where feed quality
is the poorest and is managed as a set stock lambing group. The
twins and triplets are put into the better paddocks and managed
as drift lambing groups.
Drift
vs Set Stock Lambing
There are two systems to lambing on pasture that are
widely used. One system is called set stock lambing'
and is where a specific number of pregnant ewes are
stocked in each paddock just prior to lambing. The
number is determined by the amount of feed anticipated
to be available in that paddock for the next 30 -50
days. Sufficient ewes are needed to control the grass
growth, but also must not exceed the forage reserve.
Once the ewes are set in the paddocks, very little
disturbance is permitted. Some farms will not even
enter the paddocks while lambing is in progress, the
ewes are truly on their own. The decision to use set
stock lambing is usually based on the temperament of
the ewes, the terrain available for lambing, and available
lambing labor. Generally set stock is most often used
with ewes of a wild or nervous temperament such as
Western ewes and where the terrain is rough providing
an abundance of natural shelter, but also making observation
difficult, and where labor is scarce. Under these conditions,
entering a paddock may cause more problems than it
can solve. The manager's role is restricted solely
to assuring that the paddocks are properly stocked
and feed conditions are maintained.
Drift lambing is a different system that allows a higher degree
of intervention and record keeping, but requires a more mellow
temperament in the ewe flock. Drift lambed ewes must tolerate
handling of their lambs without running off. Drift lambing also
allows greater intervention in the event of bad weather or predators
and is more likely used where natural shelter is less available
or where depredation is severe.
Drift lambing is where the flock continues the pre lambing rotation
through the paddocks, but as lambing begins, the ewes that have
just lambed are left behind in the paddock where they lambed,
and the pregnant ewes are moved on to a fresh paddock every one
to three days. Drift lambing requires a higher degree of skill
both in terms of grass management and in animal handling.
Managing
the drift lambing flock
Preparation for drift lambing began with ultra sound
scanning the flock. Prior to full green up, when the
brush is just budding, ewes begin rotation around the
farm as one flock. During this time (approximately
3 weeks before lambing begins) they will be supplemented
with a decreasing amount of hay and one to one and
a half pounds of shelled corn fed on the ground. Rotation
is rapid, the goal is just to bite off every blade
once and move on. The flock often returns to a paddock
in just 10 days. Typically two or three rotations are
made before lambing begins. This early grazing is important
to managing the quality of grass in the lambing paddocks.
Had these paddocks not been grazed prior to lambing,
the forage would rapidly mature and go to seed loosing
all quality before lambing is complete. The early grazing
serves as a protein supplement which lowers the cost
of the late pregnancy ration. The green grass also
provides vitamins E and A which are essential for vigorous
lambs.
Ewes are vaccinated for enterotoxemia types C and D approx 6 weeks
before lambing begins. Ewes are sorted into their respective lambing
groups according to fetal number and dewormed just days before
lambing begins. A minimum of 7 different paddocks per group (14
total) are needed if ewes are to be moved every three days as
lambing is usually nearly complete in just 21 days (7 paddocks
X 3 days = 21). The larger the flock, the more frequent moving
must occur to reduce congestion, the more paddocks that are required.
While I do not know the upper limit as to how many ewes can drop
in a paddock, I do encourage large flocks to consider running
several drop groups to keep numbers manageable. I might point
out how important a quick drop is to making this system flow,
however, this never seems to be an issue with May lambing.
As lambing progresses, pregnant ewes are moved regularly
into fresh paddocks while ewes with newborns are left
behind. The key is to have paddocks sized just right
so that enough ewes will have lambed in 1 to 3 days
to keep that paddock stocked at the right level for
the next 30 to 50 days. This can be estimated by making
a forage growth curve in the previous year and factoring
in 8 pounds of dm per ewe per day. A starting point,
if no information is available, might be to leave approximately
5 lambed ewes to the acre behind. This can be adjusted
up or down with experience. Getting this balance right
is critical to the success of pasture lambing. If too
many ewes are left behind, the paddock will run short
of feed and the manager is faced with having to move
ewes when lambs are small and very difficult to relocate.
If too few are left behind then the manager is faced
with an overgrown paddock that goes to seed. To some
extent the latter condition can be alleviated by running
some yearling cattle through the under stocked paddocks
to graze rank forage. A small number of yearling cattle
can be run into and out of a paddock of newborn lambs
with minimal disturbance to the bonding of the lambs.
If it should become necessary to relocate sheep on
an overstocked paddock, it is important to move the
whole group. Never move just part of the group. One
can never know for sure if a lamb is truly being reared
by its own mother and cross fostering appears to occur
more often than realized. Moving only a portion of
the group may lead to orphaning lambs.
When lambing is complete, the flock is set stock for a minimum
of 30, and if possible up to 50 days. Set stocking helps improve
lamb performance as lambs depend considerably on a specific location
where they expect to find their mother to suckle. Observation
of a flock will find that a portion of the ewes always keep their
lambs right beside them, while others plant their lambs and return
to this same spot frequently. It is the latter group that are
set back when the flock is rotated too early. If everything is
timed right, this set stocking occurs during the spring flush.
By 40 days old lambs have begun to graze significantly on their
own (grazing began seriously around 3 weeks, but by 40 days grazing
is now an important part of the lamb's nutrition). At this time
the lamb can spend significant time away from its mother (if it
should become momentarily lost in the crowd) and rotational grazing
can be resumed.
The flock can merge into one group in one of two ways. with portable
fencing, the cross fencing can be removed allowing groups to commingle,
or adjoining paddocks can be moved in together forming a larger
and larger group. Ewes rearing triplets should be kept together
as one group, while the twins and singles can be combined into
a second larger group. A leader/follower system can be used where
the triplet rearing group lead and the rest follow. Sheep producers
should become aware that triplet rearing ewes are working as hard
as a Holstein putting out 90 pounds per day, and should be managed
accordingly. just one pound of shelled corn can improve triplet
lamb weaning weights by 5 pounds (15 pounds per litter) and should
be considered where practical.
Stock
handling skills
Knowing how to handle sheep can make a world of difference
in the pasture lambing experience. A good quiet stock
dog, that can help hold new mothers near you while
you process lambs is invaluable. Generally such dogs
are only possible with well trained mature dogs over
3 years old. Young dogs are just too pushy.
If you do not have a good dog, then you can get by with a large
fishing net, and make a point of processing baby lambs within
12 hours of birth. When catching a litter, catch all of the lambs,
and hold the extras stacked upon each other between your knees,
or tie their feet together with a chord. Doing so will keep the
mother right there. If you catch only one lamb in a set of triplets,
the mother may walk off with the other two presenting significant
headaches keeping the lambs together.
Castration and docking should be done on the first day, ideally
just after the lamb has suckled and lays down to sleep the big
meal off. If done at this time, the ewe will not expect the lambs
to be walking about or following her, and she will be more willing
to stay put. Delaying the operation will not benefit the lamb
and is more likely to lead to mismothering. Many large flocks
skip docking and castration until a much later date, when the
whole flock is gathered and all the lambs are done the same day,
such as on the first deworming. Fly strike is a bigger danger
if docking and castrating are delayed.
Perhaps the most challenging skill is moving the pregnant ewes
out of the paddock while leaving the newly lambed ewes behind.
The possibility an already lambed ewe might sneak through the
gate and orphan her lamb is a genuine worry. If the fresh paddock
is right beside the one they are leaving, this does not need to
be a huge concern. Either the gate can be left open and let the
pregnant ewes trickle through, or at least come back 4 hours later
and the escapees will be waiting by the fence. But sometimes paddock
moves mean moving a fair hike to a new pasture. A trick beginners
might consider is to spray paint a dot on the forehead of the
ewes as they process the newborn lambs each morning. Then while
standing at the gate, the shepherd can watch for any painted ewes
and turn them back. The more frequently the pregnant ewes are
moved on, the less trouble there is with mistakes. Generally 3
days is the longest a flock can spend in one paddock without loosing
a few accidentally out the gate. Another important trick to assuring
newly lambed ewes do not move out with the group, is to be sure
you do not overgraze the paddock before moving. Hungry ewes forget
motherhood, at least momentarily, when offered fresh feed. If
the paddock is still full of good feed, the flock will move out
slowly, and the just lambed ewes will not be motivated to leave
at all.
To move pregnant ewes, especially if they must be gathered and
moved some distance, one or two people can walk quietly through
the paddock from one corner diagonally toward the gate. Zig zag
through the paddock, using a stick to tap the ewes that should
be moving onward, and making a point to give lambed ewes a very
wide birth so as not to disturb them. Always move the pregnant
ewes toward an open space in the paddock and away from the lambed
ewes. Once gathered, they can then be moved through the gate.
If the paddocks are side by side, it is sufficient to open the
gate first, and let the ewes drift through, offering a little
encouragement to get going. IF the shepherd has a very quiet dog,
the dog can serve the purpose of a second person and assist in
moving the pregnant ewes out. But a pushy dog would only cause
disruption and panic, causing some ewes to leave that should have
stayed behind.
Flock
health-- micro organisms
Parasites are the biggest profit robber on a pasture system, and
must be managed with a plan. It is not my purpose to go into depth
about parasite management here, but a few comments are necessary.
Pasture lambing is typically happening at the same time the spring
rise in parasite egg production. One of the most useful management
tools is to use a strategy that minimizes the contamination of
pasture with parasite eggs, hence assuring only a moderate to
low worm burden as the summer progresses. Strategic deworming
with anthelmentics can go a long way to reducing pasture contamination
by removing adults just before massive egg laying begins. Since
the typical round worm matures (from ingestion of the larvae to
egg laying adult) in just three weeks, this means deworming the
flock at three week intervals during the spring flush can go a
long way to keeping pasture contamination down. Hence I recommend
deworming the flock just prior to the start of lambing with a
drench. Then deworm again 3 weeks into lambing by using a pellet
or granule added to some corn or mineral (because at this time
the farm is full of just born baby lambs which are next to impossible
to muster), and again with a drench 6 weeks after lambing began,
which will also be the first deworming for most of the lambs.
From here on the drench schedule depends upon many factors such
as the weather and the use of clean grazing, but for most flocks
the above mentioned schedule is often a necessity if lambing on
pastures that see sheep every year.
Lambs on well managed pastures can succumb to enterotoxemia (over
eating disease) even though no grain is present in the diet. Ewes
should have been vaccinated for types C and D during late pregnancy,
but this maternal protection will be waning at about 6 weeks of
age. So while lambs are gathered together for their first drench
at 5-7 weeks of age, it is also a good time to vaccinate them
for enterotoxemia type D. A second dose should be given 3 weeks
later, which is at weaning time.
Of the diseases encountered with newborn lambs, ecoli
scours and joint or navel ill can be the most stubborn.
Both are to a large extent the function of both weather
and consumption of colostrum. Colostrum provides antibodies
to help ward off many potential diseases providing
protection for the first 6 to 8 weeks of life. A lamb
should consume at least 24 ounces of colostrum within
the first day of life (basically an ounce per hour).
Lambs born in cold, wet, rainy weather to ewes with
insufficient milk are the most vulnerable. Supplementing
extra colostrum, or colostrum substitute can help ward
off scours and joint ill, but if they do occur, prompt
antibiotic therapy, and sometimes hospitalization are
necessary. Any time one lamb from a litter must be
hospitalized (for re warming, or treatment) be sure
to bring in the whole litter. Ewes can adjust to the
idea of having only one offspring very quickly, and
may disown the treated lamb if removed even just for
a few hours. However, if her entire litter is removed,
she will usually take them all back.
Starvation/hypothermia
Starvation and hypothermia are the most common losses
of newborn lambs in a pasture lambing situation. Often
it can be difficult to determine which came first,
but the result is the same, a lamb with a temperature
below 102 degrees F probably needing nourishment and
re warming. Cold and starving lambs need to be triaged
to determine the most appropriate course of action.
Whenever possible try to manage the lamb out in the
field. Once a lamb is removed from the field the problems
of getting a ewe to take it back are compounded by
the length of time spent away.
Here is a recommended guide line, beginning with when to be watching
for hypothermia.
Usually all day rain and temperatures in the mid 60's are not
a cause for much concern. When temps drop to the mid 50's, and
rain continues steadily, the shepherd needs to keep a thermometer
handy, and temp any suspicious looking lambs. The most vulnerable
are lambs born in the rain that have never been able to get dried
off. Generally triplets are more vulnerable than singles. The
more lambs in the litter, the less body fat each is born with
and the faster they will succumb to inclement weather, especially
if not suckled quickly. Amazingly lambs just 24 hours old that
were born before the rain began are quite able to fend off this
weather. When temps drop to the mid 40's then a large segment
of the lambs born during the past 24 hours day are at risk and
the shepherd must be vigilant.
The normal temperature of a lamb is 103.5. Lambs found with temperatures
from 101 to 102 degrees F often only need to be moved to a more
sheltered area. Shelter could be a grove of trees out of the wind,
a calf hutch kept in the paddock for this purpose, or a portable
shelter such as a 6 X 6 X 6 foot range tent. Some type of wind
proof lamb coat might be useful.
When the body temperature drops below 101 but is still
above 99, the lamb is not in absolute critical condition,
but is in a dilemma because below 101 the digestion
of milk is slowed or nearly stopped, so the lamb in
effect can starve to death with a full belly if not
re warmed. Hence it is crucial to provide additional
heat to warm up lambs below 101 degrees. Often this
can be accomplished in the field by using any kind
of box or crate with a hot water bottle. Put ALL the
lambs from one litter into the crate, weather or not
they all need re warming. Never mix lambs from two
different ewes. The mixed smells will confuse the ewe
and she will reject her lamb. The crate needs to provide
protection from the elements, hold in the heat, but
allow the ewe to see, smell and hear her lambs. Leave
the crate in the location where the ewe lambed.
Lambs with a body temperature below 99 degrees need
critical care, and must be removed for re warming.
for at least the next 24 hours. Often these lambs will
become orphaned. If the lamb is unconscious (unable
to lift its head) then an inter peritoneal injection
of 25 cc of injectable sterile dextrose and 25 cc of
boiling water must be given prior to re warming. This
injection is easy to master with some instruction.
The lamb is then placed in a warming box heated to
approximately 100 degrees F and checked every 30 minutes.
When the lamb's temperature climbs to 101 to 102 the
lamb can be fed, the heat can be reduced and the lamb
monitored for the next 24 hours. Never overheat a lamb.
Lambs often get into this condition for three reasons. Either
they were rejected or lost and did not get to suckle, or they
are succumbing to an illness such as ecoli scours and need therapy,
or simply because they were born in extra ordinarily tough weather,
such as being lambed in a puddle during a cold down pour.
Weaning
Early weaning accomplishes a number of things. Ewes who are weaned
early will regain weight prior to winter weather from grazing
alone, and will require less feed for maintenance. Weaned ewes
can be used to manage any rank pasture growth without harming
lamb performance. By weaning early, the less abundant high quality
pastures can be rationed to just the lambs.
Weaning can occur too early, especially if pasture quality is
not tops. Generally I have observed significant setbacks on lambs
only 60 days old at weaning, while lambs that are 80 days old
seem to handle weaning quite well. I recommend early weaning for
pasture reared lambs to occur from 70 to 90 days of age.
Preparation for weaning includes a good deworming program, and
setting aside paddocks for the lambs close to the handling facilities.
Once lambs are parted from their mothers, the lambs can be very
frustrating to herd to more distant locations. It is helpful to
have drenched, weighed and vaccinated the lambs a day or two before
they are actually separated from their dams. Move the flock into
the paddock that lambs will returned to after separation a day
before weaning to help the lambs become familiar with where the
water, feed, and resting places are. Preparation reduces the stress
of weaning itself. Send the flock through the sorting chute, and
as soon as the dams are separated immediately move them to a location
out of earshot of their lambs. Moving the ewes far from the lambs
reduces the length of time it takes for the lambs to settle down.
If you delay a few hours, the ewes will begin to realize they
are separated from their lambs and will become much more difficult
to move. The lambs should be quickly returned to the paddock they
spent the past 24 hours in. Leave with them an old ewe or two
to serve as mentors.
Top quality grazing and abundant fresh water in familiar locations
are essential for the first 10 days after weaning. After lambs
have adjusted to weaning, they can then be moved on to other grazing.
Eventually a leader follower system can be used where lambs graze
ahead of the ewes, but bear in mind it will take 3-4 weeks before
the dams and lambs will be sufficiently accepting of weaning to
be within sight and sound of each other.
Summary
Lambing is often the bottleneck that prevents the sheep enterprise
from expanding into a more efficient size. Midwestern sheep producers
have been limited by the size of their lambing barns and available
labor, in effect preventing them from more efficiently utilizing
forage resources with sheep. By lambing on pasture, this bottle
neck can be alleviated. When combined with good grazing management
and extending grazing into the fall and early winter, returns
to sheep production can be improved.
For more information
or questions, please contact:
janet@tamaracksheep.com
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