Lambing on Pasture

Sometime in the next week, our 2013 lambing season will begin!  I thought this might be of interest to my fellow shepherds - and to others who are interested in sheep!  We will be hosting a Pasture Lambing Workshop on Sunday, March 10 in Auburn, California.  Email me at flyingmule@wavecable.com for more information!

Why not lamb in a barn?

Conventional wisdom indicates that sheep should give birth in the shelter of a barn.  Lambs, so the thinking goes, need shelter from inclement weather and a small enclosed space (a jug or a jail) in which to bond with their mother.  Since our operation exists almost entirely on leased land without this type of infrastructure, we’ve adopted a system for lambing out on pasture.  Our system builds on the experience of shepherds here and in other parts of the world – and we learn more each year.  We’ve found that pasture lambing has several advantages: 

• Lower (or no) capital costs for barns and other infrastructure.
• Healthier ewes and lambs – we see very few of the respiratory problems that often come with lambing in an enclosed area
• A ewe flock with tremendous mothering abilities (and fewer mis-mothering problems.
• Lower feed costs – we purchase very little supplemental feed during lambing.

 Like any livestock management system, pasture lambing requires careful record-keeping; knowledge of animal nutrition, health and behavior; and attention to detail.

Managing our forage

Ewes have the greatest nutritional demand during their last 6 weeks of pregnancy and their first 6 weeks of lactation.  Accordingly, we try to match our lambing period with the onset of rapid grass growth in our area.  We also try to manage our forage resources all year with the idea that we need lots of high-quality forage available beginning at the first of the year.

Sometimes the weather doesn’t cooperate (like 2012, for example).  We have several strategies for coping with poor forage growth:

• We provide supplemental protein and energy to help the ewes utilize the rougher, dry forages we’ve saved from the prior growing season.
• We seek additional pastures on neighboring properties (our portable fencing systems and stock-handling skills make this possible).
• As a last resort, we’ll feed hay.

 Ewe selection and record-keeping

Since we do not confine ewes with their lambs immediately after birth, we require ewes that have strong maternal instincts.  We also need ewes that can deliver lambs without assistance and that produce adequate milk on a forage-based diet.  Since these traits are mildly heritable, we also need a system for determining which female lambs to keep as replacements.

We’ve found that the EZ Care Lambing System provides a simple yet powerful tool for evaluating ewe performance and for selecting replacement ewe lambs.  In this system, each ewe is scored on three criteria – lambing ease, mothering ability and lamb vigor – each year at the birth of her lambs.  Potential ewe lamb replacements are evaluated based on their mother’s scores.

Criteria	-1	0	1
Lambing Ease	Lamb is breech or must be pulled	Lamb requires minor assistance	No assistance needed
Mothering Ability	Ewe leaves lambs	Ewe stands well back while lambs are being processed	Ewe follows lambs wherever they go
Lamb Vigor	Has to be suckled	Slow to suckle	Lamb is up and has full belly

Any ewe with a cumulative score of 1 or less is culled.  Any ewe lamb whose mother’s score is 1 or less is not retained (she gets a right-hand ear tag – more on this later).

The power of this system is confirmed whenever we purchase a group of ewes that have not been selected using these criteria.  Invariably, we have more mothering problems with these sheep.

Flock health and nutrition

About 30 days prior to lambing, we vaccinate all ewes for clostridial diseases, including tetanus.  This gives the ewes immunity to these diseases, which passes through the placenta to the developing lamb(s).   We also try to save our best forage for the last 30 days of gestation – a time when the fetus is developing rapidly.  Adequate selenium levels are also critical.  The commercially available sheep salt does not provide enough selenium.  We purchase mineral blocks from Western Feed Supplements in Nevada.  You can also provide selenium injections prior to lambing.

Tagging

Some ewes have soiled wool around their vaginas.  When we vaccinate, we also select ewes that need to be “tagged” – that is, ewes that need to have their hindquarters sheared.  Tagging removes the soiled wool, allowing for a cleaner delivery of lambs.  Tagging also removes wool from around the udder, which helps ensure that the lambs can find a teat (rather than a lock of wool).

Predator protection

In our area, the main predators that threaten newborn lambs are domestic dogs, coyotes, mountain lions, foxes, and owls.  We rely on a combination of electric fencing and guardian animals to protect our flocks from predators.  Guard dogs and llamas seem to be the most effective guardians for our situation.  We closely monitor the interaction of our guardian dogs with the sheep during lambing.  Some guardian dogs exhibit play behavior with the lambs (which can be lethal to the lambs), while others have an over-developed maternal instinct (which results in the dog protecting lambs from their mother).  If we observe problems, we’ll replace the guard dog(s) with a llama.

Watching the weather

While sheep (and newborn lambs in particular) are often hardier than we give them credit for, we do keep an eye on the weather during lambing.  Wet and windy weather, in particular, can pose problems.  If inclement weather is forecast, we try to put the sheep into paddocks that provide some natural shelter.  Trees, brush and topographic features provide windbreaks and shelter from rain and snow.  During stormy weather in our area, for example, our prevailing winds are from the south.  We try to put the flock on the lee side of a hill in a paddock with plenty of trees, rocks and/or brush for the ewes to shelter behind.

The best remedy for cold weather is a ewe that produces plenty of milk!  A lamb with a full belly typically will not get chilled in our climate.  Since milk production is related to forage quality, we try to make sure that the sheep have plenty of fresh forage available just before and during stormy weather.

Finally, we do not process lambs (e.g., dock and castrate) immediately prior to or during wet weather.

Managing and processing lambs

In our system, lambs are processed within 24 hours of birth (except as noted above).  Processing includes docking and castrating, spraying umbilical cords with betadine or iodine, ear tagging, and paint marking.  All ram lambs are tagged in the right ear, as are all terminal ewe lambs.  All potential replacement ewe lambs are tagged in the left ear.  We use small brass tags (adding a larger scrapie tag and a separate breeding group/ownership tag at weaning).  We record lamb number, ewe number, breeding group and EZ Care score for each lamb.  Finally, we paint mark each lamb with its mother’s ear tag number.  Single lambs are paint marked with blue paint, and multiple-birth lambs are marked with red paint.

We process within 24 hours for several reasons.  First, we’ve found that lambs older than 24 hours of age are nearly impossible to catch.  Second, docking and castrating are less stressful for the lambs because their central nervous systems have not fully developed at that age.  We use elastrators for docking and castrating.  This minimizes (or eliminates) any bleeding (which can be a problem when using guardian dogs).  We typically do not need to worry about flies during lambing, as the cooler temperatures seem to suppress fly populations.

Moving ewes and lambs

Moving ewes with newborn lambs can be a time consuming process.  Ewes will tend to want to stay on their “lambing beds” for 18-24 hours after giving birth.  This lambing bed is an imaginary circle perhaps 20 feet in diameter around the area where a ewe gives birth.  Even when we move the rest of the sheep onto fresh forage, a ewe that has just given birth will stay with her lamb(s).

Confident yet gentle dogs are a key to our system.  Ewes with lambs can be very aggressive towards dogs (desirable if they are fighting off predators – less desirable if they’re taking on a border collie).  We try to help our herding dogs walk the line between protecting themselves and not being overly aggressive towards the ewes.  New lambs haven’t learned to move away from our herding dogs – they are generally trying to follow the rest of the sheep, but they do not have any flight response.  Again, gentle dogs are a key.

When we move the flock onto fresh feed, we’ll allow the still-pregnant ewes and the ewes with lambs that are over 24 hours old to move as a group.  We’ll allow any new pairs (ewes with lambs less than 24 hours old) to stay back.  If we can’t encourage these new pairs to move on their own, we’ll carry the lambs.  This is a slow process; a ewe must be able to smell, see and hear her lamb(s) if she is to follow.  Lambs, therefore, must be carried at eye level for the ewe.

Once we’ve moved the entire flock, we’ll stay with them to make sure that ewes and lambs are matched up.  A newly moved flock is quite noisy!  Ewes are calling to their lambs and vice versa.  We try not to get in a rush – a lost lamb can get chilled quickly.

A note on catching ewes and lambs

Sometimes, we’ll need to catch a ewe to examine her or to give her medical treatment.  We also need to catch lambs for processing (and sometimes later for medical treatment).  We’ll use our border collies to help hold a group of sheep close.  I prefer a leg crook for catching ewes – these crooks are designed to hold a hind leg until the shepherd can catch the ewe.  For lambs, I prefer a neck crook.  When catching a lamb, I try to hook it around the chest (not the neck).

Handling problems

a.       Abortions

Ewes can abort their lambs for a variety of reasons.  An abortion rate of 3-5 percent is considered normal.  A more significant abortion rate (sometimes called an “abortion storm”) can indicate a serious problem.  Fortunately, we’ve not experienced this problem.  Should we have a problem in the future, we would collect several aborted fetuses and placentas and take them to the California Animal Health and Food Safety Lab in Davis.  The lab can determine the cause of the abortions, which will allow us to work with our veterinarian to address the problem.

b.      Dystocias

This is a fancy way to say that a lamb is stuck in the birth canal!  Sometimes a lamb has one leg back or is simply a bit too big.  If we can get both front legs forward, we’ll gently pull while the ewe is pushing.  A more complicated dystocia involves a breech deliver (butt-first).  If I can’t get the lamb turned myself, I’ll call my veterinarian.

c.       Mis-mothering

We’ve experienced several types mothering problems.  Sometimes, a ewe just isn’t a good mother (not often, given our system for selecting replacements).  However, it does happen – a ewe simply doesn’t know what to do.  In this case, we’ll usually take the lamb home and bottle raise it.

Some ewes don’t know how to count!  A ewe that has twins will sometimes forget her first lamb while taking care of the second one.  We’ll try penning such a ewe with both lambs with the hope that she’ll remember she has more than one lamb.

Some ewes (especially new mothers) will try to steal a lamb – especially if they are going into labor themselves.  This will usually resolve itself – the lamb’s real mother will aggressively protect her lamb.

Sometimes, a ewe that loses one of her twin lambs will adopt another ewe’s lamb.  If she has enough milk, we don’t worry too much about it.  In fact, we’ll make note of ewes that will take another lamb – sometimes this can make grafting an orphaned or abandoned lamb much easier (see below – grafting means that we try to get a ewe to take a lamb that is not her own.)

d.      Bottle lambs

We always seem to end up with a few bottle lambs.  Some are lambs that are abandoned by their mothers.  Others (in very rare cases) are orphaned when their mother dies.  We’ll also pull the smallest of a set of triplets off the ewe (so that the two strongest/biggest lambs will get plenty of milk).  Finally, sometimes a lamb gets chilled during wet and cold weather and won’t get up to nurse.

We have found that it’s most important to get a cold lamb warmed up before trying to feed it.  Once the lamb is warm (we put chilled lambs on a heating pad in front of our woodstove), its digestive system can handle milk.  We warm the milk to help continue the warming process from the inside out!  We’ve found that a cold lamb’s digestive system often shuts down, so warm milk in a cold lamb doesn’t do much good.

Some lambs don’t have a suck reflex at first.  In this case, we’ll pass a stomach tube directly into its stomach, making sure we don’t pass the tube into its lungs instead.

While we try to get sheep’s milk or goat’s milk for our bottle lambs, we do use milk replacer if necessary.  We also try to make sure that bottle lambs receive colostrum (either from their own mother or from a ewe that loses a lamb at birth – we try to strip out these ewes and save their milk).  This season, we’re trying a new recipe for lambs (up to 3 days of age):

                        ½ gallon whole cow’s milk

                        ½ gallon milk replacer

                        1 cup plain yogurt

                        1 raw egg

This formula increases the protein and probiotic content of the milk, which helps new lambs develop their digestive and immune systems. 

Bottle lambs can be weaned at 30-45 days.

e.      Lamb mortality

In 2011, we lost about 25 lambs in the first two weeks of lambing.  They would be born healthy and seem to thrive for 1-2 days, only to die for no apparent reason.  After taking a dead lamb to the CAHFS lab (see above), we found that our lambs were selenium deficient.  At that point, we gave every lamb an injection of BoSe (selenium and vitamin E) when we processed them, which eliminated the problem.  We also gave the ewes a BoSe injection.

I include this anecdote as a cautionary tale.  Some lamb mortality is normal – some lambs get cold or have other health problems that aren’t preventable.  However, if you experience an uncommonly high mortality rate, work with your veterinarian and with the lab to determine the cause.

 

A note on patience

Lambing is the most labor intensive time of the shepherd’s year, so slowing down and observing the flock may seem counterproductive.   However, experience has taught me that I am often more successful and efficient during lambing if I’m patient and observant.  Knowing when to intervene – with a ewe that’s having problems lambing, or with a lamb that can’t seem to find its mother, requires experience (obviously) – but it also requires patience.

A note on scale

While I have limited experience in lambing out large groups of ewes (1000+), I think there are some management strategies that can help make a large-scale pasture lambing system workable.  Ideally, lambs should still be processed (at least ear-tagged, paint-marked and inoculated (if necessary) within 24 hours of birth – it takes much more time to catch lambs that are more than 1 day old, and more time means more labor costs!  For a large-scale operation, I think drift lambing might make sense – ewes with older lambs and still-pregnant ewes are moved onto a fresh paddock each morning.  New lambs and their mothers, as well as ewes in late-stage labor, are left in the old paddock on their lambing beds until the ewe-lamb bond is established.  In the evening (or perhaps the next morning), these bonded pairs can rejoin the main flock.

Because I see my entire flock of 250 ewes nearly every day, they are quite comfortable with me moving through the flock at lambing time.  I think there may be some value in splitting a larger flock into smaller lambing groups (of 500 +/- ewes) and assigning one person to manage that group during lambing.  Sheep can recognize the shepherd who cares for them regularly, which makes catching and processing lambs less stressful for the flock and the shepherd.

Our Lambing Kit

We keep our lambing kit stocked with the following supplies:

• Elastrators and enough bands for season
• Ear tags and tagger
• LA200 (antibiotic)
• Survive! Drench (for weak or cold lambs)
• BoSe injectable
• 3 cc syringes and needles
• 1 cc syringes and needles
• Lambing notebook (for records)
• Betadine solution in spray bottle (for navels)
• OB lube
• Marking paint (for marking ewe #s on lambs – different colors for singles vs. twins)
• Stomach tube and 60 cc syringe (for tube-feeding week lambs)
• Halter
• Prolapse harness
• Rubber gloves
• OB s-curve needle and suture material
• Towels and rags
• Thermometer
• Slip-on dog leashes (like your vet uses) and/or a lamb puller
• Stethoscope
• Scale and sling
• Pritchard nipples and soda bottles
• Frozen colostrum (ewe, doe or cow)
• Lamb milk replacer
• Neck crook
• Leg crook
• Flashlight or head lamb
• Veterinarian’s phone number (in my case, my wife's cell phone!)