Sheep Resource Handbook
Sheep Resource Handbook
Thank you for your interest in the Ohio 4-H publication 194R Sheep Resource
Handbook (2011). The following pages show the areas in which significant
changes have been made to the 2000 edition. Pages with only minor changes are
not included.
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Ohio only: Ohio 4-H club advisors, club members, and other Ohio residents get the best price
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To the Member
After you have made the decision to take a sheep     and safe product—in other words, lamb that
project, it is important that you know what type     the consumer wants to buy. To have a successful
of animal you are looking for, how to feed it,       project you must be willing to study and review
diseases it may have, management practices, and      the information contained in this handbook and
many other important concepts.                       apply it.
By teaching you these matters through                The 4-H member project books contain activities
information and experience, this project will        that enhance learning from the information
make it possible for you to produce a high-quality   gained in this handbook.
Sentence updated.
History
                   Sheep were brought to North America by Spanish and English settlers. Columbus
                   brought the animals to the New World on his second voyage in 1493. Sheep were
                   shipped to Virginia from England in 1609. As people moved west across the United
                   States, sheep went with them. Approximately 75 percent of the sheep in the United
                   States are now west of the Mississippi River.
                   Sheep are found on many farms in Ohio. They can be a good source of income
                   with two important products—wool and meat.
	                                                                  Chapter 1 • Introduction	           7
	                                                Chapter 2
	                                                                         Chapter 2 • Selection	         9
	 Judging Market Lambs                                 	 Parts of the Lamb
The main points to consider in judging market          To be successful in raising and selecting sheep,
lambs are structure, type, muscling, and finish.       you should know the names of the various parts
(See Figures 3 and 4.) Evaluation of carcass merit     of the animal and their locations on the animal’s
is an estimate that measures the relationship          body. Using industry-accepted terms helps you
between finish and muscle.                             know what to look for and to accurately describe
                                                       an animal’s traits (Figure 1).
                Paragraph updated.
                                                                           Last sentence updated.
                                                Figure 1
                                             Parts of a Sheep
	                                                                       Chapter 2 • Selection	        11
This knowledge should be permanent, at least
for as long as you are involved in raising and
showing sheep. When talking to fellow
                                                        	 Size Considerations
4-H members, a breeder, or a judge, you will
want to sound knowledgeable about your 4-H              Regardless of breed, it is important when
project. So take some time now to study the             selecting your project lambs to select ones at the
following diagram and become thoroughly                 right size. Select a size that is appropriate to the
familiar with all the indicated parts of a lamb.        amount of time you have from project start until
                                                        fair time. Know the dates of your fair and figure
                                                        the number of days you will be feeding your
                                                        lamb. Lambs will generally be purchased at 10–
                                                        14 weeks of age and will weigh 60–90 pounds.
        Ages and weights updated.
                                                 Figure 2
                                           Sheep Skeletal System
12	      Chapter 2 • Selection
Paragraph and chart updated.
 Most lamb projects are started in April or early       When selecting size, don’t forget to consider
 May. Market lambs at fair time should weigh            frame size as well. Frame size plays an important
 100 pounds or more, with ideal being 115–              part in the weight of your lamb. If you have a
 140 pounds. Minimum weight varies due to               large-framed lamb, it can carry 130 pounds much
 individual fair requirements. An average lamb on       easier and better than a smaller framed animal.
 a good ration will gain 0.60 to 0.80 pounds per        The smaller framed lamb will appear to be fatter.
 day. Feed your lamb with a weight goal in mind,        Also, if you are buying two or more lambs,
 leaving margins for extreme hot weather, sickness,     choose animals that are similar in frame size and
 and other unforeseen problems.                         weight.
 The following chart may help you in selection:
     Anticipated weights for lambs
     gaining .68 pounds per day:                        	 Selecting the Right Type of Lamb
 	 Days Until	 Purchase	 Total	          Final
 	 Showing	     Weight	  Gain	           Weight         A good lamb should catch your eye when you
 				                                   (rounded)       first see it. Select lambs with enough length of
 	    100	        50	     68	              118          body and leg to denote growthiness but with
 	    100	        65	     68	              133          good muscle development over the hindsaddle
 	    100	        80	     68	              148          and in the rear legs. Avoid short, fat, and early-
 	     80	        50	    54.4	             104          maturing lambs or rangy, narrow types that lack
 	     80	        65	    54.4	             119          muscle development or ruggedness.
 	     80	        80	    54.4	             134
 	     60	        50	    40.8	              91
 	     60	        65	    40.8	             106
 	     60	        80	    40.8	             121
                                                                    	 1.	 Balance
                                                                    	 2.	 Size and scale
                                                                          (Height, length and width)
                                                                    	 3.	 Depth of body
                                                                    	 4.	 Length of body
                                                                    	 5.	 Levelness of rump
                                                                    	 6.	 Length of hindsaddle
                                                                    	 7.	 Depth and fullness of leg
                                                                    	 8.	 Trimness of middle
                                                                          (market lamb)
                                                                    	 9.	 Correctness of feet, legs and
                                                                          pasterns
                                                                    	10.	 Length of head and neck
                                                                    	11.	 Trimness of breast
                                                  Figure 3
 	                                                                        Chapter 2 • Selection	          13
                    Paragraph updated.
Note added.
                                                    Figure 4
14	      Chapter 2 • Selection
After viewing several lambs, you will soon realize
that the angle at the hocks varies. The greater
the degree to which this angle varies, the more
incorrect the animal is and the more serious the
fault (Figure 5).
The sickle-hocked lamb (Figure 5) has too much
set or angle at the hock. In horses, this defect
causes curbing, a bony growth on the back of the
hock that develops because of strain on the joint.
This can occur in sheep, but rarely does, because a
sheep does not strain the hock to the same extent
as a horse.
A more serious fault is a hind leg that is too
straight, or post-legged (Figure 5). This condition
changes the angulation of the bones at the hock
and the stifle joint and shortens the stride. The
patella (knee cap) at the stifle joint may be
displaced resulting in a stifled, lame, unsound
animal.
Figure 5 illustrates the proper set to the hind                          Figure 6
leg when the animal is viewed from the rear.                  (North Central Region Extension
Figure 5 shows a cow-hocked lamb. With this                          Publication #300)
condition, the hocks are too close together, the
cannons are not parallel and the toes deviate                                                    Measurements
extremely outward. A lamb with this defect has         Finish                                    updated.
an unsightly, inefficient gait.                        Correct finish is important to determine the
                                                       cutability (retail value) of a lamb. Finish is the
A lamb can also be bowlegged off the hind legs
                                                       amount of external fat on a lamb. To determine
(Figure 5).
                                                       the amount of finish, handle the lamb over the
                                                       backbone and ribs. Excessive prominence of the
Sheep Jaw Structure                                    backbone and ribs shows a lack of finish. Too
                                                       much finish is present when you cannot feel the
(See Figure 6.)
                                                       backbone or ribs by normal handling methods.
  A.	 Undershot (Parrot-mouth)—in this                 Correct finish is 0.15–0.25 inches of backfat.
      situation the lower jaw is too short.            Desirable traits in regard to finish include:
  B.	 Overshot (Monkey-mouth)—the lower jaw            smooth and uniform fat cover over the ribs; no
      is too long, and the teeth are in the front of   excessive fullness in breast; a uniform fat cover of
      the upper mouth pad.                             0.15–0.25 inches.
  C.	 Normal mouth—the top and bottom jaws             Finish or Condition is evaluated in the:
      are properly aligned. Note that the incisor      	 •	 sternum	          •	 over backbone and loin
      teeth are flush with the pad on the upper              		 (12th and 13th rib)
      jaw.                                                                                      Parenthesis added.
                                                       	 •	 lower forerib	    •	 flank
Unsound mouth diagrams such as A and B are
                                                       	 •	 upper rear rib	 •	 twist
inherited traits that interfere with the sheep’s
ability to gather food.                                The measurement over the 12th and 13th rib is
                                                       the only measurement used in the current USDA
                                                       yield grade equation.
16	      Chapter 2 • Selection                                                         Sentence added.
                    Animal A                                               Animal B
                                2
                                    4                                                   3
                                                                                                  2
                                                                           1
                       1                     3                                           4
                                        5
    Animal A is shorter bodied and too fat.            Animal B is tall, long bodied and trim but lacks
    	 1.	 Excessive depth of body                      balance, thickness and muscle.
    	 2.	 Shorter-bodied                               	 1.	 Shallow-bodied (tight hearted)
    	 3.	 Steep-rumped                                 	 2.	 Shorter-rumped
    	 4.	 Shorter hindsaddle                           	 3.	 Shorter hindsaddle
    	 5.	 Is light-muscled and fat through leg         	 4.	 Flat, narrow, shallow leg that is light
    	 6.	 Wasty-middled                                      muscled
Condition
                                                       Soundness
Condition refers to the amount of fat. In
breeding sheep, excess condition leads to              Soundness (skeletal correctness) in mouth, feet,
reproductive problems. Over-fat ewes have              legs and fleece are important in breeding sheep.
trouble breeding and lambing. Ewes that are too        The lower teeth should hit even with the upper
thin also may have trouble breeding or raising         pad. (See Figure 6.) Straight, strong legs and
lambs.                                                 adequate bones are also desirable. The legs should
                                                       be set squarely on the corners of the body. (See
	                                                                       Chapter 2 • Selection	         17
and their vulvas should be well developed and
relatively flat, not tipped. Compare each animal                  Determining Age
against the others in the class.
                              Sentences added.
	 Breeding Animals
                                                       Lamb’s teeth
In selecting breeding animals, consider the
requirements to meet your needs. Set goals for
the market for which you intend to produce,
and then select breeding sheep to meet that
goal. You might be trying to produce elite             Yearling’s teeth
breeding stock for purebred operations, or
perhaps to produce competitive wether lambs for
exhibition, or perhaps to produce market lambs
for direct marketing to consumers. Heredity and
environment will affect the animals’ ability to        2-year-old’s
meet these requirements.                               teeth
When selecting breeding animals for your flock,
define your objectives. Know what you want to
do with your 4-H breeding sheep before you start
buying animals. Ideal breeding sheep should be
                                                       3-year-old’s
structurally correct (check the mouth for age and      teeth
soundness, the testicles of rams to makes sure
they are correct in size and development), have
adequate frame size and weight for their age, be
in good body condition, and have correct breed
and sex characteristics. (See Figure 8.)               4-year-old’s
Sheep can be approximately aged by the number          teeth
of permanent incisors on their lower jaw. Lambs
have eight temporary incisors. (See Figure 9.)
Once a lamb reaches about one year of age, the
center teeth are replaced by two permanent ones.       Narrower, worn
The sheep then gets two more permanent teeth           teeth of an older
                                                       sheep
each year (one on each side of the center) until
they reach four years of age. At age four, the
sheep have all their permanent incisors.
	                                                                          Chapter 2 • Selection	             19
                                                                                  Sentences added.
		 ingredients like soybean meal, cottonseed
      meal, etc. Collective terms denote a general
      classification of ingredient origin which
                                                      	 What about Hay?
      performs a similar function, but do not
      imply equivalent nutritional values.            For proper digestion, a sheep must have a certain
      The list of ingredients can be very             amount of roughage in its ration. Hay should
      enlightening. For example, if the product       be fed in adequate amounts each day to keep
      is supposed to be a high-quality protein        the rumen of the lamb functioning properly.
      supplement and the first item on the list is    Breeding ewes will need more hay than market
      “Processed Grain By-Products”, the product      lambs. Roughage should be high in quality and
      may contain high levels of low cost, inferior   fine-stemmed. Good quality roughages are those
      carrier.                                        that are cut early. Feed a good quality legume hay
                                                      (alfalfa). Green grass is not always a good idea
	 6.	 Directions for Use. Each product tag should
                                                      because it contains too much water and does not
      provide information on how the product
                                                      provide enough fiber to the lamb. Additionally,
      is to be used. Warnings or precautionary
                                                      many believe that a ground, pelleted form of
      statements should be included. For example,
                                                      hay in a complete ration or feed is enough.
      any product containing monensin must
                                                      The addition of long stem (not ground) forage
      carry the warning that it should not be fed
                                                      improves stimulation of the rumen even more
      to horses. Ingestion of monensin by equines
                                                      through an event commonly referred to as scratch
      has been fatal.
                                                      factor. This helps ruminal health and maximizes
	 7.	 The name and mailing address of the             buffering capacity, reducing acid in the rumen.
      company responsible for making or               In other words, a certain amount of long stem
      distributing the feed. (XYZ Feed Company        forage is necessary at each feeding, regardless of
      Sheep Division, Anytown, USA 12345)             the stage of production.
	 8.	 Net Weight Statement. This may be listed
                                                      Depending upon the stage of production of the
      in pounds or kilograms. Many companies
                                                      ewe flock, different amounts and qualities of hay
      are listing net weights in the metric system.
                                                      can be fed. Ewe flocks on a maintenance diet can
      A kilogram is equal to 2.2 pounds, thus
                                                      be fed a poorer quality hay than in late gestation.
      a 50 pound bag may be listed as 22.6 kg
      (kilograms). (Net weight: 50 lbs.)
Read the tags on the products you intend to
use and fully understand what you are doing
before you start using a product. Many potential
problems can be avoided if you make sure that
you are getting a suitable product and are feeding
the correct amount to your livestock. Make sure
that withdrawal times are noted and that they
will not prevent you from showing or selling your
animal as planned.
	                                                                      Chapter 4 • Nutrition	         65
    	                                                  Chapter 6
    Quality grades are used to predict palatability           Yield grade refers to the expected yield of
    characteristics such as: tenderness, juiciness, and       boneless, closely trimmed retail cuts. The five
    flavor. The quality grade of an animal is based on        yield grades are numbered 1 through 5. Yield
    two general considerations that influence carcass         grade 1 is more desirable because it represents the
    excellence: conformation and quality. Quality             highest yield of meat from the retail cuts, while
    includes fatness, maturity, and other indicators of       yield grade 5 represents the lowest yield.
    differences in palatability of the lean flesh such as     The amount of external fat plays the primary
    flank streaking and firmness of the lean.                 role in determining yield grade. The amount of
    Conformation is the degree of total muscling in           fat is measured at the 12th rib above the loin eye
    the carcass in relationship to the skeletal frame         muscle (Figure 58). As the amount of external fat
    size and degree of finish, especially in the leg,         increases, the percent of retail cuts decreases, with
    rack, loin, and shoulder. Maturity is the age             yieldgrade moving closer to 5.
    of the animal. The lamb is an immature sheep
                                                                Sentence updated.
    usually under 12 months that has not cut its
    first pair of permanent incisor teeth, or the meat          Sentences added.
    is classified as mutton. The evaluation is based
    on physiological maturity (bone maturity), and
    not chronological maturity (actual age). When
    a lamb is physiologically mature, cartilage in the
    growth plate ossifies and turns to bone, meaning
    the animal is now classified as mutton. Flank
    streaking is the amount of fat on the surface
    of the flank muscle. (See Table 6.) Firmness of
    lean and fat is measured at the flank and is an
    indicator of carcass fatness. The lamb also must
    have a minimum amount of external fat (0.15
                                                                                     Figure 58
    inch) covering the carcass to protect it from
                                                              Side view of a lamb which shows the location
    shrinking and drying out in the meat cooler.
                                                              of the 12th rib site for backfat and loin eye area
    The USDA quality grades for lambs and yearling            estimation.
    carcasses are Prime, Choice, Good, and Utility.
    The majority of all quality graded lamb carcasses         If the carcasses are not ribbed, the muscle size can
    are Prime or Choice.                                      be estimated by evaluating the muscling in the leg
                                                              and the width and fullness over the rack and loin.
    The quality grades for slaughter (mutton)
    carcasses are Choice, Good, Utility, and Cull.
    	
Paragraphs                                                  Chapter 6 • Carcass Evaluation and Meats	              73
updated.
       The amount of external fat at the 12th–13th
       rib determines yield grade. To find yield grade      	 •	 Shorn lambs will have a higher dressing
       use the following equation: YG = 0.4 + (10 x              percent.
       adjusted fat thickness over the loin eye). Using     NOTE: Lambs with extremely high dressing
       this equation, the fat thickness range for each      percentages, greater than 56%, are usually
       yield grade is as follows:       Number changed.     exaggerated as a result of extreme feed deprivation
       	 Yield Grade	          Adjusted Fat Thickness       or restriction from water. Withholding feed or
                                                            water is not in line with good animal (livestock)
        	       1	                0.07–0.15 inches
                                                            care and handling and should be avoided at all
        	       2	                0.16–0.25 inches          costs.
        	       3	                0.26–0.35 inches                                              Note added.
        	
Note added.     4	                0.36–0.45 inches
        	       5	             0.46 inches and greater      	 Finish
       Note: If a lamb does not have at least 0.07 inch
       fat over the loin eye, it cannot be U.S.D.A.
                                                            Finish refers to the thickness and distribution
       graded (neither yield nor quality). An ideal
                                                            of external fat. In the ribbed carcass, the degree
       fat thickness meeting the desired fatness for
                                                            of finish can be determined by observing the fat
       the lamb industry is 0.12 to 0.25, a very tight
                                                            thickness directly over the top of the two loin eye
       margin. Lambs that are leaner, less than 0.12, are
                                                            muscles at the center of the longissimus muscle.
       considered to be ultra-lean and are not desired by
                                                            This usually is an indication of the total fatness of
       the meat packing industry because they dry out
                                                            the carcass. The ideal finish on a lamb is 0.12 to
       in the cooler.
                                                            0.25 inches of fat.
         and 13th rib). Then the loin eye area can be used
         as an indicator of muscling. The loin eye area
         can be measured using a plastic grid which has
         20 dots or squares for each square inch. Place
         the grid on the cut surface of the loin eye and
         count all of the dots which touch the lean of the
         longissimus muscle, being sure not to include the
         small muscles which surround the longissimus.
         (See Figure 60.) Divide the number of dots by
         20 and the result is loin eye area in square inches.
         The loin eye area should be recorded to the
         nearest 0.1 square inch. The normal range of the                                               Figure 60
         size of the loin eye is 2.0–3.0 square inches. Some                             Picture of loin eye with grid over it.
         extremely heavy-muscled lambs exceed 3.0 square                            Actual size of this loin eye is 3.0 square inches.
         inches in loin eye area. The industry average
         across commercial lambs, show lambs, and                               Goals for Lamb Production
         lambs marketed locally or through direct market
                                                                                	 1.	 Average daily gain of 0.68 pounds or better.
         channels is about a 2.7 square inch loin eye.
                                                                                	 2.	 54 percent dressing for shorn lambs.
         NOTE: Some exhibitors believe increasing the live                      	 3.	 50 percent of carcass in hindsaddle.
         weight of lambs for the show ring results in more
Note                                                                            	 4.	 2.5 square inches of ribeye area per 50
         product to the consumer. However, we have seen
added.                                                                                pounds of carcass.
         an increase in live weights over the last 25 years
         and no real significant change in loin eye area.                       	 5.	 0.12–0.25 inch fat over center of the ribeye.
                                                                                	 6.	 Choice quality grade or better.
                                                                                	 7.	 Yield grade equals 1 or 2.     Goals 1 and 5
                                                                                                                        adjusted.
                     Relationship Between Flank Fat Streakings, Maturity and Quality
                     	                               	      Young lamb	    Older Lamb	 Yearling Mutton	        Mutton
                     	                           Abundant
                     	                           Moderately
                   Degrees of Flank Streakings
                     	                           Abundant
                     	                            Slightly
                     	                           Abundant
                     	                           Moderate		                   Prime
                     	
                     	                            Modest
Choice
                     	   Slight
                     			                                                      Good
                     	   Traces
                     	 Practically
                     	  Devoid		                                             Utility		                             Cull
                     		            Young Lamb	                             Older Lamb	 Yearling Mutton	        Mutton
                     			                                                            Maturity
                                                                          Table 6
         	                                                                   Chapter 6 • Carcass Evaluation and Meats	                   75
Paragraph updated.
Callipyge Gene
           In recent years, a new heavy muscling trait has           hypertrophy is of genetic origin and is capable
           been identified in sheep. Many sheep producers            of being passed from parent to offspring.
           have been referring to the trait as “double               Researchers have named the gene “callipyge”
           muscling.” Meat scientists say this trait is not          meaning “beautiful buttocks” (x=normal,
           like the double muscling found in cattle and              X=callipyge). Lambs with the callipyge gene have
           hogs which is actually an increase in muscle cell         much more muscle and less fat but also have
           number. In sheep, extreme heavy muscling or               tougher meat. This gene is undesirable because
           muscle hypertrophy is an increase in muscle cell          the meat for the loin muscle is so tough and
           size. Observations have suggested the muscle              unpalatable that it is not wanted by consumers.
Foreshank
                                                               Table 8
           	                                                      Chapter 6 • Carcass Evaluation and Meats	         77
    Percent of Boneless, Trimmed,
    Retail Cuts from Each Yield Grade                  	 Lamb Production and
 		            % Boneless, Trimmed Cuts                  Consumption
		               from Leg, Loin, Rack
	 Yield Grade	       and Shoulder                      U.S. consumption of lamb is 1.0 pounds per
	        1	                 47.3 >                     person per year on a carcass weight basis. Most
	        2	                 45.4 to 47.2               lamb in the United States is consumed in the
	        3	                 43.7 to 45.3               Northeast and in the western coastal states. New
	        4	                 41.9 to 43.6               York and California are the top two states in lamb
	        5	                 < 41.9                     consumption.
                     Table 9
                                                         Top U.S. states in sheep and
Specifics                                                lamb production (heads):
Due to the diversity of the sheep industry, a wide       	 1.	 Texas	              820,000
range of specific requirements are acceptable
                                                         	 2.	 California	         660,000
depending upon the local lamb market for which
a sheep producer is producing lamb.                      	 3.	 Wyoming	            420,000
                                                         	 4.	 Colorado	           410,000
Weight of Live Market-ready Lamb
                                                         	 5.	 South Dakota	       305,000
Range: 100–150 pounds
Ideal: 115–140 pounds**
                              Range updated.             Ohio ranks 13 –largest sheep producing
                                                                         th
                                 Sheep Products
You will probably find it interesting and perhaps
useful to see how a market lamb contributes to        	 Meats
the Consumer Market.
Figure 61