Structure is the foundation of the animal, and correctness of structure is important to build upon for better animal productivity. The basis for “ Form to Function ” in any specie of livestock is related to the angles of bone structure and the ability to move or travel with ease. The animal ’ s ability to convert feed and forage to a usable protein product (meat, milk, or fi ber) can be compromised by structural problems and diffi culties. If an animal is unsound and not capable of performing or functioning at an optimum level because of structural problems, then emphasis on selection for any measurable trait is for naught. Production (meat, milk, or fi ber) is directly infl uenced by structural
Kid Yearling
2-year-old
3-year-old 4-year-old
Figure 5.4 Determination of age based on dental growth.
soundness or lack thereof. For this reason, selection for sound and functional breeding animals is very important to goat producers and especially to seed - stock or purebred breeders. On the judge ’ s show - ring scorecard, structural correctness is the major component used to assess general appearance.
Side - View Evaluation
The best way, visually, to evaluate structural correctness of an animal is from the side view. The length and depth of the body and the volume (to a lesser degree) of the animal, as well as both front and rear leg structures can be evaluated at the same time from the side view. For longev- ity of service, it is imperative that bucks be especially sound in rear leg and hip structure. Movement or ability to travel can be evaluated by observing the length of stride or step; placement of the rear foot in relation to the front foot; and the fl uidity of motion.
REAR LEGS
The side view of rear leg evaluation is presented in Figure 5.5 . A goat that has the “ ideal ” angulations at its rear legs will be approximately straight down from the pins to the hock and the dewclaw. The sickle - hocked condition is when an animal has too much angulation to the set or angle of the hocks. This trait is often associated with “ weak rear
Ideal Sickle-hocked
Weak rear pasterns Post-legged
Figure 5.5 Side - view rear leg evaluation.
pasterns. ” Animals that are “ post - legged ” have little or no angulations to the curvature of the hind legs. Post - legged animals are prone to suffer stifl e - joint problems and disor- ders. Usually this trait is associated with steep or straight pasterns. Animals that are “ post - legged ” are prone to become unsound much more quickly than animals that are “ sickle - hocked. ”
FRONT LEGS
The side view of front leg evaluation is presented in Figure 5.6 . A goat that has the “ ideal ” angulations at its front legs will be approximately straight down from the shoulder to the knee and the dewclaw. Common front leg structural problems include the condition of “ buck - kneed ” or “ over at the knees, ” a condition when the knees are pitched forward. This is a serious defect and is associated with steep shoulders and steep pasterns and, quite frequently, the post - legged condition, which limits the ability to travel and graze effi ciently. Steep shoulders refer to the slope of the scapula or shoulder blade. Too steep of an angle places
stress on the skeleton because the shock - absorbing ability of the forelimbs is reduced. Steep pasterns refer to the slope of the pastern. Too steep of an angle places stress on the skeleton because the shock - absorbing ability of the foot is reduced. Both of these conditions can reduce the animal ’ s ability to travel. “ Calf - kneed ” or “ back at the knees ” is a less serious defect.
Rear - View Evaluation
In viewing an animal from the rear (Figure 5.7 ), the “ ideal ” legs should come out of the center of the hindquarters and
go straight down to the ground. The most common struc- tural problem viewed from the rear is the condition known as “ cow - hocked, ” also known as narrow or close at the hocks. Larger or longer outside toes magnify this condi- tion. “ Cow - hocked ” is fairly common and seldom is a hindrance to the form and functionality of an animal. “ Bowlegged, ” or wide at the hocks, occurs less frequently and is magnifi ed by larger or longer inside toes. This con- dition is more serious and is frequently associated with animals that are base - narrow and/or have swollen or puffy hocks. Base - narrow refers to animals that lack natural
Ideal Buck-kneed Calf-kneed
Figure 5.6 Side - view front leg evaluation.
Ideal Cow-hocked Bowlegged
Figure 5.7 Rear - view leg evaluation.
muscling or thickness, boldness or spring of rib, and walk with no apparent width between the legs when viewed from either the front or the rear.
Front - View Evaluation
In viewing the animal from the front (Figure 5.8 ), the correct (ideal) knee structure is straight up and down and in - line with the forearm, the knee, the cannon, the pastern, and the foot. “ Splay - footed ” is a common defect and is associated with legs being knock - kneed — a defect in which an animal possesses knees close together and the lower forelimb and foot are wider than the knees, or turned - out — a general term describing any combination of knock - kneed and splay - footed. “ Pigeon - toed ” animals are not common, but this trait is a serious defect because it is often associated with other defects such as being wing - shouldered — extreme width of the shoulders, often causing the front legs to be bowed, base - narrow, or bowlegged. OTHER EVALUATION PARAMETERS
In goats, other anatomical parts should be considered for soundness or defects. Eyes, ears, mouth, teats, and hooves are important. Animals that are blind or cannot hear should not be used in any production scheme and should be culled. Foot structure and hoof size should be in proportion to the bone structure of the animal. Cracked or split hooves can be a concern for longevity. Animals with colored hooves tend to be preferred over animals with lighter - colored hooves.
Mouth
Certain defects of the jaw should be observed. Different conditions in jaw alignments are presented in Figure 5.9 . A mouth that is “ ideal ” in correct alignment has incisor teeth that are fl ush with the pad of the upper jaw, providing a true and even bite. The trait known as “ parrot mouth ” is the condition of an undershot jaw (bottom jaw) or over- bite (upper jaw). “ Monkey mouth ” is the condition of an overshot jaw (bottom jaw) or underbite (upper jaw). Both of these conditions lack coordination between the teeth and the dental pad, thus can hinder prehension or mastication.
Teats
Teat structure is of critical importance. Does should have no more than two functional teats for each side of the udder for meat - type goats and no more than one functional teat for each side for dairy - type goats. It is important that the structure of the udder is such that the offspring can nurse unassisted or the milking machine fi ts properly. Animals with pendulous udders, bulbous or over - sized teats should be culled. Different teat structures are presented in Figure 5.10 . One functional teat (with its milk channel) and one nonfunctional teat, or two functional teats are acceptable for meat goat type. Split teats (teats with two distinctly separate milk channels) are not preferred. Cluster teats, a grouping of three or more teats in which all, some, or none may be functional, and fi shtail teat, a teat with two func- tional milk channels with slight separation between the
Ideal Splay-footed Pigeon-toed
Figure 5.8 Front - view leg evaluation.
Parrot mouth
Monkey mouth
Figure 5.9 Different conditions in jaw alignment (mouth).
channels, should be discriminated against. Retaining off- spring for production purposes of bucks or does with teat or udder defects may not be in the best interest of the breeding program. Evaluation of the teat structure of the buck ’ s offspring (and his dam) cannot be overlooked because the buck will have a signifi cant genetic infl uence on the does retained for replacement purposes.