Structural Soundness and Body Conformation

129 Cold Winter Climates

5.3.3. Structural Soundness and Body Conformation

Bulls need to be able to withstand the physical demands of reproduction in order to have a long and productive life in the breeding herd. Correct structure and conformation is essential to ensure that bulls can walk, forage, successfully mate with many cows during a restricted period, and their calves are born without diiculty. Bulls that exhibit undesirable body conformation traits should not be considered for use in a breeding program as many such traits are heritable, and are likely to be passed on to their progeny. Sound body conformation is based around the animal’s limbs. Shoulders The shoulders and front leg structure of the bull are shown in Fig. 5.2. Ideally the shoulders should slope forward about 45–60 degrees. This angle applies even pressure on all leg joints and provides good shock- absorbing ability during mounting and dismounting cows at mating. A bull with less angle at the shoulder joint and elbow joint has straighter front legs with less shock-absorbing ability. These straight-shouldered bulls tend to walk with a short choppy gait and may have diiculty raising his head much above his backline. Quite often the tip of the shoulder blade is prominent above the backline. Usually, a bull that is straight in the shoulder will also be straight in the hind leg. These bulls are particularly prone to early breakdown through the wearing of the leg joints, and the onset of arthritis. While many straight-shouldered bulls will break down in the hind leg, they are also more susceptible to arthritis in the pasterns and knees of the front leg. Straight-shouldered bulls may also be straight in the pasterns, causing rapid wearing of the front of the hooves. Figure 5.2. Front leg and shoulder structure of the bull. Source: NSW DPI. A Ideal B Straight leg Boxy foot Straight shoulder Head down C Too much angle Long toes Calf knee 130 Beef Breeder MANUAL The shoulder should be smooth against the rib cage. Bulls whose shoulders are wide at the point of the shoulder the base of the neck or wide between the shoulder blades when observed from above may throw heavily shouldered calves, increasing the chance of calving problems Fig. 5.3. Front Legs The front legs of the bull should be straight when viewed from in front. On a structurally sound animal, a vertical line may be drawn from the point of the shoulder to the middle of the claw. This line should intersect the knee Figure 5.3. Front view of shoulder conformation. Source: NSW DPI. Fig. 5.4. As the knee joints carry more than half the bull’s body weight, deviations from this line may cause excessive wearing of these joints. A ‘knock-kneed’ bull may have turned-out front feet up to 10 degrees is considered normal. A bull is considered ‘knock-kneed’ when the knee joints lie inside this line, which may eventually lead to overgrown outside claws. A bull that is wide at the knees bow-legged presents a more serious problem. These animals are often narrow in their stance and may roll their feet as they walk. They can also be wide in their shoulders. Figure 5.4. Front view of normal and undesirable front leg structures. Source: NSW DPI. Smooth shoulders Prominent shoulders Normal Knock-kneed Bow-legged 131 Cold Winter Climates From the side, the forearm and cannon bones should be in a straight line. A knee joint forward of this line buck-kneed can be associated with steep shoulders and pasterns, and may be a serious fault. A knee joint set back of this line calf-kneed may be associated with sloping shoulders and has little impact on function. Hind Legs The structure of the hind legs is similar to that of the front legs. Again there are well-deined angles in the joints at the hip, stile, hock and pastern joints. The angles are critical, particularly during mating when large amounts of stress are placed on these joints. Deviations from the correct angles Fig. 5.5 will cause excessive wear and tear on the joints, leading to early breakdown. More bulls seem to break down from problems associated with the hind leg than from any other reason. Too much angle in the leg joints straight-legged is a serious structural fault. These cattle don’t have the lexing and shock-absorbing efect of the structurally sound animal, and they are prone to severe wearing of the hip joint, leading to arthritis. Bulls with arthritic problems are reluctant to serve many cows, as the condition can be quite painful. Straightness in the hind leg can also be seen in the hock and pastern joints, and these cattle will wear the front of the claws, resulting in short upright hooves. Figure 5.5. Normal bull hind leg structure and common structural faults. Source: NSW DPI. Correct Too straight Sickle-hocked Correct Bow-legged Cow-hocked 132 Beef Breeder MANUAL If the degree of the angle in the leg joints is less than ideal, ‘sickle hocked’ condition may exist. This is less of a problem than straight legs, but in extreme cases may cause strained ligaments pastern and hocks and long claw growth, increasing the chance of injury, and afecting serving ability. Sickle-hocked bulls may overstep the mark of the front feet as they walk out. Viewed from behind, the leg and hock joint should be in a straight line. A bull is ‘bow legged’ when the legs are turned outwards at the hocks, but the hooves are turned in. This can be a serious problem if the extra strain placed on the ligaments leads to lameness. These animals should not be considered for use in a breeding program. Less of a problem are ‘cow hocked’ animals when the hocks are rotated inwards and the hooves rotated outwards. This is only a problem in extreme cases where uneven pressure on the claws may cause the outside claw to grow long. Feet The way the claws of the feet grow often indicates structural problems higher up the legs. Long or excessively short even claws may indicate too much or not enough pastern angle, causing both claws of the hoof to grow or wear excessively. Overgrown claws afect the mobility and performance of the animal. Fig. 5.6 indicates the correct angle of the pastern joint. Uneven wearing of the two claws, where one grows longer than the other, is often due to a problem in the leg structure. It is caused by an uneven distribution of weight through the foot. Avoid overgrown, scissor or curved claws Fig. 5.7. Mild curling is normal, although it can be exaggerated by heavy feeding and soft soils. Overgrown, uneven claws are usually indications of poor limb structure or early signs of hip arthritis. Avoid extremely short feet, which are often associated with over-straight legs. Figure 5.6. Normal pastern and hoof structure, and examples of common faults. Source: NSW DPI. Correct Too much angle Too straight 133 Cold Winter Climates Walk A structurally correct bull, when walking, will place his hind foot in exactly the mark left by his front foot. If he is lame, or not moving freely, or if he is straight in his leg structure, he will short-step and not reach his mark. Likewise, if he is sufering arthritis in one leg he may tend to short-step or drag his leg on that side. Problems such as these will afect the serving ability of the bull.

5.3.4. Penis and Prepuce