The Bagpipe - American Highland Cattle Association

8
GENETICS AND SELECTION
THE HIND & FORE LIMBS
The Hind Limb
The hind limb of the ideal animal should exhibit the following characteristics:
1. Acceptable set to the hock, as viewed from the side.
2. Straight hind legs, as viewed from the rear.
In South African Simmental herds, hind leg problems are the
biggest single reason (15%) for the rejection from the herd book
(Massman, 1986). Common defects of the hind limb are
discussed in the following sections.
Post-Legged (Straight Hocks)
The post-legged condition is perhaps the most serious
skeletal defect in beef cattle, especially in bulls. Post hind legs
are often associated with steep pasterns. In severe cases, the
animal is apt to become arthritic in any one or all of the joints of
the hind limb - hock, stifle or hip (Blockey, 1981).
In a study on the pathogenetic relationship between straight
hocks and the genetic defect, spastic paresis, Rieck & Leipold
(1964) measured the hock angle of over 200 cattle. The average
angle was 143º. Animals affected with spastic paresis showed an
angle in excess of 158º. As a result of this and other research, the
WSF developed guidelines for the angle of the hock joint. The
range of acceptability was from 120º to 155º, with an ideal of
140º. In contrast, the ideal hock joint angle for the horse is 175º,
which would be much too straight for the bovine.
Results of inadequate angulation: posty hind legs,
puffy hocks, steep pasterns, steep shoulder, buck knees
and small feet.
Sickle-Hocked
The sickle-hocked condition is a serious problem if it reaches extreme proportions, especially when associated with
weak hind pasterns. Severe sickle hocks have been reported to impair the serving capacity of bulls (Blockey, 1981).
Cow-Hocked
The cow-hocked condition is relatively common but seldom has a detrimental effect on function. In extreme cases,
it can result in a long, flat outside claw on the hind feet.
Bow-Legged
The bow-legged condition is not as common as cow hocks but is more serious than the latter. It is associated with a
base narrow stance and a disproportionate amount of weight on the outside claw, often resulting in rolled or corkscrew
claw. Extreme cases may result in puffy hocks and lameness.
Front Limb
A steep shoulder reduces the shock absorbing ability of the front limb. It may also cause a short choppy stride and
reduce the animal’s ability to move long distances in extensive range country. When combined with buck knees and
steep pasterns, the problem becomes more serious. Guidelines for the slope of the shoulder have not been established
in cattle. In the horse, the ideal slope appears to be about 51º. The shoulder of the bovine should probably be no steeper
than that of a horse.
Buck-Kneed (Over at the Knees)
A correct animal’s knee should be straight up and down and in line with the forearm and cannon. A knee that
pitches forward of a line perpendicular to the ground is said to be buck-kneed. This is a very minor defect that has little
or no effect on function. In fact, in animals confined to concrete feedlots, calf knees may possibly work to their advantage
because it could have a cushioning effect and thereby reduce stress on the front limbs.