Nutritional Secondary Hyperparathyroidism in the Horse

46 Experimental Nutritional Secondary Hyperparathyroidism in the Horse . . .
less inclined to play. IHe also showed a lack of freedom in moving his forelegs.
At times his stride appearcd shortened and stilted. Percussion of his maxillary
sinuses indicated a slight loss of density.
NSH 2 became progressively worse. Some days he would hesitate to move.
He did not play spontaneously and if chased around the paddock preferred to
canter rather than trot. After this forced exercise he would stand trembling on his
forelegs. He was lying down more than the other colts. In attempting to rise he
would extend his forelcgs and start to spring to his fcet in a normal manner but
fail in the attcmpt and sink back in sternal or fall in lateral recumbency. Two or
three attempts were oftcn necessary before he rose to his feet.
The mandibular cnlargcmcnt of NSH 2 progressed slightly, as did the
“cardboard” sound on percussion of the maxillary sinuses. By week 34 the facial
crcst seemed to bc less promincnt, cspecially rostrally. Thc face began to have a
full appearancc, lacking sharp, bony angulations. The corner incisor teeth could
be moved slightly by hand.
NSH 3 bcgan to have trouble rising during week 25. tler movements with
the forelegs became stiff and stilted. If forced to canter she moved with a peculiar
“rabbit hopping” motion with her rear legs. The stiff, painful, and very short
stride secmed to account for the hopping appearance. The progress of this lameness
was similar to that of NSH 2. During week 28 NSH 3 was lame in her right
foreleg. She would not play spontaneously. Pcrcussion sound changes of the
frontal sinuses progrcsscd as in NSI-I 2. There was, however, no enlargement of the
mandible or maxilla.
During week 35 throzgh week 41 NSH 1 rcmained the same. He was destroyed
during week 41. Early in week 40 NSH 2 was unable to rise. He had suffered a
distal epiphyseal separation of the right radius. With the help of rope slings he
could be placed on his feet but would stand by himself for just a few minutes.
‘The area surrounding the distal radius was swollen and warm. The colt would
not bear weight on his injured foreleg. Subsequently, dccubital sores and rapid
weight loss occurred. He was dcstroycd during wcek 41. NSIH 3 showcd progrcs-
sive difficulty in rising. IHer stride became shorter, stiffer, and more stilted, and
she stumbled oftcn. Her toes wore down and her heels grew long. Percussion of thc
maxillary sinuses indicated a progressive decrcase in bone density. Swelling was
not evident in the mandible but was present to a mild degree in the maxilla. All
her incisor teeth could be moved by hand. She was destroyed during weck 41.
The control horse was vigorous and playful. His hoofs wore more evenly
than those of NSIH 2 or NSH 3. No symptoms of lameness were noted. In general,
his facial contours were much sharpcr than those of NSH 2 or NSH 3. He was
destroyed during week 42.
2. Clinico-pathologic Determinations
The results of weekly determinations of phosphorus, calcium, and
alkaline phosphatase levels of blood serum are presented in Charts 5
through 8 (regression equations are given in the Appendix, Table 111).
The results may be summarized as follows:
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