Delayed Osteon Formation in Long-Bone Diaphysis of an 11-Year-Old Giant Cow with Dermal Dysplasia.

Abstract

ABSTRACT. The transverse sections of radius diaphysis in an 11-year-old giant Holstein cow with dermal dysplasia of a collagen disorderrelated skin fragility (Cow 1), probably based on increasing turnover of the dermal collagen as reported previously, were morphologically and physico-chemically investigated. Cow 1 had about one and a half times as much as the body weight of normal Holstein cows, aged 5 to 6.5 years with stabilized growth. The bone samples were compared with those of a 12-year-old Holstein cow as controls (Cow 2). It has been reported that the long-bone diaphysis of young calves and some herbivorous dinosaurs are occupied with laminar bone showing a concentric appositional formation, and that such a laminar bone is characteristically seen during the growing period of some farm animals and large dogs that show very rapid growth rates. Cow 1 had a smaller number of osteons than Cow 2 in the outer-half layer of the diaphysis, and showed an intermediate type between Cow 2 and a 1-year-old Holstein ox in the entire layers, although their bone volumes were similar among them. There were no significant differences in Ca and P concentrations and the Vickers microhardness values between the bone matrix of Cow 1 and Cow 2. The bone-collagen fibrils of Cow 1 showed uneven diameters and a disordered arrangement. Thus, there may be some relation in collagen formation between the bone matrix of Cow 1 and the dermis. From the remaining volume of laminar bone, Cow 1, aged 11 years, had probably shown growth until quite recently, so that we consider that Cow 1 became a giant animal, in the same way as some herbivorous dinosaurs.-KEY WORDS: compact bone, delayed osteon formation, giant bovine, histology, laminar bone.J. Vet. Med. Sci. 61(2): 101-106, 1999 In this study, for the purpose of studying the structure of bone matrix and also for comparing with the dermal collagen fibrils [8,10], we investigated the radius diaphysis of the giant cow by using microradiography, backscattered electron (BSE) imaging, image analyzing, electron probe microanalyses including wave-dispersive X-ray (WDX) and energy-dispersive X-ray (EDX), microhardness test, and scanning electron microscopy. As controls, a 12-year-old Holstein cow and a 1-year-old Holstein ox were employed. MATERIALS AND METHODS Animals:The 11-year-old Holstein cow with dermal dysplasia of a collagen disorder-related skin fragility [8] was sacrificed, and the radius was removed. The cow (Cow 1) showed a heavier body weight (about 1,000 kg) [10] than normal Holstein cows (about 650 kg), aged 5 to 6.5 years, thus showing a maximum level in growth [9]. In clinical observations, Cow 1 was found to be in good health except for the dermal dysplasia and her behavior to be normal [11]. For controls, the radius of a 12-year-old normal Holstein cow (Cow 2) and the tibia of a 1-year-old normal Holstein ox (1-year ox) were applied. Their diaphyses were cut transversely into several slices with a diamond wheel and then fixed with 10% buffered formalin, 70% ethanol, or a 4% ...

Histological Comparison of Long-Bone Cortex between 11-Year-Old Giant Cow with Dermal Dysplasia and the Child Cow Aged 8.5 Years

“…The laminar bone has been reported to form long-bone cortex in young calf, pig, sheep, and other young large animals [2,3,5,[8][9][10][11][12]15] including some larger dinosaurs [4,6]. One laminar bone unit consists of a hypercalcified primear line in the center, woven bone on both sides of the line, and lamellar bone with laminated appositional lines [2][3][4][5][6][9][10][11][12].…”

“…One laminar bone unit consists of a hypercalcified primear line in the center, woven bone on both sides of the line, and lamellar bone with laminated appositional lines [2][3][4][5][6][9][10][11][12]. Such a laminar bone as calf bone-cortex is gradually replaced by Haversian bone with osteons during their growth periods [2,10,11,15].…”

“…Such a laminar bone as calf bone-cortex is gradually replaced by Haversian bone with osteons during their growth periods [2,10,11,15]. Previously [9], we reported that an 11-year-old giant Holstein cow with dermal dysplasia (Cow 1) [7,14] showed a delayed osteon formation in a larger number of the remaining laminar bone volume compared with a 12-year-old Holstein normal cow (Cow 2). In additions, the outer circumferential lamella formation, meaning the stop of bone growth in thickness [1,6,16], was not formed yet.…”

“…Previously [9], we indicated in the bone matrix of Cow 1, similar to the dermal collagen formation [7,14], that a larger amount of newly-formed collagen fibrils, might be calcified during laminar bone formation without bone remodeling [2]; thus, the increasing bone formation was seen in Cow 1 until 11-year-old or so [9]. There was retained as the problem whether such a delayed osteon formation succeeded to the next generation or dose not, as well as the dermal dysplasia based on collagen disorder [7,14].…”

“…It has been denoted that Holstein cow was stabilized growth in body weight and height during 5 to 6.5 years after birth in a veterinary dictionary [13]. This note will mean that the laminar bone formation on the thickness-growth of long-bone cortex [2,6,[9][10][11] is stopped during 5 to 6.5 year after birth; and then the outer circumferential lamella will be formed already [1,6,16] as shown in Cow 2 as the control of Cow 1. Child 1 at the 8.5-year-old stage was 650 to 700 kg by weight.…”