Preliminary Study of Histological Comparison on the Growth Patterns of Long-Bone Cortex in Young Calf, Pig, and Sheep

Abstract

ABSTRACT. Some young large farm animals show a laminar bone formation in the long-bone cortex. Such a laminar bone is gradually replaced by Haversian bone with osteons during their growth periods. In this preliminary study, we observed the transverse ground samples of tibia cortex in young calves, pigs, and sheep by backscattered electron imaging. The cortex bones of all the newborn (NB) animals were basically formed with laminar bone structures. The NB and 1-month-old (1-M) calves had a typical concentric structure of laminar bone, whereas the NB and 1-M pigs showed a wire-netting bone with laminar-bone units. The NB sheep was similar to the calf rather than the pig. In the growth rate of bone volume, sheep was similar to calf up to 6 months after birth (6-M). Such calf and sheep showed a more rapid ratio of bone volume than pig. A few osteons had initially appeared in the innermost layer of the 6-M calf. A 1-year-old (1-Y) calf showed scattered osteons in the bone cortex, but many laminar-bone units were still retained in the outer layer. A 6-M pig had many osteons in the entire cortex but only a few osteons in the outermost layer. In the 6-M sheep, no osteons were observed, whereas a 1-Y sheep showed a relatively small number of osteons mainly in the middle layer but a higher osteon-volume than the 1-Y calf. In the 1-Y sheep, the more widely absorbed areas by bone-remodeling with osteons were observed as compared with the 1-Y calf, and the bone volume was decreased from the 6-M into the 1-Y sheep because of the remarkable bone-absorption. Thus, calf kept on possessing many laminar-bone units for a longer time in the growth period than sheep, while pig showed the earliest bone-remodeling with osteons. These results may be caused by their different body size and withers height in calf and sheep after growing and the difference of the dependence upon mother's body during juvenile period between pig and calf with sheep. The initial region of osteon formation may be distinguishable among their animals, respectively. However, further detailed investigations of their young animals at successive stages will be necessary.

Review of Nonprimate, Large Animal Models for Osteoporosis Research

“…Yes (Ն6-mo) (120) Yes (32) Yes(1-yr) (120) Seasonal changes in BMD Possible (161,162) No No Likely Yes (163) E 2 decrease post-OX (see references in Table 2) Yes Variable: yes, no (24) Yes Yes…”

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]. 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).…”

“…This was performed on a Windows computer using the public domain Scion image program (developed at the U. S. National Institute of Health and available from the Internet by anonymous FTP from zippy.nimh.gov. ), followed by our previous study [11]. In each cow, the total bone volume including laminar bone and Haversian bone (osteons and interstitial lamellas), and the osteon number per a unit (/mm 2 ) were shown as mean values (n=4 in 4 directions including the exterior, interior, anterior, and posterior sides).…”

“…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.…”