C2-Lancaster Farming, Saturday, August 2, 1997 MEDULLARY BONE PROVIDES STRENGTH TO LONG BONES AND CALCIUM FOR EGGSHELLS Carol V. Gay, Prof. Biochemistry And Molecular Biology And Poultry Science Medullary bone is a form of bone present within the marrow cavity of some bones, most notab ly the long bones of egg-laying birds. This bone exists as a ran domly organized three dimensional meshwork. Marrow occupies the spaces within the meshwork. It has been known for many years that medullary bone serves a vital function in laying hens namely, it is a major storage site for the calcium needed for daily eggshell formation. This supply and-demand system is a fine example of how beautifully inte- WOODS WOODS WOODS - Dual WOODS - GANNON WOODS - GILL ... come in for a demonstration ECKROTH BROS. FARM EQUIPMENT New Ringgold, PA 717-943-2131 R.S. HOLLINGER & SON, INC. Mountville, PA 717-285-4538 PIPERSVILLE GARDEN CENTER Pipersville, PA 215-766-0414 LINCOLN SUPPLY & EQUIPMENT CO. Somerset, PA 814-443-1691 grated living creatures are. During the night, when most of the egg shell is formed, hens will be quies cent and will have digested food taken in during the day. To meet the needs of eggshell formation, calcium is released from medullary bone. To achieve this, a portion of medullary bone is first destroyed and then reformed in a daily cycle. This constant turnover is the result of a collaboration of two populations of bone cells ones dial form bone and ones that take it away. Research has shown that the lat ter cells adhere tightly to bone sur faces and then secrete acid and digestive enzymes onto the bone surface during the calcium release period. When sufficient calcium has been released, the digestive cells become inactive and move away. The bone forming cells then move in and replenish the thinned bones. 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Divi sion of these types of cells pro vides a continuous supply of bone forming cells throughout life. The bone destroying cells, however, are derived by fusion of one class of white blood cells in the bone marrow. When calcium is needed for eggshell formation, the white blood cells fuse and gain the abili- LAND PRIDE ANY WAY YOU CUT 1T... THE BEST VALUE. The Land Pride family ... quality from the ground up. Betts Equipment 3139 Windy Bush Road.Rt 232 New Hope, PA 18938 215-598-7501. C.B. Hoober & Son, Inc. Mam Street Intercourse, PA 17534 717-768-8231 thin-a- C.B. Hoober & Son, Inc. East Mam Street McAlisterville, PA 17049 717-463-2191 Deerfield Ag & Turf Center, Inc. RR 2 Box 212 Watsontown, PA 17777 717-538-3557 Detlan Equipment, Inc. 141 East Main St Silverdale, PA 18962 215-257-5177 Dunkle & Grieb, Inc. 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Another recently discovered role of medullary bone relates to its structure. Because this bone exists as a three dimensional meshwork, it provides strength to bones within which it resides. Results of a recent study show a SO percent increase in long bone strength when the marrow cavity is half occupied with medullary bone as compared to the same (Turn to Page C 3) Norman D. Clark & Son, Inc. Honey Grove, PA 717-734-3682 Pikeville Equipment Inc. RD 2, Oysterdale Road Oley, PA 19547 610-927-6277 Stoltzfus Farm Service Cochranville, PA 610-593-2407 Stouffer Bros Inc. 1066 Lincoln Way West Chambersburg, PA 17201 717-263-8424 Thomas L. Dunlap Rt 220, Mam St Exit Jersey Shore, PA 17740 717-398-1391 Tractor Parts Co. 335 Central Road Bloomsburg, PA 17815 717-784-0250 Frank Rymon & Sons, Inc. RD 3, Box 355 Washington, N J 07882 908-689-1464 M ary land H.B. Duvall 901 East Patrick St. Frederick, MD 21705 301-662-1125
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