1993 Fiscal Year Final Research Report Summary
Chronic laminitis as the predisposing factor for other digital diseases in dairy cows
| Project/Area Number |
03454111
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied veterinary science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SASAKI Nobuo Univ.Tokyo, Fac.Agr, Professor, 農学部, 教授 (60107414)
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| Co-Investigator(Kenkyū-buntansha) |
KADOSAWA Tsuyoshi Univ.Tokyo, Fac.Agr, Assist.prof., 農学部, 助手 (70214418)
NISHIMURA Ryohei Univ.Tokyo, Fac.Agr, Assoc.Prof., 農学部, 助教授 (80172708)
NAKAYAMA Hiroyuki Univ.Tokyo, Fac.Agr, Assoc.Prof., 農学部, 助教授 (40155891)
SAWAZAKI Touru Univ.Tokyo, Fac.Agr, Professor, 農学部, 教授 (00012047)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Dairy cow / Digital disease / Subclinical laminitis / Chronic laminitis / Arteriography / High concentrate feeding / Endotoxin / Histology |
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| Research Abstract |
A recent increase in incidence of various types of hoof disease in dairy cows has caused a significant ecomic damage on the dairy farms in Japan. From previous reports, chronic or subclinical laminitis has been indicated as an important predisposing factor for this problem and endotoxin produced in the rumen may be thought as one of the etiologic factors for laminitis.
In this research project, we initially obtained the digits of dairy cows, which were thought to be raised in the typical Japanese dairy farms, from slaughterhouses and the presence of chronic or subclinical laminitis was investigated. As a result, 52.9% of the digits were demonstrated revealed histologically as subclinical laminitis and 29% as chronic laminitis. Arteriography of these digits also revealed the extended or narrowed artery to the sensitive laminae, which may indicate that the chronic circulatory disturbance is the important factor of the various hoof diseases. In the next step, the endotoxin (ET) levels in the ruminal fluid and peripheral blood during the pre- and postparturient period were determined. According to the increase in feeding concentrates after parturition, ruminal ET considerably rised and the blood ET showed episodic increase during the first two weeks after parturition. However, each ET levels did not necessarily coincided. In goats given starch as a concentrate via the rumen fistula, the similar changes in ruminal and blood ET levels were observed and better coincidence could be observed between the two levels. These results might indicate the hypothesis that the increased ET according to the increase in high concentrate feeding is absorbed via the digestive tract and plays an important roll in the etiology of chronic or subclinical laminitis which may result in poor horn quality and other hoof diseases such as sole ulcer.
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