Die Leberverfettung der Milchkuh: Teil 2

Zusammenfassung

Die Leberverfettung bei Milchkühen ist das Ergebnis eines gestörten Gleichgewichts zwischen der Aufnahme von freien Fettsäuren (NEFA) in die Leberzellen im Verhältnis zur Kapazität der Metabolisierung und der limitierten Abgabe als very low density lipoprotein (VLDL). Die Leberverfettung mit dem Risiko einer Ketose hat sich aufgrund der primären Selektion auf Milchleistung ohne ausreichende Berücksichtigung der dieser Leistung zugrundeliegenden Mechanismen ergeben und weist eine genetische Disposition auf. Mit dem neuen Relativzuchtwert Gesamt der Deutsch Holstein Friesian Kühe wird dieser Problematik (Ketoserisiko) Rechnung getragen und damit ein genetisch bedingtes Gesundheitsrisiko bestätigt.

Die ectopische Fettablagerung in der Leber schließt eine Reihe von Reaktionsschritten wie Lipolyse, Aufnahme in die Leberzellen, Metabolisierung und Abgabe als VLDL ein, die in unterschiedlicher Weise direkt oder indirekt im Sinne einer Prophylaxe beeinflusst werden können. Diese Möglichkeiten werden zum besseren Verständnis pathophysiologischer Abläufe aufgeführt. Es handelt sich um die Verfütterung einer glucogenen Diät, um kontrollierte Fütterung während der Trockenstehperiode, den Zusatz von Niacin, Cholin, Carnitin oder eine Reduzierung der metabolischen Belastung. Indirekt können auch die Maßnahmen zu Prophylaxe der Ketose in diese Diskussion einbezogen werden.

Abtract

Hepatic lipidosis in dairy cows is the result of a disturbed balance between the uptake of non-esterified fatty acids (NEFA), their metabolism in the hepatocytes, and the limited efflux of TG as very-low-density lipoprotein (VLDL). Lipidosis and the associated risk for ketosis represents a consequence of selecting dairy cows primarily for milk production without considering the basic physiological mechanisms of this trait. The overall risk for lipidosis and ketosis possesses a genetic background and the recently released new breeding value of the German Holstein Friesian cows now sets the path for correction of this risk and in that confirms the assumed genetic threat. Ectopic fat deposition in the liver is the result of various steps including lipolysis, uptake of fat by the liver cell, its metabolism, and finally release as very-low-density lipoprotein (VLDL). These reactions may be modulated directly or indirectly and hence, serve as basis for prophylactic measures. The pertaining methods are described in order to support an improved understanding of the pathogenesis of lipidosis and ketosis. They consist of feeding a glucogenic diet, restricted feeding during the close-up time as well as supplementation with choline, niacin, carnitine, or the reduction of milking frequency. Prophylactic measures for the prevention of ketosis are also included in this discussion.

Schlüsselwörter

Kuh - Leber - Genetik - Prävention - Überforderung

Key words

Fat deposition - lipidosis - prevention - metabolic overload

Publication History

Received: 16 August 2022

Accepted: 06 March 2023

Article published online:
13 November 2023

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