Reproductive performance in high producing dairy cows: practical implications

Summary

Several studies have clearly demonstrated that the fertility of high yielding dairy cows has declined over the past 25 years. The resumption of ovarian activity post partum has been retarded and conception rates have dropped significantly from 55 to 40%. Accordingly, the calving interval has increased from about 385 days to 417 days. The percentage of cows culled because of infertility has risen from 5 to 8% per year. The “subfertility syndrome” is a multifactorial problem. As the negative energy balance and general health status after calving are known to be paramount factors hampering fertility, it is apparent that avoiding both is among the most important preventive measures to be taken. Improvement of the energy status by achieving a high dry matter intake and the provision of optimal and well balanced nutrition during the transition period as well as during early lactation are key goals in this effort. To achieve these goals, we should not only calculate the rations on paper, but should also check in the stable to determine whether the calculated amount is really being consumed by the cows. Furthermore, veterinarians should use their “clinical eyes” as well as other diagnostic tools to assess the general health status of the cows and to assess at which aspect of the process things are going wrong and need to be adjusted. Besides the control of the negative energy balance and health status, other management factors that need to be maximized include heat detection, cow comfort, insemination technique, time of insemination during estrus and sperm quality. Only if management is on a very high level high milk production and good fertility can be a feasible combination.

Zusammenfassung:

Mehrere Studien haben eindeutig gezeigt, dass die Fruchtbarkeit von Hochleistungsmilchkühen in den vergangenen 25 Jahren zurückgegangen ist. Die Wiederaufnahme der Ovarfunktion post partum findet verzögert statt und die Konzeptionsraten sind signifikant von 55% auf 40% abgefallen. Entsprechend hat sich das durchschnittliche Kalbungsintervall von etwa 385 Tagen auf 417 Tage erhöht. Der Prozentsatz an Kühen, die aufgrund von Infertilität geschlachtet werden, ist von 5% auf 8% pro Jahr gestiegen. Das “Subfertilitätssyndrom” stellt ein multifaktorielles Problem dar. Bekanntermaßen sind eine negative Energiebilanz und ein schlechter Allgemeinzustand nach dem Kalben bedeutende Faktoren, die die Fruchtbarkeit negativ beeinflussen können. Konsequenterweise gilt es als wichtigste präventive Maßnahme, diese beiden Zustände zu verhindern. Schlüsselelemente dabei sind die Verbesserung des Energiestatus durch eine hohe Trockensubstanzaufnahme sowie die Sicherstellung einer optimalen und ausgewogenen Ernährung während der Übergangsund frühen Laktationsperiode. Um dies zu erreichen, reichen schriftliche Berechnungen allein nicht aus, sondern es muss die tatsächliche Futteraufnahme der Kühe im Stall kontrolliert werden. Ferner sollte der Tierarzt seinen „klinischen Blick“ und diagnostische Verfahren einsetzen, um den Allgemeinzustand der Kühe zu beurteilen und zu erkennen, wo Probleme auftreten, damit diese behoben werden können. Neben der Kontrolle der negativen Energiebalanz und des Gesundheitsstatus gilt es, weitere Managementfaktoren wie Brunstbeobachtung, Wohlbefinden der Kühe, Besamungstechnik, Besamungszeitpunkt im Östrus und Spermaqualität zu optimieren. Nur bei optimalem Management ist eine Kombination von hoher Milchleistung und guter Fruchtbarkeit möglich.

Schlüsselwörter

Milchkuh - Milchproduktion - Reproduktionsstörungen - Management

Key words

Dairy cow - milk production - reproductive disorders - management

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