TiHo Bibliothek elib - Tierärztliche Hochschule Hannover

VII. Summary
VII. SUMMARY
Jana Horn
Concentrations of IgG1, IgG2 and IgM in plasma and colostrum of high yielding
dairy cattle during the periparturient period with special reference to energy
balance and conjugated linoleic acids as feed supplements.
In early lactation, high yielding dairy cows are unable to meet their energy
requirements for both maintenance and milk production. This leads to a high energy
deficit. During this period, there is a higher risk for “production diseases” such as left
abomasal displacement, retained placenta, lameness, ketosis, mastitis and other
febrile diseases. It is recently known, that supplementation of conjugated linoleic
acids could have positive effects on the health status of dairy cattle. Furthermore,
high energy deficit leads to negative effects on several cell types of the immune
system, such as neutrophils and T-cells.
The study aimed to characterize the development of IgG1, IgG2 and IgM during the
periparturient period in consideration of energy balance as well as supplementation
with conjugated linoleic acids.
Three weeks prior to calving, 63 pregnant German Holstein cows were assigned to
one of four dietary treatments (CLA supplement respectively control fat, high
respectively low concentrate diet). Plasma and milk samples were taken in regular
intervals over a period of 11 weeks, respectively. Furthermore, plasma samples of
their calves were taken prior and after their first Colostral uptake and on day 42.
Bovine IgG1, IgG2 and IgM in plasma and colostrum were determined by an enzyme
linked immunosorbent assay (ELISA) using isotype-specific coating and detection
antibodies.
In plasma, both IgG1 and IgM show a significant decrease around parturition. For
IgM, the decline was equalized shortly after parturition, whereas IgG1 showed initial
plasma values around 3 weeks p.p. Plasma levels of IgG2 remained unchanged
during the entire experimental period. The developing of IgG1 revealed a strong
dependency on the lactation number. Heifers had significantly lower plasma levels
over the entire period and did not show such a distinct decrease around parturition.
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