Publikationsdatenbank

Untersuchungen zu den Veränderungen im weißen Blutbild von Holstein Friesian Milchkühen 14 Tage ante partum bis 100 Tage post partum in Beziehung zur Futteraufnahme und ausgewählten Erkrankungen (2020)

Art

Hochschulschrift

Autor

Barthmann, Rudi (WE 18)

Quelle

Berlin: Mensch und Buch Verlag Berlin, 2020 — VI, 147 Seiten

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/27711

Kontakt

Nutztierklinik

Königsweg 65
14163 Berlin
+49 30 838 62261
klauentierklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

The critical phase for dairy cows is the transition period at calving, involving hormonal changes, negative energy balance at the start of lactation, as well as nutritional changes. These changes are challenging for the immune system, resulting in a high disease incidence. This is reflected by typical leukocyte changes. There were 5 objectives of this study: (1) To examine the relationship between feed intake and the differential hemogram. (2) The influence of the periparturient phase with associated diseases on the white blood differential were examined. The selected parameters include dry matter intake, rumen fill score, β-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), metabolic disorders, still birth, retained placenta, as well as reproduction disorders. (3) The precision of a manual leukocyte differential was verified. (4) Reference intervals were created for different time points during lactation. Significant changes have been observed around calving. (5) General reference intervals have been established with exclusion of those sampling dates which showed significant differences of specific leukocyte values in comparison with values of other sampling dates. The study was conducted on a dairy farm in Saxony-Anhalt. It took place in two different periods, the first one from 04.05.2015 – 07.04.2016, and the second from 12.04.2016 – 21.11.2016. High yielding Holstein-Friesian cows (>12.000 kg annual milk yield) were used. Examination and sample collection were carried out by veterinarians on three different dates for each cow in the first period and six different dates in the second period. In all, 766 blood samples from different stages in lactation derived from 192 cows were evaluated. The herd is presumed to be free from brucellosis and bovine leukemia virus. The white blood cell differential was determined by counting and differentiating 100 leukocytes on stained blood smears. For the total number of WBC, automated analysis was used. The precision of the manual method was evaluated by using an interday and intraday coefficient of variation. The manual analysis was always performed on the same workplace by the same examiner. The precision of the manual method is in an acceptable field for lymphocytes, polymorphonuclear neutrophils, and eosinophils. Leukocytes with decreased appearance (basophils, bands, or monocytes) showed a lesser precision. The stage in lactation showed a significant (p<0,001) influence on most of the different leukocytes. Particularly band neutrophils, eosinophils, and monocytes showed notable dynamics during lactation, especially around calving. The differential blood picture shows 14d ante partum (a.p.) significant (p<0,05) increased (42,7%) polymorphic nuclear neutrophils compared with 3d post partum (p.p.) (36,3%). The band neutrophils instead are showing low numbers (1,1%) 14d a.p. and increase up to a maximum (5,1%) 3d p.p. The lymphocyte percentages are at low levels (49,7%) 14d a.p. and increases 3d p.p. (54,9%). These results illustrate the influence of calving on the leukocytes. The influence is characterized by low lymphocyte values before calving and a sudden decrease in polymorphonuclear neutrophils as well as the associated increase in band neutrophils after calving. The establishment of specific lactation adapted reference intervals are not necessary, because despite prominent dynamics, the leukocyte values did not lay considerably outside the common intervals. In this study general leukocyte reference intervals were established for high yielding dairy Holstein-Friesian cows. Days in lactation with significant different values were excluded. Furthermore, the polymorphonuclear neutrophils have been found positively correlated with the ruminal fill, and the lymphocytes are slightly negatively correlated with the rumen fill 3d p.p. A correlation has not been found of any leukocytes with the dry matter intake at any point in time during lactation. Besides, the serum values of NEFA and BHB showed a negative correlation with the 8d and 28d p.p. determined leukocytes and polymorphonuclear neutrophils. Cows with low WBC and polymorphonuclear neutrophils 8d p.p. seem to have a higher risk for reproduction disorders. However, higher lymphocyte and band neutrophil values seem to be protective against reproduction disorders. There hasn’t been found a significant relation between the white blood cell differential a.p. and retained placenta. Cows with retained placenta showed highly significant increased neutrophils and decreased lymphocytes p.p. To put it in a nutshell, those findings have no clinical relevance. The white blood cell differential does not appear to be the appropriate diagnostic method at herd level, but instead it is a diagnostic method for the individual cow. The interpreting of the leukogram must be under consideration of the results derived from the clinical examination.