Prüfung des Einflusses eines pegylierten bovinen Granulozyten-Kolonie stimulierenden Faktors auf das leukozytäre Blutbild und die Akute-Phase-Reaktion von Holstein-Friesian Kühen und deren Kälbern
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Beschreibung
Background:
In the peripartal period, the dairy cow experiences a suppression of the immune system due to the increasing physical stress caused by the upcoming calving and the beginning of lactation, which is characterised by low concentrations of neutrophil granulocytes and an impaired function of these, resulting in higher disease incidences (e. g. mastitis). Granulocyte colony stimulating factors (G-CSF) stimulate the formation of neutrophil granulocytes in the bone marrow and are used in cattle to reduce clinical mastitis during the immunosuppressed transit phase. There is little information available on the influence of G-CSF on the acute phase response (APR) of gravid dairy cows and a possible effect on their calves.
Objectives:
The objective of this study was to evaluate the effects of the use of a G-CSF on the immune system and leukocytic blood count of the pregnant cow at parturition and the newborn calf. The hypothesis was that administration of a G-CSF would lead to APR and leukocytosis with neutrophilia in both dam and calf. In addition, clinical parameters were evaluated to assess possible adverse side effects and the health status of the animals.
Methods:
The study approved by the North Rhine-Westphalia State Office for Nature, Environment and Consumer Protection in accordance with §8 (1) of the Animal Protection Act (file number 84-02.04.2017.A096) took place in the period from July to December 2017. Included were blood samples from 84 dairy cows and 77 calves of the Holstein-Friesian breed with a complete data set. 41/84 cows were injected s.c. with 2.7 ml Imrestor™ (Elanco GmbH, Bad Homburg, Germany) containing 15 mg bG-CSF 5-15 days before calving and within 24 h after calving, resulting in a control group of 43 animals. In the calves, 35/77 of the treated mothers and 42/77 of the control animals had complete data.
In each case, after a clinical examination, the blood samples of the cows were taken before the 1st injection (ap), before the 2nd injection (p) and once each in the following two weeks (pp1 and pp2). The blood samples of the control animals were taken at the same time. In the calves examined, 4 blood samples were also taken (1. before colostrum intake (n), 2. within 24 h afterwards (pn1), 3. first week of life (pn2), 4. second week of life (pn3)).
EDTA and serum samples were examined. The haematological examination included an automated cell count on the ADVIA® 2120 (Siemens Healthcare, Erlangen, Germany) with manual differentiation of a May-Grünwald-Giemsa stained blood smear. Haptoglobin (Hp), albumin (Alb) and total protein (TP) concentration were determined from the serum samples on the ABX Pentra C400 biochemical analyser (ABX Horiba, Montpellier, France).
Furthermore, the cows were examined for clinical parameters such as dry matter intake, milk yield, duration of gestation period and the percentage of cows with disturbed general condition, stillbirths, fever, inflammatory, and metabolic diseases. In addition, the percentage of cows with an increase in the cell count in the milk after dry standing was determined. Calves were compared for birth weight and the presence of inflammatory diseases was evaluated.
Results and Conclusions:
The cows in the Imrestor™ group showed a significant increase in leukocyte count (WBC, p < 0.001), carried by neutrophil granulocytes (NEU, p < 0.0009) with a significantly higher number of toxic neutrophil granulocytes (TOX, p < 0.0007) and a more frequent occurrence of a left shift (p < 0.0018) compared to the cows in the control group. In addition, the treated cows had a significantly higher number of lymphocytes (LYM, p < 0.0006) and monocytes (MON, p = 0.001) compared to controls. In the 1st week of lactation (pp1), the control animals showed a 2-fold higher Hp concentration (p < 0.0004), which was accompanied by a lower Alb concentration (p < 0.0002) than in the study group. The calves of cows treated with Imrestor™ showed significantly higher numbers of WBC (p < 0.0009), NEU (p < 0.0008) and LYM (p < 0.0006) and MON (p < 0.0007), but the effect was smaller than in the dams.
The only effect of G-CSF on the clinical parameters of the dairy cows compared to the untreated control group was the lower incidence of metabolic diseases (40 % vs. 10 %, p = 0.0022).. In the calves, the treatment of the dams showed no effect on health status or development.
In conclusion, the present study showed that Imrestor™-treated cows had a significantly higher increase in leukocyte count after calving, which was accompanied by a lower APR and a lower frequency of metabolic disease. This suggests that G-CSF have a positive effect on the health status of dairy cows in the peripartum period.
The examinations of the calves of cows treated with Imrestor™ showed, similar to the results of the dams, a pronounced increase in the examined leucocyte populations compared to the control group, however, despite the statistical significance, the absolute effect was small and therefore of little clinical relevance. Thus, it can be assumed that the treatment of the dams with a G-CSF has no negative effect on the development, health and vitality of the newborn calves.
Since there are only few data on the effects of G-CSF on the leukocytic blood count and APR of calves of treated cows and since a transplacental transfer of G-CSF must be assumed on the basis of existing human medical studies, the aim of future studies should be to further investigate the consequences of peripartum therapy with G-CSF for the neonates.
Autor*in
Alina Finsterhölzl