Untersuchungen zur Diagnostik der Manganversorgung von Milchkühen
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Beschreibung
"Examination of manganese supply in dairy cows"
The adequate supply of nutrients and in particular trace elements is of major importance for a healthy and highly productive dairy herd. The dissertation at hand intends to present reference ranges for different sample media to classify the manganese status of a dairy cow herd.
Among others, manganese deficiency may clinically show a decreased fertility rate of dairy cows or the delivery of deformed and weak calves. Additionally, it is considered that the sex ratio shifts in favor of male animals. The underlying reason for this is not necessarily a primary manganese deficiency, as secondary deficiency states caused by manganese antagonists like iron, which can be found in drinking water in high concentrations, are of great importance.
A key factor in the maintenance of manganese homeostasis is the variation of the absorption rate. In cattle, manganese is absorbed throughout the entire intestinal tract at a rate of 0.5 and 5.0 % of total ingested manganese.
Manganese can mainly be found in tissue rich in mitochondria such as liver, hair or osseous tissue and is primarily incorporated into the cell by the transferrin receptor or via DMT-1.
Excretion is executed by the liver. At least 95 % of the absorbed manganese is thus eliminated in the first pass effect, excreted via the bile within the faeces. Caused by the attachment to proteins that prevents the filtration through the kidneys, the part in the urine is less than 1 % of the initial uptake.
The results presented within the thesis are based on the evaluation of data derived from the herd care section of the Clinic for Ruminants and Swine at the Department of Veterinary Medicine at the Freie Universität Berlin. They are divided into two separate studies.
The dataset of the herd tests comprises surveys of 564 dairy farms in the years from 2007 to 2014. The average number of cattle was 495 animals per farm. Most of them were Holstein-Friesian and German Black Pied Dairy Cattle. The cattle was mostly housed in stable cubicles and fed a Total Mixed Ration (TMR).
Ten clinically healthy, preferably pluriparous cows per lactation group were chosen and sampled. The manganese concentration was determined for the following substrates: blood serum, EDTA plasma, EDTA whole blood, urine and hair.
The farm test file contains data gathered on a dairy producing farm with about 1400 Holstein-Friesian cows in the winter of 2007/2008. For this study too, ten clinically healthy, preferably pluriparous cows were chosen and the following samples were collected: blood serum, EDTA plasma, EDTA whole blood, hair and liver.
The samples were analyzed spectrometrically by the ICP-OES method. The manganese concentrations in all substrates were in a low concentration range. Nevertheless, there is no clinical evidence for deficient supply conditions. Hence, manganese deficiency may not be expected when dairy cattle is kept under the usual rearing and feeding conditions.
After log-transforming the data, it could be evaluated with parametric tests.
For the manganese concentration the farm test file shows average correlations between plasma and serum values as well as between plasma and whole blood values. The herd test file shows a correlation between the manganese values in serum and the manganese values in following media: plasma, whole blood and liver.
Regarding the different trace element concentrations in the serum, positive correlations between manganese and zinc as well as a negative correlation between manganese and iron were detected.
The correlation between the serum concentration of cholesterol which is involved in the cartilage synthesis and the serum manganese concentration could also be confirmed. In this study neither the federal state nor the herd size had any traceable influence on the manganese status of a dairy cattle herd.
The average manganese values in the different blood media increased in the course of lactation and varied significantly. Moreover, seasonal variations could be verified. Accordingly, there were significant differences in the serum manganese concentration regarding month as well as year of the investigation.
The much discussed correlation between manganese concentration in the different sample media and the ratio of male to female calves could not be proven within this evaluation. Instead, a significant correlation between the manganese concentration in serum as well as in whole blood and the insemination index could be shown.
Faeces were not sampled in the study at hand. Due to the high faecal excretion of manganese and the simple and cost effective sampling it appears to be useful to analyze this substrate as a possible sample medium.
The manganese concentration in feedstuff was not part of this dissertation either. Nevertheless, a thoroughly executed analysis of the manganese content in the TMR fed to the cattle seems to be the most suitable method to evaluate the manganese status of a dairy cattle herd. Determination of the concentration of the antagonist iron within the feed as well as in the drinking water would complete this method.
The manganese concentrations in the different media determined in this study were used to calculate limit values. Reference ranges for each substrate were derived from these values.
Medium: Serum
Unit: μg/l
Recommended reference range: 1,0 - 3,0
Medium: Plasma
Unit: μg/l
Recommended reference range: 1,4 - 8,0
Medium: EDTA whole blood
Unit: μg/l
Recommended reference range: 5,0 - 14
Medium: Urine
Unit: μg/l
Recommended reference range: 0,5 - 8,0
Medium: Hair
Unit: mg/kg
Recommended reference range: 1,0 - 23
Medium: Liver
Unit: mg/kg
Recommended reference range: 3,8 - 11
Autor*in
Julia Monsees
Themen in »Untersuchungen zur Diagnostik der Manganversorgung von Milchkühen«
Blutchemie Blutproben Diagnoseverfahren Haare Leber Milch Mineralfütterung Tierernährung Urin animal nutrition blood chemistry blood samples diagnostic techniques diary cows hair