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The modified requirements in the health management of dairy cows with a focus on the prevention of disease and medical care of the herd, allowing the early recognition of disease, have become extremely important.
The progress, which has been made in the field of Precision Dairy Farming, shows a tendency in this direction. Therefore, the aim of the study was to examine, whether the diagnosis of medical conditions by means of long-term measurements of the carotenoid concentration in bovine udder skin, with the help of the newly-developed skin scanner WK1 (Opsolution GmbH, Kassel, Germany) could be realized.
The first publication was concerned primarily with partial experimental measurements on 25 clinically healthy cows, which were kept in a barn under the same conditions and with the same feed. The animals differed in regard to the stage of lactation, age and breed.
In all the animals examined, a carotenoid concentration, reproducible in the udder skin, could be detected. In the case of the skin scanner, a follow-up measurement showed a deviation of 12 %. The mean variation of the carotenoid values on three adjacent measuring points on the udder amounted to 17 %. The carotenoid concentrations on the same skin areas varied inter-individually, highly significant (p < 0.001). The median was 0.88 ± 0.25 a.u. (arbitrary units = relative units).
The variation range was 1.06 a.u., whereby the highest value was nearly four times as high as the lowest value. The mean standard deviation was 0.05 a.u. Comparing the daily milk output and the carotenoid concentration of the skin, only an extremely low correlation was evident (R2< 0.2). The second partial experiment of the first publication dealt with measurements acquired on ten clinically healthy cows, owned by the institute.
The measurements were undertaken for a period of four days under standardized conditions, whereby no significant differences in the carotenoid concentration between the individual measuring times could be established.
The mean deviation of the carotenoid concentration during the duration of the measurements was 10 %. In order to prove the objectivity of the analysis in the frame of a temperament test, the 25 cows examined in the first partial experiment of the first publication were classified parallel by two independent persons. The results showed no significant differences. With the help of the temperament test, out of a group of 12 animals, 6 were classified as “sensitive” and 6 as “robust”.
The median of both groups differed significantly (p < 0.05). The common level (median of n = 6) of the robust cattle was 1.11 ± 0.24 a.u. In the case of the sensitive cattle, the common level of carotenoids was 0.72 ± 0.10 a.u. The second publication, taking into account the measurements over a period of four weeks on the six cows owned by the institute, again supplied the confirmation that healthy cows under constant husbandry conditions exhibited a constant antioxidant potential. During the time elapsed, the deviations were shown to be ≤ 18 %.
Based on the aforementioned results, measurements were undertaken on 23 cows, suffering from a left displaced abomasum, within 12 hours p. op. as well as during convalescence and following recovery. The operative adjustment of the displaced abomasum was performed by means of the Janowitz method (n=6), or the Dirksen method (n=17), respectively.
18 of the 20 recuperated cows showed an increased skin carotenoid concentration as compared to the initial values. In the case of these animals, 20 days p. op. an average increase in carotenoid concentration occurred in the region of 53 ± 44 %, as compared to initial values. The difference was statistically highly significant (p < 0.001).
Referring to the three dead or euthanized animals, which died during the course of the study, the last carotenoid concentration measurement before death had decreased to 31 ± 27%, which was insignificant. When considering the third publication, the dermal carotenoid concentrations of the 20 healthy cattle was 0.39 a.u. up to 1.53 a.u., the interindividual differences were highly significant (p < 0.001). The median (n = 20) of the skin carotenoid concentration was in the range of 0.80 ± 0.32 a.u., whereby the ß-carotenoid concentration in the plasma showed values of 0.92 mg/L and 5.22 mg/L.
The comparison of the skin and plasma parameters was performed under the inclusion of the backfat thickness of the animals. A comparison of the parameters of all 20 cows showed only a weak correlation (R = 0.23). The correlation coefficient of the eight animals, which were in a very poor or poor nutritional condition showed a value of R = -0.23.
The correlation coefficient of the 12 animals with a moderate to obese nutritional condition was at R = 0.86, the correlation was significant (p < 0.05).
The first, as well as the second publication were able to show that the individual carotenoid values of the cows over a longer period, on account of the unchanged external conditions, had not significantly altered. However, the cattle that were examined during convalescence had on the other hand a highly significant increase in carotenoid concentration, as reported in the second publication. In summarizing, taking into account the results cited in all three publications, wherein the measurements performed by means of the skin scanner were classified as suitable, in order to measure the carotenoid concentration supported by repeated measurements, and therefore to establish conclusions regarding the state of disease. On account of the individual values of each animal, every single animal has to serve as its own control. In particular in the care of a high number of cattle, the integration of the skin scanner in the milking plant, would in the future also enable the early diagnosis of clinically inconspicuous animals.