|The aim of this study is to determine if the most recent Milk production registration (MPR) can use as a selection criteria for drying off with or without antibiotics.
The cows that participated in this study are cows from the study ‘Selective dry cow therapy’. In this study 137 cows from 27 Dutch dairy farms are sampled. The cows that participate in this study were selected on somatic cell count (SCC), only heifers with a SCC of <150,000 cells/ml or cows with a SCC of <250,000 cells/ml on the most recent MPR were included.
Quarter samples of the cows were collected aseptic for SCC and bacteriological analyses.
After a regression analysis, the production at TMPR is associated with the production at Tdry.
The days between TMPR and Tdry are not associated with the production at Tdry.
The SCC at TMPR is associated with the SCC at Tdry. The production at Tdry is also associated with the SCC at Tdry. The days between TMPR and Tdry is not associated with the SCC at Tdry.
After these first analyses, it was analysed where categories are made from the amount of days between TMPR and Tdry. These are divided per two weeks. The first analysis is from day 0 till 14 days between TMPR and Tdry, the next from 15 till 28 days and the latest from more than 28 days between TMPR and Tdry. When the data was split into categories of two weeks the R2 was changed. The R2 was much higher in the period 0-14 days than in the other periods.
This was followed by an analysis with the highest quarter SCC in combination with the SCC at TMPR. There was a link between the SCC at TMPR and the SCC at Tdry. Between the production at T dry and the SCC at T dry there was a link as well. This analysis showed that there was no link between the SSC at Tdry and the number of days between TMPR and Tdry .
Of 137 cows with a SCC less than 250,000 cells/ml on the most recent MPR, is viewed how many quarters had a SCC of ≥250,000 cells/ml on Tdry. With the adjusted Wald Method the confidence interval (95%) is calculated.
The MPR is not a good tool to predict the production at Tdry.
The dairy farmer could use the MPR for selective dry cow therapy provided that, it is not older than two weeks. When the MPR is older than two weeks, it is better for look for another tool. This could be the CMT, or maybe it is necessary to determine the SCC again. The more time between TMPR and Tdry, the chance on a new intramammary infection is higher.