Shortening or omitting the dry period improves the energy balance and metabolic status of dairy cows in early lactation, but has the trade-offs of reduction in milk production and loss of opportunity for dry-cow therapy. To balance these benefits and trade-offs, researchers in the project ‘Customized dry period’ developed a decision model to customize dry-period strategies of individual dairy cows. The evaluation of these decision trees was recently published in Journal of Dairy Science.
In the reported study, 183 dairy cows at the Dairy Campus in Leeuwarden were randomly distributed over 3 decision trees for customized dry-period management. In the control tree, all cows had a dry period of 60 days, and dry-cow therapy (i.e. intramammary antibiotic use at dry-off) was applied when cows had >150,000 cells/mL. In decision trees 1 and 2, part of the cows were selected for a conventional dry period with or without dry-cow therapy, whereas another part was selected for short or no dry periods, depending on their somatic cell count, parity and milk production prior to dry-off.
Somatic cell count as gatekeeper to apply short dry periods
The main difference between decision trees 1 and 2 was the threshold value of somatic cell count for dry-cow therapy, which was higher in decision tree 2. In decision tree 1, 89% of the multiparous cows was dried off with dry-cow therapy because of a high somatic cell count (>50,000 cells/mL), compared with 20% of the multiparous cows in decision tree 2 (>200,000 cells/mL). In decision tree 1, 8% of the multiparous cows had a short dry period of 30 days and less than 1% had no dry period. In decision tree 2, 30% of the multiparous cows had a short dry period and 48% had no dry period. In both decision trees, about 13% of the primiparous cows had a conventional dry period with dry-cow therapy due to a high somatic cell count, and the remainder was assigned to a short dry period of 30 days.
Health, body condition and milk
Somatic cell count in early lactation was lowest after decision tree 1, where the majority of cows was dried off with dry-cow therapy. However, decision tree did not have an effect on udder health or occurrence of clinical mastitis in early lactation. Decision tree 2 tended to result in fewer cows treated for diseases in the first 100 days of lactation, which may be explained by the faster recovery of body condition of cows in this group. Due to the application of short and no dry periods in decision trees 1 and 2, some milk was produced in the 8 weeks prior to calving (3.9 vs. 7.1 kg/d in tree 1 vs. tree 2), and milk yield in the 14 weeks after calving was reduced (40.0 vs. 37.0 vs. 35.2 kg/d in control vs. tree 1 vs. tree 2).
Read here the article in Journal of Dairy Science
Customized dry period
The project ‘Customized dry period’ was financed by DairyNL (Zuivel-NL, Zoetermeer, the Netherlands; organization of the Dutch dairy supply chain) and the Dutch Ministry of Economic Affairs (EZ, The Hague, the Netherlands). CRV contributed to the practical application and data.