Association of Dry Period Length with Automatic Milking System, Mastitis, and Reproductive Indicators in Cows

The goal of this study was to examine how the duration of the dry period is associated with milk production, health, and reproductive traits in a herd of cows managed with an automatic milking system. Cows with a dry period of 40-70 days showed higher energy-corrected milk production during the first 100 days of lactation compared to those with shorter or longer dry periods (p < 0.001). Additionally, cows in the 40-70-day dry period group exhibited the lowest milk electrical conductivity and somatic cell count, along with the highest milk lactose concentration. Mastitis pathogens were most prevalent in cows with the longest dry periods (>70 days), while Streptococcus agalactiae and Staphylococcus aureus were least detected in cows with a dry period of 40-70 days. The highest cow fertilization rate was observed in the group with the shortest dry period (<40 days). These findings provide insights that could help the dairy sector make informed decisions to enhance cow productivity and health. Moreover, managing dry period length effectively could serve as a critical tool for improving dairy herd management. The objective of this study was to evaluate the association between dry period (DP) length and various indicators of productivity, reproduction, and udder health in cows managed with an automatic milking system. We analyzed records from 3861 cows, categorizing them into three groups based on their DP duration: (1) <40 days, (2) 40-70 days, and (3) DP > 70 days. Cows with a DP of 40-70 days had an average energy-corrected milk production that was 8.2 kg greater than that of cows with a short DP and 5.0 kg greater than that of cows with a long DP (p < 0.001). Milk from the 40-70-day DP group exhibited the highest lactose concentration (4.64 +/- 0.01%). Additionally, cows with the longest DP had the smallest proportion of animals with a milk fat-to-protein ratio of 1.2 to 1.4. Cows with a DP of 40-70 days also showed the lowest milk electrical conductivity across all udder quarters, whereas cows with the shortest DP had the highest conductivity. The highest conception rates were observed in the group with the shortest DP. These results suggest that a DP of 40-70 days is optimal for maximizing milk production and improving both udder health and reproductive performance under AMS. Proper management of DP duration can be an effective strategy for sustainable dairy herd management.