University of Washington dairy scientists found no difference in mastitis following shortened dry periods in four herds they studied. What they did find, however, is cows with 30- to 45-dry periods produced 2,500 lb./cow less milk in the next lactation. The study was reported in the November issue of the Journal of Dairy Science, released today.
The study involved four herds and 156 cows. Cows in two herds were assigned either 60-day or 30 day dry periods. Cows in the other two herds were assigned 45- or 30-day dry periods.
New intramammary infections ranged from 6% to 9%, but were not statistically different. Nor were linear somatic cell counts during the first six to seven months of the subsequent lactations.
However, mature equivalent (ME) milk production was greater in cows with 60-day dry periods. They averaged about 26,300 lb. ME milk. Cows with 30-day dry periods averaged 23,650 lb. of ME milk. And cows with the 45-day dry periods produced no more than cows with 30-day dry periods.