Researchers at Wageningen UR and Utrecht University began a large-scale study of the length of dairy cows' dry period last summer. The objective of the WHY DRY study is to evaluate the length of the dry period from the perspective of the cows' health. WHY DRY also devotes attention to calf health, milk production, sustainability and an economic evaluation.
150 dairy cows have been divided into three lengths of dry periods (0, 30 or 60 days) for the WHY DRY study at the Waiboerhoeve in Lelystad. The cows will be followed for two lactations. In addition to the effects on the cows' health and milk production, the researchers are also interested in the effects of the length of the dry period on the cows' fertility, quality of the colustrum, calf growth and health and, ultimately, the net operating result.
A dry period of 6 to 8 weeks before calving is customary in today's dairy farm sector. International studies have also revealed that a dry period of between 6 to 8 weeks at the beginning of lactation results in optimum milk production. However, the beginning of lactation is accompanied with a high incidence of disease that results in the loss of cows and the use of antibiotics in the calving period. This high incidence of disease is primarily ascribed to the negative energy balance and limited feed intake at the beginning of lactation. The WHY DRY researchers expect that the reduction or elimination of the dry period will shift this critical period in milk production from immediately after calving to before calving, when the cow can readily meet its energy needs. This will result in a reduced risk of diseases, such as ketosis and fatty liver, and improved cow fertility.
However, reducing the length of the dry period involves more than merely postponing or eliminating drying up the cows. The WHY DRY researchers are of the opinion that an integral approach, together with changes in rations and management, is necessary for the optimisation of operations with a shortened dry period. For this reason, a reduced dry period will need to be a system innovation in dairy farming that offers interesting prospects for current issues such as well-being and the sustainability of dairy cows, the farmer's working pleasure, the reduction of the use of antibiotics and food safety.
WHY DRY is financed by the Dairy Board, Animal Feed Product Board and CRV. A network of dairy farmers is also being organised within the scope of WHY DRY for intensive exchanges of experiences and information about the first results from the study.