PhD project by Akke Kok. Since shortening and omitting the dry period have been suggested as strategies to improve cow health and fertility, it is important to evaluate the sustainability of these management innovations in dairy farming. This PhD project focuses on the sustainability impacts of omitting and shortening the dry period regarding economic viability, environmental impact and cow welfare. Knowing the impact of dry period strategies on the sustainability performance of dairy farming will contribute to science-based decision making by farmers about which dry period regime to adopt.
This study focuses on the impact of shortening and omitting the dry period (DP) on the sustainability performance of dairy farming. The conventional DP maximises milk production, but simultaneously results in a negative energy balance in early lactation, which has been associated with impaired cow health and fertility. Shortening or omitting the DP partly shifts milk production from early lactation to the months before calving and improves the energy balance. These strategies affect milk production and nutritional demands at cow level, but also management at farm level, and, therefore, will affect economic viability (e.g. farm profitability), environmental impact (e.g. use of energy; emission of greenhouse gases) and cow welfare. While several studies have focused on effects of DP length on milk production, effects on above-described sustainability issues have not at all or scarcely been addressed. This study will evaluate the multi-dimensional consequences of shortening and omitting the DP for the economic, environmental and cow welfare performance of dairy farming.
First, the effect of shortening and omitting the DP on cow productivity over multiple lactations will be quantified through the analysis of herd data of commercial dairy farms. This knowledge is required to assess economic and environmental consequences of different DP strategies. Second, economic and environmental impacts of shortening and omitting the DP will be estimated at herd-level using a simulation model at cow-level. Third, economic and environmental consequences of management and farm plan changes in response to the different DP lengths will be explored using an optimisation model at farm level. Finally, effects of a short or omitted DP on cow welfare will be evaluated based on a behavioural study at a research dairy farm.
The proposed integrated sustainability assessment of shortening and omitting the DP will yield insight into the multi-dimensional and sometimes conflicting consequences of adopting these DP strategies. Moreover, this knowledge will contribute to science-based decision making by farmers about which DP strategy to adopt and thus to the sustainable development of dairy farming.