Short Dry Period

Project entitled:

Impact of a Short Dry Period

Summary

This project was developed in order to verify whether the current recommendation of drying cows for 60 days is still suitable for today’s herds or whether a 35-day dry period management approach would be more appropriate. To assess all possible impacts, four studies were conducted. The first two studies took place on 13 commercial farms and included a total of 850 cows. The objective of the study was to assess the impacts of a 35-day dry period management approach on milk production and composition, health and metabolic diseases as well as cow reproduction. The purpose of Study 2 was to determine the economic impact of this practice in a Quebec context. Study 3 verified the effects of a shorter dry period on cell renewal and cell activity in the mammary gland. Study 4 measured the effects of a diet specific to a short dry period management approach on feed efficiency and digestibility. The results of all of these studies suggest that, in first calf heifers, the additional milk obtained by continuing to milk the heifers for an additional month compensates for the slight decrease in production during second lactation. In cows in third or more lactation, there is no impact on milk production during the next lactation. There are no major impacts on metabolic diseases or reproduction following a short dry period. Cows that have undergone a short dry period management approach consume more dry matter at the beginning of lactation and mobilize less body stores. A 35-day dry period had no impact on cell renewal or cell activity in the mammary gland at the beginning or in the middle of the following lactation. From an economic point of view, a short dry period management approach seems to be advantageous for a farm with average production costs, especially if the farmer purchases the additional quota to cover the additional production. However, the results vary for each farm.