Review: Dry period length in dairy cows and consequences for metabolism and welfare and customised management strategies

Abstract

Shortening or omitting the dry period improves the energy balance and metabolic status of dairy cows in early lactation. Metabolic, behaviour and welfare effects throughout lactation, however, are unclear. The current paper reviews long-term metabolic and welfare consequences of short and no dry period, as well as feeding strategies and individual cow characteristics that could support in optimising management of cows with a short or no dry period. The paper will conclude with impacts of short and no dry periods at herd level and in practice. Energy balance after no or a short dry period is more positive during the complete subsequent lactation. After the initial improvement in early lactation, cows after no dry period tend to fatten and may have a too low lactation persistency to be continuously milked until the onset of the subsequent lactation. Reducing dietary energy level for cows with no dry period reduced fattening during the complete lactation but did not improve lactation persistency. Feeding a more lipogenic diet for cows with a short or no dry period did not affect the energy balance or lactation persistency during the complete lactation, although a lipogenic diet resulted in lower plasma insulin and IGF-1 concentration and greater plasma growth hormone concentration, compared with a glucogenic diet. Effects of dry period length on udder health are ambiguous, whereas short and no dry periods improved fertility in most studies. Omission of the dry period changed behaviour of cows both before and after calving, with a longer lying time and greater feed intake after calving, suggesting a better adaptation to a new lactation. Individual cow characteristics like parity, genotype, prepartum body condition score, and milk yield level determined the metabolic response of cows to a short or no dry period. In conclusion, short or no dry periods increase the energy balance in the complete lactation. Feeding strategies can be used to limit fattening of cows with no or short dry period, but the studied feeding strategies did not increase lactation persistency. Improved fertility and behavioural changes around calving suggest a better adaptation to a new lactation in case of no dry period. Customised dry period lengths for individual cows could improve metabolic status of cows at risk of a severe negative energy balance while minimising milk losses.

Moisture content of high-straw dry cow diets affects intake, health, and performance of transition dairy cows

“…It could be hypothesized that the increased bulk of feed associated with water addition to the ration may limit intake for lactating cows by increasing gut fill, but because dry cows typically have much lesser DMI than lactating cows, they have a greater capacity to handle a more water-dense ration. It is important to note, despite a 45-d dry period being at the low end of the traditional 6-to 8-wk dry period recommendation (Kok et al, 2019), it is an acceptable option (Kuhn et al, 2006), particularly with a one-group dry cow TMR. The results from this study may be applicable to other management systems targeting a longer dry period, as well as those with 2-group feeding strategies; further research is needed to examine these potential effects.…”

Evaluation of customized dry-period strategies in dairy cows

“…In the current decision trees, the cow characteristics were parity, milk yield level, and SCC. In the future, other characteristics might be explored, such as BCS, disease history (e.g., elevations in SCC), and genotype (Kok et al, 2019). Moreover, the threshold for selective DCT might be reconsidered in the future (Scherpenzeel et al, 2014).…”

Effects of limits in milking capacity, housing capacity, or fat quota on economic optimization of dry period lengths

“…Treatment cost for mastitis and other diseases were not included in our model, however. Shorter DPL may lead to fewer metabolic diseases (Kok et al, 2019) which will further advantage shorter DPL. Other possible effects of DPL such as on colostrum quality are also not recognized in our results.…”

“…Increasing daily milk yields and improvements in the management of transition cows continue to spark research into the optimal DPL. Several reviews discuss the physiology related to short or omitted DPL (e.g., Bachman and Schairer, 2003;Collier et al, 2012;van Knegsel et al, 2013;Kok et al, 2019). Briefly, these reviews show that short or omitted DPL increase the total milk yield in the parity before the DPL but reduce milk yield in the subsequent parity.…”