Interpretive Summary: Extending lactation length: consequences for cow, calf, and farmer

By: Ariette T M van Knegsel, Eline E A Burgers, Junnan Ma, Roselinde M A Goselink, Akke Kok

Traditionally, a 1-yr calving interval is advised to dairy farmers to realize a yearly peak in milk yield. A 1-yr calving interval, however, implies a yearly event of drying-off, calving, and start of lactation, which are all associated with an increased risk for diseases and disorders. Deliberately extending the lactation length reduces the frequency of these challenging events both for individual cows and at herd level. This reduction in frequency of calvings can be beneficial for cow health and fertility, but also can be of interest to reduce the number of surplus calves and labor associated with drying off, calving, and disease treatments. Current concerns with respect to an extended lactation are that milk yield is too low and cows can get fat in late lactation. Moreover, limited knowledge is available with respect to consequences for cows in the subsequent lactation and for calves born to cows with an extended lactation. Moreover, response of dairy cows to an extended voluntary waiting period depended on individual cow characteristics such as parity, milk yield level, or body condition. A customized strategy based on individual cow characteristics can be a future approach to select suitable cows for an extended lactation.

Read the full article in the Journal of Animal Science.