Strategies for northern summer dairy pasture management
June 16 2022
Summer heralds the onset of the reproductive phase of cool season perennial grasses. The ‘spring flush’ is gone for another season. While the plant will divert some of its nutrient draw to growing leaf, most of its effort will go into producing a seedhead. Dry matter production will slow down during this phase and it’s up to the prudent grazer to put management strategies in place to:
  • Make sure that supply continues to meet animal grazed demand
  • Maintain as much quality forage as possible considering the time of the year
To achieve the above goals the grazer should be measuring and monitoring pasture growth rates on a regular basis. This information, plus knowing what the herd’s daily dry matter intake (DMI) of grazed pasture needs to be, will help in the decision of how slow the grazing rotation needs to be to match budgeted demand. While ‘spring flush’ rotation lengths can be as fast as 15-18 days, the progression of summer may mean stretching rotation length out to 30-40 days depending on measured growth rates that are regulated by temperature and rainfall. A lengthened rotation strategy ensures that pastures are not overgrazed, which in turn leaves more residual to (a) allow plant forage time to recover through photosynthesis and (b) protect the soil from rapid moisture evaporation.

For those grazers in the tall fescue belt, summer is also the best time to start considering which paddocks will be selected and setup for winter stockpile. Tall fescue lends itself better than other cool season perennials because of its ability to maintain high levels of nutrients through the winter months. It also tolerates hard grazing pressure due to its thick root base and its recovery ability. Field selection is important too. The grazer needs to stay away from those paddocks that are not well drained. Feed utilization is reduced when stockpile breaks become muddy.

Let’s also not forget about heat stress management. When grazing animals, notably lactating dairy cows, are under heat stress there is a marked decrease in grazed DMI. Cows will tell you they are under heat stress when they start grouping up as a herd either at the gate or at the water source. Some may even be panting. Before this occurs the prudent grazer allows his herd access to shade and fresh water, either in a treed area that has been left for the purpose or being allowed to go back to the barn.