On March 5th, 2021 the Ecological Farmers Association of Ontario hosted an event focused on best management practices for rotational grazing of sheep. The event featured a joint presentation from Jim Johnston of Pasture Hill Farm in New Liskeard and Christine O’Reilly, OMAFRA’s Forage and Grazing Specialist.
O’Reilly focused on some of the more technical aspects of rotational grazing, while Johnston discussed how those technical aspects translate into action in the field.
O’Reilly began the presentation by outlining the growth cycles of forage plants. In the spring, forage plants need time to develop their leaves, which allows them to photosynthesize and store energy in their root systems. Grazing too early in the spring (i.e. before a plant has 3 or 4 full leaves) means the plant won’t have the root development or energy stores available to bounce back from having their leaves removed.
Johnston recalled one OMAFRA employee who used a plastic two-litre pop bottle as an easy scale for when a field was ready to be grazed: once the forage was the height of the pop bottle, it was ready to go.
Once a plant is grazed, the energy in the roots is taken up into the plant and used to regrow the leaves, but in the process the roots are atrophied as their energy is used up. Before being grazed again, the plant needs to be given time not just to regrow the leaves, but also to regrow the roots. As a general rule of thumb, animals should not be left in a paddock for longer than 5 days, as at that point they’ll be eating the plant’s attempts to regrow and diminishing both the root reserves and the leaves.
The length of time between grazings varies depending on the weather, time of year, and plant species present, but, in general, leaving plants with some leaves (not grazing right down to the roots) jumpstarts the regrowth process, and allowing time for grass and roots to fully regrow will maximize the number of grazings in any field in a given season.
For Johnston, these rest periods could be 25 to 30 days in the spring and up to 40 or 50 days in midsummer and into fall. When talking about sheep, longer rest periods can help to reduce parasite loads as well as increase forage yields.
Flexibility is important when rotationally grazing animals. This means that having fencing, electricity, and water that can go wherever the sheep go is key. Johnston is a proponent of the electric net fences, which allow him to divide fields into paddocks in any way he chooses, maximizing his grazing efficiency. A powerful fence energizer is also important, especially with sheep. Since their wool acts as an insulator, sheep require a more powerful energy source than cattle. Johnston uses a combination of permanent fencing, net fencing, and polywire reels to create paddocks for sheep and to deliver energy to wherever the sheep are.
In terms of water, Johnston uses 1000-litre plastic totes mounted on wagons (or old manure spreaders), to take the water to the sheep. From the totes, he plumbs a hose that runs into a water tub rigged with a float valve to allow the sheep constant access to water whenever they need it. Compared to cattle, sheep are very water efficient, and two or three totes on a wagon could last 200 ewes about a week depending on the weather.
Johnston keeps his sheep on pasture into the fall, sometimes until mid-December, depending on the weather. In order to keep the sheep fed when the snow is on the ground, he rolls out round bales of hay for them. For this, Johnston has rigged up a set of arms that attach to the three-point hitch on his tractor. These arms wrap around either side of the bale and connect to a metal rod driven through the centre of the bale. Johnston simply drives the tractor away and the bale unrolls behind him. This ensures that seeds, chaff, and organic material from the bales are spread directly back on to the pasture, along with the manure, and is an excellent way to revitalize forage stands.
The Ecological Farmers Association of Ontario hosts a number of events on a wide range of topics. A list of upcoming events can be found on their website www.efao.ca.