J. L. Goelz, D.V.M.
International SheepLetter
Vol. 21, No. 5, July 2001

The summer months are the time of the year when the ewe flock becomes neglected. Rightfully so, this is the time of year when the ewes are not getting bred, gestating or lambing and thus about our only concern is that they stay alive. Many shepherds are simply content to make sure the ewes stay in the pasture fence and check that the watering hole hasn't dried up.
The summer months do however offer some opportunities to reduce grazing costs and maximize the use of pastures. There are a few different types of grazing systems that I will try to review along with advantages and disadvantages of each.

Intensive Grazing:This is a system of grazing that was developed in New Zealand. The pastures are divided into many small paddocks (pastures) usually with electric fencing. Sheep are confined to one paddock but are moved to a fresh paddock often such as every 7-10 days. One advantage of this system is that the sheep are constantly being moved to a paddock of fresh, growing grass that has high nutritional value. Also, by moving the sheep this frequently we prevent a buildup of parasitic larvae on pasture and the infective larvae are dead by the time we get rotated back to the pasture. Generally in this system because of the small size the sheep will graze the paddock uniformly and the sheep are moved before the paddock gets too short. The overall forage yield will be higher in intensive grazing systems than in more traditional systems. Some of the disadvantages include higher labor cost from moving the sheep and more money tied up in cross fences. Another concern is that the grass generally does not grow long enough to go to seed, which can impact the species of grass in the pasture if it is grazed intensively year after year. Also, the shepherd needs to find a way to get water to each paddock or have a moveable watering system. This type of grazing system works best in regions of heavy rainfall or low-lying pastures where moisture is not a problem
Traditional Extensive Grazing:This is grazing as most of us have grown up with. Generally the sheep are turned out on one pasture and they are grazed there for the entire grazing season. Advantages of this are simple, one perimeter fence, one water source and no labor involved in moving the sheep. Disadvantages of this system include a high buildup and exposure to parasites over the grazing season and pasture under utilization. Sheep will graze the youngest plants in the pasture because these are the most palatable (taste the best). This results in areas of the pasture that are heavily overgrazed and areas that are virtually untouched. The overgrazed areas have so much grazing pressure that the only grasses that go to seed will be the ones that sheep do not like to eat. Over a period of years these heavily grazed areas will have poor grass growth and the sheep will choose a different part of the pasture to overgraze. Also, by late in the grazing season the only grass available is mature, unpalatable grasses that have low nutritional value.

Rotational Grazing Hybrid:This is a type of grazing system that many in the Midwest prefer. It incorporates advantages of both intensive and traditional grazing systems. It involves using 2-4 pastures and rotating among the pastures during the grazing season. Often sheep will spend 4-6 weeks in each pasture before they are moved to a fresh pasture. This is not as labor or fence intensive as an intensive grazing system but still picks up many of the advantages such as pasture utilization. The pastures that are used later in the rotation are often cut for haying if the terrain permits. If there is adequate moisture this encourages a regrowth of grass and legumes which are highly palatable. Often management practices are done at the time of rotation such as deworming and foot rot treatments. Also, rotating to a fresh pasture is useful as a flushing tool prior to breeding in this system. Disadvantages include not as good of forage yield as intensive grazing and some additional fencing and labor cost.

Before choosing a grazing system or changing your current management it is worthwhile to examine your current system. Are you getting efficient pasture utilization? Are the sheep overgrazing portions of the pasture and undergrazing other portions? Do you have enough rainfall to permit intensive grazing? Will the benefits of intensive grazing outweigh the added costs of labor and fence? Can pastures be cross-fenced and still maintain a water source? The grazing system should be tailored for the region and farm. A system that is efficient in New Zealand will not be efficient in western South Dakota and one that is efficient in Oregon will not necessarily be the best for someone in Georgia. Remember the bottom line is to graze as many ewes as possible on your pastures without damaging the pasture for the future.