While sheep consume grass as 60% of their diet, they more than any other type of livestock will also eat forbs (non-woody flowering plants, commonly known as “weeds” or “wildflowers”). This makes their ecological role intermediate between cattle (true grazers that eat grass) and goats (true browsers that eat shrubs).
Also unlike cattle, sheep can consume forage on the roughest terrain. This makes them a great choice for grazing steep, rocky pastures.
Because of the way their mouths are built, sheep can crop grass much closer to the ground than cattle can, and their narrow muzzles allow them to be quite selective when grazing. Unlike cattle, they do not use their tongues to pull forage into their mouths. Instead, they pull plant material into their mouths with their thin, mobile lips and bite it off between the lower incisors and the pad on the front of the upper jaw. The optimal grazing height for sheep is between 2 and 6 inches. Either shorter or taller grass can be hard for them to handle.
Sheep graze approximately 6 to 8 hours per day. However, they do not consume their forage all at once. Typically, the day of a sheep includes about 5 to 6 periods of grazing, each interspersed with time spent ruminating and resting. Sheep tend to graze more during the cool part of the morning in summer, and perhaps even at night if necessary to meet their nutritional needs. In winter, they eat their heaviest meal toward the middle of the day, when the temperatures are warmest.
The typical dry sheep is around 0.2 animal unit equivalents (AUE), while a ewe with a lamb is 0.3 AUE. A yearling sheep is only 0.15 AUE.
Breeding sheep should be kept at a body condition score (BCS) between 3 and 4 most of the time. Prior to lambing, the ewe’s BCS should increase, erring a little more on the fat side the more lambs she is expected to have. At no time should a sheep fall below a BCS of 2, and a ewe in the early stages of gestation should never fall below 2.5.
Sheep need to take in at least 2% of their bodyweight daily in dry matter. If they are lactating or growing rapidly, they may need to consume as much as 4% of their bodyweight.
Unlike cattle, sheep typically perform better on cool-season pastures than on warm-season pastures.
Be aware that lush legume-only pastures may cause bloat in sheep. A mixed stand of legumes and grasses of multiple species is much healthier for the sheep. Sheep grazing on pastures containing a high percentage of legumes should be fed plenty of dry matter such as hay prior to being turned out on the paddock.
Grazing systems commonly used with sheep include:
- Continuous. This system is undoubtedly the easiest for the producer, as it requires little investment in fencing and other infrastructure and little time spent moving animals around. However, continuous grazing promotes selective forage consumption, resulting in weed growth. It can also result in parasite buildup, a particularly devastating problem for the sheep producer.
- Rotational. Even a very simple grazing rotation can dramatically increase the productivity of the flock, as it improves forage quality and reduces parasite load considerably. Of course, it does require more planning and preparation to implement, as every paddock must have water and possibly shade.
- Management-intensive. This system practically eliminates selective grazing and associated weed growth, and if done well it can also increase animal performance significantly. It also allows for more even manure distribution, increasing soil fertility. More fencing will be required than with other systems, and a water supply in each paddock is a must, as well. Requires considerable knowledge on the part of the grazier to avoid mistakes affecting animal performance and forage productivity.
- Strip. This involves moving animals every day between small paddocks that will be grazed very uniformly. Obviously requires more time spent in the pasture than the other systems.
Water quality affects sheep considerably more than it does beef cattle. Never allow sheep to drink directly from a pond or other water source due to the parasite risk. Expect adult sheep to drink about 2 to 3 gallons of water per day. However, lambs will only drink 1 gallon per day, while a lactating dairy ewe might require as many as 4 gallons. Sheep should never be required to walk more than 1-1/2 miles to a water source.
Sheep respond well to electric fencing, particularly woven or high-tensile wire.
If the fencing chosen is not adequate to exclude predators from the pasture, some other type of defense will be required, as sheep are extremely vulnerable. In situations where additional predator protection is required, livestock guard dogs are a common solution. Donkeys and llamas are also suitable guardian species.
Sheep are very susceptible to internal parasites, so any grazing system should take reducing the parasite load into consideration. Never allow sheep to stay in the same location for more than six days. Long rest periods (65 days or more) are necessary to allow parasites to die off before the sheep are reintroduced to the paddock. In periods of wet weather and rapid grass growth, haying the pastures will help the grass dry off enough to kill the parasites.
Another health problem commonly affecting sheep on pasture is hoof rot. This disease usually occurs when animals are forced to stand in mud and manure. Again, a rotational grazing system will help prevent the problem.
There are also a number of plants poisonous to sheep common in pastures. However, toxic plants typically do not present a major problem unless overgrazing forces the animals to eat weeds that they would normally avoid.
Adding sheep to a grazing system involving cattle or horses is an excellent way to reduce the parasite load for all species concerned. Note, however, that sheep share the same parasites as goats and camelids.
Sheep can be kept in the same paddock as the cattle, as the cattle will provide some degree of predator protection, though not as effectively as a true livestock guard animal. Be careful with this solution, however, as mineral supplements for cattle usually contain levels of copper that are toxic to sheep. Alternatively, sheep can be allowed to graze lightly ahead of the cattle to clean up some of the weeds in the paddock and to avoid the parasites prevalent lower in the forage canopy.