Mineral Nutrition in Sheep
Minerals have three main functions in ruminant nutrition:
- They give form, rigidity, and strength to the skeletal tissues and the bones and teeth.
- They help maintain a balance or neutrality of the body fluids.
- They form essential parts of organic compounds, which are found in the muscles, blood, and various secretions.
- Sodium (salt): Animals deprived of salt develop a craving for it and may resort to chewing wood and/or licking dirt. Salt should make up about 0.2-0.5% of a small ruminant’s total ration.
- Iodine: This is necessary for the formation of thyroxine, and deficiency results in an enlarged thyroid gland. Iodine deficiency symptoms are seldom observed in mature animals, but can result in weak and dead young. This problem is corrected by feeding 0.10-0.80 ppm in the diet (goats require 0.60 ppm).
- Calcium: Rations lacking in calcium and phosphorus or both result in sub-normal bone development. Calcium deficiency symptoms are sometimes slow to develop because additional calcium supplies in the body may be used to fill the body’s needs when the ration is deficient. Once these supplies run out, then signs of calcium deficiency result.Sheep require 0.20-0.90% calcium in the diet.
- Phosphorus: Because of its role in both vitamin and enzyme activity, this mineral is important in the metabolism of almost all nutrients. Phosphorus deficiency results in slow growth, high feed requirements, decreased appetite, unthrifty appearance, and listlessness. It also causes weak newborns, decreased milk production, and lower efficiency of feed utilization. Forage containing below 0.16% phosphorus is usually considered deficient for ewes/does during gestation, and 0.20% is considered borderline during lactation. Legumes and young forages are usually adequate in phosphorus. A calcium-to-phosphorus ratio of 1:1 to 2:1 is recommended.
- Cobalt: Cobalt’s function is to promote the synthesis of vitamin B12 in the rumen. Deficiency (less than 0.10 ppm) causes a loss of appetite, lack of thrift, weakness, and anemia. Cobalt "bullets" or pellets are available.
- Sulfur: Sulfur in some form is essential, and practically all common feedstuffs contain more than 0.15% sulfur.
- Magnesium: This mineral plays an important role in carbohydrate metabolism and in the proper functioning of the nervous system. Rations containing as much as 0.12-0.18% magnesium are considered adequate.
- Potassium: Most sheep and goat rations should contain 0.50-0.80% potassium. Toxicities and deficiencies are rare in sheep.
- Selenium: Selenium is associated with vitamin E metabolism and is important in prevention of muscular dysfunction. Diets should contain about 0.10-0.20 ppm for sheep.
- Molybdenum: Excess molybdenum may be toxic and cause copper deficiency. If this occurs, scouring, lameness, and loss of weight can result.
This page was last updated: February 26, 2008