Soil Trace Element Deficiency May Be Impacting Your Flock

Trace elements are crucial for the health and well-being of sheep, influencing several biological processes essential for growth, fertility, and overall productivity. However, the availability of these elements varies significantly depending on soil type, pH, and drainage. A proper understanding of the soil’s trace element content is essential for managing livestock health, especially since deficiencies can lead to subtle, yet serious, issues. For farmers, identifying potential deficiencies early can help prevent widespread health problems in sheep. 

Cobalt 

Cobalt is a vital trace element that plays a crucial role in the rumen microbiome, aiding in the production of vitamin B12. Vitamin B12 is essential for energy production and other metabolic processes in sheep. A deficiency in cobalt can be particularly detrimental to growing lambs, leading to symptoms such as poor growth, reduced appetite, poor wool quality, and in severe cases, anaemia. Lambs may also be slow to stand or suck, and they may fail to ingest enough colostrum, which further complicates their health. 

Cobalt deficiency is more likely to occur in soils that are iron-rich, alkaline, or manganese-rich, as cobalt can become locked in forms that are not readily available to plants. The availability of cobalt in pasture generally decreases as soil pH rises, meaning that liming can unintentionally lead to cobalt deficiency. Mixed pasture swards with clover are beneficial, as clover typically contains higher levels of cobalt than ryegrass. 

It is generally recommended that sheep’s diet contains 0.1 mg/kg DM of cobalt, with soil levels ideally above 10 mg/kg. Testing soil for cobalt content can give you a clear picture of whether supplementation is necessary. 

Copper 

Copper is another essential trace element, playing a crucial role in various processes. A deficiency in copper can manifest in several ways. Lambs may suffer from “sway back” – a paralysis or weakness of the back legs – due to copper deficiency in the ewe during mid-pregnancy. This condition results from impaired spinal cord development in the lamb, often resulting in euthanasia. Copper deficiency can also affect wool quality, causing it to become “steely,” and it can lead to fertility problems in ewes. 

While copper deficiencies are sometimes due to low soil copper levels, they can also result from the presence of other minerals, such as molybdenum, which can bind copper and prevent its absorption. Sheep require 10 mg/kg DM of copper to meet their needs, but care should be taken with supplementation. Overdosing on copper (more than 17 mg/kg DM) can lead to toxicity, which causes liver failure, red blood cell destruction, and jaundice. Soil copper levels should ideally be above 3.00 mg/l. 

To accurately assess the need for copper supplementation, it’s recommended to combine soil analysis with blood sampling from ewes. Consulting with your vet before beginning any supplementation program is crucial to avoid the risks of toxicity. 

Iodine 

Iodine is a critical trace element for sheep, as it supports the thyroid gland in regulating metabolism and energy production. It is also essential for proper foetal development. Deficiency in iodine often leads to poor fertility or abortion, with iodine-deficient ewes having trouble carrying pregnancies to term. This deficiency can be caused by low soil iodine levels or excessive brassica consumption, as certain forage crops can inhibit iodine’s effectiveness in the thyroid gland. 

Sheep require a minimum of 0.15 mg/kg DM of iodine, with pregnant and lactating ewes, as well as growing lambs, needing higher levels. Ideally, soil iodine content should be above 5 mg/kg. Monitoring soil iodine levels and considering dietary adjustments can help prevent fertility and development issues in your flock. Note however that over supplementation with Iodine in ewes can reduce colostrum quality and therefore affect lamb viability.    

Selenium 

Selenium plays a crucial role as an antioxidant, supporting both growth and fertility in sheep. Deficiency in selenium leads to white muscle disease in lambs, with symptoms such as stiffness, arched backs, and tucked-up flanks. Affected lambs are also more prone to pneumonia and often die. In addition, selenium deficiency can cause early embryonic death, leading to higher incidences of barren ewes and poor scanning percentages. 

Sheep need 0.1 mg/kg DM of selenium to maintain proper health, and soil selenium content should be carefully monitored to ensure sufficiency. Soil testing for selenium levels, along with regular health assessments of your flock, can help prevent these severe outcomes. 

Conclusion 

The trace elements present in soil play a critical role in the health of your sheep. Deficiencies in cobalt, copper, iodine, and selenium can result in a range of health issues that affect productivity and flock well-being. By regularly testing soil and understanding the mineral content, farmers can ensure their pastures provide the necessary nutrients for sheep to thrive. Early identification and intervention are key to preventing deficiencies from becoming widespread issues, ensuring the continued health and success of your farming operation.