Sub‑clinical deficiencies are subtle and easy to miss, often showing up as poor performance rather than clear clinical illness. Below are some of the symptoms.
Copper (Cu) Deficiency
Cattle
Common sub‑clinical signs include:
- Poor coat condition or loss of pigmentation (“spectacle eyes”)
- Poor growth rates / ill‑thrift
- Reduced fertility and reduced immunity
- Bone weakness and general ill-thrift
Sheep
Common sub‑clinical signs include:
- Steely wool (loss of crimp, harsh texture)
- Reduced growth and anaemia
Swayback in lambs (from deficiency in the ewe during pregnancy) - early stages can be sub‑clinical.
Cobalt (Co) Deficiency
Cobalt deficiency leads to low vitamin B12 production in the rumen.
Cattle
Sub‑clinical signs include:
- Poor appetite and reduced feed intake
- Poor growth / ill‑thrift
- Weakness and anaemia
Sheep
Sheep are more susceptible than cattle.
Sub‑clinical signs include:
- Pine: poor appetite, lethargy, poor wool quality, poor thrift, slow growth
- Tear staining around the eyes
- Scaly skin at base of ears (early indicator)
Increased susceptibility to infection due to poor immunity
Selenium (Se) Deficiency
Cattle
Sub‑clinical signs include:
- Reduced growth rates
- Increased stillbirth rate / reproductive issues (sub‑clinical before they become clinical)
- Poor immune function (increased susceptibility to disease)
- Retained placenta’s post calving
Sheep
Sub‑clinical signs include:
- Poor growth and weak newborn lambs
- Reduced vigour in lambs and poor mothering (before full white muscle disease develops)
Iodine (I) Deficiency
Cattle
Sub‑clinical iodine deficiency may show as:
- Reduced fertility / poor conception rates
- Weak or hairless calves at birth (can begin sub‑clinically)
- Increased stillbirths / late abortion risk
Sheep
Common sub‑clinical indicators include:
- Weak or unthrifty lambs at birth
- Hairy lambs or poor fleece quality at birth
- Increased perinatal mortality and stillbirths