All ruminants (including sheep, cattle and goats) require cobalt in their diet for the synthesis of vitamin B12. Vitamin B12 is essential for energy metabolism and the production of red blood cells. Cobalt deficiency is an acquired deficiency of a trace mineral Cobalt. A trace mineral is often required in small quantities. This deficiency causes signs of vitamin B12 deficiency with inability to metabolize propionic acid. The primary cause of this deficiency is animals feeding on plants growing on Cobalt deficient soils. A secondary vitamin B12 deficiency may occur with helminth infestation. Sheep are more susceptible to cobalt deficiency than cattle. It is seen more often in weaners and young animals due to their increased energy demand for growth.
- Chronic thinness.
- Eye discharge.
- Scaly ears.
- Drop in milk production.
- Death may occur.
- weepy eyes with damp matted wool below the eyes
- in some cases, wool break
- Affected ewes may have small lambs.
- rough, pale coat and reduced milk production
- scours in calves
- A ‘depraved appetite’ (‘pica’). Affected animals may eat bark, leaves or dirt.
This condition is recognized on the basis of signs shown. These are signs of vitamin B12 deficiency or response to vitamin B12 treatment.
The occurrence of cobalt deficiency is highly variable year-on-year. The following tests for cobalt deficiency are available:
- Blood tests– can measure the level of a specific enzyme in the blood (methylmalonic acid or MMA), which increases when vitamin B12 is low.
- Submit urine samples to the laboratory. Presence of methylmalonic acid (MMA) and forminoglutamic acid (FIGLU) indicates Cobalt deficiency.
- Post-mortem assay– At post-mortem, an assay for the level of vitamin B12 in the liver can be carried out.
- Pasture tests – Pasture tests do not routinely include a check for cobalt as it is not an essential nutrient for plants, but it can be done on request. Levels less than 0.04 parts per million (ppm) indicate the potential for deficiency (0.04–0.10ppm is considered marginal).
- Response test using injectable vitamin B12. When cobalt deficiency is suspected, a response test can be done using injectable vitamin B12. Inject some of the group and compare their live weight gains over the next few weeks with untreated animals.
- Soil tests are unreliable.
Treatment and Prevention
- Consult your district veterinary officer to give injections of vitamin B12 (100mg/week). Vitamin B12 injections provide the quickest response to treatment. A single injection of vitamin B12 will prevent the development of deficiency for 6–8 weeks. This is the best method for use for lambs at marking and calves pre-weaning. It can also be used for animals to be sold in the next two months (prime lamb, beef weaners).
- Cobalt oxide tablets or drench. Cobalt sulphate drenches are available and cobalt is often included in multi-mineral drenches. The protective effect of cobalt given in this form only lasts about two weeks so the drench must be given frequently.
- Cobalt licks are available but the intake is highly variable.
- Where pastures are likely to be low in cobalt, young animals should be treated at 6-8 weeks of age with injectable vitamin B12.
- Intra-ruminal cobalt pellets, given using a ‘bulleting gun’, are better for long-term prevention of deficiency. In sheep, pelleting is best done when lambs are weaned. Pellets are not suitable for lambs less than eight weeks old. One pellet is effective for 1–3 years.
- Cobalt sulphate as a top dressing to pasture every 3-4 years. (2kg/ha). Cobalt can be added to a fertilizer blend, but this is an expensive option and the cobalt given in marginal areas may be wasted in drier years
- Pasture sprays with cobalt sulphate are also available. It is not necessary to treat the whole grazing field. Grazing stock can be rotated through sprayed paddocks, or strips of spray can be applied in each grazing paddock during winter (July).