Applying cobalt may reduce sheep liveweight loss
30 October 2006
Applying cobalt may reduce likelihood of sheep liveweight loss
Sheep farms frequently affected by lack of vitamin B12 may benefit from applying additional cobalt sulphur to increase cobalt levels in soils.
Ballance Agri-Nutrients Agro-Scientist Jeff Morton says that by increasing pasture cobalt content, farmers can combat vitamin B 12 deficiency in sheep and reduce likelihood of sheep liveweight loss.
“Vitamin B12 deficiency in sheep is more prevalent where soil has low cobalt levels, particularly during wet summers with good pasture growth,” says Jeff. “On some sheep farms, vitamin B12 deficiency can be a problem in most years and is even present in hoggets and ewes. On these farms, it is worth considering a long-term programme of applying cobalt sulphate in fertiliser.”
Jeff recommends that farmers whose sheep have high levels of vitamin B 12 deficiency test their soil for cobalt levels. If these are less than 1 ppm on non-volcanic and 2 ppm on volcanic soils and soil manganese levels are less than 100 ppm, then cobalt topdressing is a recommended option.
“Applying high rates of 250-375 g/ha of cobalt sulphate with spring fertiliser will start to build up soil cobalt levels and also elevate pasture cobalt in the short term for the critical post-tailing period for lamb growth.
“Spraying liquid cobalt sulphate at 60 g/ha on to lamb finishing pastures and grazing straight after from weaning onwards will ensure a continuous supply of cobalt and also supplement soil cobalt levels.”
However Jeff advises that for these topdressing and spraying programmes to work to optimum capacity, it is essential that applications are carried out every year for at least five years, until soil and pasture cobalt levels are lifted into the adequate range.