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Selenium (Se)•Only nutrient whose level is
controlled by FDA•Has smallest optimal range• (difference between requirement and
toxicity)• Toxicity can be a regional problem in
Montana
Selenium (Se)• There are Se accumulating plants• Can be indicators of toxicity• Can result in acute toxicity – sudden
death•Astragalus species (locoweed)• Vetches• Some native range plants
Selenium (Se) Toxicity•Originally called Alkali disease• Chronic toxicity•Affects keratin of hair/hooves• Rough hair coat• “Bobbed” tail• Sloughed hooves•Affects adult animals
Se Deficiency• Se deficiencies that affect young
animals•Nutritional Muscular Dystrophy•White Muscle Disease•Affects ability to stand and nurse
Se Deficiency• In reproductive females• Retained placenta•Decreased fertility
Iodine (I)•Not high in feeds• Therefore we use Iodized salt• (even for humans)• Regional deficiency – Great Lakes,
Montana
Iodine Deficiency•At any age = Goiter• Enlargement of thyroid gland• Thyroxine contains Iodine• In reproductive females = stillbirths•Weak, hairless young
Mn Deficiency• Symptoms:• Lameness•Abnormal bone growth• Immune dysfunction
Mn Deficiency• In reproductive females:•Delayed estrus• Reduced ovulation• Embryonic mortality•Decreased fertility
Cobalt (Co)• Required for rumen microbes to
synthesize Vitamin B12
• Part of Vit. B12’s chemical structure
Cobalt (Co)•Deficiency regional grazing
Wasting Disease (Co deficiency)• First discovered in Australia•Australia – extreme emaciation• Because Vit B12 important in energy
metabolism
Wasting Disease (Co deficiency)• To cure:• Cobalt must be provided to rumen• Injection of Co won’t work • (because Co needed in rumen to
synthesize Vit. B12)• Injection of Vitamin B12 will work
“Organic” Minerals• Chelated•Attached to amino acids
• Proteinated•Attached to peptides
• Complexed•Attached to other organic
compounds
“Organic” Minerals•Usually Zn, Cu, Mn, & Co are included
in organic form•Hypothesis: Increased availability
Example feed tag containing organic minerals
“Organic” Minerals•Are they effective?• Conflicting research results• Positive results with animals that are:•High producing• Stressed• Immune-compromised
“Organic” Minerals•Organic forms are more expensive
than sulfates, chlorides, etc.• Therefore, they must be cost effective
“Organic” Minerals• Recommendation for organic mineral
use:• If high S, Fe and/or Mo
(antagonists)
“Organic” Minerals• Recommendation• If problems occur such as:• Calf/lamb scours• Increased reproductive failure• Change in hair color• Increased foot rot• Increased respiratory infections
“Organic” Minerals•Due to cost, recommendation is:• 70% inorganic + 30% organic• Supplementation during strategic
(stressful) times:• Cows – prior to calving through
breeding• Ewes – prior to lambing, during
breeding• Calves/lambs – prior to weaning