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