Trace minerals

MINERALS REQUIRED IN LIVESTOCK DIETS
• Major minerals (Required in large quantities)
Beef
Dairy
Swine
Ca, %
P, %
Mg, %
Na, %
Cl, %
K, %
S, %

Finishing Cow
.5
.15-.3
.2
.12-.23
.10
.12
.06
.08
.6
.6
.15
.15

Chicken

Dry Lactating Finishing Sow
.6

.8
.6
.75
.3
.4
.5
.6
.25
.3
.04
.04
.15
.25
.10
.15
.25
.30
.08
.12
1.0
1.5
.23
.20
.2
.26
-

Broiler Layer
.8
3.5

.8
.8
.05
.05
.15
.15
.15
.15
.4
.4
-

• Minor minerals (Required in very small quantities
Fe, ppm
Cu, ppm
Zn, ppm
Mn, ppm
I, ppm
Co, ppm
Se, ppm
Mo
Cr

30
10
30
20
.50
.10
.10

50
10
30
40
.50
.10
.10

100
20
80
50
.60
.30
.30

100
20
70
50
.60
.20
.30

60
4
60
2
.14

.15

80
5
50
10
.14
.15

80
8
50
60
.35
.15

45
2
35
35
.30
.10


• Minerals are often overfed
– Levels of minerals commonly fed in industry to swine
Mineral
Ca
P
Mg

Na
K
Fe
Cu
Zn
Mn

Level fed, % of requirement
160-190
140-150
400-500
147-190
390-423
470-776
440-667
298-334
770-3100

– Reasons for overfeeding of minerals
•
•
•
•
•

High levels in feeds
Supplementation to provide safety margin
No consideration of mineral bioavailability
Free choice feeding of trace mineral salt
Use of Cu and Zn salts as growth promotants for swine and poultry

Dose, ppm
Cu
100-250
Zn
2000-4000


•

Utilization rates of most minerals are low
Utilization rate Excretion rate
(% of intake)
30-50
50-70
20-50
50-80
15-30
70-85
10-25
75-90
5-20
80-95
5-30
70-95
5-30
70-95
5-30
70-95
5-10
90-95

Ca
P
Mg
Na
K
Fe
Cu
Zn
Mn

– Factors mineral utilization rates
• Mineral sources
– Organic mineral (Chelates) > SO 4 or CO3 salts > oxides

• Level fed
– Low levels > high levels

• Interactions with other minerals
– High K reduces Mg absorption
– High Zn reduces Cu absorption
– Low Cu reduces Fe absorption

• Processing
– Grinding increases mineral absorption

• Age and nutritional status of animals
– Young animals absorb minerals better than adults

• All minerals are toxic to animals if fed in excess
– Maximum tolerable concentrations
Ca, %
P, %
Mg, %
NaCl, %
K, %
S, %
Fe, ppm
Cu, ppm
Zn, ppm
Mn, ppm
Mo, ppm
I, ppm
Co, ppm
Se, ppm
Cr, ppm

Beef
2
1
.4
4
3
.4
1000
100
500
1000
5

50
10
2
1000

Dairy
2
1
.5
4
3
.4
1000
100
500
1000
10
50
10
2
1000

Swine
1
1.5
.3
8
2
3000
250

1000
400
20
400
10
2
1000

– Causes of toxicities
• Oversupplementation
• Poor formulation and/or mixing
– Wrong feeds fed to wrong species

• High concentrations in feedstuffs

Poultry
.4-1.2
.8-1.0
.3
2
2
1000
300
1000
2000
100
300
10
2
1000

Sheep
2
.6
.5
9
3
500
25
300
1000
10
50
10
2
1000


– Examples
• High K forages (associated with overfertilization)
– Health effects
» Milk fever
A calcium deficiency occurring to dairy cows in early lactation.
Results in tetany and death, if untreated.
Caused by overfeeding cations, particularly K, during the dry
period.
Prevents resorption of Ca from bone.
» Grass tetany
A Magnesium deficiency occurring to animals grazing lush,
heavily fertilized grass pastures in the spring.

Results in tetany and death, if untreated.
Caused by low Mg content of lush forage and inhibition of Mg
absorption by high levels of K and N.

• High Se forages
– Causes
» High Se soils in western U.S.
» Plant species that accumulate Se
– Health effects
» Se toxicity
Lameness
Blind staggers (Labored breathing and ataxia (loss of
coordination)
– Not yet associated with manure application


CONCERNS WITH EXCESS MINERALS IN SOILS
• In soils, most minerals act like P
– Minerals bind to soils high in clay or organic matter
• Particularly occurs at pH>6
• Occurs particularly near soil surface
• Minerals move to water sources with soil erosion

– Minerals do not bind to soils that are high in sand or have a
low pH
• Travel with infiltrating water into ground water sources

– Most minerals have limited bioavailability to plants
• < 40%
• Results in accumulation of trace minerals in soils

– Example:
» In areas where swine manure has been heavily applied in North
Carolina:
soil Zn increased 4 times
soil K increased 2 times
soil Cu increased 3 times

• Concern
– Once trace minerals have accumulated in the soil, they’re difficult to
remove.


Environmental effects of excessive application
of manure minerals
• Minerals of most concern
– P, NaCl, K, Cu, Zn

• Effects
– Toxic to plants
• NaCl, Cu, Zn, Mn

– Detrimental or toxic to animal health
– May enter water resources with soil erosion or water
infiltration


METHODS TO LIMIT MINERAL EXCRETION IN MANURE
• Use of precision nutrition of minerals
– Limit safety margins when feeding minerals
– Utilize mineral sources with high bioavailability

• Must balance for available minerals rather than total minerals

– Balance for individual minerals rather than using complete
trace mineral premixes
• Requires rapid feed analysis

– Limit use of free choice trace mineral salt

• Utilize phase feeding
• Utilize separate sex feeding
• Limit feed waste