Technical information - Nutrition

Nutrition – Microminerals for Beef Cattle

BRAHMAN NEWS MARCH 2018 ISSUE #198 PAGE 66

Contributed by Alex Ashwood

Grazing areas in the northern beef industry consist of the high rainfall coastal regions and the progressively drier inland areas, both of which periodically experience marginal deficiencies of some microminerals.

Whilst the incidence of clinical symptoms is very low it is recognised that adequate levels of microminerals are necessary for optimal production and animal welfare.

Cattle grazing pastures in the northern beef industry are most likely to have nutritional shortfalls when the pastures are mature, dormant or experiencing drought conditions.

“Stock at most risk are lactating cows and weaners due to their higher nutritional requirements.”

The rate of animal production (liveweight gain and milk production) depends on the nutritional value of the feed and the quantity of food eaten. Studies show that tropical pastures are 13-20 percent lower in digestibility than temperate pastures. Higher levels of indigestible fibre leads to lower total dry matter intake (TDMI) and reduced intakes of total digestible nutrients (TDN) including micro and macro minerals.

Studies have shown that animals grazing pastures and forages with marginal levels of microminerals can experience subclinical signs of deficiencies, that is, reduced reproduction rates, lower levels of production (eg growth and liveweight gains) and greater risk of infectious diseases.

While major nutrient deficiencies (energy and protein) are well defined for cattle, micromineral deficiencies are less well documented for cattle grazing pastures in the northern beef industry.

The intention of this article is to provide an introduction to the function of microminerals, discuss the impact of micromineral deficiencies on animal performance and examine factors that affect the microminerals requirements of beef cattle.

Micromineral Requirements

The micromineral requirements of beef cattle are based on the ability of the animal to maintain a desired level of performance. Table 1 shows the micromineral requirements for several categories of stock.

Essential microminerals are necessary for the well-being and the production and reproductive performance of cattle. Microminerals are only required in very small amounts (ppm) to promote normal tissue growth, homeostasis, energy functions, cell regulation and immune function.

“Micromineral deficiencies can be classified as primary and secondary.”

A primary deficiency is caused by inadequate dietary intake of one or more essential minerals, while secondary deficiencies are caused by interference in absorption, distribution and retention of a mineral. Deficiencies can occur simultaneously making the evaluation of mineral status and the calculation of micromineral supplementary programs complex.

Marginal micromineral deficiencies in the tropics and subtropics occurs more frequently than realised which can pose a larger problem than clinical deficiencies because losses to production and performance can go undetected and not rectified.

As with macrominerals, caution is required when providing microminerals since all elements are toxic when fed incorrectly and actual requirements are affected by many interactive factors.

“If not supplied in the correct amounts and ratios, specific metabolic diseases and/or toxicities can occur.”

Cobalt (Co)

Cobalt functions are a component of B12 (vitamin) which is synthesised by microbes in the rumen.

Cattle can tolerate approximately 100 times their dietary requirements and Co toxicity is extremely unlikely unless there are major errors in the formulation of the ration. Toxicity signs include decreased feed intake, reduced weight gain, anaemia and weakness.

Young cattle are more sensitive to Co deficiencies than older cattle. Deficiency symptoms are depressed appetite, reduced growth, immune system problems and reduced rumen microorganism production.

Whilst not common in Queensland and Northern NSW, Co deficiencies are generally seasonal and deficiencies can be accentuated when pastures receive high levels of liming and superphosphate fertiliser.

Treatment for animals showing clinical signs of Co deficiency is a vitamin B12 injection which lasts up to 3 months subject to the severity of the deficiency.

Cobalt sulphate and cobalt carbonate are examples of cobalt supplements for beef cattle. For a mineral supplement with an expected 125gms/head/day intake the supplement should contain 10ppm cobalt.

Copper (Cu)

Copper is an essential element required for enzyme systems, iron metabolism, connective tissue, metabolism and mobilisation plus the integrity of the central nervous system and immune systems.

Copper functions in the immune system through energy production, neutrophil activity and antioxidant enzyme production. It also aids the development of antibodies and lymphocyte replication. If the immune system is compromised the stock are more prone to infectious diseases and diarrhoea.

Copper is necessary in the postpartum cow for proper involution of the uterus, displaying oestrus ovulation, conception and maintenance of the new foetus (Table 2).

“Copper deficiency causes reduced reproduction and embryo deaths”

Clinical signs of Cu deficiency include illthrift and poor calf growth and loss of weight in adult animals. The hair coat will be more yellow but some Cu deficient cattle show little change in hair coat colour.

Another sign of Cu deficiency is lameness and incoordination of movement and spontaneous, fractures of bones. Tissue in the heart degenerates and is replaced with fibrous tissue leading to heart failure.

In certain geographical and topography locations (eg coastal areas and low lying poorly drained country) grazing animals are more likely to develop copper deficiency due to the low content and low availability of copper in water-saturated pastures. Copper release from plants depends on the type of forage and stage of vegetative growth. Cattle grazing low quality forages, particularly in late summer and wet winters, are more likely to be copper deficient.

“Molybdenum, sulphur, iron and zinc reduce copper status and can impact on copper deficiency.”

Forage plants may have high molybdenum (Mo) levels from high Mo soils, especially soils that are highly alkaline. Mo can limit the animal’s use of copper, especially if the diet is high in iron and sulphur. High levels of Zn and Fe depress Cu absorption and tend to increase requirements.

If the Mo content of the diet is less than 1ppm of the total dry matter, 8-15ppm (TDMI) of copper in the diet should be adequate. If the Mo content in the diet is greater than 2.5ppm copper may need to be increased by 5ppm if copper levels are marginal.

Copper is more available in concentrates than forages. Forages vary greatly in copper content and may contain variable levels of Mo, S and Fe which reduce Cu levels. Legumes generally have higher levels of copper than grasses. Oilseed meals have higher Cu levels than cereal grains.

Supplementation with selenium (Se) increases copper availability to the anima, but additional care needs to be taken when supplementing Se deficient cattle.

Copper supplements include copper sulphate, copper carbonate and copper oxide. In a mineral supplement fed at 125gms/head/day, 1200ppm copper is recommended.

Copper in excess is extremely toxic particularly with young stock.

Zinc (Zn)

Zinc is a component of many enzymes and is important for immunity systems, reproduction, skin health and plays an important role in protein production. Table 2 summarises the potential effects of Zn deficiency in cattle.

Reports of Zn deficiency are rare and difficult to diagnose since cattle have a limited capacity to store zinc. Signs of deficiency include reduced feed intake and weight gain, excessive salivation, swelling of the feet and legs and lesions around the nose and mouth.

Similar to several other minerals, zinc concentration in forages depends on many factors. Zinc is higher in legumes than grasses and generally high in cereal grains.

Supplemental sources of zinc include Zn oxide, Zn sulphur, Zn methionine and protonate forms. The oxide and sulphate forms have similar bio availabilities.

In a mineral supplement designed to provide under 125g of intake /head/day, 3000ppm of zinc is recommended

Zinc is toxic at very high levels and far higher than the animal’s requirements.

Manganese (Mn)

Manganese plays an important role in growth and reproduction. Table 3 summarises the main deficiency symptoms which relate closely to reproduction and fertility and Mn is linked to enzyme functions and skeletal growth.

Ironically, Ca and P which are closely linked to bone growth can inhibit Mn absorption when fed in high levels.

Mn requirements (Table 1) vary depending on the stage of production (eg growing cattle need 20ppm whilst pregnant lactating cows need 40ppm).

As with Co, Mn has a fairly safe feeding range with tolerance levels as high as 1000ppm. Mn, however, interacts with many different minerals which can alter the animals tolerance level for Mn and the minerals with which it interacts.

Forage Mn levels vary with plant species, soil pH, soil drainage and forages generally have sufficient Mn.

Supplements include manganese sulphate, manganese oxide, manganese methionine and manganese proteinate with different levels of bioavailability. Manganese methionine and proteinate have the highest levels of bioavailability.

Selenium (Se)

Selenium in conjunction with vitamin E boosts the function of immune systems and is important in the development of the antioxidant enzyme system. The symptoms of Se deficiency are shown in Table 3.

“Selenium is very toxic and should only be used carefully in a premixed form”

Signs of chronic selenium toxicity include lameness, anorexia, sore feet, cracked and deformed hooves, liver and kidney inflammation. In severe toxicity cases, difficult breathing, diarrhoea, muscle incoordination, abnormal posture and death from respiratory failure are observed.

Because of the low tolerance range, Se has been a difficult element to supplement although research suggests that Se tolerance is marginally greater than the literature indicates.

Selenium supplements include sodium selenite, sodium selevate, selenomethionine or selenium injections.

A mineral mix fed at 125gms/head/day should not exceed 25ppm selenium.

Iodine (I)

Iodine is an essential mineral for the function of the thyroid hormones. Deficiency symptoms are shown in Table 3 although deficiencies are very rarely seen in the northern beef industry.

Thyiocynate in white clover and glucosinolates in brassicas impair the uptake of iodine. Soyabean and cottonseed meal have also been reported to have goitrogenic effects but with no reported deficiencies when fed to cattle.

Iodine toxicity reduces weight gain, lower feed intake and causes coughing and nasal discharge.

Dietary iodine supplements include calcium iodate, ethylenediamine dehydroidide (EDDI), potassium iodide and sodium iodide. Calcium iodate and EDDI forms are very stable and have high bioavailability in cattle.

Recommended supplementation rate in a mineral mix designed to provide 125gms of intake /head/day is 80ppm of iodine.

Iron (Fe)

Iron is primarily required for the formation of hemoglobin and myoglobin, two proteins used in oxygen transport throughout the body. Deficiency symptoms are shown in Table 3, however deficiencies due to low intake are very rarely seen with grazing animals. Conditions that cause blood loss (eg parasite infections and injuries) can lead to iron deficiency.

Iron deficiency causes anemia, lethargy, lowered feed intake, reduced weight gain and pale mucous membranes. Young cattle have higher iron requirements than mature cattle.

Iron toxicity includes diarrhoea, acidosis, hypothermia, reduced feed intake and reduced weight gain.

Excess iron depletes copper levels in cattle and can contribute to copper deficiency if copper supplementation does not compensate for copper losses.

Iron sources include forages, cereal grains, protein meals, water and soil ingestion. Pastures provide variable amounts of Fe and the bioavailability is also variable.

Common Fe supplements include iron sulphate, iron carbonate and iron oxide with varying bioavailability from most to least respectively.

Bottom Line

Microminerals are needed for vitamin syntheses, hormone production, enzyme activity, tissue syntheses, oxygen transport, energy production and other physiological processes related to growth, reproduction and health.

“The requirements for microminerals are based on the levels required for optimal performance”

The main microminerals are copper (Cu), zinc (Zn), manganese (Mn), cobalt (Co), iodine (I), iron (Fe) and selenium (Se).

There are many factors that affect an animals response to microminerals supplementation such as the duration and concentration of mineral supplementation, physiological status, the absence or presence of dietary antagonists, environmental factors and the influence of stress on micromineral metabolism.

Microminerals (trace elements) whilst required in relatively small amounts (less than 100ppm) compared to macrominerals (greater than 100ppm) are equally, if not more important.

It is essential that microminerals are supplied within narrow concentrations in the diet. Acute deficiencies and clinical symptoms are not common but subclinical deficiencies reduce growth, lower reproductive rates, use feed less efficiently and may cause the animal to be more susceptible to infectious diseases due to depressed immunity functions.

“Since many factors can affect responses to microminerals supplementation, feeding programs can be challenging”

Given the complexity of establishing micromineral deficiencies and the need for correct balances, proper ratios and amounts of microminerals it is important to consult with a nutritionist when assessing, designing and implementing micromineral supplementation programs.

Further Reading

Health – Immune Systems and Micronutrients for Beef Cattle – Brahman News, March 2017, issue 194

Nutrition – Macrominerals for Beef Cattle – Brahman News, September 2016, issue 192


Table 1: Generally accepted beef cow mineral requirements and potential mineral formulations.


Beef NRC requirements

Suggested mineral composition

Mineral

Pregnant Dry Cow

Lactating cow

General formulation

High magnesium

Macrominerals (%)

Calcium

0.25

0.25-0.36

10-12

12-16

Phosphorus

0.16

0.17-to 0.23

6-12

2-4

Potassium

0.60

0.70

-

-

Magnesium

0.12

0.20

4-5

10

Salt

0.07

1.10-0.15

<15

15-25

Sulphur

0.15

0.15

2-3

0-3

Microminerals (ppm)

50

50

-

-

Iron

40

40

4,000

4,000

Manganese

30

30

3,000

3,000

Zinc

10

10

1,200-2,000

2,000

Copper

0.5

0.5

100

100

Iodine

0.1

0.1

60

60

Selenium

0.1

0.1

30

Cobalt

30

Note:

(1) Recent research suggests that chromium (Cr) and molybdenum (Mo) are also important microminerals.

(2) Source – NRC 2000. Adapted from NRC Requirements for Beef Cattle.

(3) One part per million (ppm) = 1mg/kg

(4) Microminerals are maintained within a narrow concentration and where elements can be toxic, recommended levels of requirements are justifiabibly low (eg Se).

(5) Disease, stress and illthrift can reduce the function of microminerals.

(6) Macromineral intake is expressed as a percentage of TDMI and micromineral intake as ppm of TDMI.


Table 2: Symptoms of copper and zinc deficiencies in beef cattle


Mineral

Cow

Bull

Copper (Cu)

  • Illthrift & liveweight loss
  • Delayed oestrus
  • Embryonic death
  • Decreased conception
  • Delayed puberty
  • Decreased ovulation
  • Reduced immunity and increased infection
  • Illthrift & reduced liveweight
  • Decreased libido
  • Decreased sperm production
  • Delayed puberty
  • Reduced immunity and increased infection

Zinc (Zn)

  • Increased dystocia
  • Abnormal oestrus
  • Reduced immunity and increased disease
  • Reduced locomotion due to lameness and reduced foot health
  • Abnormal oestrus
  • Impaired growth
  • Delayed puberty
  • Decreased testicle size
  • Decreased libido
  • Reduced movement due to lameness and reduced foot health
  • Reduced immunity and increased infection

Table 3: Symptoms of Mn, I, Se and Fe deficiency in beef cattle


Mineral

Deficiency Symptom

Manganese (Mn)

  • Impaired reproductive performance (silent heats)
  • Skeletal Deformities
  • Reduced birth weight

Iodine (I)

  • Weak or stillborn calves
  • Impaired fertility
  • Retained placenta
  • Increased susceptibility to soft tissue infection
  • Foot problems

Selenium (Se)

  • Reduced disease resistance
  • Retained placenta
  • Weak or dead calves
  • Chronic diarrhoea

Iron (Fe)

  • Generally affects young animals
  • Poor feed intake and weight gain
  • Depressed immune system and increased sickness and mortalities

Appendix 1


Table 1: Source, empirical formulas, micromineral concentrations and relative bioavailabilities of common
inorganic mineral sources


Supplement

Empirical formula
Mineral concentration
(%)
Relative bioavailability
(RV)
Mineral availability
(% of DM)
Cobalt

Cobaltous sulphate

CoSO4(H20)

21

100

21.00

Cobaltic oxide

Co3O4

73

20

14.60

Cobaltous cargonate

CoCO3

47

110

51.70

Copper

Cupric sulphate

CuSO4(H2O)5

25

100

25.00

Copper EDTA

Variable

Variable

95

Variable

Cupric chloride (tribasic)

Cu2(OH)3Cl

58

115

66.70

Cupric oxide

CuO

75

15

11.25

Cupric sulphide

CuS

66

25

16.50

Cuprous acetate

CuC2O2H3

51

100

51.00

Iron

Ferrous sulphate heptahydrate

FeSO4(H2O)7

20

100

20

Ferric citrate

Variable

Variable

110

Variable

Ferric EDTA

Variable

Variable

95

Variable

Ferric phytate

Variable

Variable

45

Variable

Ferrous cargonate

FeCO3

38

10

3.80

Selenium

Sodium Selenite

NaSeO3

45

100

45.00

Cobalt selenite

Variable

Variable

105

Variable

Zinc

Zince sulphate

ZnSO4(H2O)

36

100

36.00

Zinc carbonate

ZnCO3

56

60

33.60

Zinc oxide

ZnO

72

100

72.00

Appendix 2

Table 1: Example of mineral mix for lactating beef cows

Note

i) Magnesium should be increased to 10% if grass tetany is a concern

ii) Sulphur supplementation if necessary can be provided using sulphate found in other minerals (eg sodium sulphate, calcium sulphate, potassium sulphate, magnesium sulphate).

Mineral

125gms/head/day

  • Macro
    Calcium (Ca)
    Phosphorus (P)
    Sodium (Na)
    Magnesium (Mg)
    Sulphur (S)


10-15%
4-8%
15-20%
1%
0.5%

  • Micro
    Zinc (Zn)
    Cobalt (Co)
    Iodine (I)
    Selenium (Se)
    Copper (Cu)


0.03% (3000ppm)
0.001% (10ppm)
0.008% (80ppm)
0.0025% (25ppm)
0.12% (1200ppm)

Appendix 3

Table 2: – Micromineral levels in various feeds

Feed Name

K

Fe

Co

Cu

Mn

Zn

  • Energy Supplement
    Wheat
    Barley
    Maize
    Oats
    Sorghum
    Molasses


5.8
6.0
5.0
4.0
3.0
31.7


50
60
30
80
50
420


0.1
0.1
0.0
0.1
0.3
0.0


8.1
9.1
3.6
6.6
10.8
5.0


40
18
8
42
17
90


42
16
11
30
16
32

  • Protein Supplement
    Canola meal
    Coconut meal
    Cottonseed meal
    Safflower meal
    Sunflower meal


6.0
6.0
13.0
13.0
10.0


200
200
230
600
100


0.1
0.1
0.2
2.2
0.3


11.0
15.0
20.0
97.4
4.0


11.0
15.0
20.0
97.4
4.0


40
53
22
44
20

  • Tropical Grasses
    Kikuyu early
    Kikuyu late
    Paspalum early
    Paspalum late
    Seteria early
    Seteria late
    Rhodes early
    Rhodes late


31.0
12.8
13.8
16.4
27.6
37.6
10.0
13.0


48.6
280
54
70
48.6
70
270
280


-
-
-
-
-
-
-
-


1.8
10.2
5.2
6.5
4.7
6.5
26
26


9.5
56
36
30
32.4
74
180
120


10.1
38
11.2
9.5
10.1
9.5
56
38

  • Temperate Grasses
    Ryegrass early
    Ryegrass late
    Oats early
    Oats late


20
18
20
16


280
200
200
200


-
-
-
-


5.2
7.0
9.0
9.0


85
90
80
65


24
30
63
59

  • Tropical Legumes
    Cowpeas early
    Cowpeas late
    Dolichos early
    Dolichos late


4.5
4.7
1.9
1.9


90
90
180
180


0.7
0.7
-
-


14.0
14.0
12.0
12.0


15
15
20
20


35
35
30
30

  • Temperate Legumes
    Lucerne early
    Lucerne late
    Clover early
    Clover late


22
25
26
26


250
200
413
413


0.1
0.1
0.2
0.2


16.0
12.0
10.0
10.0


42
35
95
95


24
27
17
17

  • Tropical Forages
    Sorghum
    Sudan grass


14.7
18.7


200
190


0.3
0.1


30
37


50
90


30
38

  • Hays Temperate
    Ryegrass High ME
    Clover High ME
    Clover Low ME
    Lucerne High MELucerne Low ME


16.0
12.0
24.9
22.0
25.0


280
180
164
250
200.


0.1
0.2
0.2
0.1
0.1


4.0
7.6
9.0
11.0
9.0


75
35
164
45
30


30
29
19
24
25

  • Hays Tropical
    Seteria
    Sorghum
    Sudan grass


17
19
15.4


210
190
200


-
0.1
0.1


26
30.0
36.8


120
90
93


38
38
36

  • Silage
    Maize
    Oasts
    Cl/Ryegrass


9.8
32.8
24.0


260
110
180


0.1
-
-


4.0
10.9
7.0


48
128
90


93
65
28

Note: Total mineral intake depends on the digestibility and quality of the feedstuff. Subsequently, lower mineral intakes are experienced with tropical grasses, forages and legumes compared to temperate pastures and energy and protein supplements.