Christian PunzProduct Manager Nutritional Products

Trace elements in cattle nutrition

2

For cattle, copper, zinc, manganese, cobalt, iodine and selenium are among the most important and are usually added to various supplementary feed. Since iron has a decisive infl uence on the interactions between the ele-

ments, it will be discussed in later chapters as well.Regarding the bioavailability of trace elements from

the feed, there are signifi cant diff erences due to the bind-ing form of the elements. In general, two main binding types can be distinguished:

• Inorganic bound trace elements (sulfates, oxides, chlorides, carbonates, …)

• Organic bound trace elements (chelates, protein-ates, glycinates, polysaccharides, fatty acids, methi-onine-analogues, …)

Inorganic bound trace elements are likely to have specifi c interactions and must be bound to transporters to be absorbed in the metabolism. Organic bound trace

elements are absorbed into the small intestine via the amino acid–peptide way. Th e most effi cient absorption is when trace elements are bound to single amino ac-ids. Trace elements bound in chelate form are a mixture of all naturally occurring amino acids and are absorbed through the diff erent amino acids absorption mecha-nisms in the body.

Th is article will provide guidance on the basic func-tion of trace elements in ruminants, demonstrate the dif-ference in bioavailability of diff erent binding forms and show practical eff ects in examples from cattle.

What are trace elements?Trace elements are defi ned by their extremely low

concentrations in the body, such as less than 50 mg of iron per kg of tissue. Based on this, daily animal require-ments of trace elements are in the milligram range as well. Needs for trace elements are determined by nutri-ent requirement models and nutrient response models.

Trace elements in cattle nutritionThe importance of trace elements in livestock nutrition is undisputed. As the name implies, even small amounts of these elements have large and diverse effects on the animal organism. The function of enzymes and hormones is essentially linked to trace elements. This key role in metabolism cannot be replaced by other kinds of nutrients, that’s why we call them „essential“ (irreplaceable) trace elements.

Christian PunzProduct Manager Nutritional Products

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Biological functions of trace elementsIron

Iron is a part of hemoglobin, the pigment of red blood cells and myoglobin, the muscle pigment that is necessary for their formation. In addition, iron is responsible for oxygen storage and oxygen transport in the body. As an enzyme component iron plays an important role in energy metabolism as well as in the anti-oxidative system (immune system).Iron deficiency is not common in dairy cows because many feedstuffs (mainly forage) contain iron in suf-ficient amounts. However, it may lead to deficiency symptoms in calves supplemented with whole milk. Deficiency symptoms manifest themselves in the form of anemia, poor immunity and growth. In fact that iron is much more common than other trace elements, iron excess can lead to poor absorption for copper and manganese.

CopperCopper is mainly stored in the liver and is an enzyme component that is part of many essential metabolic processes. As an enzyme activator, copper provides strong bones and joints and is heavily involved in the utilization of iron and thus the synthesis of hemoglo-bin. In addition, the pigmentation of the hair coat is fundamentally influenced by copper levels. Through the promotion of superoxid dismutase, which deac-tivates free oxygen radicals, copper is also involved in cell protection and thereby in a healthy immune system.Copper deficiency in dairy cows is often reflected in reduced fertility and poor immunity. Similarly, dis-turbances in pigmentation (“Copper glasses”), anemia and bone fragility may occur. Zinc

Beside iron, zinc is the most common trace element. As an activator and a component of more than 300 enzymes and hormones, zinc plays an important role in metabolism. In particular, protein biosynthesis and the regulation of gene activity can be affected by zinc. Zinc is mainly stored in the liver, pancreas, bone, skin and hair.Zinc deficiency causes poor growth, loss of appetite, and a bad feed conversion rate. Due to its crucial function in defense enzymes (copper-zinc superoxid dismutase), zinc deficiency reduces resistance. In dairy cows, zinc deficiency is visible through bad hoof horn quality, reduced fertility and poor udder health.

ManganeseManganese is mainly stored in the bone, liver, kidney and pancreas. It works as an enzyme activator and is crucial for energy-, protein- and fat metabolism. Fur-thermore, it has important enzymatic functions in cell protection. Deficiencies in manganese are reflected in reduced growth, skeletal deformities, poor fertility and birth defects in newborn calves.

IodineIodine is located in the thyroid glands and is responsi-ble for the formation of thyroid hormones (T3 and T4 hormone). These hormones in turn take over import-ant control processes in the energy metabolism and are thus particularly important for growth, fertility and milk yield. Iodine deficiency can be detected by an enlarged thy-roid gland and poor milk production.

CobaltCobalt serves as a central atom of Vitamin B12 (Co-balamin). If ruminants are adequately supplied with Cobalt, they can synthesize their need for Vitamin B12 itself in the rumen. Vitamin B12 is necessary for a functioning energy- (utilization of propionic acid, gluco neogenesis) and protein metabolism (methi-onine formation) in the liver.A prolonged deficiency in cobalt leads to a decrease in feed intake, limited growth and reduced milk yield.

SeleniumSelenium is an essential component of the enzyme glutathion peroxidase, which deactivates harmful hy-drogen peroxide radicals and is thus crucial in cell pro-tection. In addition, it supports the effects of Vitamin E and vice versa. A slight lack of one element can be compensated by a higher supply of the other element to a certain extent. Moreover, Selenium also regulates the thyorid hormone metabolism and thus indirectly affects fertility in dairy cows. Selenium deficiency causes fertility disorders, muscle dystrophy and weak calves as well as retained placenta and mastitis in dairy cows. Also a sufficient selenium supply is important in dry cows because still births or aborts can otherwise occur.

Source: ZinproFigure 1: „Copper glasses“ caused by copper deficiency

They are responsible for specific functions in the organ-ism for certain metabolic processes and must be regu-larly supplied with feed.. An essential function of trace elements is that they act as an activator and part of many enzymes. Furthermore they are present in proteins and carry out several tasks in the hormonal system. There-fore, basic functions such as reproduction of dairy cows depend a lot on the supply of trace elements.

Regulation of absorption and excretionFor a functioning metabolism, trace elements always

have to be present at a specific concentration in the tar-get tissue. To avoid an over-concentration and thus the risk of poisoning, the trace element metabolism is strict-ly controlled by the homeostatic regulation. This means that the input and outflow are regulated such that the interior of the body always has the same concentration in different target tissues. The processes of acquisition, storage and excretion of trace elements are overlapping and always in a dynamic equilibrium.

Interactions of trace elementsIn the uptake of trace elements, it is always import-

ant to consider certain adverse interactions with other

trace elements, macro elements or other food sources. For example phytate can build complexes with zinc, copper, manganese and iron and negatively impair their absorption into the body. Crude fibre can block the ab-sorption of metal ions.

Figure 2: Interactions between micro- and

macro minerals (Graphic: Punz; Source: Miller, 1979)

Ca

P

Co Cu

K

W

Se

Cd

Mg

F

Pb As

Te Hg

Al

I

Zn

S

Mn

Na

Mo Fe

Table 1: Trace element content of the most important forages and concentrates in Austria. (ÖAG-Futterwerttabellen für das Grundfutter im Alpenraum, Resch et al. 2006; Daten aus dem Futtermittellabor Rosenau 1998-2008)

Feed stuff Trace element content (mg/kg DM)

Iron Manganese Zinc Copper

Forages

Grass silage, 1st cut 696 90 50 7.9

Grass silage, 2nd -5th cut 746 103 46 8.7

Corn silage 125 27 38 3.9

Concentrates

Barley 64 19.6 32.9 5.4

Corn 40 8.3 26.0 2.5

Triticale 39 39.9 35.7 6.2

Dried beet pulp 605 67.6 27.4 6.0

Wheat 50 39.8 30.3 5.3

Brewers' grain (dried) 195 57 104.1 14.9

Peas 169 18.1 91 14.9

Rape seed extracted 190 76.2 78.9 7.1

Rape seed cake (8-12% fat) - 63.4 63.1 5.5

DDGS (from bioethanol production) 160 75.2 65.0 10.0

Soy bean full fat 103 30.5 51.5 15.8

Soy bean extracted 301 42.0 56.9 18.6

Soy bean extracted HP 303 50.5 59.0 15.9

Sunflower seed extracted (dehulled) 177 33.5 79.1 28.5

Christian PunzProduct Manager Nutritional Products

Diets rich in calcium, and drinking water or silages high in iron can build hardly soluble complexes with copper or manganese and reduce their availability dra-matically. In the presence of high levels of molybdenum and sulfates, copper sulfide can occur which is hardly soluble as well and nearly unusable for ruminants.

If the diet contains too much sulfur, the uptake of Selenium in the body is negatively affected. Calcium and phosphorus inhibit zinc absorption. Figure 2 shows an overview of the various antagonsims between minerals.

Trace element concentrations in forages and concentrates

In principle it should be noted that forages and con-centrates do not contain enough trace elements to cover the needs of high yielding dairy cows. Therefore the total rations have to be supplemented with additional trace elements.

Analyses show that corn silage has lower levels of trace elements than grass silage. In pastures, the location, plant population, utilization intensity and fertilization have a big influence on trace element contents.

Energy concentrates are different from protein con-centrates. Protein concentrates are richer in trace ele-ments than energy concentrates.

Are my cows adequately supplied?The need for trace elements is mainly determined by

the growth stage, milk or beef usage and performance of cattle. Thus, calves and growing cattle have quanti-tatively different demands than a high yielding dairy cow. Trace element recommendations are derived from dose-response studies. In consideration of bioavailability and intermediate interactions, safety margins are con-ducted to ensure an adequate trace element supply. On the other hand, there are legal limits on maximum values for trace elements in cattle. An overview of recommenda-tions and legal limits can be found in Table 2.

From a practical point of view, demand for trace el-ements increase at certain production stages of a cow. In times of high temperatures (heat stress), in stressful situations (around calving, disease) and in times of high performance we can expect increased trace element re-quirements.

The meaning of the term bioavailability is fairly am-biguous, but it generally describes mineral absorption by and/or retention within the animal. Theoretically, a min-eral supplement that is more bioavailable than another will provide a greater proportion of absorbed minerals to support animal production and health.

Table 2: Recommendations and legal limits for trace elements in dairy cows

Recommendations(mg/kg DM)

Legal limits(mg/kg com-plete feed)

Jeroch et al. 2008; GfE

2001

NRC 2001

Iron 50 13-22 750

Zinc 50 21-73 150

Manganese 50 16-21 150

Copper 10-15 11-16 35

Iodine 0,5 0,4-0,77 5

Cobalt 0,1-0,2 0,11 2

Selenium 0,2-0,25 0,3 0,5

One tool to check the efficiency of the trace element supply is the analysis of blood serum. For this, some representative dairy cows of the herd (including healthy cows, high lactating, low lactating and dry cows) were selected to have their blood samples taken by a veterinar-ian. Depending on the results of the analysis, any lack can be balanced and oversupply prevented. In some cases it makes sense to analyse forages for their trace element contents as well. By calculating minerals intake based on the animal’s diet, specific levels can be supplemented to meet the animal’s needs.

Organic bound trace elementsTo avoid negative interactions between inorganic

minerals and trace elements, organic bound trace ele-ments are increasingly used in cattle diets successfully. In particular, amino acid chelates work very efficiently as a binding partner for trace elements. This means that a trace element ion is bound to an amino acid chelate. The target is to improve the bioavailability and thus the intake of trace elements. Thereby the organic binding form uses a separate resorption process in the intestinal tract resulting in higher trace element contents in the blood, tissue, etc. An improved trace element content in the metabolism is the basis for healthy and highly productive cattle.

Numerous studies have proven that organic bound trace elements are absorbed more effectively. For exam-ple Wolfram (1999) documented that different forms of selenium have different pathways into the body. Fur-thermore Kincaid et al. (1999) reported higher zinc val-ues in the liver of calves after supplementing them with organic bound zinc. However, the different transport mechanisms of various trace element sources from the feed into the body are not completely known.

Source: ZinproFigure 3: Molecule structure of a trace element – amino acid chelate bond (Metal Ion= Copper, Zinc or Manganese)

Results from practiceIn practice, the supply with trace minerals from dairy

cows can be measured with certain parameters. Supple-menting trace elements in organic form over a longer period results in benefi cial eff ects as described in the pre-vious chapters. Technically it is possible, to supplement copper, zinc and manganese in organic form. Moreover it is also very common to use selenium in a rumen stable form in cattle diets.

• LamenessIn a trial, 150 Holstein cows were supplemented either with inorganic trace elements (sulfates) or with organ-ic bound trace elements (copper-, zinc- and manga-nese chelates). Th e experimental period lasted 21 days prior to calving until 250 days after calving. Th e use of organic bound trace elements signifi cantly reduced the incidence of lameness 75 days after calving. At 250 days after calving, it was observed that there were even fewer cows with claw disease.

Mean values with different superscripts are signifi cantly different

(P=0,15)

Ballantine et al., 2002. Professional Animal Scientist 18:211-218

• Fertility

In the same study, the infl uence of organic bound trace elements (copper-, zinc- and manganese chelate) in comparison to inorganic trace elements (sulfates) on fertility was investigated. Th rough the supplemen-tation with organic bound trace minerals a positive

eff ect on a variety of fertility parameters could be sci-entifi cally demonstrated, as shown in Table 3.

Source: ZinproFigure 4: Lame cows show poor fertility and low milkproduction

Table 3: Effect of trace element sources on the fertility of lactating dairy cows

Parameter Trace elements

Inorganica Organicb

Days to fi rst insemination 101 97

Pregnant cows 150 days after calving, %

42,7 54,8

21 day pregnancy rate, % 18,4 27,4

Insemination index 2,6 2,3

Days open 169 147

a Application of sulfates Application of organic bound trace elements (Zinpro Performance

Minerals®)

Ballantine et al., 2002. Professional Animal Scientist 18:211-218

Udder healthIn a study with 306 Holstein cows the eff ect of dif-

ferent trace element sources on udder health was inves-

34,1a

17,7

23,6b

10

0

10

20

30

40

75  d  after  calving 250  d  after  calving

Cows  w

ith  claw

 diso

rders,  %

Influence  of  different  trace  element  sources  on  the  incidence  of  lameness

Inorganic  trace  elements Zinpro  Performance  Minerals®

183

136

50

100

150

200

Somatic  cell  count  in  the  milk

Somatic  cell  coun

t  in  th

e  milk,  1

000/ml

Influence  of  different  trace  element  sources  on  the  somatic  cell  count   in  the  milk

Inorganic  trace  elements Zinpro  Performance  Minerals®

Christian PunzProduct Manager Nutritional Products

DeFrain et al., 2009. Professional Animal Scientist 25:709-715

tigated. The experimental period lasted 21 days prior to calving until 250 days after calving. The application of organic bound trace elements resulted in a significant decrease in the somatic cell count in the milk.

Figure 5: A healthy udder requires an adequate supply of highly available trace elements

ConclusionIt is important to ensure high performing cattle

receive an adequate level of trace minerals in their di-ets. This requires knowledge of the contents in forages, concentrates and mineral feed as well as their specific usage in feeding. The possible negative interactions due to an oversupply of a certain element also have to be considered. Therefore it is crucial that all minerals and trace elements are supplemented completely to meet the animal’s needs. A toxification has to be avoided in any case. Applications of organic bound trace elements have shown clear positive effects in practice, and their usage prevents any negative interactions. Trials demonstrate that bioavailability increased and thus the performance and health status in dairy cows could be improved as well. There is a positive effect on claw and udder health. Furthermore organic bound trace elements support fer-tility in dairy cows. With higher bioavailability of trace elements, it is possible to reduce the levels of trace el-ement supplementation. This also ensures a lower dis-charge in the manure which benefits the farming envi-ronment.

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