Iron metabolism in the veal calf. The availability of different iron compounds

Relative Bioavailability of Trace Minerals in Production Animal Nutrition: A Review

The importance of dietary supplementation of animal feeds with trace minerals is irrefutable, with various forms of both organic and inorganic products commercially available. With advances in research techniques, and data obtained from both in-vitro and in-vivo studies in recent years, differences between inorganic and organic trace minerals have become more apparent. Furthermore, differences between specific organic mineral types can now be identified. Adhering to PRISMA guidelines for systematic reviews, we carried out an extensive literature search on previously published studies detailing performance responses to trace minerals, in addition to their corresponding relative bioavailability values. This review covers four of the main trace minerals included in feed: copper, iron, manganese and zinc, and encompasses the different types of organic and inorganic products commercially available. Their impact from environmental, economic, and nutritional perspectives are discussed, along with the biological availability of various mineral forms in production animals. Species-specific sections cover ruminants, poultry, and swine. Extensive relative bioavailability tables cover values for all trace mineral products commercially available, including those not previously reviewed in earlier studies, thereby providing a comprehensive industry reference guide. Additionally, we examine reasons for variance in reported relative bioavailability values, with an emphasis on accounting for data misinterpretation.

2.1 The Nutritional Basis for Trace Element Deficiencies in Ruminant Livestock

The role of trace element deficiencies in the causation of clinical diseases is often questioned because of the poor correlations which are found between the trace element status of the animal or its diet and the incidence of disease. The most striking example is that relating to the copper (Cu) nutrition of sheep, in which concentrate diets containing 8 mg Cu/kg DM can cause poisoning (Hogan, Money and Blayney, 1968) while pastures containing twice as much Cu can cause a deficiency disease (swayback) to develop (Allcroft and Lewis, 1957; Alloway, 1973). Unidentified stress factors are often invoked to explain such anomalies. However, the poor relationships between nutritional status and disease incidence reflect the inadequacies of past methods of assessing the extent that a trace element is absorbed from the diet and its functional activity in the animal and the fact that requirements vary during an animal's life. The object of this paper is to re-emphasize the nutritional component of trace element disorders by looking at the quantitative and functional basis of trace element requirements, the factors which predispose animals to deficiencies and how these might be countered.

Effect of abomasal ferrous lactate infusion on phosphorus absorption in lactating dairy cows

The objective of this study was to evaluate the effect of ferrous lactate infusion on postruminal P absorption in lactating dairy cows. Four ruminally cannulated lactating cows were used in a 4×4 Latin square design with 14 d per period. Cows were fed a basal diet containing 0.39% P, providing 100% of the calculated P requirement. On d 8 to 14 of each period, each cow was infused with 0, 200, 500, or 1,250mg of Fe/d in the form of ferrous lactate solution (ferrous lactate in 1L of double-distilled water) into the abomasum. Infusate was formulated to approximate 0, 2, 5, or 12.5mg of Fe/L in drinking water with 100L of water intake/d. Total fecal collection was conducted in the last 4 d of each period to measure nutrient digestion and excretion. Dry matter intake, milk yield, and milk composition were not affected by treatment. Digestibility of DM, NDF, and nitrogen decreased linearly with increasing ferrous lactate infusion. Infusion of ferrous lactate did not affect intake and digestibility of total P, inorganic P, or phytate P. In lactating cows, P absorption was not negatively influenced by abomasally infused ferrous lactate up to 1,250mg of Fe/d.

Energy exchanges of veal calves fed a high-fat milk replacer diet containing different amounts of iron

1. A total of 33 energy balance trials was conducted with veal calves offered a high-fat milk replacer diet containing 10, 20, 40 or 100 mg iron/kg DM.

2. There were no significant differences in weight gain, food conversion or energy retention between calves receiving 20, 40 or 100 mg iron/kg DM in their diet. Calves receiving only 10 mg iron/kg gained weight and retained energy at significantly lower rates than those in the other groups.

3. The metabolic heat production of calves receiving the liquid diet was greater than that of calves given the same amount of gross energy from a barley diet. The recommended air temperature of about 20°C for veal calf houses is therefore unnecessarily high.

Growth performance, haematological traits, meat variables, and effects of treadmill and transport stress in veal calves supplied different amounts of iron

Effects of serum iron (Fe), haematological variables and on blood lactate levels before and after treadmill exercise or transport to the slaughterhouse, on meat traits, and on growth performance of feeding milk replacer (MR), planned to contain 10, 20, 30, 40, 50 or 80 mg Fe/kg, were studied in veal calves. If supplied less than 50 mg Fe/kg MR, calves developed hypoferraemia and anaemia, the degree of which was dependent on Fe intake. Serum Fe concentration, saturation of transferrin with Fe and the degree of anaemia in calves fed 20 or 10 mg Fe/kg MR were nearly identical. Serum Fe concentration and haematological traits barely changed in calves fed 50 mg Fe/kg MR during the growth trail, but serum Fe concentration increased when MR contained 80 mg Fe/kg in calves fed 50 or more Fe/kg MR. Growth performance was smaller in calves fed 10 mg Fe/kg MR than in those fed greater amounts of Fe/kg MR. Carcass taxation was inversely related to Fe intake. In conclusion, MR containing only 10 mg Fe/kg caused marked anaemia and reduced growth performance. Feeding MR with only 20 mg Fe/kg is not necessarily sufficient to prevent development of severe anaemia. Feeding MR with 50 mg Fe/kg would seem to be physiologically the most appropriate amount of Fe for veal calves, but was too high for acceptable carcass taxation.

Trace element deficiencies in cattle

Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of trace elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of trace element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a trace element deficiency.

Effect of excess iron in milk replacer on calf performance

Milk replacers containing 100, 500, 1000, 2000, or 5000 ppm iron were fed to 3-d-old calves for 6 wk to estimate the lowest amount of dietary iron (added as ferrous sulfate) that would reduce calf performance. Calves tolerated all iron treatments except 5000 ppm. At this intake calves showed reduced weight gains, DM intake, feed efficiency, and digestibility of DM and protein. There were no other signs of iron toxicity and no gross abnormalities were found on postmortem examination. Percent of dietary iron in feces increased with higher dietary iron and ranged from 65 to 84%. Elevated iron intakes caused relatively small increases in iron concentration of blood plasma, bile, kidney, heart, and muscle but marked increased in spleen and liver iron, particularly in liver for the 2000 and 5000 ppm treatments. At 100 ppm iron intake, nonheme iron in liver, spleen, and kidney was composed of similar proportions of ferritin and hemosiderin, but at 5000 ppm iron intake, hemosiderin predominated in these tissues. Thus, the preruminant calf tolerated between 2000 and 5000 ppm iron in milk replacer. At toxic iron intake, calf performance and feed efficiency were reduced; there was a characteristic change to higher liver than spleen iron; and hemosiderin became the predominant iron storage compound in both tissues.

Some aspects of extra iron supply in veal calf fattening

Extra iron (5 ppm) in a normal commercial milk replacer given from the end of the sixth week until the end of the sixteenth week of the fattening period influenced food conversion positively without a loss in meat quality. Even when the extra iron was given to the end of the fattening period there was no perceptible improvement of the haematological status of the calf, though liver iron concentration was increased. During all the experiments no stainable iron could be found in bone marrow smears. Iron and copper concentration measured in liver biopsies appeared to give reliable information about, respectively, iron and copper status of the veal calf. In relation to the colour of the meat at slaughter the blood haemoglobin concentration during the fattening period was found to be the most reliable parameter.

Observations on the pancreas of cattle deficient in copper

Lesions were found in the pancreas of clinically normal cattle of low copper status. In comparison with the pancreas of cattle with normal hepatic copper reserves, the abnormalities were an increase in the dry matter content and reduction in the concentrations of protein and copper in the wet tissue. Cytochrome oxidase activity and protein-to-RNA ratio were also reduced. Histologically, there were defects in acinar basement membranes, splitting and disorganization of acini, cellular atrophy and dissociation, and stromal proliferation. The pancreatic ductular system did not show atrophy or disorganization.

Dietary fibers and supplementary iron in a milk replacer for veal calves

Thirty 1-wk-old male Holstein calves were allotted randomly to six groups into a 3 X 2 factorial design. The control diet was skim milk, whey, tallow, vitamins, and minerals. Either Alpha-Floc or pectin was added at 5% dry matter. Supplementary iron was added at 30 and 50 ppm (dry basis). The six diets were fed for 14 wk. Calves without supplementary iron were mildly anemic at 6 wk and severely at 14 wk (7 and 5 g/dl hemoglobin). At 14 wk, both fibers had decreased blood hemoglobin in calves given supplementary iron. Feed refusal began at 8 wk with the appearance of anemia for calves unsupplemented with iron, but both Alpha-Floc and pectin decreased feed refusal. Supplementary iron practically eliminated feed refusal. Supplementary iron improved average daily gain and feed conversion, but dietary fibers had no effect. Adding Alpha-Floc and pectin to the diets reduced frequency of diarrheic feces. Mean carcass weight of calves fed supplementary iron was 11.6% higher than that of unsupplemented calves. Supplementary iron decreased liver lipids and increased glutamic oxaloacetic transaminase activity in blood plasma.

Developmental changes in serum ferritin concentration of dairy calves

Serum ferritin concentration of nursing calves was measured by a two-site immunoradiometric assay to assess developmental changes and to evaluate relationships of serum ferritin with iron-related blood characteristics. Serum ferritin concentration of calves was low at birth and elevated slightly at 3 days of age. From 1 wk of age onward, serum ferritin concentration of untreated calves and calves fed only whole milk for 4 wk decreased and remained low throughout the nursing period. This finding almost coincided with hematological characteristics. However, that nearly normal hematological measures and weight gain persisted and that they did not develop any anemic symptom indicate that serum ferritin concentration is more sensitive than other hematological characteristics to iron depletion. However, serum ferritin concentration of calves administered 130 mg of ferrous fumarate (40 mg iron) daily from 3 to 22 days of age or injected with 4 ml of iron-dextran intramuscularly (400 mg iron) at 3 days and 2 wk of age increased sharply just after treatment and persisted high for 2 to 6 wk of age. However, there was large variation between animals for serum ferritin concentration. Thus, it seems likely that serum ferritin concentration is an index for monitoring prelatent iron deficiency of calves.

[Oral and intramuscular ferridextran intervention in male breeding calves. 3. Nutrient and feed uptake during the stay in the weaning range]

The influence of an oral and intramuscular Fe-application on the nutrient (dry matter, energy, protein and iron) and feed intake resp. (skim milk, calf rearing feed and lucerne hay) of calves during their 56-day stay in the weaning range of a rearing farm was investigated. There were significant differences between the test animal groups with regard to nutrient intake; their levels had the following sequence: B (Fe orally) greater than C (Fe i.m.) greater than A (without Fe-supplement). In the calf rearing organised as graded production the effect of iron intervention on nutrient intake probably occurs as a consequence of the reduction of the depression of feed consumption caused by disease. By comparison with the nutrient and feed intake of weaning calves from a different rearing farm one can further conclude that this secondary effect of iron intervention does not only depend on the more or less rapid remedy of the differently marked states of iron deficiency of the calves but also on the other rearing conditions (particularly the drinking regime). It is improbable that the oral ferridextran intervention (200 mg Fe/d) carried out provokes excessive iron supply.

[Reference values of hemoglobin content, hematocrit and mean concentration of corpuscular hemoglobin of calves reared without iron supplementation. 3. Comparison of the observed age dependency with literature values]

The average hemoglobin (Hb) and hematocrit (Hc) values determined in our own investigations with 491 rearing calves in the first five months of their lives were compared with the nationally and internationally published data of the dependence of these hematologic values on the age or rearing resp. milk fattening calves. The main influencing factors on the ageing development were the initial level of Hb and Hc, the length of the milk feeding period, the time of the beginning of feed supplementing, the development of dry matter consumption resp. the supply with milk, the iron content of the milk exchanger and the live weight increase achieved under the respective nutritional conditions. This dependence on the development proves that anaemia occurring with rearing calves in the first few weeks of their lives is mainly caused by iron deficiency. From the similarity of the average Hb resp. Hc values one can derive the conclusion that the considerable anaemia frequencies observed in one's investigations are not a phenomenon specific of one farm or of time but represent a general problem of the rearing of calves without iron substitution.

[Investigations of anemia of male rearing calves. 4. Relations between weight at birth, duration of keeping and increase of the ive weight in the period of the calves being fed on colostrum as well as the count erythrocytes in the weaning period of the calves]

With 195 male rearing calves which received concentrates ad libitum beside fluid feed with milk from their 5th day of life onward, investigations were made if and how far the characteristics of the development of the calves while they are fed on colostrum (body weight at birth, live weight increase and duration of keeping or stalling age) correlate with the hemoglobin content (Hb), the hematocrit (Hc) and the average corpuscular hemoglobin concentration (MCHC) of the animals on the 3rd, 28th resp. 56th day of keeping in the weaning period. There was a significant simple dependence particularly between body weight at birth, live weight increase and stalling age on the one hand and the hematologic values on the 3rd day of keeping in the weaning period on the other. A partial correlation analysis showed that the live weight increase while the calves were fed on colostrum was the main variable for all three hematologic parameters at the beginning of the weaning period of the calves. With increasing live weight, Hb, Hc and MCHC were diminished. This analysis was supplemented by the results of a cross--section investigation of the development of the milk and concentrate consumption and the Fe-intake of the calves fed on colostrum. The calculation of the Fe-balance showed that the mere ad libitum supply with feed supplements rich in Fe cannot prevent Fe-deficiency. Anaemia developing in the first month of the calves' lives is not a physiologic one but essentially caused by Fe-deficiency.

Copper, iron, manganese and zinc concentrations in the carcases of lambs and calves and the relationship to trace element requirements for growth

1. The minced carcases of twenty-seven lambs, ranging from 18 to 69 kg in live weight, and twenty-five calves (30–90 kg) were analysed for copper, iron, manganese and zinc. The lambs were weaned whereas the calves were reared exclusively on milk.

2. Mean concentrations of Fe, Mn and Zn for groups of lamb carcases fell within the ranges 52.6–75.1, 0.7–1.2 and 20.8–25.6 mg/kg fresh carcase weight respectively. The concentrations of Fe and Mn decreased while that of Zn increased slightly with age at slaughter. The concentrations of Fe, Mn and Zn in calves were close to thosein lambs.

3. For both species, the concentration of Cu in the carcase varied erratically: variation in hepatic Cu storage was implicated. In an additional study of ten full-term foetuses from Cu-depleted or Cu-supplemented ewes, a dietary Cu supplement (10 mg/kg dry matter (DM)) increased foetal Cu status 10-fold, due largely to an increase in foetal liver Cu.

4. The mean retentions of trace elements in the lamb carcases (%intake) were approximately: Cu 2.0, Fe 1.3, Mn 0.08, Zn 4.0. The corresponding values for the milk-fed calves were all probably much higher (Cu 23, Fe 43.7, Mn 4.9, Zn 34.0) but Cu intake was not accurately measured.

5. After allowing for tissue storage of Fe and Mn, values of 55, 0.85 and 24 mg/kg carcase gain were taken to represent the approximate net growth requirements of lambs for Fe, Mn and Zn respectively: the corresponding value for Cu was probably < 1.0 mg/kg. Values for calves were similar to those for lambs.

6. It was concluded that the total net requirements of ruminants for Fe and Zn shouldbe considered in terms of daily intakes of the metans rather than dietary concentrationsbecause of the relatively large and constant contribution of the growth component to thetotal requirement.

Iron metabolism in the veal calf. 2. Iron requirements and the effect of copper supplementation

1. The iron requirements of eighteen Ayrshire bull calves reared on fat-supplemented skim milk for 14 weeks fromc.16 d of age have been studied. There was a highly significant relationship between dietary Fe intake (10, 40 and 100 mg/kg dry diet) and blood haemoglobin concentration, packed cell volume and plasma Fe concentration.

2. A microcytic normochromic anaemia developed in the calves given a diet containing 10 mg Fe/kg diet, but not in the other calves.

3. Plasma Fe concentrations increased to > 5 μg Fe/ml in calves receiving 100 mg Fe/kg diet but there were no effects of Fe treatment on plasma Fe-binding capacity, which rose from 4·9 to 8·4 μg Fe/ml during the experiment. Saturation of plasma transferrin was only 3% in the Fe-deficient calves.

4. There were some significant effects of Fe treatment on tissue concentrations of Fe and cytochromec.

5. Dietary supplementation with 5 mg copper/kg dry diet had little effect on the growth or haematological status of the calves, although there were significant Cu × Fe interactions for mean corpuscular haemoglobin and mean corpuscular volume. There was no evidence of Cu deficiency in the calves, as measured by blood and liver Cu concentrations and by ceruloplasmin and cytochrome oxidase activities.