Suckling piglets: Are there alternatives to iron injections?

Since the natural iron supply from the sow’s milk is not sufficient for healthy piglet development, additional iron should be provided by administering a suitable iron supplement. Studies show that iron deficiency in suckling piglets leads to dramatic changes. As the central atom of hemoglobin, iron is important for oxygen transport in the blood and energy production. This trace element is also a component of important coenzymes, especially of various cytochromes, which are responsible, among other things, for electron transport in the respiratory chain. Iron is therefore essential for the animal’s organism.

In the wild, newborn piglets absorb sufficient iron by rooting in the soil. In conventional pig farming, iron must be supplemented to ensure animal vitality, health, and performance. There are several causes for iron deficiencies in suckling piglets. The piglet’s iron reserves are low at birth. The iron requirement is extremely high due to rapid growth of the piglets (Fig. 1). This is because iron is required for new blood formation. At the same time, the iron supply from colostrum and later from the sow’s milk is insufficient. Iron requirements for suckling piglets are shown in Table 1.

Figure 1: proportional growth of body weight in the first 6 weeks after birth (adapted from Miller and Ulley, 1977).

Table 1: Approximate iron balance in suckling piglets (Honal, 2003).

An iron injection between the 3^rd and 5^th day of life is a proven mode of application for the safe supply of iron to piglets. The various products available on the global market differ in composition with regard to the type of iron compound and iron content. Combination products that supply iron and reduce protozoan pressure are also available.

Ultimately, there are two ways to supply piglets with iron:

1. Injection: A needle is used to intramuscularly (IM) or subcutaneously (SC) inject iron in sufficient quantity, either one time only or with a subsequent booster shot. This creates a tiny injection site, which can also be an entrance for pathogens. The injected iron is available to the animal after a short time. This method of administration has been proven to be safe and reliable. Iron injection solutions are veterinary pharmaceuticals and generally available from a veterinarian.

2. Oral application: Iron is administered via the piglet’s mouth and absorbed in the gastrointestinal tract. This is basically a voluntary form of intake (e.g., by means of soil, pellets or drinking bowl) or a direct (controllable) oral application (by means of a drench or paste) that is administered by hand into the animal's mouth. The latter is a safe application: each piglet is taken in hand and the product is safely administered. 

Both methods of administering iron should be accompanied by supplying sufficient iron in the piglet's feed. This is because an adequate supply of iron is especially important during weaning as a means of supporting the animal's subsequent performance and health.

An oral administration of iron is very close to the natural uptake of this element because it utilizes the regulatory mechanisms in the intestine. Iron deficiency at the beginning of a piglet’s life can be substantial. Newborn piglets vary in terms of size, weight, growth rate, and health status. The iron content of the mother’s milk is also variable. This results in differences in the amount of iron supplied to the animals—not only between litters, but also within the same litter. While iron can be individually administered orally at an early stage, an injection is recommended for older animals. This directly compensates for early deficits and ensures an optimal start in the animal’s life.

The oral application of iron should always be checked. Handling errors can occur with oral administration (e.g., paste is not swallowed properly), but they are significantly less risky than with injections (needle inserted too deeply or in the wrong place). The oral administration of iron products should be closely monitored in cases of suckling piglet diarrhea (higher risk). On the other hand, the injection site is a potential entry point for pathogens that also use the iron as a nutrient. In many cases, oral products are combined with vitamins, probiotics, or other ingredients to provide additional benefits.

The most frequently asked question is: Can oral administration of iron replace injections? Different methods for ensuring an adequate supply of iron have already been described. In addition to the points mentioned, it is important to take a closer look at the alternative product:

Type of administration (controlled/voluntary):

Iron is necessary for hemoglobin synthesis and thus for the formation of red blood cells that ensure oxygen transport and other vital body functions. In the literature, hemoglobin content is defined as follows:

The hemoglobin level can be used to define an optimal supply. A comparison of oral iron applications is shown in Fig. 2. A single administration of Lactiferm^® Fe paste (iron fumarate + probiotics + vitamins) in combination with an iron-containing peat or pellet (until weaning) was tested. In contrast to the purely voluntary intake of a pellet, the combination of Lactiferm^® Fe with peat/pellet shows a sufficient hemoglobin level, which suggests an optimal supply for a suckling piglet.

With orally administered iron, different additives can be combined in a single product. For iron to be absorbed in the intestine, it must be reduced to divalent iron (Fe²⁺). The direct use of a divalent iron source therefore makes sense. There are also differences in bioavailability, e.g., iron (II) fumarate is more bioavailable than iron (II) sulfate. In general, organic iron sources are more bioavailable than inorganic iron sources. The absorption rate of iron increases in line with the following factors:

The absorption rate can be improved, for example, by vitamin C, cysteine, hydrochloric acid, and glutathione.

High doses of iron sulfate reduce the number of e.g., Lactobacilli and Bifidobacteria in the intestine. On the other hand, larger amounts of iron sulfate increase the number of pathogenic bacteria such as Escherichia coli and Salmonella typhimurium. Probiotic supplements can reduce pathogens. Host iron status can also be increased by probiotic supplementation. A possible reason for improved iron absorption with a probiotic is the p-hydroxyphenyllactic acid secreted by Lactobacilli, which reduces Fe³⁺ to Fe²⁺ and makes the iron more available to the animal.

Fig. 3: Advantages of glycine-bound trace elements based on the example of E.C.O.Trace^® compared to sulfates in the gastrointestinal tract.

To compensate for an iron deficiency in suckling piglets, iron must be administered by injection or oral application. Both methods are accompanied by advantages as well as disadvantages, which should be evaluated by the user. Oral administration can supply the piglet with just as much iron as an injection. However, the source of iron, the iron content, and the method and duration of application should be taken into account. To ensure a sufficient iron supply, it is advisable to check the hemoglobin content.

If you would like to learn more about administering Lactiferm^® Fe paste, or you are interested in our E.C.O.Trace^® products, visit our website for details or contact our product manager.