Anaemia causes ill thrift in piglets. Anaemic piglets are pale and accumulate fluid around the throat, brisket and internal body spaces. They are likely to scour and are susceptible to various other conditions and diseases. Anaemia is responsible for about 10% of pre-weaning deaths in untreated litters.
Anaemia is a lack of haemoglobin, the part of blood that transports oxygen through the body, and in piglets is caused by a shortage of iron.
Newborn piglets have insufficient iron in their systems to maintain satisfactory blood levels of haemoglobin until weaning, and sows' milk provides only minute amounts of iron. Under natural conditions piglets may obtain sufficient iron from soil, but as piglets are now generally reared indoors on concrete, metal or wooden floors without access to soil, they require iron supplementation.
Anaemia can also be brought on by blood loss through navel bleeding. Navel bleeding can be an inherited trait, but is also linked with vitamin-K deficiency, and has been observed in litters on sawdust or shavings from preservative-treated wood.
Faster growing piglets require more iron to maintain the same level of blood haemoglobin than slower growers. Normal dose rates of supplementation cover this. The trend to earlier weaning has reduced the level of required iron supplementation.
Piglet anaemia is diagnosed by examining unclotted blood samples and smears at post-mortem. By itself, the apparent paleness of pigs can be misleading and should not be relied upon to diagnose anaemia.
Piglets may get additional iron from injections, dosages by mouth or by other methods. Once weaned, pigs will generally receive enough iron in their diets.
Injecting piglets with iron dextran, iron galactan or other iron compounds is the most common method of supplementation. The injection is most commonly given before piglets are 72 hours old. Follow the manufacturer's instructions and inject into the muscle or under the skin. Sterilise needles and syringes before use and clean the injection site. Avoid excessive leakage from the injection site by using a suitable gauge of hypodermic needle. Piglets are frequently bruised at the injection site and injections in the leg can cause lameness, increasing the likelihood of being inadvertently overlaid by the sow.
Iron compounds can cause staining of the muscle at the injection site and these areas do not cure properly and are difficult to detect. The fault is frequently only detected by consumers, which lowers the image of a good quality product.
A further problem is the occasional development of infections or abscesses at the injection site.
These problems of lameness, staining and infection are lessened if piglets are injected in the neck behind the ear rather than in the leg.
When injecting into the neck, turn the pig's head away to one side to stretch the skin and muscle at the injection site. After injection, place your thumb over the site and allow the pig's neck to straighten. This helps prevent the dose leaking from the injection site.
Alternatively, with the piglet held between the left elbow and body, the left hand is used to pull the piglets right ear forward, exposing and stretching the skin of the neck. The needle is used to push the skin forward, and then is pushed into the muscle. The needle is withdrawn and ear released simultaneously. Pushing the skin forward before the injection helps prevent dose leakage.
The most suitable needles to use are 18 gauge and 12 mm, or 20 gauge for thinner liquids. Subcutaneous (under the skin) injections can be given over the rib cage.
Organic iron in a preparation with iron galactan given to newborn piglets within 18 hours of birth, avoids many of the problems of iron injections. Staining, lameness and infections are eliminated but the preparation is more expensive.
Piglets must be dosed within 18 hours of birth as iron galactan is only absorbed from the gut very early in life; similar to the absorption of colostrum. Piglets should receive the full recommended dose and a second dose should be given if the first is regurgitated. It is unwise to rely on this method if piglets are scouring as absorption through the gut is likely to be less efficient. Use an alternative preparation if 18 hours has elapsed.
In some piggeries, anaemic piglets have been seen even though they have been dosed with iron galactan. The most likely causes are ill-timed administration, incorrect dosing technique or early scouring. There have been reports that orally administered iron can itself cause scouring, through the enhancement of bacterial growth in the gut.
Inorganic iron may be given to piglets orally to prevent anaemia. Limited quantities are absorbed daily through the gut wall so repeated administration is necessary. Compounds such as ferrous sulphate are cheap, but require repeated doses, increasing time and labour.
Iron compounds, uncontaminated soil or both may be sprinkled in farrowing pens, and the provision of creep feed with a high-iron content can be useful. It has also been reported that piglets can obtain iron by licking bare steel fittings in farrowing pens and from sow udders coated with iron compounds.
Raising iron levels in lactating sow diets can result in litters receiving more iron, but the source is not the sow's milk but her dung.
Although these other methods are worthwhile backups, individual dosing is preferable as it ensures that all piglets receive the iron supplement.