W R Webster, Mrs C K Dimmock (retired) DPI&F and M J Moore, Rural Solutions South Australia*
Summary
- Suckling piglets receive insufficient iron from their mother's milk.
- Piglet anaemia develops if there is no iron supplement.
- Iron injections, and oral dosing with organic iron preparations within 18 hours of birth, are the most efficient methods of supplementation.
- Staining, lameness and infection may follow iron injections.
- Regurgitation and reduced gut absorption in scouring pigs are disadvantages of oral iron administration.
- Prevention of anaemia relies on efficient administration technique as well as choice of iron compound.
Introduction
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 constituent 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 cover this. The trend to earlier weaning has reduced the level of iron supplementation required.
Diagnosis
Piglet anaemia is diagnosed by examination of unclotted blood samples and smears, and by post mortem examination. By itself, the apparent paleness of pigs can be misleading and should not be relied upon to diagnose anaemia.
Methods of iron supplementation
Piglets may be dosed with additional iron by injection, by mouth or by other methods. Once weaned, pigs will generally receive enough iron in their diets.
Injection
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. The manufacturer's instructions concerning dosage and method of injection (into the muscle or under the skin) should be followed. Needles and syringes should be sterilised before use and the injection should be made through clean skin. Excessive leakage from the injection site should be avoided 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.
Injection technique
When injecting in the neck, it's a good idea to turn the pig's head away to one side in order to stretch the skin and muscle at the injection site. After injection, place a thumb over the injection 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.
Oral dosage
Organic iron in a preparation with iron galactan given to newborn piglets as soon as possible 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.
For acceptable results, piglets must be dosed within 18 hours, as iron galactan is only absorbed from the gut very early in life, in much the same way as 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. Other preparations should be used if 18 hours have elapsed.
Anaemic piglets have been seen in some piggeries using 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 dosage, increasing time and labour.
Other methods
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 sows' 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.
Further information
For further information about this disease, contact your veterinarian, iron supplement supplier or government extension officer.
To access DPI&F's information and services
DPI&F Business Information Centre from 8 am to 6 pm weekdays: Phone 13 25 23 (Queensland residents), non Queensland residents phone +61 7 3404 6999; e-mail callweb@dpi.qld.gov.au
DPI&F's web site www.dpi.qld.gov.au
As well as being published on DPI&F's pig industry web site atwww.dpi.qld.gov.au/pigs/, this DPI&F Note will be published on the DPI&FPrimeNotes CDROM and will be published on DPI&F's national Pig Technotes CD.
* Rural Solutions South Australia is the consulting business within the Department of Primary Industries and Resources, South Australia (PIRSA)
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
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Last revised 17 January 2005
