Anyone that has had a go at rearing orphan lambs is quite likely to have had to deal with abomasal bloat. It can often strike your “good doers” well into the rearing process, which can be quite devastating, particularly for the younger lamb rearers out there.
There are however, some simple steps that you can take to help minimise the risk in your lambs – whether you’re rearing a couple for pet day at school or even if you are rearing lambs on a larger scale. Abomasal bloat is primarily caused by bacteria that feed on lactose. When there is an influx of lactose into the stomach these lactose-consuming bacteria increase in activity, converting the lactose into lactic acid. This in turn changes the environment of the abomasum and causes a build-up of gas, which in severe cases can cause death. Abomasal bloat is such a common issue in lambs that are reared artificially, because lambs naturally prefer their milk feeds “little and often” – much more so than calves do. This means that in an artificial rearing system, when feeds per day are decreased and the volume of milk is increased per feed due to practicality and time constraints, the influx of lactose into the system is higher than naturally would be, which sets off the chain of events causing bloat. When milk is overfed even in one isolated feeding event, abomasal bloat can occur, so it’s worth taking some practical steps to decrease the risk.
- Use a milk replacer designed specifically for lambs. Calf milk replacers tend to have a higher lactose level than lamb milk replacers and generally higher copper levels, so are not appropriate for lambs.
- Stick to the feeding recommendations on the bag for lamb milk replacers in terms of mixing rates, volume fed per feed and number of feeds per day.
- Do not allow lambs to gorge on milk. Some lambs will have stronger suckling reflex than others, particularly if you are keeping a mixture of ages together. Using compartment feeders or individual bottles can help to control how much each lamb drinks. Pay attention at feeding time and as lambs fill up, take them off the feeder (make sure to keep a close eye on children if they are helping at feeding time).
- Automatic milk feeders are the gold standard for rearing lambs, as they allow lambs to milk feed as and when they want to, which mimics natural suckling behaviour. This is obviously not an option for everyone but is worth considering for larger scale rearing operations. One study looking at the feeding behaviour of lambs on an automatic feeding system found that lambs had an average of 9.5 feeding events per day, which averaged 176ml per feed*, so this just demonstrates how important “little and often” is for lambs.
- Check the teats on your feeder are in good working order. If the rubber is worn out, milk will be able to flow more readily through the teats and can encourage gorging.
- Consider “yoghurtising” the milk before it is fed. This is a technique that has proven very effective in commercial situations. It involves making up a yoghurt culture with the lamb milk replacer and feeding this rather than just the lamb milk replacer and water alone. This technique is thought to work through adding beneficial bacteria to the milk, as well as shifting the pH of the milk. Beef + Lamb New Zealand has created a fact sheet on this method, “Artificial lamb rearing – managing abomasal bloat”, which can be found on their Knowledge Hub at www.beeflambnz.com
- Consider feeding milk replacer cold rather than warm (mix up warm as per instructions on the bag and then allow to cool before feeding).
- Offer a hard feed option to lambs early on. Not only does it help stimulate rumen development and allow earlier weaning off milk but it can also help to keep them satisfied between milk feeds. NRM’s new Lamb Start Mix with Deccox is a great option and has the added benefit of helping to protect lambs against coccidiosis.
For more information, contact your local Nutrition Specialist.
*Feeding behaviour of artificially reared Romane lambs. March 2014. I. David, F. Bouvier, E. Ricard, J. Ruesche and J. L. Weisbecker.