Carrot diet gives lamb performance a boost

A team from the University of Queensland fed the carrots to Merino wether lambs as part of a study back in 2019 and found that replacing barley grain with 45 per cent dry matter in the lambs' total mixed ration for 11 weeks improved animal performance, specifically by boosting average daily gain by 33 grams and feed conversion efficiency by 25 per cent.

Unsaleable carrots were supplied by Kalfresh's Kalbar farm and transported to the University of Queensland Gatton campus via refrigerated truck once or twice a week where they were chopped using a mixer wagon.

The end results showed that carcase weight of the carrot-fed lambs increased by 1.7kg, while dressing percentages were boosted by 2.7pc.

The study also found loin meat in the carrot-fed lambs was more colour-stable and therefore more resistant to oxidation than the control meat.

Researchers say the work proves that redirecting unsaleable carrots into ruminant feeds can both reduce waste and produce an economical alternative feed source.

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Senior Lecturer in Animal Science and Production Sarah Meale said the research was done as a PhD project for her student Daniel Forwood and the topic of alternative feeds was a hugely relevant one within Australia.

"The biggest reason why we looked at carrots is they are highly digestible,"Dr Meale said.

"We have also looked at things like pumpkin, purely because of availability.

"For us, we're quite close to Kalfresh, one of the largest carrot producers in Southern Queensland so accessibility was a really important factor and that's one of the key components of feeding any sort of fresh vegetable.

"Carrots were important to us purely because so many of them are wasted, up to 80 per cent of them do actually end up in landfill.

"They're discarded because they look strange, they're not straight for example but the nutritional value is exactly the same."

Dr Meale said it was exciting to see the lambs eat less while achieving better growth and heavier carcases.

"Our follow-up on work on this relates back to the difficulty in feeding fresh carrots as they go bad," she said.

"We've actually then ensiled them and done some studies on how much we can include and how it affects the quality of the silage.

"We've ensiled up to 40pc at this point of carrots and also pumpkins... the silage quality is just as good and it actually increases the digestibility of the silage so the animal can get more out of it at the end of the day."

Dr Meale said further research would look at including green beans and onions in silage.

"Eventually we will feed that silage to the animals and hopefully get as good a result as we can see with fresh carrots," she said.

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