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Ms Manchee was supported by:


Meat & Livestock Australia


Elizabeth Manchee

Nuffield Australia 2016 Scholar

Feedlots: risks and opportunities of using antibiotic alternatives  


The Australian feedlot industry has an opportunity to unlock new markets while maintaining the highest ethical and animal welfare standards, by exploring alternatives to the use of in-feed antibiotic agents, according to a report released today by 2016 Nuffield Scholar, Liz Manchee. As a beef producer from Narrabri, in northern NSW, Ms Manchee’s understanding of changing consumer demands and the growing market for ‘natural’ and ‘antibiotic free’ beef motivated her global research into evidence for and against the continuation of the use of ionophore antibiotics in feedlots. Supported by Meat & Livestock Australia, Ms Manchee researched beef production systems across the United Kingdom, Europe, North and South America and New Zealand.  She found that there are both risks and opportunities inherent in producing beef to target the market between organic or grassfed and conventional lot-fed cattle.


“Seeing this gap in the market, I wanted to understand approaches to grainfed beef production that don’t use ionophores, and the genetic gain required to offset any potential associated production losses,” Ms Manchee said.


“Ionophores are technically classed as an antibiotic as they alter the rumen microbiota. They play an important role in feedlots today, by preventing disease and infection, reducing animal mortality rates and aiding digestion, live weight gain and feed efficiency. Ultimately, ionophore use improves animal health and welfare, and has a positive effect on the productivity and profitability of feedlots. While the World Health Organisation does not consider ionophores to be important in human medicine, consumer perceptions around antibiotic resistance and market desire for increasingly ‘natural’ products can’t be ignored, and it’s important that we explore alternatives as an industry,” she said.


Ms Manchee’s report examines a range of ionophore alternatives, including direct-fed microbials such as probiotics and prebiotics, which have the ability to control and balance gastro-intestinal microbiota and are considered beneficial to the host animal. The report details cutting edge nutrigenomic technology developed by Kentucky-based company, Alltech, which uses a specialised gene chip to collect data from 22,000 data points to analyse tissue samples and show how a change in diet or environment can impact gene expression in an animal.


“A better understanding of how nutrition impacts lot-fed animals at the genetic level allows feed efficiency, growth rates and other important traits to be improved through the use of probiotics, prebiotics, trace minerals and vitamins to the exclusion of conventional ionophore usage,” she said.


The report also details a commercial trial conducted by Alltech, using its feedlot additive, EPNIX, which is 100 per cent organic and contains no antibiotics, antimicrobials or beta-agonists.


“Conducted at the Cactus Feeders’ Wrangler Feedyard in Texas, the trial comprised 1,928 head on feed for 169 days, comparing the Alltech product with conventional trace mineral sources containing ionophores. The trial showed cattle fed the Alltech additives increased carcase weight by 6.4kg, dressing yields by 4.6 per cent and rib eye area by 1.5cm². Combined with a five per cent increase in carcase premium for being antibiotic free, overall per head profit was increased by $155.”


Recognising the tension between satisfying growing consumer demands for antibiotic free beef, and maintaining the highest standards of animal welfare for lot-fed cattle, Ms Manchee’s report concludes that the industry has the capability to find a balance between the two.


“While recent studies have found very low levels of resistance in bacteria isolated from Australian cattle, the issue of shared-class antibiotic resistance developing through continued use of antibiotics in food production is an ongoing debate for all food producing industries. It’s a difficult path to navigate, but through proactive research, education and industry collaboration, we will be better placed to unlock the market opportunities on offer for beef producers to satisfy changing consumer demands, while maintaining the highest level of animal health and wellbeing possible,” she said.

Final Report Link

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