Australia is a country with a population of approximately 24 million people . Annually, sufficient food to feed 60 million people is produced domestically; the vast majority of this food is fresh and readily available . By 2100, the Australian population is projected to reach between 42.3 – 69.5 million people . Should this increase materialise, Australia could be in the position of needing to import core food products to meet domestic demand. This scenario would markedly increase the dependence of Australia’s food and nutrition security on international markets and food policies .
In 2013-2014, 406 million hectares (ha) of Australia (53% of total land area) were used for agricultural purposes ; only 45 million ha were classified as arable (range 5.5%- 6.2% from 2006-2015) . Sheep and other foregut fermenters graze on non-arable agricultural land (i.e. rangeland), converting plants that are inedible for people, into nutritious red meat and fibre.
The significance of extensive grazing systems within the Australian rural sector is supported by the volume and value of sheep and beef commodities produced. Globally, Australia is one of the leading wool producers, the second largest producer of sheep meat and is a top five producer of beef and veal . In financial year 2015, beef and sheep meat commodities and wool produced in Australia were valued at AUD 17.5 billion.
The effect of grazing ruminants on rangeland ecosystem health has long been debated in the literature. A recent review by Eldridge et al.  concluded that ruminants grazing on non-improved pastures in Australia were likely to have a negative impact on the ecosystem, even at low stocking densities. With climate change and weather variability predicted to heighten the vulnerability of the Australian agricultural sector in the coming decades ,  it will become increasingly important to optimise the productive capacities of broadacre farms in Australia . This will strengthen environmentally sustainable food and fibre production and maintenance of Australia’s international agricultural competitiveness .
After an all-time high of 180 million head of sheep in 1970 , the Australian sheep industry has seen significant decline in the past 25 years, as a result of the wool minimum price reserve scheme ending and a global reduction in demand for wool. On 30 June 2014, the national sheep flock stood at 72.6 million, an overall decrease in numbers of 4% from the previous fiscal year, although breeding ewe numbers increased by 1%. Merinos accounted for more than 50% of the national flock in 2014 .
In the 2015 financial year, the gross value of sheep and sheep products totalled close to AUD 6 billion (Table 1), accounting for 11% of the gross value of agricultural products in Australia. More than half the lamb produced and three-quarters of mutton produced were exported.
|Animals slaughtered/exported (‘000,000)||Total Volume Produced (kt)||Volume Exported (kt)||Gross Value (AUD million)||Value of Exports (AUD million)|
|Sheep live export||2.2||Not applicable||Not applicable||Not applicable||244.8|
|Edible offal (species not specified)||Data not published||Data not published||162||Data not published||Data not published|
|Wool (greasy)||Not applicable||428.0||459||2,675.9||3,152|
The Australian Standard for the hygienic production and transportation of meat and meat products for human consumption  states one of five dispositions must apply to carcases and carcase parts (Figure 1).
The Australian Bureau of Statistics and Department of Agriculture and Water Resources only publish data on livestock products that are passed for human consumption. There is an undetermined but significant quantity of nutrient-dense, energy-dense sheep meat and offal condemned in processing or used as animal feed annually in Australia .
One possible option to support sustainable production of sheep meat and wool production in Australia would be to reduce food loss and wastage. Mason et al.  identified that there is limited publicly available data regarding food loss and wastage in Australia, particularly at the farm and processing level of meat production.
The National Sheep Health Monitoring Project (NSHMP) “monitor(s) lines of adult sheep in abattoirs for animal health conditions that reduce farm profit through productivity losses or increase meat processing wastage”. The significant animal health conditions monitored as part of the NSHMP are: arthritis, knotty gut/ pimply gut, bladder worm, liver fluke, cancer, melanosis, cheesy gland, pleurisy, dog bites, pneumonia, grass seeds, sarcocystis, hydatids, sheep measles, Johne’s disease and vaccination lesions. Data is published as overall percentage of (inspected) animals infected, average percentage of (inspected) animals infected per line, percentage of inspected lines with at least one infected animal, percentage of inspected Property Identification Codes (PICs) with at least one infected animal (Table 2). In 2014-2015, 708,263 sheep and lambs from NSW were inspected. This data is used by individual producers, industry and government to reduce preventable losses both on farm and at processing .
|Disease||Percentage of (inspected) animals infected||Caseous lymphadenitis||4.4|
* (average percentage of (inspected) animals infected per line)
Meat and Livestock Australia periodically report on the economic cost of priority endemic diseases in the sheep industry (Table 3). This report identifies gaps in the data in relation to prevalence of the disease, health impact of the diseases and cost of prevention and treatment . This report can be used to guide producers, veterinarians and government in the decision-making process for disease control measures to be implemented on properties and in regions, to reduced loss and wastage of sheep meat and offal.
|Disease||Cost Annually (AUD millions)||Neonatal mortalities||540.4|
|Weaner ill-thrift & mortality||187.6|
|Perennial ryegrass staggers||105.0|
Livestock Data Link and other processor reports provide feedback to producers on their mutton and lamb based on carcase traits, dentition, sex of the slaughtered sheep and animal health conditions. The data included in these processor reports is not uniform nationally. These feedback systems do not include information on offal . Sheep producers are only paid for dressed carcase weight and skins.
In 2011, the Food and Agricultural Organization (FAO) reported wastage of edible offals in Australia and a significant volume of mutton and goat meat (included lamb and kid meat) and edible offals put to other uses (Table 4). There was no record of bovine meat, pig meat or poultry meat being wasted or put to other uses in the same time frame .
The reasons why this meat and offal failed to enter the human food chain are not discussed by the FAO. Based on recommendations in the Australian Dietary Guidelines , the volume of Australian mutton that was put to other uses in 2011, would provide more than 650,000 adults with red meat for a year. Establishing cause and preventing avoidable losses has the potential to improve yields for producers and processors, while also contributing to the sustainability of sheep production by reducing the number of sheep required to achieve acceptable yield at enterprise level. The ability to reduce stocking rates will be a major advantage in an uncertain climate while still meeting a growing global demand for animal source food.
|Commodity||Food Supply Quantity (t)||Other Uses (t)||Waste (t)||Export Quantity (t)||Import Quantity (t)||Mutton and Goat Meat*||255,000||23,882||Not recorded||259,952||1,100|
*includes lamb and kid meat
Mutton meat and sheep offal are energy-dense, nutrient-dense foods, rich in protein, iron and other micronutrients . Despite this, mutton is rarely eaten by Australians today; there is no publicly available data on current sheep offal consumption . Mutton is a lean red meat that is the richest source of iron, vitamin B12, riboflavin and copper of all major meats produced on land domestically. Compared to chicken breast, mutton has ten times the iron and five times the zinc levels (Figure 2) . This is significant when considering the food and nutrition security. Chickens are intensively raised, fed grain and animal-source food that both have the potential to be fed directly to people; sheep are extensively raised in rangeland that has limited capacity for any other form of agriculture.
The most recent Australian Health Survey reveals widespread suboptimal micronutrient intake in the Australian community. The elderly (≥ 71 years old) showed as a cohort with significant inadequate micronutrient intake with greater than 50% of this group having inadequate intake of vitamin B6, magnesium, calcium or zinc and, 14% of males failing to meet protein needs. In this cohort 66% of males and 12% of females had inadequate zinc intake . This is of significance for Australia, as the population is projected to age in the coming decades with the number of people aged 85 years and over climbing from 420,300 in 2012 to 5.5 million in 2101.
Women of reproductive age have an increased need for iron and this is reflected in the level of inadequate dietary intake in Australia, with 38-40% of females aged 14-50 years old having inadequate iron intake, while only 3% of males of all ages have low intake . The World Health Organization monitors iron levels globally. Anaemia affects half a billion women of child bearing age worldwide and contributes to maternal and neonatal mortality, impaired cognitive and motor function, fatigue and low productivity. Based on data from 2011, anaemia is rated as a mild to moderate public health issue in Australia, as approximately 15%, 17% and 25% of children (6-59 months old), non- pregnant women (15-49 years old) and pregnant women (15-49 years old) respectively, are estimated to have low blood haemoglobin concentrations .
Mutton and offal are not included as part of current Australian Dietary Guidelines. Through dietary modelling, Norman  showed that including one serve (equivalent to 100 g of raw product) of mutton or lamb offal weekly into the diet for Australian women aged 31 to 50 years of age did not adversely affect the ability of a diet to meet guidelines, thus showing that mutton and offal are appropriate choices in a healthy diet. Could promoting the direct consumption of mutton and sheep offal improve the nutrient profile of Australian women, the elderly and food insecure households?
The project “Mutton and sheep offal have a role to play in Australia’s food and nutrition security” is being carried out by researchers at the University of Sydney and forms the basis of Kate Wingett's PhD.
This research aims to 1) determine the volume of Australian sheep meat and offal disposed of for human consumption, put to other uses or condemned at processing and where these products are ultimately consumed or used; 2) determine reasons for final dispositions and end point markets; 3) examine current communication along the sheep meat value chain; 4) calculate the amount of mutton and sheep offal that is diverted from the human food chain due to preventable losses and wastage; 5) provide recommendations for key actors in the sheep meat value chain on how to profitably improve yields and hence strengthen the sustainability of production of wool and sheep meat commodities in Australia and 6) assess the availability of mutton and sheep offal currently at the retail level in Australia.
This will be achieved through a mixed methods approach using questionnaires of sheep producers and meat retailers and semi-structured interviews of meat processors and full-service supermarket managers.
Australia relies on extensive grazing ruminant systems as a food source and export income. Sustaining these industries in the face of limited carrying capacity in an increasingly unpredictable physical and financial environment is challenging. Utilising more of the carcase and carcase parts of wool producing sheep for direct human consumption may be part of the solution. Clear, informative feedback systems along the sheep meat value chain are integral for this to be achieved. Once in place, sheep producers and veterinarians can work together to develop property plans to economically minimise preventable losses from diseases and parasites. In turn, this would reduce the number of sheep required to be raised to meet current food production from sheep. This enables producers and veterinarians to contribute to improved human nutrition security and animal welfare.