31. game meats i

MEAT418/518 Meat Technology - 31 - 1 ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

31. Game Meats I

Peter Wynn and Nicole Spiegel

Learning objectives On completion of this topic you should have an understanding of: • The species that are used for game meat consumption both in Australia and the rest of the

world • The characteristics of meat for each species that are different from those in the major

commercial meat animals, cattle, sheep and pigs. • Methods of farming and harvesting that are unique to each species. • Export legislation and quality control standards • The utilisation of Australia’s own game meat animal • An example of turning non-conventional farming into mainstream farming in Australia • Effects of stunning methods on carcase and meat quality • The importance of shelf life and colour stability of fresh meat and its relation to temperature

and nutritive value

Key terms and concepts: Carcase composition and leanness; Sustainable production from wild resources; Domestication of species; Maintaining food hygiene standards; Exploiting these resources to meet world demand for dietary protein.

31.1 Introduction The use of wild animals as a source of protein for human ancestors has been identified as long as 5 million years ago. The appearance of Homo sapiens around 250,000 years ago ushered in an era in which animals were hunted for sources of both meat for food and skins for clothing.

Figure 31.1. Cave painting of hunters. Source: www.hiandlomodern.com/IMAGES/METAL/BARWARE/hunterstray.jpg

Early European populations used their survival instincts to combat cold weather by hunting animals for these purposes. In many ways, the exploitation of animals in the wild for both food and skins persists in many parts of the world for similar purposes. Of course, the animals had to survive under these same rigorous climatic conditions. They too had to evolve homeorhetic mechanisms to enable them to store energy in the form of fat reserves in times when dietary energy resources were plentiful, which would then be available for mobilization when feed intake was limited. As a consequence of its highly calorific value, this tissue then assumed great importance in providing a source of energy for human diets.

31 - 2 – MEAT418/518 Meat Technology ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

Animals in the wild undergo seasonal changes in carcase composition in order to survive in environments in which the availability of dietary energy sources fluctuates markedly. In many instances, these animals have adopted the strategy of altering their metabolic rate in order to conserve body energy reserves for the most essential of physiological functions including the maintenance of brain, heart, lung, visceral organ and reproductive function. Under such conditions, severe depletion of fat depots was possible with the consequence that meat products developed from harvested carcases may be extremely low in fat content. The influence of farming: Many species were domesticated as nomadic lifestyles gave way to more permanent farming systems. Species chosen for animal production were generally the most productive and were present in large numbers in that environment. Thus the horse, camel, cattle and goat dominated farming systems in the grasslands of central Asia, while the llama and alpaca of the South American Highlands, the yak of Central Asia and the reindeer of the cold north dominated in these environments. In contrast, pigs, cattle, sheep and horses adapted rapidly to wide regions of the populated world, thus these animals are no longer considered as game animals. Conventional animal breeding practices have resulted in the evolution of animals that are far more efficient at converting dietary nutrients into carcase tissues, which includes substantial deposition of adipose tissue.

31.2 Species used for game meats Typically, indigenous animal populations are used for domestic meat production to meet dietary needs for animal protein in both developing and developed countries. These animals are mostly harvested from the wild, however a number of species have been domesticated into conventional farming systems under which their nutritional and health status can be monitored closely. In these systems, animals have typically not been subjected to commercial genetic selection programs, although there may be an inadvertent selection process for animals that are more tractable in semi-confined grazing systems. Inevitably, those with great commercial potential will be subjected to these processes and become part of the mainstream of commercial livestock production systems, and as such, may no longer be classified as game meats. An example is the farming of deer to provide a reliable high quality source of venison to meet the increasing world demand, particularly in Europe. At the other end of the spectrum some species are exploited as a source of animals for leisure hunting activities. New Zealand, for instance has on offer an array of wild species for one to track down if they wish to do so, such as the Red deer, Elk, Chamois, Tahr, wild boar and Sika, but only through the assistance of local knowledge or a good guide. Traditionally, the populations of large cats such as tigers and lions have been decimated by this industry in Asia and Africa. They are of course valued more for their skins than for meat. Other examples of species exploited are abound, particularly on the veldts of southern Africa, such as the rhinoceros, elephants, leopards, wildebeest, zebras, baboons, gorillas, gazelles, bush pigs, hippopotamus, and ostriches, all of which as well as many others are on offer for those affluent enough to afford these exotic adventures. Safari companies offering these services are readily locatable on the Internet. Bushmeat Bushmeat is the term used that describes any wild animal hunted for food, or simply, the meat of wild animals. Bushmeat remains the sole source of animal protein for many communities across the globe. Although duikers (small antelope), rats, porcupines and monkeys are most commonly eaten, bushmeat can include any type of terrestrial wild animal from snails to elephants. While some amphibious or semi-aquatic freshwater animals, such as frogs, turtles and crocodiles, are also regarded as bushmeat, fish are not included under this category Meat form Zebras, for instance, is a bushmeat. It is much like horse meat, where the colour of fresh zebra meat is very dark due to high myoglobin level, and cooking losses are low. There are several species of African zebra in the genus Equus and dressed carcase weights range from around 114 to 187kg, with dressing percentages from 53 to 60% (Swatland, 2004). Other bushmeat examples, or alternative animals that can be used as meat producers include: the one-humped camel, water


buffalo, kangaroo, harp seal and ostrich. The kangaroo, for instance, produces a lean carcase, where the mean percentage of carcase muscle in the liveweight has been reported as 51.7% (Tribe and Peel, 1963). In a study using nine Red and four Grey Kangaroos, Tribe and Peel (1963) showed that kangaroos were a lean alternative, where they exhibited more muscle and less total fat compared with domestic livestock of similar liveweights, refer to Table 31.1 below. Table 31.1. A comparison of carcase protein composition from different species. Source: Modified from Tribe and Peel, (1963) Species Carcase Muscle as

% of Liveweight Number of Animals

Pig 31.9 ± 2.0 20 Cattle (Bos Taurus) 31.7 ± 1.8 14 Cattle (Bos indicus) 32.5 ± 2.0 30 Goat 31.3 ± 2.6 13 Sheep 26.9 ± 0.6 13 Wildebeest 41.6 ± 2.6 5 Gazelle 45.6 ± 2.8 5 Kangaroo 51.7 ± 0.5 12 Bushmeats also are often of favourable nutritive value and can compare well with the quality of more conventional meat types. Below (Table 31 2) is a list of mineral profiles for different alternative meat species compared with beef and chicken. The conflict between commercial hunters who have no regard for the principles of conservation and sustainable harvesting and indigenous communities intent on maintaining an equilibrium between their needs and those of the animal species to persist in viable and sustainable numbers, remains an important imperative for legislators world-wide Regrettably, the commercial value of the resource often overrides community needs and corrupt legislators are rewarded financially for their lack of diligence in enforcing laws designed to protect the needy. Table 31.2. Mineral composition (mg / 100 g edible portion) of meat from different species. Source: Modified from Sales, (1995) Mineral Camel

(n=7) Water buffalo

Harp seal (n=15)

Ostrich (n=12)

Beef Chicken (n=24)

Zinc 3.81 - 2.80 - 4.3 1.54 Calcium 5.20 7.5 591 1.72 7 12 Potassium 345 324 288 - 350 229 Magnesium 19.63 - 34.2 - 20 25 Sodium 77.91 111 159 70.55 61 77 Copper 0.080 - 0.10 - 0.14 0.053 Manganese 0.007 - <0.10 - 0.04 0.019 Iron 1.28 2.7 64.6 2.87 2.1 0.89 Phosphorus 189.1 213 504 - 180 173

: 31.3 Species harvested from the wild: Australian

marsupials Kangaroos, also known as macropods (meaning ‘great footed’ and belonging to the super family Macropodidae) are harvested for both meat and leather production, which forms an industry worth over $200 million and employing between 3,000 and 4,000 people in rural towns. Many of these jobs are located in isolated areas of Australia thus the industry plays a significant role to the economy of Australia’s rural communities. Of the 60 species of macropod marsupials known, half have decreased in number or distribution while only 14 have either sustained or increased their population since 1960 when records were first kept. Ten species are extinct on the mainland while 4 of these are still found in Tasmania. The larger species of macropods continue to thrive, where 4 of the largest and most abundant in Australia are top of the list of the 5 species utilised for commercial harvesting. This list, as follows, also includes the Whiptail wallaby.


• Eastern Grey (M. giganteus) • Western grey (M. fuliginosus) • Reds (M. rufus), and • Wallaroos (M. robustus), as well as the smaller • Whiptail wallabies (found and harvested in Queensland).

These species of kangaroos are distributed widely throughout Australia (Figure 31.4)

Figure 31.2. Distribution of commercially exploited species in Australia Source: Parks and Wildlife: Kangaroos, Editor C. Haigh, ISSN 0 310 6756

Export of kangaroo meat: The first exports of Kangaroo meat as a game meat for human consumption took place in small amounts in the 1950s and 1960s to the Federal Republic of Germany, (Corrigan, 1988). This was short lived, however, due to poor quality standards and the absence of proper government supervision. The export of kangaroo meat then started up again on official grounds in the early 1980s, where government conducted research in collaboration with the Game Meat Industry proceeded in the late 1970s and early 1980s. This involved the inspection of the process of field shooting and short dressing kangaroos in paddocks as well as the further processing in plants, and the approval of these methods and incorporation in the Export Game Orders. Key to these industry driven studies were hygienic methods, the absence of dogs, head shooting of kangaroos only, and hygienic delivery of kangaroo carcases to processing plants to control any potential for Salmonella contamination. An internationally recognized Code of Practice for game meat production, first developed by Codex in association with FAO/WHO Food Standards, was instrumental for the development of Australia’s guidelines for exporting kangaroo meat. Between 1985 and 1987 saw the export of ~110,000 kg of edible kangaroo meat. Countries included The Netherlands, France, West Germany (at the time), Papua New Guinea and Japan. In comparison, export non-edible kangaroo meat, i.e. for pet consumption, totalled ~600,000 kg during this time, where the main markets were Japan and Hong Kong, as well as Indonesia and Malaysia.


Kangaroo numbers: The national kangaroo population fluctuates according to the availability of feed, which can vary markedly over the various geographic zones. There has been a marked upswing in total numbers since 2000 to reach a population of 60 million. The annual total harvest rarely exceeds 3 million and does not impact on total numbers, nor on the numbers of each individual species. The population in any single area can vary from year to year according to seasonal rainfall patterns and associated feed availability. Given the variation in rainfall and therefore feed resources across any single region, the kangaroo population can travel long distances in search of feed.

Figure 31.3. Changes in the total kangaroo population of Australia. Source: Kangaroo Industry Association of Australia (KIAA).

31.4 Background to the industry: The modification of kangaroo habitat with the introduction of European farming systems has resulted in a reduction in populations of the smaller kangaroos and wallabies, while the numbers of the larger species of kangaroos has increased. This change in equilibrium was soon recognized as a threat to wildlife conservation: thus during the 1950’s and 1960’s legislation was enacted to control the destruction of kangaroos and wallabies. These acts extended to the implementation of policies to allow for the harvesting of the most numerous species without threatening the sustainability of the population. This has been achieved through the implementation of a government regulated quota system, where a specific number of tags for each species is issued annually and must accompany each animal that is shot in the field, regardless of whether it will be utilised or under specific state based provisions left ‘to let lie’.


Figure 31.4. Changes in the population of red kangaroos in Australia. Source: Kangaroo Industry Association of Australia (KIAA).

Although these policies provoke much controversy in the community, it is generally considered that without adequate control of kangaroo numbers through regulated harvesting, the economic viability of pastoral activities and the environmental sustainability of vast areas of land would be seriously threatened. The harvesting of kangaroos in Australia is regulated though detailed ‘Kangaroo Management Programs’, defined uniquely for each state and territory by the relevant National Parks Authority (NPWS, 2003). Annually, each of the kangaroo and/or wallaby species, with the potential to be harvested, is surveyed to determine the estimated total species population via aerial manual survey (Kelly, 2002; Anon, 2003; Grigg, 1988). Based on the total species population estimate, a maximum allowable take (quota) is set depending on feed availability as well as current and future rainfall predictions, usually between 10-15% of the total population (refer below to Table 31.3 for an example of the quotas set across Australia in 1999, based on 1998’s estimated kangaroo populations). Table 31.3. below has been modified from a report titled Situation Analysis Report: Current state of scientific knowledge on kangaroos in the environment, including ecological and economic impact and effect of culling (by Penny Olsen and Mike Braysher), which was put together for the Kangaroo Management Advisory Committee in November 2000. The issuing of kangaroo harvest tags is only possible to accredited, licensed kangaroo harvesters and, in certain clearly defined and unusual circumstances, to landholders with proof that there are excessive numbers of animals that require destruction. Professional kangaroo harvesters must complete thorough training in the form of TAFE accreditation covering animal welfare, hygienic harvesting practices and initial carcase inspection. Firearm competency is tested annually, ensuring the continued adherence to the strict guidelines set out in the federal government’s ‘Code of Practice for the Humane Shooting of Kangaroos’ (Anon, 2003). The level of accuracy required by this code is very high, requiring animals to be only head shot. In brief, kangaroos are harvested at night under spotlight whilst animals are grazing in paddocks. The stunning effect of the light places them in a slightly dazed but fixed upright position, and the instantaneous destruction of the brain by the bullet to the head ensures an effective, clean and minimal stress kill (pers comm., 2006).


Table 31.3. Numbers of kangaroos killed under commercial harvest quotas in 1999. Source: Environment Australia (2000), modified by Olsen and Braysher.

State

Red

Eastern Grey

Western Grey

Euro/ Wallaroo

Other species1

Total

% of quota taken up

NSW2

450,020

355,845

122,481

9,296

0

937,642

56

QLD

457,177

570,101

0

119,767

1,279

1,148,324

41

SA3

231,327

0

63,672

18,988

0

313,987

42

WA

139,945

0

54,574

4,731

0

199,250

46

Total

1,278,469

925,946

240,727

152,782

1,279

2,599,203

46

1Whiptail Wallaby M. parryi; Bennetts Wallaby M. rufogriseus; Tasmanian Pademelon Thylogale billardierii. 2Beginning in 1977 NSW has included a provision for animals previously killed in the commercial zone under non-commercial permits to be included as an identified component of the quota (damage mitigation quota). This part of the quota will be released only when the regional commercial quota has been used and then only based on consideration of property inspections, kangaroo population trends and climatic trends. 3In 1996, SA refined the setting of the commercial harvest quota to provide for the separate identification of a sustainable use component to the quota and an additional land mitigation component. This latter component will be released only when there is an identified threat to land management goals in an area that the sustainable component of the quota has been taken.

This in-field slaughtering practice has been reviewed by the RSPCA of Australia, and was concluded to be one of the most humane, low stress slaughter methods possible (RSPCA, 1985; RSPCA, 2002). 31.5 Carcase composition, nutritional value and muscle

selection: Table 31.4. Nutritional value of kangaroo meat relative to other meats Source: Ford and Fogerty, (1982) Protein

(%) Fat (%)

Kilojoules (per 100g)

P/M/S ratio1

Cholesterol (mg/100g)

Iron (mg/100g)

Kangaroo 24 1-3 500 1.5(1)1 56 2.6 Lean Lamb

22 2-7 530 0.1(0.9)1 66 1.8

Lean Beef

22 2-5 500 0.1(0.9)1 67 3.5

Lean Pork

23 1-3 440 0.2(1.3)1 50 1.0

Lean Chicken Breast

23 2 470 0.4(1.5)1 50 0.6

Rabbit 22 2-4 520 0.8(0.5)1 70 1.0 1P/M/S: polyunsaturated, monounsaturated and saturated fatty acid ratio.


Male and female red kangaroos can reach 90 kg and 40 kg live weight, respectively, but most harvested animals are about half this weight. Male Eastern Grey kangaroos may also reach 90 kg, but are more likely to be around 70 kg, with females reaching half that weight. Dressing percentages are about 65% for males and females, and for red and grey kangaroos, within an empty body weight range from 15 to 40 kg. Carcases produce about 80% muscle, 14 % bone and 6% waste. Refer to Table 31.1 in the bushmeats section for a comparison of carcase muscle of kangaroo with other meat species. A nutritional break down of kangaroo meat compared with other species can be seen in Table 31.4.

Figure 31.5. Commercial kangaroo cuts from the leg. Source: King River Kangaroo and Game Meats.

RUMP WK 15

SILVERSIDE WK 16

TOPSIDE WK 14

LEG RUMP-ON BONE-IN WK 7

LEG RUMP-ON BONELESS WK 9

LEG RUMP-ON/ SHANK-OFF BONELESS WK 11

LEG RUMP-Off/ SHANK-OFF BONELESS WK12

KNUCKLE (Round) WK 17

Figure 31.6. Commercial kangaroo loin cuts excluding the tenderloin.

Source: King River Kangaroo and Game Meats.

LOIN FILLET -

DENUDED WK 32

LONG FILLET -

DENUDED WK 33

STRIPLOIN -

DENUDED WK 31

LOIN FILLET - SKIN ON

WK 28

LONG FILLET - SKIN ON

WK 29

STRIPLOIN PAIR

WK 27

Australia’s Kangaroo Industry suffers from an image problem, particularly in its own country, where many Australians regard it as an important Australian icon that is seen on the coat of arms and not on the dinner plate, or as vermin and only fit for pet consumption. This image problem also dates back to the days of European pioneers in Australia, as even though kangaroo provided an important source of food, it did become socially unacceptable as people grew wealthier and eating meat from wild animals suddenly became an indication of poverty.


The social issues raised above, however, have not affected the increasing popularity of kangaroo outside Australia. Currently the industry estimates that it exports kangaroo meat to more than 55 countries, of which the European Union and Russia are the most significant markets, with the USA and Asia becoming increasingly important. It is a lean red meat that claims health benefits when incorporated in the diet, particularly when it comes to cholesterol lowering diets (refer to O’Dea, 1988), and has its own characteristic game meat flavour, texture and colour. The recent report of high levels of conjugated linoleic acid in this product certainly testifies to it value, where work is currently been undertaken by CSIRO and the University of Western Australia in this area.

31.6 Venison Venison, flesh of deer as food, is meat derived from deer. Several species of deer exist (family Cervidae), where foremost in commercial imagery is the red deer, Cervus elaphus, depicted by Edwin Landseer as “The Monarch of the Glen”. Other sources of venison include wild caribou and farmed reindeer, as well as moose and elk. Venison has long been sought after as a source of game meat for the European community for centuries and large semi-domesticated herds were kept on the estates of aristocrats for both sport and meat. This was the beginning of deer farming throughout the world with the major deer producing countries now being New Zealand, Ireland, Great Britain and Germany. Venison consumption has become popular in countries outside Europe with consumption increasing in the USA for example, from 500 tonnes in 1992 by about 30% per year. Deer are not indigenous to Australia. They were introduced into Australia during the nineteenth century under the acclimatization programs governing the introduction of exotic (non-native) species of animals and birds into Australia. Six species of deer were released at various locations. The animals dispersed and established wild populations at various locations across Australia, mostly depending upon their points of release into the wild. These animals formed the basis for the deer industry in Australia today. Commercial deer farming in Australia commenced in Victoria in 1971 with the authorized capture of rusa deer from the Royal National Park, NSW. Until 1985, only four species of deer, two from temperate climates (red, fallow) and two tropical species (rusa, chital) were confined for commercial farming. Late in 1985, pressure from industry to increase herd numbers saw the development of import protocols. This resulted in the introduction of large numbers of red deer and red deer/North American elk (wapiti) hybrids from New Zealand and North American elk (wapiti) directly from Canada. Statistics compiled during 1997/99 suggest that in 1997/98 there were approximately 190,000 deer in Australia. Fallow deer comprise about 49%, red deer (including red hybrids) comprise about 39%, rusa 6.5%, elk/wapiti about 3%, and chital about 2.5% of the total farmed deer population (www.deerfarmer.com). The Australian industry relies heavily on the export marketplace for sales, where only 10% of production is consumed locally. Thus, it is subject to fluctuations in international market forces and quality assurance regulations. Best practice codes for deer production to maximize the quality of product have been developed, which can be found at www.rirdc.gov.au or www.diaa.org.au. Stags, male deer that have not reached buck status, sometimes reach 450kg live weight. For wild deer, there is a lag period of a couple of months between the seasonal availability of food and the muscularity of the carcase. In Canada, ranched wapiti are finished on good quality alfalfa or a part-grain diet for at least 60 days before slaughter. This gives dressing percentages from 59 to 66% with more than 77% saleable meat cuts from the carcase (Swatland, 2004). In New Zealand, where the deer industry is well established, premium carcases are from 50 to 70 kg and are discounted if they have excess fat. Red deer from 12 to 27 months may give carcases with 8 to 12 % fat, having 0.23 kg fat for each1 kg carcase weight. For carcases from animals over 27 months, this increases by 0.34 kg fat per 1 kg carcase weight.


Factors influencing venison meat quality: Deer have been show to yield more meat from the desirable high value hind quarter cuts of the carcase. The lean: bone ratio is also improved compared with, for example, Angus bulls, where 50-80% less carcase fat exists in deer carcases relative to comparable sheep and cattle carcases (Drew, 1985). However, the levels of ‘fatness’ or adipose tissue in deer is greatly influenced by season. In studies of mature red deer stags slaughtered pre- and post rut, those slaughtered immediately after the rut (at the beginning of winter) have 25-30% lower carcase weights than those slaughtered pre-rut (autumn). Total carcase fat decreases dramatically over the rut from 21% to 1.3%, which is largely due to the fact that animals do not eat over this period of intensive reproductive activity. In terms of intramuscular fat, venison fat levels will vary depending on species but are low compared to domestic species. In a comparative investigation that looked at composition and selected sensory attributes (Rincker et al., 2005), both caribou and reindeer were found to contain lower levels of fat (1.18% and 2.76%, respectively) compared to domestic beef (4.02%). Table 31.5 below further demonstrates the desirably lower fat levels in venison (as indicated by the nutritional composition of Mule deer - Odocoileus Hemionus). Table 31.5: Calories, protein, and fat in 100 grams of uncooked, lean meat. Adapted from: http://ces.uwyo.edu/PUBS/B-920R.htm

Comparative data collected by Fisher et al. (1998) showed the average lean percentage of red deer to be superior (75.3%) when compared to cattle (65.8%) and sheep (57.6%). The average concentrations of intramuscular fatty acids, measured as mg/100 g muscle, were 1.6% for red deer, 3.8% for cattle and 4.9% for sheep. In terms of fatty acid composition, for beef and sheep, the fatty acid found in the highest concentration was oleic, followed by palmitic acid. In deer, palmitic acid was the highest. The ratio of polyunsaturated to saturated fatty acids was 0.41 for deer, 0.11 for cattle and 0.15 for sheep. The desirable higher polyunsaturated fatty acid levels of deer meat is further emphasised below in table 31.5. Table 31.6: Fatty acids in 100 grams of uncooked lean meat. Adapted from: http://ces.uwyo.edu/PUBS/B-920R.htm Fatty acid class Mule deer Range-grazed beef Grain-fed beef Saturatedb 972 933 2028 Stearic 401 327 651 Myristic, Palmitic 571 606 1377 Mono-unsaturatedc 732 754 2114 Polyunsaturatedd 463 191 291 Omega-6e 359 139 275 Omega-3f 104 52 16

aUncooked, lean only dLinoleic, arachidonic, and linolenic acid

bMyristic, palmitic, and stearic acids eLinoleic and arachidonic acids

cPalmitoleic and oleic acids fLinolenic acid

Nutritional Content Mule deer Range-grazed beef Grain-fed beef Calories, Cal 119 112 136 Protein, g 22.6 21.8 21.7 Fat, g 2.7 2.4 5.0


Although deer have been domesticated successfully, they are known to be susceptible to stressors likely to impact on the quality of meat. They appear to be more susceptible than other species to capture myopathy resulting from fear and anxiety, excessive body heat and too much adrenaline. Some of the problems arise from the need to slaughter deer in facilities designed specifically for the commercial processing of sheep and cattle. Thus the flow of animals from lairage through to stunning and onto exsanguination most often is not optimal for deer, resulting in quality defects in the venison obtained from these animals. One important quality defect to which venison is susceptible, is ecchymosis or blood splash (or freckles as referred to by some butchers) – refer below to Figure 31.9, which shows up as small red blotches resulting from the disruption of blood capillaries within the subcutaneous fat, presumably through the rapid activation of the sympathetic neurones regulating blood flow).

Figure 31.7. Ecchymosis in venison. Source: R Mulley, Pers Comm

Recent work (R.Mulley, www.rirdc.gov.au/pub/shortreps/sr62.html) has shown that this can be minimised if: § The thoracic stick method of exsanguinations is used; § The time between stunning and exsanguinations is reduced to less than 5 seconds; § Captive bolt stunning is used where the interval between stunning and exsanguination is

limited to less than 10 seconds; § Procedures for electrical stunning are optimized for voltage and timing when used; § Restraining device that limits the movement of the hind limbs to less than their maximum

potential after rendering the animal insensible by stunning are used. § Castration of fallow deer for slaughter are minimized; § Entire bucks are slaughtered immediately after but not during the rutting season. Product marketing: The importance of colour of meat in its marketing is well recognized. Freezing venison causes a significant darkening of the thawed product as well as increasing the loss of water and soluble proteins through drip. The ultimate pH of the meat will also affect the appearance, where high pH meat is darker in colour than normal or low pH meat. This is because as the pH moves further away from the isoelectric point of the muscle proteins (approximately 5.0) the water will be more tightly bound and less light will reflect. Rincker et al. (2005) showed venison to be of a higher pH compared to beef: 5.60 for reindeer, 5.61 for caribou and 5.48 for beef, although results were not significantly different. These results were consistent with their findings for colour, where the lower L*, a* and b* values (objective ‘Minolta’ colour determination) indicated a darker appearance (less red and yellow colours) than beef. The stability of the colour, indicated by the time taken for meat to turn red to brown, is dependant on storage conditions: time the product remains in a vacuum package and at what temperature. In New Zealand, for instance, where over 90% of all their venison is exported, the chilling of meat at -1.5oC in vacuum packages is reported by the NZ Game Industry board as their standard way to store fresh venison for up to 14 weeks (Wiklund et al., 2001).


Colour is a very important attribute since consumers make their initial decision to buy a product based on appearance. In contrast, repeat purchase is typically based on palatability, a multifaceted measure of meat quality that is determined by the consumers overall eating experience for that product but more importantly, reflects what the most important factors are influencing their liking for that product, whether it be tenderness or flavour for instance. Palatability: Tenderness is regarded as one of the most important sensory attributes affecting meat acceptability. Generally speaking, reindeer meat (as source of venison) is tender (Wiklund et al., 1997), and emphasised by the short ageing times required; usually no more than 2 days storage before cutting and/or freezing. Wiklund et al. (1997) have indicated that the muscle fibre-type composition of deer greatly influences the rate of tenderisation, where the fast-twitch-glycolytic fibres (as indicated by the higher type IIB fibres) induce more rapid ageing. Taylor et al. (2002) have also suggested that the smaller fibre size in reindeer contributes significantly to the tenderness. As with other species the optimal ultimate pH for tenderness is around 5.5, which then decreases to a pH of 6 and thereafter increases again through to pH 6.3. However, this higher pH meat will be characteristically darker in colour and become more susceptible to bacterial spoilage, and thus is downgraded quality wise due to an unfavourable appearance and reduced shelf life. Readings

The following readings are available on CD: The NSW Kangaroo Management Program (KMP), available at: 1.

http://www.nationalparks.nsw.gov.au/npws.nsf/Content/Kangaroo+management+program

Activities

Available on WebCT Multi-Choice Questions

Submit answers via WebCT Useful Web Links

Available on WebCT Assignment Questions

Choose ONE question from ONE of the topics as your assignment. Short answer questions appear on WebCT. Submit your answer via WebCt

Summary Summary Slides are available on CD Refer to the next sequel of lecture notes


References Anon 2003. Biodiversity: Wild Harvest of Native Species – Kangaroos, Australian Government –

Department of the Environment and Heritage. Corrigan, P. 1988. Export of kangaroo meat, Australian Zoologist, Vol 24(3), pp 179-80. Environment Australia, 2000. Situation Analysis Report: Current state of scientific knowledge on

kangaroos in the environment, including ecological and economic impact and effect of culling. P. Olsen and M. Braysher, for the Kangaroo Management Advisory Committee, November, 2000.

Fisher, A.V., Bayntun, J.A. and Ender, M., 1998. Carcase and meat quality characteristics: Venison in a competitive market. Proceedings of the 2nd World Deer Farming Congress, Limerick, Ireland, June 1998 (No.) pp 211-218.

Ford, G.L. and Fogerty, A.C. 1982. The fatty acids of kangaroo and wallaby meat, CSIRO Food Research Quarterly, vol 42, pp 57-60.

Grigg, G. 1988. Kangaroo harvesting and the conservation of the sheep rangelands. Australian Zoologist, vol 24(3) pp 124-128.

Haigh, C. (ed) Parks and Wildlife: Kangaroos. NSW National Parks and Wildlife Service. ISSN 0 310 6756.

Hi+lo modern, 2005. Cave painting of hunters; retrieved 10th November 2006 from http://www.hiandlomodern.com/IMAGES/METAL/

BARWARE/hunterstray.jpg Kangaroo Industry Association of Australia (KIAA). Kangaroo Populations. Kelly, J. KIAA, July

2002. Retrieved November 10th 2006 from KIAA website http://www.kangaroo-industry.asn.au/morinfo/BACKGR1.HTM#I

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Glossary of terms Exploitation of wild animals: utilisation of wild animal species Domestication main-stream/conventional production of animal species

under genetically selected and controlled farming environments to ensure a more reliable source of meat.

Bushmeat meat from wild animals Venison meat from deer, but other exotic meats can also be classed

as venison such as kangaroo or emu venison.

Rut periodic sexual excitement among animals Stag male deer Hind female deer Buck: o reach the rank of buck, an aspiring male red deer must

pass through five yearly ranks, from fawn, through pricket, sorel, sore, and bare back. The lucky ones reaching six years and beyond become great bucks.

Capture Myopathy also known as ‘overstraining disease’ is an acute or subacute post capture syndrome where stress induced in the animal is caused by the actual capture and restraint of the animal and can lead to death. It has been reported in a wide variety of wild animals such as antelope and zebra, as well as in deer and macropods.

Ecchymosis blood splash’, is a quality defect that is an important problem economically rather than hygienically. It takes the form of discrete spots of haemorrhage ranging from pin-head size to about 1 cm in diameter. All stunning methods increase the incidence but to varying degrees.

Palatability is eating quality and encompasses 3 main characteristics: texture, juiciness and flavour/odour

31. game meats i

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