MEAT PRODUCTION POTENTIAL OF IMPALA

(Aepyceros melampus)

R.A. Engels & Prof. L.C. Hoffman

Introduction

• Game farming - a successful enterprise• Game animals:

Introduction

• Game industry is based on four pillars• Initial success due to hunting & ecotourism• Expansion in breeding -› growth in industry• More stud breeders: stronger genetic selection• Surplus of splits & inferior colour variants• Potential for expansion in meat production

Hunting

Ecotourism

Breeding

Meat production

• Fresh meat quality cues: important for consumer

• Game meat: sustainable resource• Marketing opportunity for fresh game meat

• Most abundant• Wide distribution• Variety of habitats• Rapid reproductive rate• Sustainable cropping• Knowledge of fresh meat quality traits required

24.1

11.8

11.6

52.5

Impala

Kudu

Springbok

Other

Introduction: Impala

Problem Many factors not yet quantified

• Required to increase meat production

Research Aim

To quantify factors influencing impala meat quality:

Experimental locations

Part A

Part A: Methodology

Harvested during the day using .22 or .243 rifles

Deboned after 24h: 6 main

muscles

Physical &chemical analysis

Skinned and eviscerated

Carcasses hung in cool room (4°C)

11 Male and 11 female

impala

Part A: Sex Comparison

Undressed carcass weight (Kg)

Dressedcarcassweight (Kg)

Dressing percentage

Shear Force (N)

36.38a 21.55a 59.13a 23.18b

37.80a 21.00a 55.63b 29.75a

Male

Fem

ale

Male impala:Higher dressing percentage

More tender meat

No differences:• Carcass weights• Muscle weights

Female impala:Higher protein contentRedder meat

Higher intramuscular fat

a,b,cMean values with no common superscript in the same column are

significantly different from each other (P < 0.05)

Part A: Muscle Comparison

Parameter Muscle type

Hindquarter Forequarter

LTL BF SM ST IS SS

Weight 0.85a 0.61c 0.64b 0.18d 0.17de 0.15e

Shear force (N) 25.49b 30.14a 31.75a 25.74b 19.19c 23.65b

Protein (%) 22.07b 22.90a 22.90a 22.66a 21.50c 21.44c

IM fat (%) 1.53b 1.46b 1.81a 1.27c 1.93a 1.51b

Tender: N<43High proteinLow intramuscular fat: <3%

Impala meat

a,b,cMean values with no common superscript in the same row are

significantly different from each other (P < 0.05)

Part B

Part B: Production Systems

All impala harvested at ±15 months of age

Part B: Methodology

12 Sub-adult male impala per

production system

Harvested during the day using .22 or .243 rifles

Skinned and eviscerated

Carcasses hung in cool room

(4°C)

Deboned after 24h:

LTL muscles removed

Physical, sensory and

chemical analysis

Part B: Production System Effect

No significant differences:• Carcass weights of

intensive vs semi-extensive

• Dressing percentages

37.9

21.9

57.9

35.5

20.7

58.3

46.5

26.6

57.1

0

10

20

30

40

50

60

70

Undressed carcassweight (Kg)

Dressed carcass weight(Kg)

Dressing %

Carcass characteristics

Intensive Semi-extensive Extensive

Extensive system:• Higher carcass weights

Part B: Production System Effect

a

ab

a

a

a

a

b

b

a

0

5

10

15

20

25

30

35

L* a* b*

Meat colour

Intensive Semi-extensive Extensive

Intensive

Semi-

extensive Extensive

No colour differences

DarkerLess red

Lighter Redder

Part B: Sensory Analysis

Descriptive Sensory Analysis:Aroma, flavour, texture & overall eating quality

Undesirable

• Gamey

• Metallic

• Liver-like

Desirable

• Beef-like

• Sweet-associated

Consumer perspective:

Sample preparation

Part B: Descriptive Sensory Analysis

Parameter Intensive Semi-extensive Extensive

Overall aroma intensity 65.1b 66.3b 69.1a

Gamey aroma 54.7b 56.1b 58.5a

Beef-like aroma 37.2b 38.5b 42.4a

Metallic aroma 6.3a 6.0a 2.4b

Liver-like aroma 1.8a 2.2a 1.5a

Herbaceous aroma 6.8b 8.0b 13.2a

Sweet-associated aroma 8.4b 9.5b 11.5a

Overall flavour intensity 62.9b 64.2ab 65.7a

Gamey flavour 54.0b 55.9a 56.7a

Beef-like flavour 39.4b 38.5b 45.0a

Metallic flavour 8.4a 8.4a 3.3b

Liver-like flavour 1.2b 2.2a 0.6b

Herbaceous flavour 7.1b 8.2b 12.1a

Sweet-associated taste 10.5b 10.2b 12.6a

Extensive:• Highest overall aroma & flavour

intensity• Highest gamey, beef-like,

herbaceous and sweet-associated aromas

• Highest beef-like, herbaceous flavours and sweet-associated taste

• Lowest metallic aroma & flavour

a,b,cMean values with no common superscript in the same row are

significantly different from each other (P < 0.05)

Intensive vs. Semi-extensive:• No significant differences except

gamey & liver-like flavour

Part B: Meat quality parameters

Production system

Parameter

Shear force (N) 52.48a 37.21b 52.33a

Protein (%) 22.73b 22.02c 23.38a

IM fat (%) 1.97a 1.76b 1.52c

Less tenderModerate protein

Highest fat

Most tenderLowest proteinModerate fat

Less tenderHighest protein

Lowest fat

Part C

Part C: Post-mortem ageing of meat

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16

Days aged post-mortem

Meat tenderness & weep loss

Weep loss (%) Shear force (N)

Optimum ageing period at 4°C: 8 days

High weep loss:× Unattractive to consumers

Low shear force: High tenderness Desirable for consumers

No difference between male & female impala

General conclusions

Post-mortem ageing:

• 8 days post-mortem is optimum ageing period for ideal meat tenderness

Intensive

• Lower gamey & liver-like flavours

• Highest IM fat content

• No substantial advantage i.t.o. carcass yields, meat quality or production

Semi-extensive

• Most tender meat

• Lighter, redder meat

• Flavour & aroma attributes similar to intensive system

Extensive

• Darker, less tender meat

• Highest aroma & flavour intensity

• Highest protein content

• Lowest IM fat content

Sex & muscle comparison:

•Male impala have higher dressing % than females

•All muscles produce tender meat with high protein & low IM fat

Part B: Production system effectPart A Part C

General conclusions

Impala overall:

Desirable physical, sensory & nutritional

meat quality traits

High dressing percentage

(±58%)

High protein, low

intramuscular fat

Recommendations

• Repetition of the experiment with impala of different age groups (sub-adult vs. adult)

• Investigate the effect of different diets/biomes on sensory meat quality

• Compare different cropping methods to evaluate ante-mortem stress effect on meat quality & production

Acknowledgements

Support, advice & assistanceProf. L.C. Hoffman

Fellow postgraduate students

Sponsorship of animalsCastle de Wildt

Financial supportNRF

SASASTHRIP/SARChI

Thank you! Questions?