Effect of genotype and immunocastration on pork quality

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1.1 What is meat quality? ... 13

1.2 Muscle structure ... 14

1.3 From muscle to meat ... 16

1.4 Meat quality parameters ... 16

1.4.1 pH ... 16

1.4.2 Water-holding capacity ... 17

1.4.3 Colour ... 18

1.4.4 Intramuscular fat content ... 19

1.4.5 Tenderness ... 20

1.5 Meat quality defects ... 20

1.5.1 PSE ... 20

1.5.2 DFD ... 21

1.5.3 Acid meat ... 21

1.6 Factors affecting meat quality... 22

1.6.1 Breeding level ... 22

1.6.1.1 Selection possibilities ... 22

1.6.1.2 Breed ... 23

1.6.1.3 Single gene effects ... 24

1.6.2 Farm level ... 26

1.6.2.1 Sex... 26

1.6.2.2 Production system ... 28

1.6.2.3 Pig diet composition ... 29

1.6.2.4 Feeding system ... 33

1.6.2.5 Live weight at slaughter ... 34

1.6.2.6 Feed withdrawal prior to slaughter ... 34

1.6.2.7 On-farm handling ... 35

1.6.3 Transport to the slaughterhouse ... 35

1.6.3.1 Transport duration... 36

1.6.3.2 Loading density ... 36

1.6.3.3 Ambient temperature ... 37

1.6.4 Slaughterhouse level ... 37

1.6.4.1 Reception at the abattoir... 37

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1.6.4.2 Lairage ... 37

1.6.4.3 Stunning ... 38

1.6.4.4 Chilling techniques ... 38

1.6.5 Consumer level ... 39

1.6.5.1 Cooking method ... 39

1.6.5.2 Freezing/storage ... 40

1.6.5.3 Aging ... 40

2.1 Introduction ... 44

2.2 Materials & Methods ... 45

2.2.1 Management and feeding ... 45

2.2.2 Performance ... 48

2.2.3 Slaughter and carcass traits ... 48

2.2.4 Carcass selection and sampling ... 48

2.2.5 Cooked ham processing ... 49

2.2.6 Meat quality assessment... 49

2.2.6.1 Instrumental meat quality analyses of fresh meat ... 49

2.2.6.2 Instrumental meat quality analyses of cooked ham ... 51

2.2.6.3 Sensory evaluation ... 51

2.2.6.3.1 Trained sensory panel: loin ... 51

2.2.6.3.2 Trained sensory panel: cooked ham ... 52

2.2.7 Statistical analysis ... 53

2.3 Results ... 54

2.3.3 Meat quality ... 56

2.3.3.1 Meat quality of the loin (LT) ... 56

2.3.3.2 Meat quality of the fresh and cooked ham ... 57

2.4 Discussion ... 59

2.5 Conclusions ... 62

2.6 Acknowledgments ... 62

3.1 Introduction ... 66

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3.2 Materials & Methods ... 67

3.2.4.1 Instrumental meat quality analyses... 69

3.2.4.2 Cooked ham processing ... 70

3.2.4.3 Sensory evaluation of loin (LT) ... 70

3.2.4.3.1 Trained panel ... 70

3.2.4.3.2 Consumer panel ... 71

3.3 Results ... 73

3.3.1 Performances ... 73

3.3.3.1 Meat quality of the loin (LT) ... 74

3.3.3.2 Meat quality of fresh and cooked ham ... 78

3.4 Discussion ... 80

3.4.2 Carcass quality ... 81

3.5 Conclusions ... 83

3.6 Acknowledgments ... 83

4.1 Introduction ... 88

4.2 Materials & Methods ... 90

4.2.3 Blood sampling and analysis ... 93

4.2.5 Testes and fat sampling and boar taint analysis ... 94

4.2.6.1 Instrumental meat quality ... 95

4.2.6.2 Sensory evaluation ... 95

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4.3 Results ... 96

4.3.4 Evolution of serum testosterone and efficacy of immunocastration ... 104

4.4 Discussion ... 108

4.4.1.1 Effect of sex and timing of vaccination ... 108

4.4.1.2 Effect of sire line ... 109

4.4.4 Efficacy of immunocastration ... 113

4.5 Conclusions ... 114

4.6 Acknowledgments ... 115

5.1 Introduction ... 120

5.2 Materials & Methods ... 121

5.2.1 Survey design ... 121

5.2.2 Data collection and processing ... 121

5.2.2.1 pH measurements ... 121

5.2.2.2 Animal and slaughter data ... 122

5.2.2.3 Data pre-processing ... 122

5.2.3 Statistics ... 124

5.3 Results ... 124

5.3.1 Carcass quality according to genotype and sex ... 125

5.3.2 Effect of genotype ... 126

5.3.3 Effect of carcass quality ... 127

5.3.4 Effect of sex ... 130

5.3.5 Effect of transport and lairage duration... 130

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5.4 Discussion ... 131

5.4.1 Genotype ... 131

5.4.3 Sex ... 133

5.4.4 Transport duration ... 133

5.4.5 Lairage duration ... 133

5.4.6 PSE prevalence ... 134

5.5 Conclusion ... 135

5.6 Acknowledgments ... 136

6A.1 Introduction ... 142

6A.2 Materials & Methods ... 142

6A.2.1 Experimental setup... 142

6A.2.2 Statistical analysis ... 143

6A.3 Results ... 144

6A.4 Discussion ... 146

6A.5 Conclusions ... 147

6B.1 Introduction ... 152

6B.2 Materials & Methods ... 153

6B.2.1 Experimental setup... 153

6B.2.2 Data pre-processing ... 154

6B.2.3 Statistical analysis ... 155

6B.3 Results ... 155

6B.3.1 Growth rate ... 155

6B.3.2 Carcass traits ... 156

6B.3.3 Instrumental traits of the loin ... 158

6B.3.5 Technological traits of cooked ham... 163

6B.4 Discussion ... 164

6B.5 Conclusion ... 169

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7.1 General discussion ... 173

7.1.1 Improvement of meat quality by management strategies ... 174

7.1.2 Implications of management strategies on performance and economic margins... 180

7.2 Complexity of measuring meat quality ... 186

7.3 Challenges ... 189

7.4 Future perspectives ... 193

PUBLICATIONS ... 234

A1 publications ... 234

A4 publications ... 234

Proceedings & abstracts ... 235

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𝐿𝑒𝑎𝑛 𝑡𝑖𝑠𝑠𝑢𝑒 𝑔𝑎𝑖𝑛 =(𝑐𝑜𝑙𝑑 𝑐𝑎𝑟𝑐𝑎𝑠𝑠 𝑤𝑒𝑖𝑔ℎ𝑡 𝑥 𝑙𝑒𝑎𝑛 𝑚𝑒𝑎𝑡 %/100) − (𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑤𝑒𝑖𝑔ℎ𝑡 𝑥 0.45) 𝑑𝑎𝑦𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑎𝑡𝑡𝑒𝑛𝑖𝑛𝑔 𝑏𝑎𝑟𝑛

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Numerical total colour difference = √(ΔL ∗)²+ (Δa ∗)²+ (Δb ∗)²

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𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑟𝑜𝑢𝑛𝑑𝑠 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 =days in fattening barn of pen with lowest growth rate+5 days 365

𝐵𝑎𝑙𝑎𝑛𝑐𝑒 𝑝𝑒𝑟 𝑝𝑖𝑔 𝑝𝑙𝑎𝑐𝑒 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 = (𝑏𝑒𝑛𝑒𝑓𝑖𝑡𝑠 − 𝑐𝑜𝑠𝑡) ∗ 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑟𝑜𝑢𝑛𝑑𝑠 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟

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