About Book

Dairy science refers to the study of milk production along with the production of cheese, yogurt, butter, etc. Dairy Cattle include replacement heifer calves and yearlings, dry cows, lactating cows and breeding bulls used for research and teaching purposes related to milk production. A dairy science professional also studies the operations and management of a cattle ranch and a dairy plant. Milk production and milk components are of prime economic importance for dairy farmers. Although milk production depends largely on numerous dietary nutrients, energy and protein are most critical. Feeding plays a very crucial role in growth, development and productivity of dairy animals. Modern breeds of dairy animals are able to produce huge amount of milk. The book is a valuable compilation of topics, ranging from the basic to the most complex theories and principles in the field of dairy science and technology. It explores genetic improvement, lactation in crossbred, organic milk production, milk removal, mammary development, heat stress management, dermatobiosis, light scattering, lameness and subclinical endometritis. While understanding the long-term perspectives of the topics, the book makes an effort in highlighting their impact as a modern tool for the growth of the discipline. This compendium will be of immense interest for students, researchers, as well as practitioners associated with dairy science, animal science, food science, nutrition, physiology, biochemistry, veterinary medicine and other related fields.

Preface ..................................................................................................................... v

1 Subclinical Endometritis in Dairy Cattle .......................................................... 1

Abstract ........................................................................................................... 1

1. Introduction ................................................................................................... 1

2. Etiopathogenesis ............................................................................................ 2

3. Diagnosis ......................................................................................................... 4

4. Prevalence ....................................................................................................... 8

5. Effects of SE on productive and reproductive performance ................... 8

6. Treatment of subclinical endometritis ..................................................... 11

7. Conclusions .................................................................................................. 12

Acknowledgements ..................................................................................... 12

2. The Impact of Lameness on Dairy Cattle Welfare: Growing Need for ........

Objective Methods of Detecting Lame Cows and Assessment of Associated

Pain ........................................................................................................................ 24

Abstract ......................................................................................................... 24

1. Introduction ................................................................................................. 25

2. Materials and methods ............................................................................... 26

3. Claw lesions causing lameness ................................................................. 27

4. Pain associated with lameness .................................................................. 29

5. Pain assessment in lame cows .................................................................. 30

6. Impact of lameness on animal-based welfare measures ....................... 35

7. Conclusion .................................................................................................... 40

Acknowledgements ..................................................................................... 40

3. Twin Calving and its Connection to Other Economically Important Traits

in Dairy Cattle ...................................................................................................... 51

Abstract ......................................................................................................... 51

1. Introduction ................................................................................................. 52

2. Factors impacting twinning ...................................................................... 52

3. Reproductive traits in twin- and single-calving cows before calving 56

4. Production traits in twin- and single-calving cows before calving ... 58

5. Reproductive traits in twin- and single-calving cows after calving .. 58

6. Production traits in twin- and single-calving cows after calving ...... 61

7. Consequences of twinning .......................................................................... 63

8. Conclusion .................................................................................................... 70

4. Measurement of Casein Micelle Size in Raw Dairy Cattle Milk by Dynamic

Light Scattering ................................................................................................... 77

Abstract ......................................................................................................... 77

1. Introduction ................................................................................................. 77

2. Casein micelle structure ............................................................................. 78

3. Dynamic light scattering ............................................................................ 81

4. Measurement of casein micelle size by dynamic light scattering

(DLS) ............................................................................................................... 83

5. Conclusion .................................................................................................... 88

5. Abundance and Risk Factors for Dermatobiosis in Dairy Cattle of an .........

Organic Farm in the Tropical Region .............................................................. 93

Abstract ......................................................................................................... 93

1. Introduction ................................................................................................. 93

2. Literature review ........................................................................................ 94

3. Materials and methods ............................................................................... 98

4. Results and discussion .............................................................................. 103

5. Conclusions ................................................................................................ 113

6. Heat Stress Management for Milk Production in Arid Zones ................. 117

1. Introduction ............................................................................................... 117

2. Global warming and dairy farming ....................................................... 118

3. Physiological changes in dairy cows attri-butable to heat stress .... 120

4. The temperature-humidity index (THI) ................................................. 122

5. Effects of heat stress on production and reproduction of dairy

cattle ............................................................................................................. 124

6. Nutritional and feeding strategies to minimize effects of heat stress

in dairy cattle ............................................................................................. 127

7. Environmental modifications to minimize effects of stress in dairy

cattle ............................................................................................................. 129

8. Conclusions ................................................................................................ 135

7. Regulation of Mammary Development as It Relates to Changes in

Milk Production Efficiency ............................................................................. 140

1. Introduction ............................................................................................... 140

2. Hormonal regulation of mammary function ........................................ 142

3. Local regulation of mammary function ................................................. 150

4. Lactation persistency ................................................................................ 157

5. Conclusions ................................................................................................ 162

8. Milk Removal: The Key to Maintaining Milk Production and a Tool to ......

Enhance Efficiency ............................................................................................ 181

1. Introduction ............................................................................................... 181

2. Frequent milking or suckling during early lactation:

a window of opportunity ......................................................................... 189

3. Local regulation of the milk yield response to frequent milking ....... 193

4. Endocrine response to frequent milking or suckling ............................ 196

5. Cellular response to frequent milking .................................................... 197

6. Conclusions ................................................................................................ 199

9. Dairy Cattle Welfare Status Measured by Animal-Linked Parameters ........

Under Tunisian Rearing Conditions .............................................................. 208

1. Introduction ............................................................................................... 208

2. Material and methods ............................................................................... 210

3. Results ......................................................................................................... 216

4. Discussion ................................................................................................... 221

Acknowledgement ..................................................................................... 225

10. Dissemination of Scientific Data for Sustainable, Organic Milk Production

Systems ............................................................................................................... 233

1. Introduction ............................................................................................... 233

2. Farming trends .......................................................................................... 235

3. Organic vs. conventional vs. biodiversity ............................................ 236

4. Consumer trends ....................................................................................... 240

5. Conclusion .................................................................................................. 245

Acknowledgement ..................................................................................... 246

11. Control of Mammary Function During Lactation in Crossbred Dairy Cattle

in the Tropics ...................................................................................................... 253

1. Introduction ............................................................................................... 253

2. Water metabolism and mammary circulation in different

stages of lactation of crossbred cattle ..................................................... 255

3. Role of substrates supply for milk production ..................................... 264

4. Role of changes of hormone supply ........................................................ 275

5. Other physiological responses in different stages of lactation in

crossbred Holstein cattle .......................................................................... 278

6. Conclusion .................................................................................................. 279

12. Genetic Improvement of Livestock for Milk Production ......................... 288

1. Introduction ............................................................................................... 288

2. Functional traits genetics ......................................................................... 289

3. Milk production traits genetic determinants ....................................... 290

4. Genotype by environment interactions ................................................ 292

5. Genetic variations ..................................................................................... 293

6. Molecular genetic technologies ................................................................ 294

7. Genetic markers ......................................................................................... 295

8. Genetic marker technologies applied in animal breeding .................. 297

9. Cloning adult dairy animals ................................................................... 304

10. Transgenic dairy animals ......................................................................... 305

11. Conclusions ................................................................................................ 307

Citation ................................................................................................................ 313

Index .................................................................................................................... 317

About Author

Kane Kellar holds a Ph.D. in Dairy Science from State University, Denizli. He is an Ad-Hoc Professor at Veterinary Science Institute, Shobak. He has contributed numerous articles and research papers on animal reproduction, sources of protein for animal production, and animal diseases. His research focus is in the field of animal physiology relating to agricultural science and biomedical science disciplines. His specialized area of working is the dairy farming and animal nutrition.