Quantification of sleep in dairy cows in three different stages of lactation

.........................................................................................................................................4 Sammanfattning ..........................................................................................................................4 Introduction..................................................................................................................................5 Literature review ........................................................................................................................6 Sleep......................................................................................................................................................... 6 Sleep stages ....................................................................................................................................................... 6 Factors affecting sleep time in mammals ................................................................................................ 6 Sleep deprivation............................................................................................................................................. 7 Lying behaviour.................................................................................................................................... 8 Heat stress.............................................................................................................................................. 8 Transition period ................................................................................................................................. 8 Material and Method..................................................................................................................9 Animals and experimental design ................................................................................................... 9 Housing .................................................................................................................................................10 Recording equipment........................................................................................................................10 Data collection.....................................................................................................................................11 Data analysis........................................................................................................................................12 Results......................................................................................................................................... 13 Methodology ........................................................................................................................................13 Excluded electrophysiological data.........................................................................................................13 Health problems ............................................................................................................................................14 Equipment issues ..........................................................................................................................................14 Body temperature .........................................................................................................................................14 Body position..................................................................................................................................................15 Sleep-, body positionand body temperature data...................................................................15 Total sleep time..............................................................................................................................................15 NREMand REM sleep time .......................................................................................................................15 Body position..................................................................................................................................................16 Sleepand lying time distribution between night and day ..............................................................16 Body temperature .........................................................................................................................................16 Discussion .................................................................................................................................. 16 Total sleep time ..................................................................................................................................16 Sleep quality ........................................................................................................................................19 Lying behaviour..................................................................................................................................20 Body temperature ..............................................................................................................................20 Sleep deprivation ...............................................................................................................................21 Conclusions ..........................................................................................................................................21 References.................................................................................................................................. 21 Appendix..................................................................................................................................... 25