A comparison of daily total locomotor activity between the lactation and the dry period in dairy cattle

The objective of this study was to investigate the influence of farming management on the total locomo- tor activity (TLA) behaviour in dairy cattle. We recorded 24 h/day TLA in five not pregnant Holstein Frie- sian cows during parts of the lactation and dry periods, by means of an activity monitoring system (Actiwatch miniÒ) for seven days in each period. During mild lactation (period 1) animals were milked and fed twice a day. During the dry (period 2) they were kept to graze all day. In both periods hay and water were available ad libitum. Differences between the photophase and the scotophase were evaluated with a Student t-test. One-way repeated measure ANOVA was used to determine a statistical significant effect of time. A trigonometric statistical model was used to describe the main rhythmic parameters: mean level, amplitude, acrophase and robustness of rhythm. Our results showed a circadian rhythm of daily TLA in both periods, with different percentages of robustness, and acrophase in the middle of the photophase. The different patterns of activity in the two periods were attributed to the management practise during milking period. These results could be taken in consideration during farming management for the evaluation of such systems used in livestock, with respect to production and welfare.