Rumination time around calving: An early signal to detect cows at greater risk of disease

The main objective of this experiment was to evaluate the use of rumination time (RT) during the peripartum period as a tool for early disease detection. The study was carried out in an experimental free-stall barn, and involved 23 Italian Friesian cows (9 primiparous and 14 multiparous). The RT was continuously recorded with an automatic system (Hr-Tag), and data summarized in 2-h intervals. Blood samples were collected from 30 days before calving to 42 DIM to assess biochemical indicators related to energy, protein, and mineral metabolism, as well as markers of inflammation and some enzyme activities. The Liver Functionality Index (LFI), which includes some negative acute-phase proteins or related parameters (albumin, cholesterol and bilirubin), was used to evaluate the severity of inflammatory conditions occurring around calving. The cows were retrospectively categorized according to the level of RT observed between 3 and 6 DIM into the lowest (L) and highest (H) RT. The average RT before calving (-20 to -2 d) was 479 min/d (range 264 to 599), reached the minimum value at calving (30% of RT before calving), and after 15 DIM was nearly stable (on average 452 min/d). Milk yield in early lactation (on average 26.8 kg/d) was positively correlated with RT (r = 0.33). After calving, the L cows compared with H cows had higher values of haptoglobin (0.61 and 0.34 g/L at 10 DIM in L and H) for longer time, had a greater increase of total bilirubin (9.5 and 5.7 μmol/L at 5 DIM in L and H), had a greater reduction of albumin (31.2 and 33.5 g/L at 10 DIM in L and H) and paraoxonase (54 and 76 U/mL at 10 DIM in L and H), and had a slower increase of total cholesterol (2.7 and 3.2 mmol/L at 20 DIM in L and H). Furthermore, a lower average value of LFI was observed in L (-6.97) compared with H (-1.91). These results suggest that severe inflammation around parturition is associated with a slower increase of RT after calving. Furthermore, above 90% of the cows in the L group have shown clinical diseases in early lactation in comparison to 42% of the H cows. Overall, our results demonstrate the utility of monitoring RT around calving and in particular the first wk of lactation as a way to identify in a timely-fashion those cows at a greater risk to develop a disease in early lactation.