Correlation between rumination time, productivity, lactation and health indices of dairy cows | Sakarības starp slaucamo govju ruminācijas laiku, laktāciju, produktivitātes un veselības rādītājiem

Rumination is quintessential activity of dairy cows, and observing this behavior provides useful information regarding the cows’ health. The aim of the current research was to analyze correlation between “HeaTime Pro System” registered daily rumination times and cows’ average milk yield, number of lactations, milk fat, somatic cell count (SCC) and incidence of mycoplasmosis in the herd "X" with 362 lactating cows. The individual rumination time for each cow was collected daily at 24:00 seven days before and after milk sampling day (MSD) which was held on 26/12/2016. The obtained rumination data were divided into groups by following criteria: milk yield above 40 litres a day (30 cows) and below 20 litres a day (41); milk fat below 3.1% (27) and above 5% during the first 40 days of lactation (12); SCC higher than 1 million (10). The average rumination time on milk sampling day (RM) and average rumination time seven days before, during and after milk sampling day (R15) did not differ significantly (p is greater than 0.05). In high yield group, milk yield on MSD 43.3±3.0 kg was significantly (p is less than 0.05) higher than in the low yield group 17.9±1.6 kg, but RM 616.1±70.5 min and 556.4±174.4 min (p is greater than 0.05), respectively – because of high fluctuation in daily rumination times of low yield group. In low yield group, R15 was below 600 min/a day, but in the high yield group it was below 600 min/a day only for 2 cows. In the high yield group, R15 in the third and fourth lactation (L3, L4) was higher than in L1 and L2. The lowest R15 was found in the group with mycoplasmosis. On MSD, all high yield cows showed significant decrease of RM, but the low yield cows showed an increase of RM due to changes in herd management. Cows within the first 40 days of lactation with milk fat above 5% showed a negative correlation with R15 (r = -0.75), but L2 cows’ R15 was significantly (p is less than 0.05) higher than L1 and L4 cows. In cows with milk fat below 3.1%, R15 was significantly (p is less than 0.05) higher than in low yield cows. Eight out of 10 cows with high SCC R15 were registered below 500 min/a day.