Knowledge about individual daily herbage dry matter (DM) intake (DMI) helps
identifying efficient dairy cows and adapting supplementation better to herbage
intake and nutrient requirements of grazing dairy cows. With the aid of
behavioural characteristics, raw data recorded with the RumiWatch (RW) system
and processed with the RW converter 0.7.3.31 (C31), estimation of herbage DMI
may be possible. First, C31, which allows differentiation of prehension bites and
mastication chews, was validated through direct observation of behavioural
characteristics and compared to the previous RW converter 0.7.3.11 (C11).
Further, the influence of a low and high pre‐grazing herbage mass (HM), with the
same target herbage allowance (HA), on bite mass, DMI, number of prehension
bites, and milk production was investigated. In total, 24 lactating Holstein cows
were pairwise allotted to one of two HM treatments. The cows received a new
pasture paddock twice per day with a daily target HA of 22 kg DM per cow/day.
On average, low HM (LHM) and high HM (HHM) paddocks had an HM of 589 and
2288 kg DM/ha, respectively, above 6.7 click units (1 CU = 0.5 cm). Overall, LHM
cows produced 2.7 kg/day more milk and 2.5 kg/day more energy‐corrected milk,
had the same herbage DMI and a similar prehension bite mass. The averaged
bite mass per week was 0.49 g DM/bite (LHM) or 0.47 g DM/bite (HHM),
respectively. A longer eating time (617 vs. 559 min/day) and a shorter rumination
time (297 vs. 365 min/day) were observed for the LHM cows compared with the
HHM cows. The validation of the RW showed similar results for C11 and C31
apart from prehension bites, where C31 showed a mean absolute deviation
of 12.4%. Pre‐grazing HM had no effect on relevant behavioural characteristics
for prospective intake estimation, namely, bite mass and number of prehension
bites.