Effect of colostrum feeding method and presence of dam on the sleep, rest and sucking behaviour of newborn calves

In rats, sucking milk reduces anxiety and promotes non-rapid eye movement (NREM) sleep, and in calves it induces resting but the effect on sleep is unknown. Here, we investigated how calves’ sleep was affected by colostrum feeding methods. Forty-one calves were blocked by birth date and randomly allotted within blocks to the experimental treatments. Calves were housed for four days either with their dam (DAM) or individually with warm colostrum feeding (2 L four times a day) from either a teat bucket (TEAT) or an open bucket (BUCKET). DAM calves suckled their dam freely. Calves’ sleeping and sucking behaviour was filmed continuously for 48 h at the ages of two and three days. Behavioural sleep (BS) was defined as calves resting at least 30 s with their head still and raised (non-rapid eye movement) or with their head against their body or the ground (rapid eye movement, REM). Latency from the end of colostrum feeding to the start of BS was recorded. We compared behaviour of TEAT calves with that of DAM and BUCKET calves using mixed models. Milk meal duration was significantly longer for TEAT calves than for BUCKET calves (mean ± S.E.M.; 8.3 ± 0.6 min vs. 5.2 ± 0.6 min), but equal to that of DAM calves. We found no effect of feeding method on the duration of daily BS (12 h 59 min ± 1 h 38 min) but we found a tendency for the daily amount of NREM sleep; BUCKET calves had less NREM sleep per day than TEAT calves (6 h 18 min vs. 7 h 48 min, S.E.M. = 45 min) and also longer latencies from milk ingestion to BS (21.9 ± 2.0 min vs. 16.2 ± 2.0 min). DAM calves slept longer bouts than TEAT calves (10.8 ± 1.0 min vs. 8.3 ± 1.0 min) and less often (78 ± 4 vs. 92 ± 4). Sucking colostrum from a teat bucket compared with drinking from an open bucket increased sleepiness and the amount of NREM sleep. Individually housed, teat-bucket-fed calves slept more fragmentarily than dam-reared calves.