Data from: Hay provision affects 24-h performance of normal and abnormal oral behaviors in dairy calves

Dairy calves often perform abnormal repetitive behaviors (ARBs) including
tongue rolling and non-nutritive oral manipulation (NNOM) when
opportunities to perform feeding behaviors are restricted. Many US dairy
farms limit access to milk, a well-studied risk factor for ARBs. However,
farms also commonly do not feed forage to young calves, and the motor
patterns of oral ARBs resemble those necessary for acquiring and chewing
solid feed. Our objective was to assess how access to hay from birth
influenced time engaged in normal and abnormal oral behaviors across 24 h.
Holstein heifer calves were housed individually on sand bedding and fed ad
libitum water and grain (Control, n = 11) or given additional access to
hay (Hay, n = 11) from birth. Calves were fed 5.7-8.4 L/d (step-up) milk
replacer via a teat. At the start of step-down weaning (50 ± 1 d), all
calves were given access to a total mixed ration (TMR). Feed and water
intake were measured daily. Oral behaviors (eating, ruminating, sucking
milk, drinking water, panting, grooming, tongue flicking, tongue rolling,
and NNOM) were recorded by direct observation at weeks 2, 4, 6, and 8
using 1-0 sampling at 1-min intervals for 24 h. Grain, hay, and water
intake increased over time in the preweaning period. One polydipsic calf
regularly consumed >10 L water/d. During weaning, Hay calves tended
to consume increasingly more TMR, significantly more water, and less grain
than Control calves. Access to hay led to more observations spent eating
solid feed (7% vs. 5%, mean percentage of intervals) and ruminating (24%
vs. 16%) during the preweaning period compared to calves fed only grain,
though Control calves appear to ruminate in absence of forage to re-chew.
Rumination occurred, to a large extent, overnight. Hay calves also spent
less time self-grooming (12% vs. 14%), tongue flicking (14% vs. 18%), and
performing NNOM (17% vs. 21%) than Control calves. While NNOM peaked
around milk feedings, all 3 behaviors were performed throughout the day.
Tongue rolling was rare across treatments, as was panting, which occurred
most frequently around 14:00. There were no behavioral differences during
weaning (wk 8). Overall, we found that hay provision affects most oral
behaviors that calves perform: it promotes natural feeding behaviors and
reduces abnormal ones, suggesting hay should be provided. We also found
that calves perform other behaviors, including polydipsia, repetitive
grooming, and apparent sham rumination, that may suggest a degree of
abnormality in these behaviors that has not been previously identified.
These results highlight the importance of utilizing all oral behaviors to
better understand calf welfare.