Relationship of milk intake by sucking and by drinking to reticular-groove reactions and ingestion behavior in calves.

Two pairs of rumen-fistulated calves in early development of the rumen were fed milk by sucking and by drinking in alternating sequences to compare effects on swallowing behavior, openings and closings of reticular groove, and leakage of fluids into reticulorumen. These responses, determined primarily by palpation of the groove throughout feeding, revealed that sucking in comparison with drinking effected: longer times to complete first swallows, smaller amounts of milk per swallow, slower rates of milk intake and of swallowing, fewer sequential openings and closings of groove, lower incidence and shorter duration of groove openings, less spillage into reticulorumen, and less variability of these reactions among calves. Alternation of feeding methods from meal to meal did not change groove responses, but sucking immediately prior to drinking reduced incidence of groove openings in the latter. Presence of milk in the reticulorumen was not a consistent indicator of states of groove during ingestion. Observations emphasize importance of monitoring throughout feeding to determine changes of groove reactions and of role of calf individuality in response to feeding treatments.