Evaluation of different liquid diets associated with environmental enrichment in the performance and behaviour of dairy calves

This study aimed to evaluate the effect of two liquid diets and the use of environmental enrichment (EE) in individually housed calves fed in open buckets. The treatments were arranged in a 2 × 2 factorial design, with factor 1 as the liquid diets: Whole Milk (WM) or Milk Replacer (MR); and factor 2 as absence or presence of environmental enrichment (brushes and a dry teat). Twenty-four newborn Holstein calves were distributed in four treatments: (1) WM; (2) WM + EE; (3) MR; and (4) MR + EE. Calves had free access to water and calf starter concentrate and were fed in a step-up/step-down feeding program and were weaned at 56 days of age. There was no effect of the association of different liquid diets with EE on the performance of the animals. The association of liquid diet with EE did not affect metabolic parameters, but WM-fed calves had higher concentrations of β-hydroxybutyrate (P < 0.05). Likewise, the interaction of liquid diet and EE did not affect the faecal score (P > 0.05), but animals fed with MR had more fluid faeces (P < 0.05). There was no change in the animals' behavioural repertoire as a function of liquid diets associated with EE. The animals used the EE approximately 1.4% of the time only and vocalized for 1.7% or performed non-nutritive feeding for 1.9%. There was a tendency (P < 0.06) for a reduction in vocalization by EE availability. However, the possibility of improved animal welfare using environmental enrichment is not ruled out since the animals vocalized less during the weaning process.