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 ß-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.

Comparative study of different liquid diets for dairy calves and the impact on performance and the bacterial community during diarrhea.

The liquid diet composition can affect dairy calves' performance and diarrhea incidence. The effect of three liquid diets on performance, incidence of diarrhea, and microbial community during diarrhea occurrence in dairy calves were evaluated. At birth, 35 dairy calves (20 male and 15 female) were randomly assigned to one of three treatments-refrigerated whole milk (WM), acidified whole milk (AWM), and milk replacer (MR). Intake, fecal score, and rectal temperature were evaluated daily, and performance and blood parameters were evaluated weekly during the preweaning period. Fecal samples from diarrheic calves were collected, and one initial and one final sample for each episode were selected. The bacterial community was assessed by sequencing the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. Calves fed WM had higher body weight at weaning, average daily gain, body measurements, and concentration of blood metabolites. The AWM-fed calves had a lower rectal temperature and fever days. Moreover, the MR-fed calves had lower beta-hydroxybutyrate concentration and a higher incidence of diarrhea. The fecal bacterial community of diarrheic calves showed dissimilarity among the AWM and the other treatments. At the compositional level, we observed a higher abundance of Fusobacterium and Ruminococcus genera (AWM), Prevotella (WM), and Lactobacillus (MR). In the AWM and MR diarrheic calves' feces, we also observed some beneficial bacterial genera. The performance and incidence of diarrhea of dairy calves were influenced by the liquid diet consumed and the bacterial composition of diarrhea.

Does algae ß-glucan affect the fecal bacteriome in dairy calves?

ß-glucans has been reported to be associated with many health-promoting and improvements in animal performance, however, information about their effects on the bacterial community remains unknown. This study aimed to investigate how the addition of ß-glucans can affect the fecal bacterial community with possible consequences on animal growth and health. For this, newborn Holstein calves (n = 14) were individually housed in tropical shelters and blocked according to sex, date, and weight at birth and randomly assigned to one of the following treatments: (1) Control: milk replacer (14% solids, 24% CP, 18.5% fat); (2) ß-glucans: milk replacer supplemented with ß-glucans (2 g/d). All calves were bucket fed 6 L/d of milk replacer and received water and starter concentrate ad libitum starting on d 2. To evaluate the bacteriome, fecal samples were collected at weeks 1, 2, 4, and 8. The bacterial community was assessed through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. No differences for Shannon and Chao1 indexes were observed for treatments, but both indexes increased with age (P < 0.001). There were dissimilarities in the structure of the bacterial community during the pre-weaning period (P = 0.01). In a deeper taxonomic level, Collinsella (Actinobacteriota), Prevotella (Bacteroidota), and Lactobacillus (Firmicutes) were the most abundant genera (9.84, 9.54, and 8.82% of the sequences, respectively). ß-glucans promoted a higher abundance of Alloprevotella and Holdemanella, which may indicate a beneficial effect of supplementation on dairy calves. The bacterial community was highly correlated with the fecal score at weeks 1 and 2 and with starter concentrate intake at week 8. In conclusion, algae ß-glucan supplementation could be beneficial to fecal bacteriome and consequently to the health and performance of dairy calves.