Gastrointestinal disease (GI) is the most common illness in pre-weaned dairy calves. Studies have associated the fecal microbiome composition with health status, but it remains unclear how the microbiome changes across different levels of GI disease and breeds. Our objective was to associate the clinical symptoms of GI disease with the fecal microbiome. Fecal samples were collected from calves (n = 167) of different breeds (Holstein, Jersey, Jersey-cross and beef-cross) from 4–21 d of age. Daily clinical evaluations assessed health status. Calves with loose or watery feces were diagnosed with diarrhea and classified as bright-sick (BS) or depressed-sick (DS) according to behavior. Calves with normal or semiformed feces and no clinical illness were classified as healthy (H). One hundred and three fecal samples were obtained from consistently healthy calves and 64 samples were from calves with diarrhea (n = 39 BS; n = 25 DS). The V3-V4 region of 16S rRNA gene was sequenced and analyzed. Differences were identified by a linear-mixed effects model with a negative binomial error. DS and Jersey calves had a higher relative abundance of Streptococcus gallolyticus relative to H Holstein calves. In addition, DS calves had a lower relative abundance of Bifidobacterium longum and an enrichment of Escherichia coli. Species of the genus Lactobacillus, such as an unclassified Lactobacillus, Lactobacillus reuteri, and Lactobacillus salivarius were enriched in calves with GI disease. Moreover, we created a model to predict GI disease based on the fecal microbiome composition. The presence of Eggerthella lenta, Bifidobacterium longum, and Collinsella aerofaciens were associated with a healthy clinical outcome. Although lactobacilli are often associated with beneficial probiotic properties, the presence of E. coli and Lactobacillus species had the highest coefficients positively associated with GI disease prediction. Our results indicate that there are differences in the fecal microbiome of calves associated with GI disease severity and breed specificities.

Propolis is a natural product produced by bees and sold commercially. It is well known for its antioxidant and anti-inflammatory effects and the ability to improve immune system functions in humans and animals. Many of its positive effects can contribute positively to animal productivity. The aim of this study was to evaluate possible beneficial effects of red propolis supplementation on growth performance, metabolism, and health status of dairy calves during the preweaning phase. Thirty-two newborn calves were individually housed, with free access to water and concentrate, and fed 6 L/d of whole milk. Animals were distributed in 2 treatments: (1) control and (2) supplementation with 4 mL/d of red propolis ethanolic extract (30%; EEP) in whole milk. Feed consumption and fecal and health scores were monitored daily from 1 d of age to 56 d. Calves were weighed and measured weekly. Blood samples were collected weekly, 2 h after morning milk feeding, for determination of glucose, total serum protein, urea, lactate, β-hydroxybutyrate, total iron binding capacity, and total leukocytes (white blood cells) and erythrocytes (red blood cells). Starter feed intake, daily weight gain, and body measurements were not affected by the EEP supplementation. Blood parameters were also not affected, with the exception for the red blood cell counts, which were lower in animals supplemented with EEP. Supplementation with EEP significantly decreased fecal score, days with diarrhea, and veterinary treatments of diarrhea. These results indicate that red propolis supplementation has potential to improve calf health and reduce the incidence of diarrhea and, as a consequence, the use of antibiotics in calf rearing systems.

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This study aimed to evaluate the performance and metabolic changes in dairy calves supplemented with lysine and methionine in milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in Control without supplementation (1) and; Lysine and Methionine supplementation to achieve an intake of 17 and 5.3 g/d in the SC (2) and to achieve of 17 and 5.3 g/d in the MR (3). MR was fed (6 L/d) until the 8th week of life when weaning occurred. Calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly. Blood samples were collected biweekly to evaluate the intermediate metabolism. The AA supplementation resulted in lower body weight at weaning and week 10. Calves fed SC Lys:Met had lower SC intake and lower total feed intake at weaning when compared to control. Calves fed control had higher heart girth, hip-width, and plasma glucose concentration. The supplementation with Lys and Met did not benefit dairy calves’ performance nor metabolism in this study. Supplementation through the MR was more efficient than SC to result in adequate daily intakes of AA. Further studies are needed to understand the negative effects of AA on calf starter intake.