Hematological and immunological development from birth to six months of age in Holstein calves

Enrichment of medium-quality colostrum by adding colostrum replacer, combined or not with transition milk in the feeding of dairy calves

Fifty Holstein calves were allocated in randomized blocks and distributed in a 2 × 2 factorial arrangement; (A) two sources of Ig: (1) Control: bovine colostrum (25% Brix); (2) Enriched colostrum: mid-quality bovine colostrum (20% Brix) enriched with colostrum replacer to 25% Brix; and (B) two transition feeding diets: (1) Whole milk (WM): supply of 4 L/day of whole milk for 3 days after the colostrum feeding; and (2) Formulated transition milk (FTM): supply 4 L/day of whole milk enriched with 70 g/L of colostrum replacer for 3 days after the colostrum feeding. Blood samples were collected at 0, 24, 48, and 72 h of age to determine total serum protein (TSP), glucose, non-esterified fatty acids (NEFA), erythrocyte and leukocyte concentrations. IgG was measured at 48 h. During the preweaning period, calves received 6 L/day of whole milk. Blood samples were collected weekly to determine TSP, glucose, and lactate. The colostrum protocols were equally efficient for transfer of passive immunity with IgG concentration at 48 h ≥ 49.6 g/L. Colostrum or transition feeding program did not influence the erythrocyte and leukocyte concentrations. The TSP concentration measured until 72 h was higher for calves fed maternal colostrum. Calves fed milk in the transition period had higher glucose concentrations. Calves receiving bovine colostrum and FTM had higher glucose concentrations in the preweaning period, while the enriched colostrum decreased plasma lactate concentrations. In summary, enrichment of mid-quality colostrum is an alternative in situations of a shortage of high-quality colostrum; however, feeding 4 L/day of FTM only for 3 days after colostrum feeding does not show additional benefits.

Hematologic profiles and development of innate immune function in healthy Holstein calves during the pre-weaning period

BACKGROUND

The development and state of innate immune cell function during the first 90 days of life in dairy calves have not been fully described.

OBJECTIVE

This transversal study attempted to examine the changes that occur in circulating blood cells and the innate immune response in healthy calves from birth to 89 days of age.

METHODS

Healthy Holstein calves represent three windows of development, G1 from 1 to 7 days old (n = 26), G2 from 30 to 40 days old (n = 28), and G3 from 60 to 89 days old (n = 36) were sampled once each from a single herd. A few biomarkers of the general health and innate and inflammatory immune responses were measured.

RESULTS

The youngest calves had the lowest red blood cell (RBC) counts, cell hemoglobin concentration means (CHCMs), red cell distribution widths (RDWs), and cell hemoglobin contents of mature red blood cells (CHm) compared with the other groups. They also had the lowest iron concentrations and highest intracellular myeloperoxidase indices. However, white blood cell (WBC) and lymphocyte concentrations gradually increased from G1 to G3. G2 calves had the lowest serum protein concentrations and highest number of innate immune cells compared with the other groups. Calves were able to mount phagocytic and ROS responses from birth.

CONCLUSIONS

The physiologic responses of circulating blood cells and innate immune responses in dairy calves are shown according to age. Neonates had limitations in several RBC and WBC indices and immunologic responses that would likely impact overall vigor and health. Fortunately, these limitations resolve by 90 days of age.

Year-Long Phenotypical Study of Calves Derived From Different Assisted-Reproduction Technologies

Assisted reproductive technologies play a major role in the cattle industry. An increase in the use of in vitro-derived embryos is currently being seen around the globe. But the efficiency and quality of the in vitro-derived embryos are substandard when compared to the in vivo production. Different protocols have been designed to overcome this issue, one of those being the use of reproductive fluids as supplementation to embryo culture media. In this study, in vitro-derived calves produced with reproductive fluids added to their embryo production protocol were followed for the first year of life pairwise with their in vivo control, produced by artificial insemination (AI), and their in vitro control, produced with standard supplementation in embryo production. The objective was to assess if any differences could be found in terms of growth and development as well as hematological and biochemical analytes between the different systems. All the analysed variables (physical, hematological, and biochemical) were within physiological range and very similar between calves throughout the entire experiment. However, differences were more evident between calves derived from standard in vitro production and AI. We concluded that the use of reproductive fluids as a supplementation to the embryo culture media results in calves with closer growth and development patterns to those born by AI than the use of bovine serum albumin as supplementation.

Early supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 in newborn dairy calves increases IgA production in the intestine at 1 week of age

The early development of immunity and microbiota in the gut of newborn calves can have life-long consequences. Gut microbiota and the intestinal barrier interplay after birth, establishing a homeostatic state whereby mucosal cells cohabit with microorganisms to develop a healthy gut. We hypothesized that postnatal codevelopment of gut immunity and microbiota could be influenced by early-life supplementation with live yeast. Starting from birth, calves either received a daily supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB, 10 × 10⁹ cfu/d, n = 10) in the morning meal for 7 d or no supplementation (n = 10). Each animal received 2 adequate colostrum replacer meals at 2 and 12 h of life (expected total IgG fed = 300 g) before being fed milk replacer twice a day. Passive transfer of immunity (total protein, IgG, and IgA) through colostrum was evaluated and endogenous production of IgA was investigated by measuring IgA-producing plasma cells, IgA relative gene expression (PIGR and CD79A), and secretory IgA concentration in the gut. The concentration of targeted microbial groups was evaluated with quantitative PCR in the gut digesta collected at d 7 of life. Early SCB supplementation did not impair immunoglobulin absorption and all calves had successful passive transfer of immunity (serum IgG concentration >15 mg/mL at d 1 and d 7 of age). Although the expression of IgA relative gene expression (PIGR and CD79A) was not different, SCB calves had higher secretory IgA concentrations in the ileum (1.98 ± 0.12 mg/g of dry matter; DM) and colon (1.45 ± 0.12 mg/g of DM) digesta compared with control animals (1.18 and 0.59 ± 0.12 mg/g of DM, respectively). In addition, the number of IgA-producing plasma cells were greater in both ileum (2.55 ± 0.40 cells/mm²) and colon (3.03 ± 0.40 cells/mm²) tissues for SCB calves compared with control (respectively 1.00 ± 0.40 and 0.60 ± 0.42 cells/mm²). Endogenous IgA production in the gut of SCB calves was enhanced, which could make them less prone to pathogen intrusion. In addition, SCB calves had higher Lactobacillus and tended to have higher Faecalibacterium prausnitzii in the jejunum compared with control calves, which suggests that SCB supplementation during early-life gut colonization may have a positive effect in newborn calves. Direct SCB supplementation or the cross-talk between SCB and bacteria may be responsible for stimulating IgA production and may play a key role in shaping early colonization in the gut of newborn calves.