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Body systems once thought sterile at birth instead have complex and sometimes abundant microbial ecosystems. However, relationships between dam and calf microbial ecosystems are still unclear. The objectives of this study were to (1) characterize the various maternal and calf microbiomes during peri-partum and post-partum periods and (2) examine the influence of the maternal microbiome on calf fecal microbiome composition during the pre-weaning phase. Multiparous Holstein cows were placed in individual, freshly bedded box stalls 14 d before expected calving. Caudal vaginal fluid samples were collected approximately 24 h before calving and dam fecal, oral, colostrum, and placenta samples were collected immediately after calving. Calf fecal samples were collected at birth (meconium) and 24 h, 7 d, 42 d, and 60 d of age. Amplicons covering V4 16S rDNA regions were generated using DNA extracted from all samples and were sequenced using 300 bp paired end Illumina MiSeq sequencing. Spearman rank correlations were performed between genera in maternal and calf fecal microbiomes. Negative binomial regression models were created for genera in calf fecal samples at each time point using genera in maternal microbiomes. We determined that Bacteroidetes dominated the calf fecal microbiome at all time points (relative abundance ≥42.55%) except for 24 h post-calving, whereas Proteobacteria were the dominant phylum (relative abundance = 85.10%). Maternal fecal, oral, placental, vaginal, and colostrum microbiomes were significant predictors of calf fecal microbiome throughout pre-weaning. Results indicate that calf fecal microbiome inoculation and development may be derived from various maternal sources. Maternal microbiomes could be used to predict calf microbiome development, but further research on the environmental and genetic influences is needed. Published version

This issue includes articles about the federal margin protection program for dairy farms, and about antibody concentration in colostrum in milk for calves.

Articles in this issue provide details on feeding regimens for cattle, and on the quality of fats in milk.

Stresses the importance of cleaning colostrum containers for healthy calves, and discusses milk quality in Virginia.

Discusses ethanol and the Renewable Fuel Standard, and milk replacers for calves.

This study investigated the microbial colonization and maternal influences on the neonatal calf gut microbiome. Microbiome samples were collected from dams (n = 6) and calves (n = 6) using sterile flocked swabs. The vaginal, oral, and fecal bacterial communities were examined from the dam and the fecal community of calves was examined from birth to 60 d of age. Microbial communities varied by anatomical location and age of the calf. Metagenomic analysis 16s ribosomal DNA revealed ten phyla associated with microbiomes of the dam and the same ten phyla associated with calf feces at various time points: Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, Cyanobacteria, Verrucomicrobia, Spirochaetes, Tenericutes, Fibrobacteres, and Lentisphaerae. Overall, the calf meconium and fecal microbiome is influenced by a combination of the maternal vagina, oral, and fecal microbiomes. Further studies will be needed to identify the transference mechanisms of maternal microbes to offspring and the associated host-microbial interactions. Master of Science in Life Sciences This study investigated the microbial colonization and maternal influences on the neonatal calf gut microbiome. Microbiome samples were collected from dams (n = 6) and calves (n = 6) using sterile flocked swabs. The vaginal, oral, and fecal bacterial communities were examined from the dam and the fecal community of calves was examined from birth to 60 d of age. Microbial communities varied by anatomical location and age of the calf. Metagenomic analysis 16s ribosomal DNA revealed ten phyla associated with microbiomes of the dam and the same ten phyla associated with calf feces at various time points: Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, Cyanobacteria, Verrucomicrobia, Spirochaetes, Tenericutes, Fibrobacteres, and Lentisphaerae. Overall, the calf meconium and fecal microbiome is influenced by a combination of the maternal vagina, oral, and fecal microbiomes. Further studies will be needed to identify the transference mechanisms of maternal microbes to offspring and the associated host-microbial interactions.

Newborn Holstein (n = 48) and Jersey (n = 30) calves were studied to compare the absorption of immunoglobulin G (IgG) from maternal colostrum (n = 39) or a colostrum replacement product derived from bovine serum (n = 39). Calves were also fed milk replacer with (n = 38) or without (n = 40) animal plasma to 29 d of age to determine the effect of plasma protein on IgG status, health, and growth. Colostrum or colostrum replacement was fed at 1.05 and 13.5 h of age and provided a total of 250, 180, 249, or 186 g IgG for Holsteins and Jerseys fed replacement or colostrum, respectively. Milk replacer (12.5% DM) was fed at 31% of metabolic birth weight (2 feedings/d). Jugular blood was sampled at 0 h, 24 h, and weekly to determine plasma IgG. At blood collection calves were weighed and measured to determine growth. Health scores, fecal scores, and grain intake were measured daily. Mean plasma IgG at 24 h did not differ between calves fed colostrum (13.78 ± 0.39 g/L) and replacement (13.96 ± 0.38 g/L). Average daily gain, wither height, hip height, body length, heart girth, health, and incidence of diarrhea were not different between treatment groups. Plasma IgG and performance were not affected by addition of animal plasma to milk replacer. The colostrum substitute successfully replaced colostrum as the source of IgG for newborn calves. Animal plasma was an acceptable source of protein, but did not enhance growth or immunity. Master of Science

In experiment 1, 24 multiparous Holsteins and 24 multiparous Jerseys were assigned at random to one of four diets containing either 1.25, 1.38, 1.50, or 1.63 Mcal NEL/kg DM to determine the effects of prepartum energy density on productivity. Cows were assigned to diets 28 d before expected calving and received a similar diet 0 to 60 d postpartum. Prepartum DMI increased linearly as dietary energy density increased. Non-esterified fatty acids did not differ for energy density and were greater for Holsteins. Milk and 4% FCM increased linearly as dietary energy density increased, although postpartum DMI was quadratic for energy density. Fat yield increased linearly with energy density and protein yield did not differ. Increasing prepartum diet energy density increased yield of milk and 4% FCM. In experiment 2, 26 multiparous and 18 primiparous Jerseys were assigned to one of two CP and rumen undegradable protein (RUP) concentrations 30 d before expected calving to determine the effects of CP and RUP on productivity. Cows received a similar diet 0 to 60 d postpartum. Prepartum CP concentrations were 12 and 15% and prepartum RUP (% of CP) concentrations were 30 and 45%. Dry matter intake was not affected by CP or RUP. Milk yield and 4% FCM yield did not differ for CP or RUP. In addition, milk protein concentration and yield were similar for CP and RUP. Positive calculated metabolizable protein balance for 12% CP and 30% RUP concentrations may have precluded responses to increasing prepartum CP and RUP. In experiment 3, 12 Holstein and 12 Jersey multiparous cows were assigned at random to diets containing 0 or 500 mg FeCO3/kg DM to investigate the effects of dietary Fe on milk production and Cu status. Hepatic Cu did not differ for breeds or Fe supplementation. For Jerseys, hepatic Fe was greater for cows receiving supplemental Fe. Hepatic Zn was similar for breed and Fe supplementation. Plasma Cu was greater for Jerseys compared to Holsteins and did not differ for Fe supplementation. Plasma Fe and Zn did not differ for breeds or Fe supplementation. Iron supplementation did not affect yield of milk or 4% FCM. Dietary Fe did not affect Cu status of Holstein and Jersey cows in this experiment. Ph. D.