In the present study, we evaluated whether the nasopharyngeal, ruminal, and vaginal microbiota would diverge (1) in virgin yearling beef heifers (9 months old) due to the maternal restricted gain during the first trimester of gestation; and (2) in pregnant beef heifers in response to the vitamin and mineral (VTM) supplementation during the first 6 months of pregnancy. As a secondary objective, using the microbiota data obtained from these two cohorts of beef heifers managed at the same location and sampled at the same time, we performed a holistic assessment of the microbial ecology residing within the respiratory, gastrointestinal, and reproductive tract of cattle. Our 16S rRNA gene sequencing results revealed that both α and β-diversity of the nasopharyngeal, ruminal and vaginal microbiota did not differ between virgin heifers raised from dams exposed to either a low gain (targeted average daily gain of 0.28 kg/d, n = 22) or a moderate gain treatment (0.79 kg/d, n = 23) during the first 84 days of gestation. Only in the vaginal microbiota were there relatively abundant genera that were affected by maternal rate of gain during early gestation. Whilst there was no significant difference in community structure and diversity in any of the three microbiota between pregnant heifers received no VTM (n = 15) and VTM supplemented (n = 17) diets, the VTM supplementation resulted in subtle compositional alterations in the nasopharyngeal and ruminal microbiota. Although the nasopharyngeal, ruminal, and vaginal microbiota were clearly distinct, a total of 41 OTUs, including methanogenic archaea, were identified as core taxa shared across the respiratory, gastrointestinal, and reproductive tracts of both virgin and pregnant heifers.

Abstract The objectives of these studies were to evaluate the effects of biochar (0%, 0.8%, or 3% of diet dry matter) on diet digestibility and methane and carbon dioxide production from cattle on growing and finishing diets. The growing diet consisted of 21% brome hay, 20% wheat straw, 30% corn silage, 22% wet distillers grains plus solubles, and 7% supplement. The finishing diet consisted of 53% dry-rolled corn, 15% corn silage, 25% wet distillers grains plus solubles, and 7% supplement. In both trials biochar replaced fine ground corn in the supplement. Six crossbred steers (initial body weight [BW] 529 kg; SD = 16 kg) were used in both the growing and finishing trial. The growing diets were evaluated over 6 periods followed by the finishing trial with 3 periods. Digestibility measures were taken over 4 d after at least 8 d of adaptation to diets followed by 2 d of gas emission measurements using headbox calorimeters. Dry matter intake (DMI) was not affected (P ≥ 0.43; 7.91 kg/d) by biochar inclusion in the growing study and increased quadratically (P = 0.07) in the finishing study with 0.8% biochar inclusion having the greatest DMI (12.9 kg/d). Organic matter (OM) and neutral detergent fiber (NDF) digestibility increased quadratically (P = 0.10) in the growing study whereas OM digestibility tended to linearly decrease (P = 0.13) and NDF digestibility was not affected (P ≥ 0.39) by biochar inclusion in the finishing diet. Digestible energy intake (Mcal/d) was not affected (P ≥ 0.25) by biochar inclusion in the growing or finishing study. Methane production (g/d) tended to decrease quadratically (P = 0.14) in the growing study and was decreased 10.7% for the 0.8% biochar treatment relative to the control. There were no statistical differences in methane production (g/d) in the finishing study (P ≥ 0.32) but cattle on the 0.8% biochar treatment produced numerically less (9.6%) methane than the control. Methane production as g/kg DMI of the 0.8% biochar treatment relative to the control was numerically reduced 9.5% and 18.4% in the growing and finishing studies, respectively (P ≥ 0.13). Carbon dioxide production (g/d and g/kg of intake) quadratically decreased (P ≤ 0.06) in the growing study but was not affected by treatment in the finishing study (P ≥ 0.34). Although biochar is not a U.S. Food and Drug Administration -approved feed for cattle, the initial research shows potential as a methane mitigation strategy in both growing and finishing diets.

As the hemp industry continues to develop in the US, there is interest in feeding byproducts of industrial hemp production to livestock. A completely randomized design experiment using crossbred finishing heifers [initial body weight (BW) ± SE = 494 ± 10 kg] was conducted to determine the effects of feeding hempseed cake in a corn-based finishing diet (10% forage) formulated to meet or exceed ruminally degradable and metabolizable protein requirements on growth performance, carcass characteristics, feeding behavior, and plasma parameters. Dietary treatments were inclusion of 20% [dry matter (DM) basis] of: dried corn distillers grains plus solubles (DDGS, n = 16), or hempseed cake (HEMP, n = 15). Cattle were housed in two pens, had ad-libitum access to feed and water, and individual intakes and feeding behavior were monitored using the Insentec feeding system. Cattle were fed treatment diets for 111 days, and every 14 days BW were measured, and blood samples collected. Blood plasma was analyzed for glucose, urea nitrogen, and individual amino acids and results analyzed using repeated measures analysis in SAS. Final BW, average daily gain, gain:feed, and hot carcass weight decreased (P ≤ 0.05) by 2.3%, 7.7%, 7.7%, and 2.6% respectively in heifers fed the HEMP diet than in heifers fed the DDGS diet. Net energy for maintenance and gain (Mcal/kg of feed, DM basis), estimated based on heifer intake and performance, were greater (P = 0.02) for the DDGS diet than the HEMP diet. All other performance and carcass characteristics were not different (P ≥ 0.20) between treatments. Heifers fed the HEMP diet had greater (P < 0.05) plasma urea nitrogen concentration in samples from each collection day compared to heifers fed the DDGS diet, although there was a treatment by day interaction (P < 0.01) because of variability in the magnitude of treatment differences over time. Plasma glucose concentration was not influenced (P = 0.17) by dietary treatment. Plasma concentrations of total amino acids, non-essential amino acids, and essential amino acids were not different between treatments (P ≥ 0.09), although there were several interactions between treatment and day (P ≤ 0.04) for individual amino acids. These data suggest that hempseed cake has a lower NEm and NEg relative to dried corn distillers grains plus solubles when adequate metabolizable protein is supplied, while still providing adequate nutrition to support acceptable performance of finishing cattle.

A growing number of studies have investigated the feasibility of utilizing hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers (19-months old, initial body weight = 494 ± 10 kg [SE]) were fed a corn-based finishing diet containing 20% hempseed cake as a substitute for 20% corn dried distillers’ grains with solubles (DM basis; Control; n = 16/group) for 111 days until slaughter. Ruminal fluid and deep nasopharyngeal swabs (days 0, 7, 42, 70 and 98), and vaginal and uterine swabs (at slaughter) were collected, and the microbiota assessed using 16S rRNA gene sequencing. Diet affected the community structure of the ruminal (d 7−98; 0.06 ≤ R2 ≤ 0.12; P < 0.05), nasopharyngeal (d 98; R2 = 0.18; P < 0.001), and vaginal (R2 = 0.06; P < 0.01) microbiota. Heifers fed hempseed cake had increased microbial diversity in the rumen, reduced microbial richness in the vagina, and greater microbial diversity and richness in the uterus. In addition to the distinct microbial communities in the rumen, nasopharynx, vagina and uterus, we identified 28 core taxa that were shared (≥ 60% of all samples) across these sampling locations. Feeding hempseed cake appeared to alter the bovine gut, respiratory and reproductive microbiota. Our results suggest that future research aiming to evaluate the use of hemp by-products in livestock diet should consider their impact on animal microbiome and microbiome mediated animal health and reproductive efficiency. Our findings also highlight the need for research evaluating the impact of hemp-associated food and personal care products on the human microbiome.

Two trials were conducted to evaluate the effects of biochar (0, 0.8, or 3% of diet dry matter) on diet digestibility and methane production in growing and finishing cattle diets. The growing diet consisted of 21% brome hay, 20% wheat straw, 30% corn silage, 22% wet distillers grains plus solubles (WDGS), and 7% supplement. The finishing diet consisted of 53% dry rolled corn, 15% corn silage, 25% WDGS, and 7% supplement. Biochar replaced fine ground corn in the supplement. Growing diets were evaluated over 6 periods in a switchback design, followed by the finishing trial with 3 periods in a crossover design using 6 steers (529 kg initial BW). Digestibility measures were taken over 4 d after at least 8 d of adaptation to diets followed by 2 d of gas emission measurements using headbox calorimeters. Statistical analysis included treatment and period as fixed effects and steer as a random effect with PROC IML of SAS used to generate coefficients for orthogonal contrasts. In the growing study, OM and NDF digestibility increased quadratically (P = 0.10) while OM digestibility tended to linearly decrease (P = 0.13) and NDF digestibility was not affected (P ≥ 0.39) by biochar inclusion in the finishing diet. Methane production (g/d) tended to decrease quadratically (P = 0.14) in the growing study and was decreased 10.7% for the 0.8% biochar treatment relative to the control. There were no statistical differences in methane production (g/d) in the finishing study (P ≥ 0.32). Methane production (g/kg DMI) from the 0.8% biochar treatment relative to the control was numerically reduced 9.5% and 18.4% in the growing and finishing studies, respectively (P ≥ 0.13). Although biochar is not an FDA-approved feed for cattle, initial research shows potential as a methane mitigation strategy in both growing and finishing diets.