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Herein, we investigate the effects of a long-term release trenbolone acetate and estradiol implant (200 mg and 40 mg respectively, Revalor-XS; Merck Animal Health; Summit, NJ) on implanted [IMP; n = 9, body weight (BW) = 473.13 kg ± 25.22] and non-implanted (NIMP; n = 9, BW = 481.13 kg ± 21.78) finished Angus Hereford steers fed a single diet three times daily (0600, 1100, 1600 h). The objectives were to identify water and feed efficiency parameters and mechanisms of IMP and NIMP steers. Parameters evaluated included daily dry matter intake (DMI), freshwater intake (FWI), average daily gain (ADG), animal water units (AWU), drinking behavior, feed conversion (FC), feed conversion ratio (FCR), water conversion (WC), water conversion ratio (WCR), residual growth rate (RGR), and Kleiber index (KI). Linear mixed models were fitted to analyze the data under assumption of a completely randomized design, and variable relationships examined through partial correlation networks and principal component analysis. Implanted animals were more feed efficient than NIMP for FC (P < 0.001; SEM = 0.00), FCR (P < 0.001; SEM = 0.29), RGR (P < 0.001; SEM = 0.0.02), and KI (P < 0.001; SEM = 0.00). When evaluating water efficiency, IMP animals had less WCR (P < 0.001; SEM = 1.54) and greater WC (P < 0.001; SEM = 0.001). No differences were observed on marbling and carcass grades, but carcass weight, final BW, and rib eye area were greater for IMP groups (P < 0.001, P < 0.001, P = 0.004, respectively). For IMP, multivariate variable contribution (values > 10) appeared to associate FWI on the first and second eigenvectors with DMI, FC, and FCR. For NIMP, FWI was associated with WC, WCR, and AWU. The FWI of Implanted animals was associated with AWU, WCR, while NIMP was associated with AWU. Feed conversion ratio and DMI had the greatest node strength for the IMP animals, whereas for NIMP, KI was the only node with strength greater than 2. Our results indicate that feed and water efficiencies may share mechanistic pathways. We present a simple metric that accurately remains relevant in evaluating water requirements for both IMP and NIMP steers as AWU. We show how relationship strength is related to gain and efficiency for IMP animals, whereas metabolic activity, potentially in relation to body composition changes, drives the variation and relationships for NIMP animals. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine how different backgrounding and finishing systems might affect nitrogen (N) metabolism, and consequently water requirements of cattle. Further, we investigated if the previous plane of nutrition might affect the results obtained in the subsequent phase. Cattle (n = 24) were randomly distributed into either a moderate (MP; crude protein (CP): 9.10%) or high (HP; CP: 12.62%) plane of nutrition during the background phase for 85 d. Animals were then blocked by their previous plane of nutrition and were moved onto a 105-d finishing phase. The forage-finished group received only high-quality alfalfa hay (CP: 21.3%), whereas the grain-finished group received a high grain diet (80% whole corn and 20% alfalfa hay; CP: 10.8%). Animals on MP diets excreted less N through urine (P < 0.01) and feces (P < 0.01), while retaining more N (P < 0.01), which resulted in an increased N efficiency (P < 0.01) when compared with HP animals. No differences were observed for water intake or microbial N being observed (P > 0.05). Grain-fed animals consumed less N and water (P < 0.01), but still had a greater amount of N being digested when compared with forage-fed animals (P < 0.01), as well as the least excretion of N through feces (P < 0.01) and urine (P < 0.01), and consequently a greater rate of N being retained (P < 0.01) and a greater efficiency on utilizing the ingested N (P < 0.05). Further interaction was also observed between treatment and previous plane of nutrition, where animals coming from a MP had the least dry matter intake, greatest amount of N being digested and least N excretion, fecal output, and excretion of N through the feces (P < 0.05). These results indicate that animals receiving MP will reduce their excretion of N without modifying the required amount of water while producing the same amount of microbial N due to more efficient N recycling. Extremely important is the fact that efficiency is carried over after these animals are transitioned to grain-fed finishing systems. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the effects of dietary restriction and subsequent re-alimentation on body composition and hepatic gene expression of epigenetic markers of DNA methylation, RNA m6A methylation, and histone acetylation in the liver of postpubertal beef bulls. Twelve Angus × Hereford crossbred bulls (n = 6, 23 ± 0.55 mo [young bulls], 558 ± 6.1 kg; and n = 6, 47 ± 1.2 mo [mature bulls], 740 ± 30.5 kg) were submitted to two dietary regimes per offering of the same hay: low plane of nutrition (90 d) and compensatory growth (90 d). Each animal acted as its own control and were fed Beardless wheat (Triticum aestivum) hay and mineral mix during the trial. Statistical analyses were performed using SAS 9.4 following a pre-post repeated measures design. Bulls in negative energy balance (NEB) decreased (P < 0.001) empty body weight (EBW; 23.1% [−139.1 kg]), empty body fat (EBF; 39.8% [−85.4 kg]), and empty body protein (EBP; 14.9% [−13.5 kg]) and fully recovered at the end of the trial. Body fat accounted for 77.1% of daily changes in body energy status, whereas body protein accounted for only 22.9% (P < 0.001). Relative abundance of epigenetic markers transcripts was analyzed via qPCR. Bulls at NEB tended (P ≤ 0.097) to increase gene expression of epigenetic markers of RNA m6A methylation (METTL14, VIRMA, and WTAP) and increased (P ≤ 0.050) the gene expression of epigenetic markers of DNA methylation (DNMT3A) and histone-acetylation (SIRT3 and SIRT7). Young bulls had a tendency (P ≤ 0.072) of higher RNA m6A methylation, VIRMA, and WTAP than mature bulls. Effect of diet × age interaction was not detected (P ≥ 0.137) for METTL14, VIRMA, WTAP, DNMT3A, SIRT3, or SIRT7. Younger bulls tended to have greater RNA m6A methylation levels than mature bulls, indicating that, while contemporaneously fed the same diet during periods of undernourishment followed by compensatory growth, age has an impact on this epigenetic mechanism. In conclusion, metabolic status seems to carry a greater impact on regulating bovine hepatic epigenetic mechanisms that modulate gene transcription, such as DNA methylation and histone acetylation, than on epigenetic mechanisms that regulate gene translation, such as RNA m6A methylation. During periods of undernourishment followed by compensatory growth, body fat pools appear to change more dynamically and are easily detected having a greater impact on epigenetic markers that modulate hepatic gene transcription rather than translation. [ABSTRACT FROM AUTHOR]

Aiming to characterize the effects of nutritional status on epigenetic markers, such as DNA 5-methyl cytosine (mC) methylation and RNA N6- methyladenosine (m6 A) methylation, of bovine sperm, 12 Angus × Hereford crossbred breeding bulls were submitted to nutritional changes for a period of 180 d: no change in body weight (BW) (phase 1 = 12 d), BW loss (phase 2 = 78 d), and BW gain (phase 3 = 90 d) in a repeated measures design. Animals were fed Beardless wheat (Triticum aestivum) hay and mineral mix. Statistical analyses were performed using SAS 9.4 (SAS Inst., Cary, NC). Higher levels of RNA m6 A (P = 0.004) and DNA methylation (P = 0.007) of spermatic cells were observed at phase 2 compared with phase 1. In phase 3, sperm RNA m6 A methylation levels continued to be higher (P = 0.004), whereas the DNA of sperm cells was similar (P = 0.426) compared with phase 1. Growing bulls had a tendency (P = 0.109) of higher RNA m6 A methylation levels than mature bulls. Phase 2 altered scrotal circumference (P < 0.001), sperm volume (P = 0.007), sperm total motility (P = 0.004), sperm progressive motility (P = 0.004), total sperm count (P = 0.049), normal sperm (P < 0.001), abnormal sperm (P < 0.001), primary sperm defects (P = 0.039), and secondary sperm defects (P < 0.001). In phase 3, bulls had scrotal circumference, sperm volume, sperm motility, sperm progressive motility, total sperm count, normal and abnormal spermatozoa, and primary and secondary spermatozoa defects similar to phase 1 (P > 0.05). Serum concentrations of insulin-like growth factor-1 and leptin decreased during phase 2 (P = 0.010), while no differences (P > 0.05) were detected between phases 3 and 1; growing bulls tended (P = 0.102) to present higher leptin levels than mature bulls. Specific for mature bulls, DNA methylation was positively correlated with leptin concentration (0.569, P = 0.021), whereas for young bulls, DNA methylation was positively correlated with abnormal spermatozoa (0.824, P = 0.006), primary spermatozoa defect (0.711, P = 0.032), and secondary spermatozoa defect (0.661, P = 0.052) and negatively correlated with normal spermatozoa (−0.824, P = 0.006), total sperm count (−0.702, P = 0.035), and sperm concentration (−0.846, P = 0.004). There was no significant correlation (P > 0.05) between RNA m6 A and hormones and semen traits. In conclusion, the nutritional status of breeding bulls alters epigenetic markers, such as DNA methylation and RNA m6 A methylation, in sperm, and the impact of change seems to be age dependent. These markers may serve as biomarkers of sperm quality and fertility of bulls in the future. Detrimental effects on sperm production and seminal quality are observed at periods and places when and where environmental and nutritional limitations are a year-round reality and may carry hidden players that may influence a lifetime of underperformance. [ABSTRACT FROM AUTHOR]

Water requirements for beef cattle are often computed according to body weight (BW) and environmental variables. Inherent variation in environmental conditions within geographical locations, in addition to a cascade of physiological changes triggered as consequence of such variability are somewhat fomented by multicollinearity amongst these variables. This conundrum generates instability of current predictive models in reaching optimization equilibrium inflating its overall predictability and robustness. The goals herein involved the identification of physiologically relevant parameters and the generation of robust, data-driven, individualistic models through high frequency data loggers. Further, we evaluate re-parametrized and current proposed equations (e.g.: Hicks et al., 1988 and Arias and Mader, 2011) for the prediction of water intake for beef cattle at different life stages and physiological conditions. The dataset utilized consisted of more than 30,000 observations, including longitudinal data on lactating animals (n = 23), grass finished steers (n = 12), grain finished steers (n = 21), and grain finished implanted steers (n = 9), steers backgrounded on a low (n = 20) or moderate (n = 20) plane of nutrition bulls under negative (n = 13), maintenance (n = 13) and positive energy balance (n = 13). Individual monitoring systems allowed for the daily collection of BW, water and feed intake, and ingestive behavior. Additionally, an on-site data-logging weather station (1-min intervals) collected relative humidity, temperature, wind speed, wind direction, solar radiation, and precipitation. All reported statistics were generated on out-of-bag randomly split portions of the dataset. For identification of relevant predictive parameters of water intake, several feature selection and penalization techniques were examined. When comparing our equations to current, the errors generated for water intake predictions using physiological classification and on-site environmental variables, explained 50% more of the variation in predicting water intake (r² = 0.38 vs r² = 0.22-0.27). When evaluating the errors of prediction (root mean squared error, RMSE and mean absolute error, MAE), significant decreases of up to three-fold were observed on the equations generated herein (RMSE = 9.05 vs 28.8 to 35.31, MAE = 7.04 vs 26.9 to 33.9). Accurate monitoring of individual parameters such as feed intake were better predictors of water intake than environmental parameters when evaluating re-parametrization of models. Further, inclusion of a physiological stage (categorical variable) was more significant than any of the other environmental predictors. Overall, the results discussed highlight the importance of appropriately accounting for the water requirements of beef cattle and how far-off current assumptions are. Further, it raises concern on current equations that use environmental monitoring equations and techniques that attempt to describe nutrient requirements of the animals, and potentially brings the approach to requirements rather than environment. [ABSTRACT FROM AUTHOR]

Changes to native plant compositions of drylands are often associated to loss of wildlife, increased frequency, and severity of wildfires; further, it complicates the grazing permits and allocation during periods of restoration. The goals herein investigate the germination rates of native seed species after in situ incubation to evaluate their potential dispersal as supplements for grazing cattle. Native: Indian ricegrass (Achnatherum hymenoides; ACHY), white yarrow (Achillea millefolium; ACMI), crested wheatgrass (Agropyron cristatum; AGCR), sagebrush (Artemisia tridentata; ARTR), fourwing saltbrush (Atriplex canascens; ATCA), bottlebrush squirreltail (Elymus elimoides; ELEL), bluebunch wheatgrass (Pseudoregneria spicata; PSSP), and gooseberryleaf globemallow (Sphaeralcea grossulariifolia; SPRT) and nonnative: cheatgrass (Bromus tecorum, BRTE; fall BRTEf and spring seeds BRTEs) seeds were examined. Four ruminally canulated Angus x Hereford steers adapted to a forage kochia-alfalfa diet were utilized for seed incubations. Seeds were weighed into 84 bags at a rate of 5 g per bag (duplicated within and in different animals). Seeds were incubated sequentially (0, 6, 12, 24, 36, 48, and 96 h) and removed at the 96-h point when seeds were thoroughly washed and immediately counted (50) on square 80 mm 80 mm commercial sterile petri dishes with moisture pads and 5 mL of water. Seeds were incubated at 20 °C with 12 h of light/no-light intervals. Germination plates were incubated for 50 d and counted every 10 d for germinations. Generalized linear models assuming a Poisson distribution with separation of means through Dunnett's multiple comparisons test. Statistical significance was declared at P < 0.05. All statistical analyses were performed on R (R Core Team 2022). Incubation times inside of the rumen linearly decreased germination rates across most seed species. For BRTEs, germination completely stopped at 48 h with a steep decrease observed after 24 h incubation. The BRTEf were also incubated but showed low germination both before and after rumen exposure (winter dormancy). Though ARTR is very important in rangeland restoration in the intermountain west, its germination declined more than 85% within just a 6 h incubation in situ (P < 0.001). A significant germination decrease was observed for AGCR at 36 h; however, germination was full at 48 h and 50% of the original at 96 h (P < 0.05). For ACMI, germination rates significantly declined after 36 h incubation, and for PSSP after 24 h. Low germinations were observed for ACHY, SPRT, and ATCA even with high reported in-bag tetrazolium chloride viabilities. Our results highlight that cattle grazing of cheatgrass does not spread seeds through fecal pats. Additional tests are required to determine seed viability of the dormant (low germination) BRTEf. Seed toleration to ruminal degradation highlights the potential targeted seed supplementation during grazing for rangeland restoration. [ABSTRACT FROM AUTHOR]

The use of cover crops in agriculture has had positive effects on soil health and sustainability. In the western US, utilizing cover crops for silage production provides many of the same soil health benefits while providing forage for ruminants, serving multiple sectors with the same water costs. Therefore, the aim of this study was to determine the effects of mixed grass and legume silage combined with different inoculants on silage quality and in vitro rumen fermentation. Four silage mixes (100% sorghum [0SB], 67% sorghum + 33% soybean [33SB], 33% sorghum + 67% soybean [67SB], and 100% soybean [100SB]) were prepared and 6 treatments were applied to each mix 1) homofermentative lactic acid producing bacteria (LB), 2) heterofermentative lactic and acetic acid producing bacteria (LB+), 3) molasses, 4) molasses and LB (MLB), 5) molasses and LB+ (MLB+), and 6) no inoculant (control). Silage mixes plus inoculants were made in triplicate, vacuum sealed in plastic bags, and ensiled for 60 days at 25°C. Once bags were opened, 200 mg air-dried of each silage treatment were incubated in 14 mL of buffering media and 4 mL of rumen inoculum. Each incubation spanned for 48 h with gas production measured at 0, 2, 4, 8, 12, 18, 24, 36, and 48-h post-incubation. Total gas production (TGP), pH, ammonia and total volatile fatty acids (VFA) were determined. Ammonia concentrations were greater when samples were inoculated with LB, and the least for MLB+ (P < 0.05); however, no differences were observed between silage mixes (P > 0.05). Total VFA concentrations were similar across treatments (P > 0.05). However, butyrate was greater for 33SB silages mixes inoculated with MLB (P > 0.05). Valerate concentration was greater for all treatments inoculated with molasses (P < 0.001). Isobutyrate and Isovalerate concentrations were only different when comparing between silage concentrations, where 0SB silages had the greatest concentration (P < 0.05). Although no differences were observed on TGP (P > 0.05), pH of samples incubated with no inoculant, LB, and LB+ were higher than all samples inoculated with molasses (P < 0.001). In conclusion, the use of mixed grass and legume silages with up to 33% soybean inclusion appears to be beneficial to ruminal fermentation. However, variable results might be produced depending on the inoculant used. The incorporation of these cover crop varietals and their subsequent inclusion in silos for livestock feed represents a viable and effective application for producers currently utilizing cover crops in their operations. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of hemp varieties and cannabidiol (CBD) concentrations on in vitro ruminal microbiota diversity and abundance relative do alfalfa (Medicago sativa). Two ruminally cannulated Angus steers were used as inoculum donors for in vitro incubation. Two 160-mL serum bottles containing 200 mg air-dried of either alfalfa, fedora 17 (F17) and felina 32 after late harvest (F32S) or without seeds (F32O) were incubated in 14 mL of buffering media and 4 mL of rumen inoculum. A stock solution of 1mg/mL of CBD was prepared and added in increasing concentrations into each bottle to reach a final concentration of 0.001%, 0.002%, 0.003%, and 0.004% of CBD. After a period of 48 hours, the whole content inside of the serum bottles was used immediately for DNA extraction followed by 16S rRNA sequencing with an Oxford Nanopore technologies MiniON. Amplicon sequence data were bioinformatically processed in QIIME2 version 2022.2. Alpha diversity was measured by the Shannon diversity index. Bray-Curtis's dissimilarity matrix was constructed to estimate the differences among the samples and CBD levels, and differential abundance was then evaluated using analysis of compositions of microbiomes with bias correction (ANCOM) testing. Statistical significance was established at P < 0.05. All data were visualized in R version 4.1.2 (R Core Team, 2022) using the qiime2R package. Shannon diversity index was the highest for alfalfa (P < 0.05), but no difference was observed among the different CBD inclusion levels. When looking at beta diversity through Bray-Curtis, differences were only observed when comparing the different alfalfa and hemp varieties (P < 0.05), where alfalfa grouped separately from all the hemp samples. The most abundant phyla included Firmicute, Bacteroidetes, Proteobacteria, and Fusobacteria (P < 0.05). At family level, alfalfa samples had greater Aerococcaceae and Enterobacteriaceae than all the hemp treatments, but less Lactobacillales (unclassified), Streptococcaceae, Succinivibrionaceae, and Bacilli (unclassified) than F32S and F17 (P < 0.05). In conclusion, these results suggest that sample type might play a larger role on microbiome than CBD lconcentrations. Further studies are required to determine if greater concentrations of CBD than those examined herein could also lead to a shift on rumen microbes. [ABSTRACT FROM AUTHOR]

Understanding and mapping the specific effects of smoke inhalation on cattle performance provides strategic insights for producers and policy makers to better prepare or adjust when faced with sporadic or even seasonal reductions in air quality. As of now, no current studies have attempted to investigate the effects of seasonal fires on performance and health adequately in livestock while addressing obvious confounding effects, controlling exposure, and examining fuel for differential oxidative radicals and particulate smoke. Herein, we propose the design of the first cost-effective controlled system for investigating smoke, particulate matter, and varied oxidative radicals through a premixing chamber. The mask main body is constructed from 8" nominal diameter schedule 40 PVC pipe. The endcap was designed in an online CAD software to provide an interface for standard 2 7/8" bulkhead fittings and was produced via additive manufacturing (3D printing). A silicone SCUBA neck seal was used to line the face orifice and is the component that directly contacts the animal's nose and mouth. A neoprene rubber sheet and an insulation hose were used as padding under the silicone seal to help maintain an airtight connection and animal comfort when the mask is worn. Bulkhead fittings used provide 1 1/2" female national pipe thread connection to allow for modular connection of inlet and outlet hoses, check valves for airflow isolation, filters, or any number of connections can be made via these gasket sealed fittings, making this platform extremely adaptable. In its shown configuration, 3D printed adapters were made to attach 4" suction hose to 2" socket union joints for quick connect/disconnect functionality. An inlet and outlet gas/smoke flow regulator are attached to a mixing chamber where particulate and chemical composition sensors are utilized to deliver the desired composition of smoke delivered to the animals. Negative pressure fans and pumps regulate the flow to the animals and are utilized for exposure of smoke in time-specific intervals. An additional fully 3D printed version enables the mask design to be lower in weight through regulation of the density of the internal matrix, and after an initial investment in the equipment also represents a cost-efficient approach to generating multiple masks. Understanding the effects of particulate and reactive oxidative molecules on livestock health and performance requires the study of a controlled exposure, the system presented herein represents a viable and cheap alternative for bettering a mechanistic model and understanding of the effects of smoke on animal health and performance. Ultimately, the proposed mask paired with currently available sensors permit for the controlled exposure of smoke particulate with different chemical compositions for accurate evaluation of prolonged exposure effects on livestock. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate how the previous nitrogen levels (PNL) in the diet might affect nitrogen balance and nitrogen-related genes in the rumen of either forage-fed or grain-fed steers during finishing. Twenty-four crossbred Angus steers were randomly distributed into one of two backgrounding nutritional plans: moderate (MP; crude protein (CP): 9.10%) or high (HP; CP:12.6%). After 85 d, animals were blocked by PNL, transitioned, and fed a finishing diet for 105 d, which consisted of either alfalfa only (forage-fed; CP: 21.3%) or predominantly whole grain (grain-fed; CP: 10.8%). Feed, orts, feces, and urine samples were collected in both phases. By the end of the finishing phase, animals were slaughtered, and ventral sac rumen tissue was collected. Gene expression of Aquaporins (AQP) -3 and -7, and UT-B from rumen tissue were assayed via real-time qPCR; 18S rRNA was used as an endogenous control. Animals on MP diets excreted less N through urine (P < 0.01) and feces (P < 0.01), while retaining more N (P < 0.01), which resulted in an increased N efficiency (P < 0.01) compared with HP animals. No differences were observed for microbial N production (P > 0.05). Grain-fed animals consumed less N (P < 0.01), but still had a greater amount of N being digested compared with forage-fed animals (P < 0.01), as well as the least excretion of N through feces (P < 0.01) and urine (P < 0.01), and consequently a greater rate of N being retained (P < 0.01) and a greater efficiency on utilizing the ingested N (P < 0.05). Further, an interaction was also observed between treatment and PNL, where animals coming from a MP had the least dry matter intake, greatest amount of N being digested and least N excretion, fecal output, and excretion of N through the feces (P < 0.05) when finished on a grain-based diet. In the rumen, steers coming from a low PNL that were finished as forage-fed, had the greatest expression of AQP7, with no statistically significant differences observed for the other groups. When comparing only animals backgrounded on MP, AQP7 (P < 0.01) expression was greater in forage-fed animals, with a trend for greater expression of UT-B in grain-fed animals (P < 0.1). Overall, these results indicate that animals receiving MP will reduce their excretion of N while producing the same amount of microbial N due to more efficient N recycling. Further, carried-over effects were also observed after these animals were transitioned to grain-fed finishing systems. In the rumen, PNL affects expression of AQP7 and UT-B, which may ultimately impact nitrogen metabolism, since both genes are also related with urea transport. [ABSTRACT FROM AUTHOR]

Identifying causal relationships on a large-scale system is highly complicated, and when not careful, statistical theories may be violated, and biological spurious claims generated. The causality between livestock health/performance and wildfire smoke has not been investigated. To critically evaluate the effects of wildfire, air quality data was obtained and validated with sensors (1.6 km from feedlot) before analyses. Herein, we examine the influence of environmental quality parameters effects on dry matter intake (DMI), body weight (BW), water intake (WI), and average daily gain (ADG) over a period of three years in Reno, Nevada. The datasets comprised represented controlled no-smoke exposure instances and days with air quality indexes (AQI) as high as 453 (hazardous). The dataset consisted of over 10,000 observations with daily mapping of WI, DMI, ADG, and BW. To evaluate the potential relationship between air quality and animal performance, variable tree length Bayesian additive regression trees (BART) were utilized to investigate the relationships between AQI, particulate matter (PM) 2.5 um and 10 um, NO2, SO2, ozone, and CO levels in the air were utilized as covariates for BART. All statistical analyses were performed on R Statistical Software (R Core Team 2022), with use of the bartMachine package. The correlation values (), 95 % confidence intervals (CI), root mean squared error (RMSE), and coefficient of determination (r2) are reported. A significant correlation was detected between the environmental parameters and BW, (= 0.863, CI = [0.849, 0.877], P > 0.001, r2 = 0.75, RMSE = 51.27) with PM2.5 and PM10 being the most included parameters in the regression trees. For WI, correlation was also significant (= 0.447, CI = [0.402, 0.490], P < 0.001, r2 = 0.20, RMSE = 14.57), the most included variables on the regression trees were the 10-um particulate matter followed by the CO. For DMI (= 0.727, CI = [0.700, 0.752], r2 = 0.53, RMSE = 2.58) PM10 and AQI were the most important inclusion proportion parameters. Similarly, for ADG (= 0.354, CI = [0.305, 0.401], r2 = 13, RMSE = 1.60) with ozone and PM10 being the most included parameters. In conclusion, our results more carefully examine relationships between smoke parameters and livestock performance. Uncertainty of relationship estimates, and variable importance highlights how performance parameters are differently affected by different environmental parameters highlighting the need for experiments with controlled exposure through time. [ABSTRACT FROM AUTHOR]

Target grazing has exhibited itself as an effective method of invasive weed mitigation across degraded rangelands in the Great Basin. Additionally, if the seeds of target species are supplemented into the diets of ruminants, they can serve as vectors for the dispersal of native seed species through fecal pats, which may prove to be a useful tactic for rangeland rehabilitation. However, a challenge associated with seed supplementation, is that the seeds of many target species are sufficiently degraded in the rumen. Therefore, the aim of this study was to evaluate the effects of seed coating technologies on germination rates post ruminal in vitro incubation. In vitro incubations were performed on seven species of seeds pertinent to the Great Basin: Achnatherum hymenoides (ACHY), Achillea millefolium (ACMI), Agropyron cristatum (AGCR), Atriplex canascens (ATCA), Elymus elymoides (ELEL), Pseudoregneria spicata (PSSP), and Sphaeralcea grossulariifolia (SPRT) uncoated (control) or coated with either Polyvinylpyrrolidone (PVP) or PVP+ ethocel, as well as uncoated Bromus tectorum (BRTE) seeds. A Daisy II incubator (Ankom Technology, Macedon, NY) was used for the in vitro analysis with rumen inoculum from two rumen-cannulated crossbred Angus steers (body weight = 910.5 ± 34.5 kg) and a buffer ratio of 1:4. Two F57 filter bags containing 1 g of seeds per treatment (control, PVP or PVP+ethocel) were then placed inside of the Daisy II incubator and kept at 39°C for 12 and 24 h for the control treatments, and for 12, 24, and 48 h for the PVP and PVP+ethocel coating treatments. For uncoated seeds, ACHY germination by 24 h was greater when compared with 0 h (P < 0.05), whereas ATCA germination rate decreased linearly by 12 h (P < 0.05). No differences were observed over time on germination rates of BRTE, as well as all of the other uncoated seeds (P > 0.05). When seeds were coated with PVP, ATCA germination rates started to linearly decrease by 12 h (P < 0.05), whereas PVP coated ACMI germination rates only started to decrease by 24 h (P < 0.05). The germination rates of PVP coated ELEL and PSSP seeds only started to significantly decrease by 48 h (P < 0.05). When coated with PVP+ethocel, the observed germination rates were similar to those observed for PVP coated seeds. However, when compared with uncoated seeds, coating with PVP+ethocel seem to decrease germination rates of ACMI and ATCA by 0 h (P < 0.05). No changes on germination rates were observed over time for coated and uncoated AGCR and SPRT (P > 0.05). In conclusion, seed germination rates after in vitro incubation were not increased by coating the seeds with PVP or PVP+ethocel. [ABSTRACT FROM AUTHOR]

The widespread growth in microbreweries presents a unique byproduct in spent brewer's grains (SBG). However, incorporation of SBG into livestock production systems requires further consideration due to potential variety in end-products due to beer styles and beer makers. Herein, we aim to characterize and cluster SBG according to nutritional composition to determine if nutrient composition groups in SBG are of nutritional and environmental concern. A total of five breweries with over twenty-nine SBG were collected for a period of three years in Reno, Nevada. Proximate chemical analysis and long chain fatty acid (LCFA) analysis were performed on all SBG. A hierarchical clustering (HC) of principal components (PC; HCPC) was performed on the nutrients to characterize maximum variation explainable through PC, followed by grouping of varietals on the multivariate axes through HC. A Ward's Linkage with scaled Euclidean distance was utilized for the HCPC. The greatest variance in the nutritional groups was explained through the first two PC (PC1, PC2). For PC1, non-fibrous carbohydrates had correlation values of 40.34% (-0.98), neutral detergent fiber assay with heat stable amylase and expressed exclusive of residual ash and protein (apNDFom) 30.39% (0.73), ether extract 17.32% (0.64) and crude protein (CP) 11.94 % (0.53). For PC2, the nutrient correlations were CP 74.26% (0.81) and apNDFom 23.77% (0.21). Ultimately, the variance explained in the PC represents energy (PC1), and protein (PC2). For the HC on the PC, four main clusters were obtained. For the PC generated from the LCFA, there were no superficial patterns detectable along the multivariate space. The distribution into the clusters represent an overlooked reality when considering SBG as livestock feed highlighting the need for a better classification of the varietals as livestock feed. Better classification of SBG will allow producers to better utilize the feed to maximize both productivity and reduce potential nitrogen runoff. [ABSTRACT FROM AUTHOR]

As freshwater sources continue to deplete, federal policy will likely marginalize water distribution towards agricultural communities more harshly. This ever-limiting resource highlights the significance of proactively improving quantification and water utilization of livestock operations. The goals herein investigated the effects of long-term implants on animal performance and water footprint. Eighteen crossbred F1 Angus x Hereford steers were randomly assigned to implanted (IMP; n = 9) or non-implanted (NIMP; n = 9) groups in two pens equipped with individual feeding gates and four RFID-automated water intake and body weight scales for a period of 135d. Steers were fed the same finishing diet across groups (400 g/kg alfalfa hay, 402 g/kg ground corn, 161 g/kg ground barley, 23.4 g/kg soybean meal, 10.8 g/kg mineral mix, and 2.7 g/kg limestone). Water footprint was classified as green, blue and grey (rainwater, surface/groundwater, and waste/contaminated water, respectively). Statistical analyses were performed on R Statistical Software following a linear mixed model methodology with the implanting treatment as a fixed effect and animal as a random effect to the intercept. Overall, expected increases in feed efficiency and performance were observed on this experiment where implanted animals had greater carcass weights (p < 0.0001), average daily gains (p < 0.0001), and body weights (BW; p = 0.001) all while consuming less feed by unit of BW (p < 0.0001). With regards to water, the implanted animals consumed less water per kilogram of body weight gain (p < 0.0001). No differences were observed for water footprint evaluations in this experiment (p > 0.5). These results highlight that genetic and metabolic mechanisms regulating feed efficiency on implanted animals may also regulate water efficiency directly or indirectly, and therefore, further warrants the investigation of these pathways in future research. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate how the background diet can affect the feedlot performance and carcass characteristics of finishing steers. Crossbred Angus steers (n = 24; 298.01 ± 10.17 kg) were fed either a low plane of nutrition (LP, n =12; triticale only, 91g/kg CP, 0.25Mcal/kg NEm, and 0.10Mcal/kg NEg) or adequate plane of nutrition (AP, n =12; 850g/kg alfalfa and 150g/kg beardless wheat, 126.2g/kg, 0.25Mcal/kg NEm, and 0.13 Mcal/kg NEg) during the background phase (85d). After this period, body weight (BW) of LP (362.81 kg ± 10.237) was less than the BW of AP (405.97kg ± 10.237). Animals were then transitioned to a finishing diet (800 g/kg whole corn and 200 g/kg alfalfa; 108 g/kg, 0.97Mcal/kg NEm, and 0.65 Mcal/kg NEg) and fed for 105d. Water intake (WI) and dry matter intake (DMI) were individually measured daily. Animals were then havested, and hot carcass weight (HCW) was obtained. Carcasses were chilled for 24 h, and qualified personnel measured longissimus dorsi area via direct grid reading between the 12th and 13th rib, USDA marbling score and yield grades. Differences amongst treatments were compared via orthogonal contrast using the GLIMMIX procedure of SAS (version 9.4). No differences were observed for WI, DMI, final BW and average daily gain among groups. Carcass characteristics such as HCW, yield grade, rib eye area, and dressing percentage were also similar between groups. On the other hand, animals previously on LP had a reducedr marbling score (421.11) than the AP treatment (493.21) (P = 0.0014). Therefore, even though the previous plane of nutrition did not affect intakes, performance, and carcass characteristics, the decreased amount of nutrients during the background decreased marbling of LP animals, which affects the final quality grade of the carcass as well as price per kg of carcass. [ABSTRACT FROM AUTHOR]

Water footprint (WF) of livestock can be manipulated to improve water use efficiency. The dynamics of water use by Holstein nursing bull calves (HBC) is not very well stablished. The physiological and anatomical status of HBC permits for precise-diet manipulation aiming to decreasing voluntary water intake (WI); however, WI mitigation raises concerns about potential adverse effects on hydration and health. The goals herein involve investigation of the effects of two isoenergetic supplements top-dressed on ad libitum non-medicated milk-replacer (MR) on health, hydration, and WF of HBC. A total of 23 HBC weighing 94.67 ± 12.07 kg, 2 months old, were distributed in a completely randomized design receiving one of three diets for 67 days: control (CON; n = 7) received MR only, the lipid (FAT; n = 8) received MR supplemented with fish oil (3%), and the carbohydrate (CHO; n = 8) received corn starch (7%). All animals were offered mineral mix and water ad libitum, and 120 g daily dried brewer's spent grains. Data were analyzed with the GLMMIX procedure of SAS 9.4 with diets as fixed effect. The WF was significantly decreased for the CHO group (P < 0.01). When WF values were adjusted by cold carcass weight (CCW), the CHO and FAT groups displayed a 100 L decrease in WF values compared to the CON. Though statistically significant differences were observed for Neutrophil count, lymphocyte count, and their ratio (NLR, as well as for total protein and fecal fluidity score (P < 0.05), the observed ranges were within healthy thresholds for HBC. Skin hydration was assessed through use of a skin moisture meter which resulted in the CHO group having significantly higher skin capacitance of 5.30 compared to CON = 3.76, and FAT= 3.99. These results evidence the possibility of increasing water use efficiency with precision diet formulation without adverse health and hydration effects. [ABSTRACT FROM AUTHOR]