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Enterocytes are the major cell lineage of the small intestinal epithelia along the crypt-villus axis in gut mucosa. Enterocytes participate in the gut terminal nutrient digestion and absorption; and have essential roles in nutrient and metabolite recycling and efflux, nutrient and hormonal sensing, interactions with symbiotic microbiome and binding to infectious viruses, thus influencing the host homeostasis and whole-body physiological status. Intestinal membrane vesicles have been widely used for studying various gut functions in the past several decades. Villus enterocytic brush border membrane and the apical membrane vesicles along the crypt-villus axis in gut mucosa can be prepared and isolated by Mg²+- and Ca²+-precipitation and differential centrifugation procedures. Whereas, gut mucosal basolateral membrane vesicles can be prepared, fractionated and differentiated from other intracellular organelles such as the mitochondrial inner membrane by the Percoll gradient ultracentrifugation. Nutrient transport and exchange activities in the membrane vesicles in vitro are conducted often by rapid hand filtration, and in excess, in an automated fast sampling apparatus. Nutrient transport and exchange activity kinetics are derived according to the wellestablished classic Michaelis-Menten and the tracer inhibitory kinetic models with a simple linear diffusional component. Physiological and biochemical properties associated with various nutrient uptake systems such as pH optimum, requirements for co-transported ions (e.g., Na+, K+, Cl- ), transporter affinity and substrate specificity can be effectively investigated in vitro with the membrane vesicles by altering the compositions of uptake buffers and intra-vesicular pre-loading buffers. Some of the fundamental gut functions are established via using the membrane vesicles in different mammalian species. And these include H+-peptide cotransport, Na+-cotransport and Na+-independent systems of hexose uptake across the apical membrane and the low-affinity Na+-independent hexose bidirectional uptake across the basolateral membrane that were characterized in rodents; Na+-dependent cotransport and Na+-independent systems of amino acid (AA) transport across the apical membrane that were revealed in rodents and pigs; as well as the Na+-hexose and AA cotransport and the co-expression of the coronavirus SARS-CoV-2 host epithelial apical membrane binding receptor, i.e., the angiotensin-converting enzyme-² (ACE2), along the gut crypt-villus axis that were identified in liquid formula-fed piglets. In the post genomic and metagenomic sequencing era, further research efforts need to pursue understanding of expression and various functionality of the gut terminal hydrolases, nutrient transporters, nutrient exchangers, nutrient sensors, substrate and particle receptors, taste receptors, viral binding receptors such as ACE² and hormonal receptors and their interactions with luminal factors such as nutrient, metabolites, symbiotic bacterial outer membrane vesicles etc., along the longitudinal and crypt-villus axes, through using the mammalian primary enterocytic apical and the basolateral membrane vesicles under various research settings. [ABSTRACT FROM AUTHOR]

The adaptation of animals to highconcentrate diets is crucial for optimizing performance in the finishing phase. However, the transition to concentrate-rich diets can lead to metabolic disorders and fluctuations in feed intake. Typically, the same adaptation protocol is used regardless of the previous feeding history of the animal. However, it is possible that the backgrounding period duration may influence initial feed intake and subsequently affect animal performance in the finishing phase. Thus, the objective of this study was to evaluate the effects of implementing different high-forage backgrounding (HFB) durations on daily dry matter intake (DMI) and DMI variance over a 28-d period following the 14-d step-up adaptation to the finishing diets of Nellore bulls. Young Nellore bulls [n = 36; average initial body weight (BW) = 265.25 ± 5 kg; age = 7 ± 1 mo] were used in a completely randomized design and assigned to one of four treatment groups (n = 9/group): 0 (HFB), 28 (HFB28), 56 (HFB56), or 84 (HFB84) d of HFB before starting the 14-d step-up adaptation period to the finishing phase. The HFB diet consisted of 800 g/kg of sorghum silage and 200 g/kg of concentrate, while the finishing diet contained 200 g/kg of corn silage and 800 g/kg of concentrate. The diets were formulated according to BR-CORTE (2016) to achieve ADG of 0.4 kg/d during the HFB phase and 1.2 kg/d during the finishing phase. All animals were fed for ad libitum intake in an electronic feeder (INTERGADO, Intergado Ltd., Contagem, MG, Brazil), and individual daily feed intake was recorded. Additionally, DMI variance was calculated for each bull from daily DMI data over the 28 d of the finishing phase after the 14-d step-up period. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) assuming the significance level of 0.05. The Tukey test was employed to compare means. Daily DMI was analyzed as repeated measures. The HFB duration had no influence on average DMI of the first 28 d of the finishing phase (P = 0.10; Averages per treatment (kg/d): HFB0 = 7.34, HFB28 = 6.53, HFB56 = 6.71, HFB84 = 6.02). However, a significant interaction was observed between treatments and day on finishing phase (P < 0.001), indicating that the effects of different HFB duration may vary over time during the finishing phase, influencing the daily DMI. Furthermore, the HFB84 presented a higher DMI variance, while the remaining treatments did not differ significantly among themselves (P < 0.001; Averages per treatment: HFB0 = 0.927, HFB28 = 0.616, HFB56 = 0.980, HFB84 = 3.487). In conclusion, the HFB84 increased the variation in daily DMI after adaptation to the finishing diet, indicating that a longer adaptation period may be needed for animals fed high-forage backgrounding diets for longer durations [ABSTRACT FROM AUTHOR]

Traditional heifer feeding strategies typically involve modest rates of body weight (BW) gain and include a relatively low proportion of concentrate feeds. In situations of limited forage or high feed costs, additional concentrates may be included in the diets and fed at a limited rate. High-concentrate diets can enhance the efficiency of nutrient utilization, alter characteristics of the gastrointestinal tract (GIT), and influence the composition of gain. The objective of this study was to evaluate the strategy of limit-feeding highconcentrate diets on feeding behavior, carcass characteristics, and GIT morphometrics in replacement beef heifers. Crossbred beef heifers (n = 20) began receiving either a high forage (75% forage:25% concentrate; HF, n =10) or high concentrate (25% forage:75% concentrate; HC, n =10) diet 74 ± 4 d before breeding. Heifers were inseminated with sexed male semen from a single bull. Individual intake and feeding behavior data were recorded using the Insentec Roughage Intake Control system, and heifers were weighed, and diet deliveries were adjusted every 2 wk to target a BW gain of 0.45 kg/d for both groups. Heifers were harvested at 180 d of gestation, where the viscera were removed, and weights of the full gastrointestinal tract, including the stomach complex, and small and large intestines were recorded. After removing digesta, weights of the empty gastrointestinal tract, rumen-reticulum, omasum, abomasum, small and large intestine, and mesenteric fat were recorded. Carcass characteristics were assessed 24 h after slaughter. Data were analyzed using the MIXED procedure of SAS, with heifer as the experimental unit. No differences were observed in final BW, average daily gain, or body condition score (P ≥ 0.18) between treatments (Table 1). Reflecting that HC heifers were limit-fed to a greater extent than HF heifers, therefore, dry matter intake, number of meals, visits to the feed bunk, time spent eating, and time per meal were less in HC heifers than in the HF group (P ≤ 0.001). In contrast, HC heifers had greater (P ≤ 0.001) eating rates of DM per minute, per visit and per meal compared with HF heifers. Though no differences were observed in back (P = 0.31) or rib fat (P = 0.37), HC heifers had greater (P = 0.04) marbling score and tended to have greater carcass weight (P = 0.06) and ribeye area (P = 0.07) as compared with HF heifers (Table 2). Greater (P < 0.001) full weights of GIT and stomach complex, empty weight of rumen-reticulum, weight of total digesta, and digesta as a proportion of BW (i.e., fill) were observed in HF heifers. In contrast, HC heifers had greater (P < 0.001) weights of full small intestine and mesenteric fat than HF heifers. These findings demonstrate that, despite similar rates of gain, limit-feeding high-concentrate diets can alter the composition of weight gain, favoring fat, muscle, and GIT development, potentially altering dam efficiency throughout her productive life. [ABSTRACT FROM AUTHOR]

Ruminal methane (CH4) emission from cattle represents about 2 to 12% gross energy loss and is considered as one of the main contributors to the greenhouse gas emissions by the livestock industry. Recent multiple lines of research indicated that maternal gut microbiome may influence offspring ruminal CH4 emission phenotype via potential influence on fetal programming and transmission of methanogens from the dam to calf perinatally. Our objective was to evaluate the effects of altering maternal microbiota via feeding high forage (HF) and high concentrate (HC) diets during the entire gestation on the maternal ruminal CH4 emissions in beef heifers. For this, Crossbred replacement beef heifers (n = 61) bred with male sexed semen were randomly assigned into two groups and were fed either a high forage (75% forage:25% concentrate; HF, n = 29) or high concentrate (25% forage:75% concentrate; HC, n = 32) diet with limited feed intake to gain 0.45 kg/d during the gestation. Individual feed intake was monitored and body weight (BW) were measured bi-weekly and diet deliveries were adjusted to ensure the target BW gain. A subset of pregnant heifers (n = 10 per treatment group) was harvested at 180 d of gestation. Ruminal fluid was collected by stomach tubing on d 180 (20 heifers slaughtered), d 238 of gestation, and at the postpartum (within 3 h of calving). The ruminal fluid was placed in 15 mL falcon tube, kept in a warm thermos and immediate processing for the in vitro CH4 production assay. About 12.5 mL of ruminal fluid was placed into separate 120 mL serum bottles each containing 0.62g of feed (HC or HF diet) and 50 mL of McDougall buffer under CO2 infusion before the bottle sealed with stoppers. The cultures were incubated at 39°C for 24h. Immediately after incubation, total biogas production, headspace CH4 concentration (using Gas chromatography), and pH of the 24 h culture was measured. Overall, the mean total volume of gas produced over 24 h was not statistically different (P > 0.05) between HF and HC heifers at any of the day measured, although it was numerically greater on d 238 (219 vs. 197 mL) and at postpartum (246 vs. 219 mL) in HC than HF heifers. Methane concentration in per milliliter gas was ranged between 13.3 and 16.3% but was not different between HF and HC heifers on any of the day evaluated (P > 0.05). Total volume of CH4 gas produced over 24 h was tended (P = 0.067) to be greater in HC heifers on d 238 (37.5 vs. 25. 7 mL). The culture pH from the ruminal fluid of HC heifers was less on d 238 (6.08 vs. 6.57) and at postpartum (P < 0.05). Overall, in vitro ruminal CH4 was not different in the ruminal fluid of HF and HC pregnant heifers. [ABSTRACT FROM AUTHOR]

Despite the increased appreciation of the involvement of maternal nutrition in fetal development, its effects on jejunum programming remain largely unexplored. Here, we investigated the impact of maternal vitamin and mineral supplementation throughout gestation on the differential gene expression and underlying biological pathways in the jejunum of neonatal calves. For this, beginning 60 d before breeding and continuing throughout gestation, crossbred Angus heifers (n = 14) were fed either a basal diet (CON; n = 7) or the basal diet plus 113 g•heifer-1•d-1 of VTM supplement (VTM; n = 7). All heifers were gestating female calves, which were euthanized 30 h after birth. Samples of jejunum mucosa were collected, stored at -80°C, then subjected to total RNA isolation and RNA sequencing. After quality control, the reads were mapped using STAR aligner and differentially expressed genes (DEGs) were identified using DESeq2. Maternal VTM supplementation did not affect calf organ mass, including jejunum weight. However, high-resolution respirometry analysis revealed greater mitochondrial efficiency in jejunum of calves from VTM supplemented dams. Additionally, we identified 528 DEGs between the VTM and CON calves (P-value ≤ 0.05 and |log2FC| > 0.5). Among them, the genes IGFBP2 and IGFBP6, which are key genes in insulin pathway and involved in regulation of insulinlike growth factors (IGF), IGF transport, and uptake, were upregulated in the VTM group. Additional pathways were identified using ShinyGO, which included the pancreatic secretion pathway, over-represented by genes such as PLCB1, CCK, and SLC26A3. The gene PLCB1 has been associated with feed efficiency, growth, and carcass traits in multiple species. Likewise, the SLC26A3 gene encodes a key intestinal chloride anion exchanger associated with enhanced feed efficiency in cattle. Genes encoding signaling molecules involved with immune response, T cell activation, and defense response were also among the DEGs upregulated in the VTM calves, including the TNFSF18 and TNFRSF4 genes. Our findings suggest that maternal prenatal vitamin and mineral supplementation throughout gestation affects the expression of genes involved in the jejunum function of offspring at a neonatal time point. The long-term consequences of these changes, however, warrant further investigation. [ABSTRACT FROM AUTHOR]

Vitamins and minerals have key roles in hormone production and action, enzyme activity, tissue synthesis, oxygen transport, and energy production. These micronutrients are efficiently transferred from the dam to the fetus during gestation to be partitioned for metabolic use and stored as postnatal mineral reserves. Maternal nutrient intake is one of the main factors that influence the availability of vitamins and minerals to the fetus. Thus, an inadequate supply of these critical nutrients can have a long-lasting impact on offspring growth and health. Evidence suggests that biological processes regulating normal growth, development, and nutrient utilization are programmed in utero, even during the earliest developmental stages. Therefore, there is a critical need to evaluate the effects of micronutrient supplementation during gestation on fetal physiology and metabolic programming. Our research group has developed research models examining the impact of maternal vitamin and mineral supplementation (VTM, supplemented vs. NoVTM, not supplemented) during the periconceptual period or throughout gestation in beef heifers. A metabolomic analysis revealed that metabolites in the oxidative phosphorylation pathway were more abundant in the liver of fetuses from VTM than NoVTM dams, suggesting that a greater supply of micronutrients during the periconceptual period and first trimester of pregnancy may positively modulate mitochondrial energy metabolism in offspring. These changes in the abundance of metabolites suggested physiological adaptations to meet fetal metabolic needs. Further, high-resolution respirometry analysis revealed greater efficiency of energy utilization in small intestinal samples of neonatal calves from VTM dams. In fact, VTM offspring were heavier from weaning to breeding phase than NoVTM offspring, suggesting that maternal nutrition affects physiological mechanisms in utero that modulate offspring energetics and efficiency of nutrient utilization in the postnatal period. Furthermore, we reported increased concentrations of histidine, aspartate, and 12 out of 14 neutral amino acids in the allantoic fluid of VTM-supplemented dams. Finally, genes involved with amino acid transport in fetal liver were upregulated in response to VTM supplementation, highlighting the intricate relationship between maternal and fetal nutrition. Vitamin and mineral supplementation were also associated with changes in gene expression, biological processes and pathways in placental tissue at d 83 of gestation. We observed an upregulation of genes in the calcium signaling and cyclic guanosine monophosphate (CGMP)-PKG signaling pathways in response to micronutrient supplementation. Calciummediated systems may modulate cell proliferation and steroidogenic activity in bovine placentomes, while CGMP-PKG plays a key role in vascular homeostasis. Placental blood vessel vascularity at term was indeed increased in heifers supplemented throughout gestation, emphasizing the importance of micronutrient supplementation beyond early pregnancy. Altogether, our findings suggest that vitamin and mineral supplementation in the periconceptual period and during gestation play a pivotal role in fetal metabolic programming with consequences extending to the postnatal period. [ABSTRACT FROM AUTHOR]

The relationship between weather variables and dry matter intake (DMI) in beef steers was examined using daily intake data from 790 beef steers collected through a computer-controlled feeding system in nonsummer months. Daily data were condensed into weekly averages (N  = 13,895 steer-weeks). The variables considered to predict DMI (2.50 to 23.60 kg/d) were body weight (197 to 796 kg), dietary net energy for maintenance (NE m ; 0.79 to 2.97 Mcal/kg), ambient temperature (−23.73 °C to 21.40 °C), range of temperature (2.79 °C to 19.43 °C), dew point (−27.84 °C to 14.34 °C), wind speed (2.08 to 6.49 m/s), solar radiation (30.8 to 297.1 W/m2), and 2-wk lag (average of previous 2 wk's values) and monthly lag (average of previous 4 wk's values) of each weather variable. Toeplitz variance-covariance structure for repeated measures was used to determine the model to predict DMI, while accounting for the effects of body weight, dietary NEm, and other variables in the model. Two-week lag of ambient temperature interacted (P  ≤ 0.005) with 2-wk lag of range of temperature, monthly lag of wind speed, 2-wk lag of solar radiation, and dew point to predict DMI. Interactions (P  = 0.0001) between 2-wk lag of range of temperature vs. dew point and monthly lag of wind speed vs. 2-wk lag of solar radiation were also detected. This study reports important weather variables associated with differences in DMI of growing and finishing steers and will help improve the accuracy of DMI prediction equations for beef cattle. Improvements in the accuracy of predicting DMI should give producers better tools to plan and execute efficient feeding management programs. The R2 of the overall model was 0.8891. [ABSTRACT FROM AUTHOR]

Five ruminally and duodenally cannulated red angus steers (n = 5; initial body weight [ BW ] = 542 kg, SD = 40 kg) were used in a three-period Youden square design consisting of three 21-d periods, three treatments, and five steers (one or two steers per treatment within each period) to evaluate the effect of feeding hempseed cake on ruminal fermentation parameters, organic matter (OM) intake, total tract nutrient digestion, and nitrogen (N) balance in steers fed finishing diets. The control (CON) diet contained 75% dry-rolled corn, 20% corn silage, and 5% supplement (DM basis). The dried corn distillers grains plus solubles (DDGS) and hempseed cake (HEMP) diets contained 55% dry-rolled corn, 20% corn silage, 20% dried corn distillers grains plus solubles or hempseed cake, and 5% supplement (DM basis). Total ruminal volatile fatty acid concentration was greater (P < 0.01) in steers fed the HEMP diet than in steers fed the DDGS or CON diets. Ruminal fluid pH was not influenced (P = 0.93) by treatment. Organic matter intake tended (P = 0.07) to be greater and OM total tract digestibility was less (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS or CON diets. Ruminal true and total tract apparent N digestibility was greater (P < 0.01) in steers fed the HEMP diet than steers fed the DDGS or CON diets. Duodenal flow of essential, nonessential, and total amino acids was not influenced (P ≥ 0.37) by dietary treatment, but the lack of response was likely because ruminally degradable protein (RDP) supply exceeded the RDP requirement. Steers fed the HEMP diet had greater (P < 0.01) N retention (g/d) than steers fed the DDGS diet, which was greater (P < 0.01) than steers fed the CON diet, suggesting that feeding hempseed cake improved utilization of N. Although inclusion of hempseed cake decreased total tract OM digestibility compared with dried corn distillers grains or corn, improvements in N utilization suggest that hempseed cake could be a useful alternative feed ingredient for finishing cattle diets. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to evaluate effects of postruminal flows of casein or glutamic acid on small intestinal starch digestion and to quantify changes in energy and nutrient balance. Twenty-four steers (body weight = 179 ± 4 kg) were duodenally infused with raw cornstarch (1.46 ± 0.04 kg/d) and either 413 ± 7.0 g casein/d, 121 ± 3.6 g glutamic acid/d or water (control). Measures of small intestinal starch digestion and nutrient excretion were collected across 4 d after 42 d of infusion and measures of respiration via indirect calorimetry were collected across 2 d after 48 d of infusion. Ileal starch flow was least among calves provided casein, but ileal starch flow was not different between glutamic acid or control. Small intestinal starch digestion tended to be greatest among calves provided casein, least for glutamic acid and intermediate for control. Casein increased ileal flow of ethanol soluble oligosaccharides compared to glutamic acid and control. Large intestinal starch digestion was not different among treatments. By design, N intake was greatest among cattle provided casein, intermediate among calves provided glutamic acid and least for control. Nitrogen retention was greater in response to casein compared to control and glutamic acid. Intake of gross energy from feed was similar across treatments, and gross energy from infusate was greatest for casein, intermediate for glutamic acid and least for control. Variation in gross energy intake from feed resulted in no difference in overall gross energy intake across treatments. Similar to measures of small intestinal starch digestion and N retention, casein increased calories of digestible energy and metabolizable energy, compared to glutamic acid and control, which did not differ. Postruminal infusions did not influence methane production, but heat production was greatest in steers infused with casein, intermediate for steers provided glutamic acid, and least for control. Overall, amounts of energy retained by casein tended to be nearly 34% greater than control, but glutamic acid had no impact on energy balance. Improvement in small intestinal starch digestion in response to casein increased energy and N retained; however, glutamic acid did not influence small intestinal starch digestion and energy or N balance in cattle, which seems to suggest that responses in small intestinal starch digestion to greater postruminal flows of glutamic acid become refractory across greater durations of time. [ABSTRACT FROM AUTHOR]

The nutrients required by cattle are influenced by body composition. Indirect methods, such as DXA scanning, have been used to predict lean, fat, and bone tissues without the need for carcass dissection. The rib section between the 9th and the 11th ribs (HH section, Hankins and Howe, 1946) is the most used section to estimate carcass chemical composition through DXA or other approaches. However, to facilitate application in commercial packing plants, alternative approaches need to be developed. We hypothesized that carcass chemical composition can be precisely estimated using DXA data from alternative sections that would be easier to accomplish in a commercial facility. Therefore, this study aimed to develop equations to predict the whole carcass chemical composition of crossbred bulls using DXA scanning a different carcass section. The carcasses from Red Angus x Nellore growing bulls (n = 24) receiving maintenance (n = 4), and the ad libitum (n =20) diets with 20:80 (forage:concentrate) on a dry matter (DM) basis with corn silage as the forage. After 24 h of chilling, the left half-carcass of all animals were weighed, divided into 3 sections. The sections were obtained considering the carcass was hanging by Achilles, as following: longitudinal cut after the second rib (S1), the HH section, and the remaining section after the removal of S1 and HH section. The S1 and HH sections were scanned in a medical DXA unit (GE Healthcare, Lunar Prodigy Advance, USA). The small animal configuration mode of the GE Healthcare enCORE software, version 18, was used for DXA. The DXA scanning provided data on fat, lean, and bone mineral content (BMC). After scanning, each section was dissected into fat, muscle, and bone. DXA variables of carcass sections were used to predict carcass chemical composition (EE, CP, and ash) using general linear regression models in RStudio software. To develop prediction equations based on the input variables, a leave-one-out cross-validation method was utilized. The precision of the predictions was assessed based on the coefficient of determination (R2 ), root mean square error (RMSE), and Akaike’s information criterion (AIC). The predictive equations of carcass chemical composition based on DXA measurements of the different sections are reported in Table 1. Prediction equations for S1 for CP, EE, and Ash content had lower RMSE and AIC values and a greater R² when compared with the equations based on the HH section. In general, all equations had relatively high precision. However, S1 may be better for predicting carcass chemical composition because of improved goodness of fit and because this section can be more easily collected in a commercial packing plant. Nevertheless, further studies are needed to improve accuracy and evaluate the equations using an independent dataset. [ABSTRACT FROM AUTHOR]

As the hemp industry continues to develop in the United States, there is an increasing 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 the 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 d, and every 14 d BW were measured and blood samples were collected. Blood plasma was analyzed for glucose, urea nitrogen, and individual amino acids, and results were 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 for 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 with 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, nonessential 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 net energy for maintenance and gain relative to DDGS when adequate metabolizable protein is supplied, while still providing adequate nutrition to support the acceptable performance of finishing cattle. [ABSTRACT FROM AUTHOR]

Six ruminally cannulated steers [475.0 ± 49.6 kg initial body weight (BW)] were used in a 6 × 3 incomplete Latin square design (six treatments and three periods), to evaluate the impacts replacing of corn silage with pelleted soyhulls as roughage in high-concentrate finishing diets containing 30% modified distillers grains with solubles. Treatments were based on increasing dietary inclusion of soyhulls and consisted of: (1) Control (0), roughage supplied by dietary inclusion of 20% corn silage [dry matter (DM) basis]; (2) 50% replacement of corn silage with soyhulls (50); (3) 100% replacement of corn silage with soyhulls (100), and the same three treatments repeated with 3% added wheat straw (DM basis) replacing corn in the diet (0S, 50S, and 100S, respectively). Absolute dry matter intake (DMI; kg/d basis) tended to decrease both linearly and quadratically (P ≤ 0.09) and proportional DMI (% of BW) decreased linearly (P = 0.04) with increasing soyhull inclusion but was not affected by the addition of straw in the diet (P = 0.68). Total tract digestibility of organic matter and crude protein were not affected by soyhull inclusion or added straw (P ≥ 0.32). Ruminal pH did not differ (P = 0.65) with increasing soyhull inclusion but increased with the addition of straw (P < 0.01; 5.9 vs. 6.1 for no straw and straw, respectively). Molar proportions of acetate and butyrate decreased while propionate increased with increased soyhull inclusion (P ≤ 0.03; linearly and quadratically, respectively). Ruminal fluid kinetics were unaffected by either rate of replacement of corn silage with soyhulls or wheat straw inclusion (P ≥ 0.13). Decreases in DMI observed in this study would likely decrease finishing cattle performance and underscores the need for additional research before recommending this practice to cattle feeders. [ABSTRACT FROM AUTHOR]

Sci. 101: skac402. doi: 10.1093/jas/skac402 Google Scholar Crossref Search ADS WorldCat 22 Troyer, B. C., E. J. Dennis, A. DiCostanzo, and G. E. Erickson. Graph The NCCC308 Multistate Research Coordinating and Information Exchange Group currently consists of members from 18 Agricultural Experiment Stations with a long and strong history in conducting applied finishing cattle nutrition and management research and Extension. Sci. 101: skac348. doi: 10.1093/jas/skac348 Google Scholar Crossref Search ADS PubMed WorldCat 15 Nickles, K. R., A. E. Relling, A. Garcia-Guerra, F. L. Fluharty, and A. J. Parker. NCCC308: Nutrition and Management of Feedlot Cattle to Optimize Performance, Carcass Value, and Environmental Compatibility - Feature Collection - Nutrition and Management of Finishing Cattle. [Extracted from the article]

The article focuses on grazer activity concentrated by rangeland management practice Patch-burn grazing (PBG) in burned patches within rangeland pastures. Topics discussed include livestock production through alteration of physiology of vegetation creating crude protein content, patch-burning increases mineral concentrated of forage in rangeland pastures and grazing cattle's mineral requirements.

Maternal nutrient restriction during gestation adversely affects offspring growth and development of liver and skeletal muscle tissues. Realimentation following nutrient restriction may alleviate these negative impacts on development but may alter metabolism and tissue composition. Forty-eight ewes, pregnant with singletons, were fed to meet 100% National Research Council (NRC) recommendations starting at the beginning of gestation. On day 50 of gestation, seven ewes were euthanized (BASE), and fetal liver, skeletal muscles, and blood samples were collected. The remaining animals were fed either 100% of NRC recommendations (CON) or 60% NRC recommendations (RES), a subset were euthanized at day 90 of gestation (n = 7/treatment), and fetal samples were collected. Remaining ewes were maintained on the current diet (CON-CON, n = 6; RES-RES, n = 7) or switched to the alternate diet (CON-RES, RES-CON; n = 7/treatment). On day 130 of gestation, the remaining ewes were euthanized, and fetal samples were collected. At day 130 of gestation, maternal nutrient restriction during late-gestation (RES-RES and CON-RES) decreased fetal liver weight (P < 0.01) and cross-sectional area in triceps brachii (P = 0.01; TB), longissimus dorsi (P = 0.02; LM), and semitendinosus (P = 0.05; STN) muscles. Maternal nutrient restriction during mid-gestation increased hepatocyte vacuole size at day 130 of gestation. Late-gestational maternal nutrient restriction increased mRNA expression of insulin-like growth factor (IGF) binding protein-1 (P < 0.01), glycogen synthase 2 (P = 0.01; GYS2), and pyruvate dehydrogenase kinase 1 (P < 0.01; PDHK1) in the liver and IGF receptor 1 (P = 0.05) in the LM. Lipid concentration in the LM was decreased by late-gestational nutrient restriction (P = 0.01) and increased by mid-gestational nutrient restriction in STN (P = 0.03) and TB (P < 0.01). Principal component analysis of lipidomics data demonstrated clustering of principal components by day of gestation and elastic net regression identified 50, 44, and 29 lipids that classified the treatments in the fetal liver, LM, and blood, respectively. In conclusion, restricting maternal nutrition impacts fetal liver and muscle morphology, gene expression, and lipid metabolism, whereas realimentation attenuated some of these effects. Therefore, realimentation may be a viable strategy to reduce the impacts of nutrient restriction, but can lead to alterations in lipid metabolism in sheep. [ABSTRACT FROM AUTHOR]

This experiment evaluated the influence of protein supplementation frequency (SF) and amount offered on intake, nutrient digestibility, and ruminal fermentation by rumen-fistulated beef steers consuming low-quality [2.9% crude protein (CP); dry matter (DM) basis], cool-season forage. Seven Angus × Hereford steers (300 ± 27 kg) fitted with ruminal cannulas were randomly assigned to 1 of 7 treatments in an incomplete 7 × 4 Latin square. Treatments, in a 2 × 3 factorial design plus a non-supplemented control (CON), consisted of 2 levels of supplemental soybean meal, 100% (F) or 50% (H) of the estimated rumen-degradable protein requirement, provided daily (D), once every 5 d (5D), or once every 10 d (10D). Experimental periods were 30 d and dry matter intake (DMI) was measured from days 19 to 28. On days 21 (all supplements provided) and 30 (only daily supplements provided; day immediately prior to supplementation for 5D and 10D treatments) ruminal fluid was collected for ruminal pH, ammonia-N (NH3), volatile fatty acids (VFA), and determination of ruminal fermentation variables. Forage and total DM, organic matter (OM), and nitrogen (N) intake increased with supplementation (P ≤ 0.04). However, a linear effect of SF × amount of supplement interaction was observed for forage and total DM, OM, and N intake (P ≤ 0.04), with each variable decreasing as SF decreased, but the decrease being greater with F vs. H. Apparent total tract DM, OM, and neutral detergent fiber digestibility was not affected by supplementation or amount of supplement provided (P ≥ 0.10). In contrast, N digestibility increased with supplementation and for F vs. H (P < 0.01). Digestibility of DM, OM, and N increased linearly as SF decreased (P ≤ 0.03). When all supplements were provided, ruminal NH3 , total VFA, and molar proportions of all individual VFA increased with supplementation (P ≤ 0.04), whereas acetate:propionate ratio decreased (P < 0.01). When only daily supplements were provided, none of the aforementioned fermentation parameters were affected (P ≥ 0.09). In summary, reducing the amount of supplemental CP provided to ruminants consuming low-quality forages, when supplementation intervals are >5 d, can be a management tool to maintain acceptable levels of DMI, nutrient digestibility, and ruminal fermentation while reducing supplementation cost. [ABSTRACT FROM AUTHOR]

Background Perhaps, as never before, we need innovators. With our growing population numbers, and with increasing pressures on our education systems, are we in danger of becoming more rigid and formulaic and increasingly inhibiting innovation? When young can we predict who will become the great innovators? For example, in medicine, who will change clinical practice? Aims We therefore determined to assess whether the current academic excellence approach to medical school entrance would have captured previous great innovators in medicine, assuming that they should all have well fulfilled current entrance requirements. Methods The authors assembled a list of 100 great medical innovators which was then approved, rejected or added to by a jury of 12 MD fellows of the Royal Society of Canada. Two reviewers, who had taken both the past and present Medical College Admission Test as part of North American medical school entrance requirements, independently assessed each innovator's early life educational history in order to predict the innovator's likely success at medical school entry, assuming excellence in all entrance requirements. Results Thirty-one percent of the great medical innovators possessed no medical degree and 24% would likely be denied entry to medical school by today's standards (e.g. had a history of poor performance, failure, dropout or expulsion) with only 24% being guaranteed entry. Even if excellence in only one topic was required, the figure would only rise to 41% certain of medical school entry. Conclusion These data show that today's medical school entry standards would have barred many great innovators and raise questions about whether we are losing medical innovators as a consequence. Our findings have important implications for promoting flexibility and innovation for medical education, and for promoting an environment for innovation in general. [ABSTRACT FROM AUTHOR]

Consumption of high-grain diets by cattle can result in large quantities of starch that flow to the small intestine for potential enzymatic digestion. However, small intestinal starch digestion is potentially limited because of insufficient activity of pancreatic and/or small intestinal carbohydrases. Studies suggest regulation of carbohydrase activity is complex in cattle and perhaps uncoordinated in response to luminal carbohydrate flow. The objective of this experiment was to use postruminal casein infusion and exogenous glucagon-like peptide 2 (GLP-2) administration, known stimulators of pancreatic and small intestinal function, to evaluate their effects on pancreatic and small intestinal carbohydrase activities. Twenty-four Holstein steers [250 ± 23 kg body weight (BW)] were used in a randomized complete block design with a 2 × 2 factorial arrangement of treatments. Steers were fed an alfalfa cube-based diet to limit dietary starch intake. Steers received a continuous abomasal infusion of 4 g/kg of BW of raw corn starch combined with either 0 or 1.33 g/kg of BW of casein for 7 d. Steers received subcutaneous injections in two portions daily of excipient (0.5% bovine serum albumin) or 100 μg/kg of BW GLP-2. This resulted in four treatments: control, casein, GLP-2, and casein + GLP-2. At the end of the 7-d treatment period, steers were slaughtered for pancreatic and small intestinal tissue collection. Data were analyzed using the GLM procedure of SAS. Postruminal casein infusion increased (P = 0.03) pancreatic mass by 12.6%, total pancreatic a-amylase activity by 50%, and postruminal starch disappearance from 96.7% to 99.3%. Exogenous GLP-2 increased (P < 0.01) total small intestinal mass and small intestinal mucosal mass by 1.2 kg and 896 g, respectively. Relative to control, GLP-2 and casein + GLP-2 treatments increased (P = 0.04) total small intestinal a-glucosidase activity (sum of maltase, isomaltase, glucoamylase) by 83.5%. Total small intestinal maltase, isomaltase, and glucoamylase activity was 90%, 100%, and 66.7% greater for GLP-2 and casein + GLP-2 steers compared with control. The use of postruminal casein infusion and exogenous GLP-2 administration resulted in four distinct carbohydrase activity phenotypes. Relative to control, casein increased pancreatic a-amylase activity, GLP-2 increased small intestinal a-glucosidase activity, and the combination of casein and GLP-2 increased both pancreatic a-amylase activity and small intestinal a-glucosidase activity. This approach provides a novel in vivo animal model to selectively increase endogenous carbohydrase activity to overcome complications of coordinating carbohydrase activity with luminal nutrient flows. This model could be useful to understand physiological mechanisms that might improve small intestinal starch assimilation and efficiency of cattle consuming high-grain diets. [ABSTRACT FROM AUTHOR]

Improving feed efficiency on forage-based systems can be an important tool for beef producers to reduce their environmental footprint. The objective of this project is to assess the relationship between traditional residual feed intake (RFI) efficiency classification, enteric gas emissions, and apparent total tract nutrient digestibility in late gestation beef heifers. Pregnant Angus crossbred heifers in late gestation (n = 72, BW = 576 ± 45.8 kg) were blocked by expected calving date and randomly assigned to pen groups. Heifers had ad libitum access to a common haylagebased diet formulated to meet nutritional requirements for the last eight weeks of gestation. Individual feed intake and behavior data were recorded daily using Insentec feeding stations (Insentec B.V., Marknesse, The Netherlands). Groups of heifers were rotated through pens with access to GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) to measure enteric gas emissions of methane (CH4), carbon dioxide (CO2), and oxygen (O2). To determine individual apparent total tract digestibility, fecal samples were collected from each heifer every 9 h over three days, mixed, dried at 65 °C for 96 h, and analyzed for nutrient values (A&L Canada Laboratories, London, ON, Canada). Nutrient digestibility was determined for each heifer using acid-insoluble ash (AIA) and undigestible neutral detergent fiber (uNDF) as internal markers. Heifer RFI was determined using predicted DM intake as a regression of midpoint BW and ADG, and heifers were classified by RFI quartile group. Data were analyzed using PROC GLIMMIX in SAS, with efficiency quartile group as the fixed effect and pen as a random effect, comparisons between quartile groups were assessed with a Tukey test. Heifers classified as efficient (lowest RFI) had decreased DMI (8.2 vs 10.7 ± 0.21 kg/d, P < 0.01), less bunk visits (43 vs 64 ± 5 visits/day, P < 0.01) and greater time per visit (4.8 vs 3.0 ± 0.53 min/visit, P = 0.05). Efficient heifers also had reduced CH4 (219 vs 245 ± 6.2 g/d, P = 0.03) and CO2 (7,517 vs 8,074 ± 165.9 g/d, P = 0.01) emissions compared with inefficient (greatest RFI) heifers. However, apparent total tract digestibility of organic matter, crude protein, NDF, ADF, starch, and sugar using AIA (P > 0.08) or uNDF (P > 0.06) as internal markers were not correlated with heifer efficiency. These data indicate that more efficient heifers in late gestation consume less feed and have reduced enteric emissions, despite no differences in apparent total tract digestibility. [ABSTRACT FROM AUTHOR]

Improving feed efficiency in beef heifers may help reduce enteric emissions and improve economic returns for producers. The objective of this project is to assess the relationship between traditional residual feed intake (RFI) efficiency classification, enteric gas emissions, and apparent total tract nutrient digestibility in growing yearling heifers. Angus crossbred heifers (n = 74, BW = 408 ±27.1 kg) were blocked by BW and randomly assigned to pen groups. All heifers were fed a common haylage-based diet for ad libitum intake. Insentec feeding stations (Insentec B.V., Marknesse, The Netherlands) were used to measure individual feed intake and feeding behavior data. To measure enteric gas emissions of methane (CH4), carbon dioxide (CO2), and oxygen (O2), heifer groups were rotated through pens with GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) weekly. Apparent total tract digestibility was determined by collecting fecal samples from each heifer every 9 h over three days, composited and dried at 65 °C for 96 h, and analyzed for nutrient values (A&L Canada Laboratories, London, ON, Canada). Nutrient digestibility was determined for each heifer using acidinsoluble ash (AIA) and undigestible neutral detergent fiber (uNDF) as internal markers. RFI was determined using a regression of midpoint BW and ADG and then heifers were ranked by RFI quartile group. Data were analyzed using PROC GLIMMIX in SAS, with efficiency quartile group as the fixed effect and pen as a random effect, comparisons between quartile groups were assessed with a Tukey test. As expected, efficient (least RFI) heifers had decreased dry matter intake (8.5 vs 10.1 ± 0.20 kg/d, P < 0.01), less bunk visits (70 vs 112 ± 6 visits/day, P < 0.01), spent greater time per visit (2.46 vs 1.31 ± 0.249 min/visit, P < 0.01), and consumed more feed per visit (145 vs 104 ± 11.9 g DM/visit, P < 0.03), which resulted in a faster eating rate (65 vs 98 ± 5.0 g DM/min, P < 0.01), and produced decreased enteric CO2 emissions (7,653 vs 8,120 ±122.6 g/d, P = 0.05) compared with inefficient (greatest RFI) heifers. Additionally, when using AIA as the internal marker, efficient heifers showed greater digestibility of organic matter (89.8 vs 91.4 ± 0.49 %, P = 0.02) and NDF (20.2 vs 30.0 ± 2.66 %, P = 0.04) apparent total tract digestibility, while using uNDF as the internal marker showed no difference (P > 0.20) between efficiency groups. These data indicate that more efficient yearling heifers consume less feed, have reduced enteric gas emissions, and have improved organic matter and NDF apparent total tract digestibility. [ABSTRACT FROM AUTHOR]

Due to the unique nature of the rumen, unlike monogastric animals, ruminants like cattle largely depend on microbial hydrolysis of feed rather than postruminal enzymatic degradation. However, in ruminants fed high-grain diets, significant amounts of starch can bypass ruminal fermentation, where pancreatic and small intestinal enzymes play a vital role in digestion. Ruminal microbiota, as well as the host animal, require protein as a nitrogen source to optimize digestibility. Hempseed cake (containing >30% of crude protein) is a by-product of hempseed oil production, but currently is not used as a feed source as it is not an FDAapproved feed ingredient. Presently, the availability and costs of protein supplements are volatile, and sourcing alternative protein sources is needed. Therefore, information is necessary on the effect of feeding hempseed cake on ruminant digestive function. This study aimed to evaluate the effects of feeding hempseed cake on pancreatic and intestinal enzymatic activity in finishing heifers. Angus-crossbred finishing heifers (494 ± 10 kg BW) were fed for 111 days with one of two dietary treatments: 20% [dry matter (DM) basis] of dried corn distillers grains plus solubles (n = 16, control) or hempseed cake (n = 16, hemp). All animals were slaughtered at the end of treatment. Intestinal tissues for digestive enzyme assays were isolated and stored at -800C following immediate flash freezing with liquid nitrogen. The MIXED procedure in SAS was used to analyze the data. There was a tendency (P = 0.09) of greater pancreatic tissue mass in the hemp group than in the control group. The activity of pancreatic α-amylase, trypsin, and lipase relative to protein (U/g protein) was less (P < 0.01) in heifers fed hemp than in heifers fed distillers grains primarily because protein concentration (mg/g) and content (g/pancreas) were greater (P < 0.01) in the hemp group than the control group. However, there were no differences (P ≥ 0.2) in digestive enzyme activity (U/g of tissue) in pancreatic and small intestinal tissues. Overall, our results suggest that there was no adverse effect of feeding hemp on the enzymes responsible for nutrient digestion in the small intestine and that hempseed cake may be useful as an alternative source of protein in cattle fed finishing diets. [ABSTRACT FROM AUTHOR]

During gestation, alterations in maternal nutrition during fetal development may alter growth trajectory and metabolic function in the developing fetus. Additionally, there is increasing evidence that the fetal microbiome also influences developmental outcomes. Research in this area is limited, and gastrointestinal microbiota has been the primary focus in cattle. Our objective was to assess the whole-body biogeography of the newborn calf microbiota and the response of these microbial communities and the calf immune system to prenatal vitamin and mineral (VTM) supplementation. Samples were collected from the hoof, liver, lung, nasal cavity, eye, rumen (tissue and fluid), and vagina of female beef calves that were born from dams that received either prenatal VTM or no VTM (Control; n = 7/group) throughout gestation. Calves were separated from their dams immediately after birth and fed colostrum replacement until euthanasia at 30 h post-initial colostrum feeding. The microbiota from swab and tissue samples were assessed using 16S rRNA gene sequencing (V4) and qPCR. Serum samples were processed for multiplex quantification of 15 cytokines and chemokines. Sequencing revealed the presence of a relatively diverse and complex microbiota in each of the 7 anatomical locations. The community structure of the hoof, liver, ocular, and vaginal microbiota were significantly different from the ruminal microbiota (0.64 = R2 = 0.12, P = 0.003). The respiratory. (nasal and lung) had similar community structures to that of ocular, vaginal, and ruminal fluid microbiota (P > 0.11). The ocular, hoof, and vagina had the greatest microbial richness (observed ASVs; P < 0.05) but similar diversity (Shannon; P > 0.05) compared with other samples. The liver and ruminal fluid had the least microbially rich communities, the latter also being the least diverse (P < 0.05). Firmicutes, Actinobacteriota, and Proteobacteria were the dominant phyla across all sample types, but their abundance varied by location. The ruminal fluid and hoof had the greatest bacterial concentration, while the liver, lung and ruminal tissue had reduced bacterial abundance as estimated by qPCR. An influence of VTM supplementation on microbial community structure was only detected in the ruminal fluid microbiota (P < 0.01). While prenatal VTM supplementation did not affect the nasal, lung, liver, and hoof microbiota, differences (P < 0.05) were detected in microbial richness (vagina), diversity (ruminal tissue and fluid, ocular), composition at the phylum level (ruminal tissue, ocular, and vagina), and total bacterial abundance (ocular and vagina). Among the 15 cytokines evaluated, the concentration of IP-10 was increased (P = 0.02) while IL-4 and IL-17A were reduced (P < 0.05). [ABSTRACT FROM AUTHOR]

To determine the effects of maternal supplementation on the mRNA abundance of genes associated with metabolic function in fetal muscle and liver, pregnant sows (Landrace × Yorkshire; initial body weight (BW) 221.58 ± 33.26 kg; n = 21) fed a complete gestation diet (corn–soybean meal based diet, CSM) were randomly assigned to 1 of 4 isocaloric supplementation treatments: control (CON , 378 g/d CSM, n = 5), sucrose (SUGAR , 255 g/d crystalized sugar, n = 5), cooked ground beef (BEEF , 330 g/d n = 6), or BEEF + SUGAR (B+S , 165 g/d cooked ground beef and 129 g/d crystalized sugar, n = 5), from days 40 to 110 of gestation. Sows were euthanized on day 111 of gestation. Two male and 2 female fetuses of median BW were selected from each litter, and samples of the longissimus dorsi muscle and liver were collected. Relative transcript level was quantified via qPCR with HPRT1 as the reference gene for both muscle and liver samples. The following genes were selected and analyzed in the muscle: IGF1R , IGF2 , IGF2R , GYS-1 , IRS-1 , INSR , SREBP-1C , and LEPR ; while the following were analyzed in the liver: IGF2 , IGF2R , FBFase , G6PC , PC , PCK1 , FGF21 , and LIPC. No effect of fetal sex by maternal treatment interaction was observed in mRNA abundance of any of the genes evaluated (P > 0.11). In muscle, the maternal nutritional treatment influenced (P = 0.02) IGF2 mRNA abundance, with B+S and SUGAR fetuses having lower abundance than CON, which was not different from BEEF. Additionally, SREBP-1 mRNA abundance was greater (P < 0.01) for B+S compared with CON, BEEF, or SUGAR fetuses; and females tended (P = 0.06) to have an increased abundance of SREBP-1 than males. In fetal liver, IGF2R mRNA abundance was greater (P = 0.01) for CON and BEEF than SUGAR and B+S; while FBPase mRNA abundance was greater (P = 0.03) for B+S compared with the other groups. In addition, maternal nutritional tended (P = 0.06) to influence LIPC mRNA abundance, with increased abundance in CON compared with SUGAR and B+S. These data indicate limited changes in transcript abundance due to substitution of supplemental sugar by ground beef during mid to late gestation. However, the differential expression of FBPase and SREBP-1c in response to the simultaneous supplementation of sucrose and ground beef warrants further investigations, since these genes may play important roles in determining the offspring susceptibility to metabolic diseases. [ABSTRACT FROM AUTHOR]

To examine the effects of nutrient restriction during midgestation to late gestation on maternal and fetal digestive enzyme activities, 41 singleton ewes (48.3 ± 0.6 kg of BW) were randomly assigned to dietary treatments: 100% (control; CON; n = 20) or 60% of nutrient requirements (restricted; RES; n = 21) from day 50 until day 90 (midgestation). At day 90, 14 ewes (CON, n = 7; RES, n = 7) were euthanized. The remaining ewes were subjected to treatments of nutrient restriction or remained on a control diet from day 90 until day 130 (late gestation): CON-CON (n = 6), CON-RES (n = 7), RES-CON (n = 7), and RES-RES (n = 7) and were euthanized on day 130. The fetal and maternal pancreas and small intestines were weighed, subsampled, and assayed for digestive enzyme activity. One unit (U) of enzyme activity is equal to 1 µmol of product produced per minute for amylase, glucoamylase, lactase, and trypsin and 0.5 µmol of product produced per minute for maltase and isomaltase. Nutrient restriction during midgestation and late gestation decreased (P < 0.05) maternal pancreatic and small intestinal mass but did not affect fetal pancreatic or small intestinal mass. Maternal nutrient restriction during late gestation decreased (P = 0.03) fetal pancreatic trypsin content (U/pancreas) and tended to decrease (P < 0.08) fetal pancreatic trypsin concentration (U/g), specific activity (U/g protein), and content relative to BW (U/kg of BW). Nutrient restriction of gestating ewes decreased the total content of α-amylase (P = 0.04) and tended to decrease total content of trypsin (P = 0.06) and protein (P = 0.06) in the maternal pancreas on day 90. Nutrient restriction during midgestation on day 90 and during late gestation on day 130 decreased (P = 0.04) maternal pancreatic α-amylase-specific activity. Sucrase activity was undetected in the fetal and maternal small intestine. Nutrient restriction during late gestation increased (P = 0.01) maternal small intestinal maltase and lactase concentration and tended to increase (P = 0.06) isomaltase concentration. Realimentation during late gestation after nutrient restriction during midgestation increased lactase concentration (P = 0.04) and specific activity (P = 0.05) in the fetal small intestine. Fetal small intestinal maltase, isomaltase, and glucoamylase did not respond to maternal nutrient restriction. These data indicate that some maternal and fetal digestive enzyme activities may change in response to maternal nutrient restriction. [ABSTRACT FROM AUTHOR]

The article presents a study examining the role of leptin in reproductive characteristics of commercial beef cows and heifers. Topics discussed include challenges associated with selection for better reproductive performance as it is a time-consuming process; role of Leptin (LEP/Sau3AI) and leptin receptor (LEPR/T945M) in milk production traits, calving interval (CI), and age at first calving (AgeFC); and LEP single nucleotide polymorphism markers in Holstein heifers and cows.

Objectives were to investigate the effects of supplementation with corn dried distiller's grains plus solubles (DDGS) to late gestating beef cows on arterial blood flow to the mammary glands during late gestation and early lactation; colostrum and milk production; dystocia and immunity; and calf BW. Cows were fed a control (CON ; n = 15; 5.1% CP; 36.2% ADF) diet consisting of 90% corn stover and 10% corn silage on a dry basis offered ad libitum or CON diet with supplementation of DDGS (0.30% of BW; SUP n = 12). Mammary gland blood flow was assessed on day 245 of gestation. At parturition, maternal and calving parameters were assessed; colostrum and jugular blood was sampled; and dams were weighed. Mammary gland blood flow and milk production was measured on day 44 of lactation. Calves were weighed fortnightly for 8 wk and at weaning. Colostrum production tended to be greater in SUP dams than in CON dams (837 vs. 614 ± 95 g, P = 0.10). Calves of SUP dams were heavier at birth and 24 h (0 h, 43.2 vs. 39.8 ± 1.0 kg, P = 0.02; 24 h, 44.0 vs. 40.4 ± 1.1 kg, P = 0.02). At birth and 24 h, blood pCO2 was greater in calves born to SUP dams (6.82 vs. 6.00 ± 0.41 kPa, P = 0.04). Serum IgG did not differ (P = 0.21) at 24 h. Ipsilateral mammary gland blood flow of SUP cows was greater than CON cows (2.76 vs. 1.76 ± 0.30 L/min; P = 0.03); however, when summed with contralateral, total blood flow was similar (P = 0.33). Hemodynamic measures on day 44 of lactation were similar (P ≥ 0.32). Milk production tended to be increased (13.5 vs. 10.2 ± 1.2 kg/d, P = 0.07) in SUP vs. CON cows. Despite similar BW through 56 d, calves from SUP cows were heavier (P = 0.04) at weaning (309.7 vs. 292.0 ± 6.0 kg). In conclusion, we accept our hypothesis that DDGS supplementation during gestation influenced mammary blood flow, milk production and calf weights. These findings implicate maternal nutrition's leverage on both nutrient and passive immunity delivery to the calf early in life as well as potential advantages on long-term performance. [ABSTRACT FROM AUTHOR]

One-hundred thirty-two finishing steers (300 ± 2.7 kg body weight [BW]) predominately of Angus, Simmental, and Shorthorn breeding were used to study the effect of metabolizable protein (MP) intake on growth performance, carcass characteristics, and feeding behavior. Steers were stratified by initial BW across five pens and randomly assigned to one of four dietary treatments to supply an average of 626, 906, 1,209, and 1,444 g MP/d (n = 33 per treatment). Feed intake and feeding behavior were measured using radio frequency identification tags and the Insentec feeding system. For feeding behavior, a visit was defined as each time the Insentec system detected a steer at the feed bunk. A meal was defined as eating periods by intervals no longer than 7 min. Steers were fed until they reached an average BW of 598 ± 3.1 kg. Average daily gain (ADG) responded quadratically (P < 0.01) with ADG increasing in steers fed 906 g MP/d and plateauing thereafter. Dry-matter intake (DMI; kg) responded quadratically (P = 0.009) with DMI increasing with MP intake up to 1,209 g/d MP and decreasing thereafter. Gain to feed ratio (G:F) increased linearly (P = 0.04) and tended (P = 0.10) to respond quadratically, as G:F increased up to 906 g MP/d and plateaued thereafter. A quadratic response (P = 0.04 and P = 0.02, respectively) was observed for marbling score and 12th rib subcutaneous fat thickness with steers fed 1,209 g MP/d having the greatest marbling score and back fat thickness. A quadratic effect for visits and meals per day was observed (P < 0.01) with steers fed the 1,209 g MP/d treatment having the least visits and meals per day. In addition, time eating per visit responded quadratically (P = 0.05) with time increasing from 626 to 906 g MP/d. There was a linear increase (P ≤ 0.02) in time eating per meal and per day with increasing MP intake. A quadratic effect (P < 0.03) was observed for DMI per visit, meal, and minute with steers fed 1,209 g MP/d having the greatest DMI. In summary, steers fed 626 g MP/d had increased visits and meals per day. However, DMI per visit, meal, and minute were greater in steers fed 1,209 g MP/d. A day × treatment interaction (P < 0.001) was observed for plasma urea N as concentrations increased to a greater extent over time in the higher MP treatments than in the lower MP treatments. These data indicate that MP supply (from deficient to excess) influences growth performance, carcass characteristics, and feeding behavior of finishing steers. [ABSTRACT FROM AUTHOR]

Ractopamine hydrochloride (RAC) is a β-adrenergic agonist that functions as a repartitioning agent to improve muscling in feedlot cattle. Many studies have investigated the effects of RAC on growth performance and carcass characteristics; however, there is minimal information about the influence of RAC on feeding behavior. Sixty-nine steers (body weight [BW] = 364 ± 3.9 kg) predominately of Angus and Simmental breeding were subjected to a 126-d (n = 46) or 154-d (n = 23) feeding period and randomly assigned to one of two treatment groups: supplementation to provide 0 (CON; n = 34) or 267 ± 4.9 mg/d of RAC (n = 35). Ractopamine was provided as Optaflexx 45 at 0.024% of the diet (dry matter [DM] basis; Elanco Animal Health, Greenfield, IN). Dietary treatments were fed the final 42 d in the feed yard (treatment period). Feeding behavior and growth performance were measured using radio frequency identification tags and the Insentec feeding system. Following the final day of treatment, steers were slaughtered and carcass measurements were recorded. Data were analyzed using MIXED models in SAS. There were no differences in BW, average daily gain (ADG), DM intake (DMI), gain:feed ratio (G:F), or feeding behavior during the pretreatment period (P > 0.44). Ractopamine supplementation increased G:F during the treatment period (P = 0.02) and during the total period (P = 0.03) and tended to increase ADG during the treatment and total period (P ≤ 0.08). DMI was not affected during the treatment or total period (P > 0.67). Eating time per visit, per meal, and per day were decreased (P < 0.02) in steers supplemented with RAC during the treatment period. DMI per minute was increased (P = 0.02) in steers supplemented with RAC. Hot carcass weight, dressing percentage, and 12th rib fat were not influenced by RAC supplementation. Ractopamine supplementation decreased marbling (P = 0.008) and kidney, pelvic, and heart percentage (P = 0.04) and increased longissimus muscle area (P = 0.01). These data demonstrate that RAC supplementation for 42 d improves feed efficiency, increases the rate of DMI without altering DMI, and increases muscling in finishing cattle. [ABSTRACT FROM AUTHOR]

The article focuses on maternal nutrition and programming of offspring energy requirements and managing nutrient supply to match demand is critical for sustainable and efficient livestock production. It mentions livestock can often experience a poor or compromised nutritional environment during gestation and increased risk of health complications throughout life. It also mentions effects of fetal nutrient restriction during gestation depend on timing.

In feedlot systems, feeding non-protein nitrogen sources, such as urea, instead of true protein sources, such as soybean meal (SBM), could be an alternative way to reduce dietary costs. This study aimed to evaluate the effects of partial or total replacement of SBM by urea on feed intake and apparent total-tract digestibility of organic matter (OM) and crude protein (CP), and on nitrogen (N) balance in bulls. Four Nellore × Red Angus crossbred bulls (292 ± 14.6 kg BW) were randomly assigned to treatment in a 4×4 Latin square design. The experimental treatments consisted of different replacement levels of SBM by urea (DM basis): 0% replacement (R-0%); 54% replacement (R-54%); 78% replacement (R-78%); 100% replacement (R-100%). Diets were formulated according to the BR-CORTE system to provide approximately 130 g CP/kg DM. The diets consisted of 20% corn silage and 80% ground corn-based concentrate containing SBM and/or urea+ammonium sulfate, mineral mix, and virginiamycin. Each experimental period was 21 d, with 14 d adaptation, and 4 d of total feces and urine collection. Data were analyzed using the MIXED procedure in SAS and statistical significance was declared at P < 0.05. Dietary treatment did not influence (P > 0.05) OM and CP intake. Apparent total-tract OM and CP digestibility were not influenced (P > 0.05) by dietary treatment. Daily total urinary and fecal N were not influenced (P > 0.05) by dietary treatment. Dietary treatment did not influence (P > 0.05) N retention. Therefore, these data suggest that SBM may be partially or totally replaced by urea as the dietary N source without affecting feed intake, apparent total-tract digestibility, and N balance in Nellore × Red Angus crossbreed young bulls fed a high concentrate diet. [ABSTRACT FROM AUTHOR]

In Brazil, it is common practice to feed young bulls a low-concentrate diet (LCD) after weaning, followed by a high-concentrate diet (HCD) during the finishing phase to optimize animal growth while reducing the cost of concentrated feed. By restricting the concentrate intake during the early phase, the animals can potentially adapt better to a high-energy diet during the finishing phase, leading to improved performance. Thus, the objective of this study was to evaluate the impact of different LCD feeding periods after weaning, followed by feeding a HCD, on dry matter intake (DMI), average daily gain (ADG), feed efficiency (G:F), and final body weight (BW) of young Nellore bulls. Thirty-two young Nellore bulls (average initial BW = 265 ± 5 kg; age = 7 ± 1 mo) were used in a completely randomized design into four groups (n = 8/group) and assigned to receive one of 4 treatments containing different periods of LCD. The LCD consisted of 800 g/kg of forage sorghum silage and 200 g/kg of concentrate, while the HCD contained 200 g/kg of corn silage and 800 g/kg of concentrate. The diets were formulated according to BR-CORTE (2016) to achieve ADG of 0.6 kg/day and 1.2 kg/day for the LCD and HCD, respectively. The experiment lasted 154 days (14 days for adaptation to the HCD). The LCD and HCD feeding periods respectively were 0 and 140 (T0), 28 and 112 (T28), 56 and 84 (T56), and 84 and 56 (T84) days. All animals were fed ad libitum in an electronic feeder (INTERGADO, Intergado Ltd., Contagem, MG, Brazil), and individual daily feed intake was recorded. The bulls were weighed at the beginning and the end of the LCD and HCD feeding periods after undergoing 16 h of fasting to measure BW and ADG of both periods. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) assuming the significance level of 0.05. There was no evidence that different LCD feeding periods impacted DMI (P = 0.99), ADG (P = 0.59), or G:F (P = 0.48) during the LCD feeding period. The DMI during the HCD feeding period of T0 did not differ from the others, the T28 was not significantly different from the T84, and the T56 treatment was greater than T28 and T84 (P < 0.05). No significant difference was found between the treatments for ADG (P = 0.09) and G:F (P = 0.98) during the HCD feeding period. The T0 had the heaviest final BW, while there was no difference between the T28 and T56 groups, and the T84 group had the lightest final BW(P < 0.01). Given that the final BW was heavier for T0, it may be inferred that there are no benefits to using LCD feeding periods. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of increased concentrations of metabolizable protein and lysine from heat-treated soybean meal (TSBM) in forage-based growing cattle diets predicted to have positive metabolizable protein balance. Seventy Angusbased steers (298 ± 16 kg initial BW) were utilized in an 85-d randomized generalized block design with animal as the experimental unit. Dietary treatments were arranged to replace a proportion of the basal protein source, DDGS included at 16% dietary dry matter (DM), with TSBM at rates of 0% (TSBM0), 4% (TSBM4), 8% (TSBM8), and 12% (TSBM12) dietary DM. Steers were provided with ad libitum access to feed and water in a monoslope barn with dry-lot access. The basal diets contained (DM basis) 44% corn silage, 37% oat hay, and 3% supplement. Steers were blocked by BW into light, medium, and heavy blocks. Daily feed disappearance was measured using an automated feed system (Insentec Roughage Intake Control, Hokofarm B.V., Marknesse, The Netherlands), with disappearance assumed to be intake. Steers were individually weighed every 28 d to calculate average daily gain (ADG) throughout the experiment. Growth performance and feed intake were analyzed utilizing the MIXED procedure of SAS with fixed effects of body weight block and TSBM inclusion level. Treatments were evaluated when the F test was significant (P = 0.05). There were no differences (P = 0.16) for ending BW, ADG, dry matter intake (DMI), or gain:feed (G:F) among treatments (Table 1). Therefore, in growing diets predicted to be sufficient in metabolizable protein, replacing distillers grains with a source of metabolizable protein and amino acids provided by heat-treated soybean meal did not affect growth performance. [ABSTRACT FROM AUTHOR]

Cereal rye is used to diversify crop rotations in the Northern Great Plains and can be harvested through grazing, processed as forage (hay or silage), or allowed to reach maturity for grain and straw. Although rye has not traditionally been used in growing and finishing cattle diets due to the occurrence of ergot. Recent hybrid germplasms have shown promise with increased yields and decreased ergot incidence. This study aimed to determine the effects of substituting dry-rolled or ground hybrid rye for dry rolled corn (DRC) on dry matter intake (DMI), growth performance and gain:feed (G:F) of growing beef steers. One-hundred-fifty crossbred steers [260 ± 22.3 kg, initial body weight (BW)] were transported to the Carrington Research Extension Center near Carrington, North Dakota, stratified by BW, and assigned to one of fifteen pens (n = 10 steers/pen) and three dietary treatments in a randomized block design. Hybrid rye was substituted on a dry matter basis for DRC as follows: a basal diet formulated 33.8% corn silage, 23.6% forage barley hay, 17.5% modified distillers grains and solubles (MDGS), and 3% supplement and limestone with either 22.1% DRC (CON), 22.1% dry rolled hybrid rye (RRYE), and 22.1% ground hybrid rye (GRYE) on a dry matter basis. Due to extreme cold windchill temperatures, steers were fed for a total of 64 days beginning October 24, 2022. Body weights were taken before feeding on Day 1, 2, 28, 63, and 64 with a 4% pencil shrink applied to the initial and final BW. Performance data including animal BW, average daily gain (ADG), DMI and G:F ratio were calculated. The monthly average of growth performance were analyzed using the repeated measures procedure of PROC MIXED in SAS 9.4 with pen serving as the experimental unit. Pre-planned contrasts (control vs rye; rolled rye vs ground rye, rolled rye vs control, and ground rye vs control) were analyzed. No differences in BW (P = 0.35), ADG (P = 0.19), DMI (P = 0.83), or G:F (P = 0.21) were detected due to the replacement of DRC with hybrid rye throughout the study (Table 1). Steers assigned to GRYE had increased G:F (P = 0.04) and tended (P = 0.05) to have greater ADG compared with RRYE throughout the study. Steers fed hybrid rye tended to have lesser BW (P = 0.06) than those fed DRC after the first 28-day weigh period. During the final 36 days, steer assigned to GRYE had increased ADG (P = 0.03) compared with RRYE and tended (P = 0.05) to have greater ADG than those assigned to CON. Results from the study suggest that steers fed processed hybrid rye grain in a high forage backgrounding diet performed similarly to calves fed DRC. [ABSTRACT FROM AUTHOR]

The microbial communities residing within the gastrointestinal and reproductive tracts are vital to cattle health; not only for their involvement in nutrient metabolism, but also for their ability to influence infectious and metabolic diseases as well as reproductive efficiency. Therefore, harnessing the ruminal and vagino-uterine microbiomes for improved cattle health and productivity have recently become an active area of research in an era where microbiome manipulation holds as much potential as genetic selection and management refinement for enhancing herd productivity. New developments highlight that the maternal gut and reproductive microbiome extend their impact to offspring development and health. These developments include the demonstrations of maternal gut microbiota involvement in developmental programming in murine models, and increased evidence supporting the existence of in utero microbial colonization and the role of maternal nutrition on fetal programming in cattle. Our recent work has focused on understanding the role of the maternal microbiota and feto-maternal microbial crosstalk in fetal programming and offspring microbiome development. Our lab has investigated the impacts of maternal dietary restriction, supplementation of one carbon metabolites or vitamins and minerals during gestation on maternal ruminal and vaginal microbiota; as well as pre- and postnatal microbial colonization in offspring calves. Our results indicate that maternal dietary alterations during pregnancy may influence ruminal and vaginal microbiota of dams, which may subsequently impact early life microbial colonization in calves being gestated. Our findings call for further research in the area of maternal gut and reproductive microbiome alterations and their impacts on fetal programming and offspring development in ruminants. [ABSTRACT FROM AUTHOR]

Soybean meal (SBM) is the primary protein source used worldwide for livestock. but is a high-cost protein source than other alternative protein sources such as urea. This study aimed to evaluate the effects of partial or total replacement of SBM with urea on dry matter intake (DMI), average daily gain (ADG) and feed efficiency of finishing Nellore × Red Angus crossbreed bulls. Nellore × Red Angus crossbred bulls (n = 30; average initial BW = 383.5 ± 8 kg; age = 9 ± 1 mo) were utilized in a completely randomized design for 93 days (9 d adaptation period + 84 d finishing period). Bulls were randomly assigned to receive 1 of 3 dietary treatments containing different replacement levels of soybean meal with urea (diet DM basis): 0% replacement (R-0%); 50% replacement (R-50%); 100% replacement (R-100%). Diets were formulated according to the BR-CORTE system to achieve an ADG of 1.3 kg and to contain 130 g CP/kg DM. The diets consisted of 20% corn silage and 80% concentrate that was formulated with ground corn, soybean meal and/or urea, ammonium sulfate, mineral mix, and virginiamycin. All animals were fed for ad libitum intake using an electronic feeder (INTERGADO, Intergado Ltd., Contagem, Minas Gerais, Brazil) and individual daily feed intake was recorded. The bulls were weighed at the beginning and end and every 28 d throughout the finishing period. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) assuming the significance level of 0.05. There was no influence on final BW (P = 0.39), DMI (P = 0.22), ADG (P = 0.47), or feed efficiency (P = 0.98; Table 1). These results suggest that SBM can be replaced with urea and may be used as a strategy to reduce diet costs for Nellore × Red Angus crossbred bulls without affecting DMI, ADG, and feed efficiency. [ABSTRACT FROM AUTHOR]

The sorghum hybrid, AGRI002E, sorghum was developed for high dry matter (DM) production per area. However, there are no reports in the literature evaluating the use of this silage with different inclusion levels of concentration on the ingestive and digestive variables of beef cattle. Therefore, this study aimed to access the effects of different concentrate levels in diets containing AGRI002E sorghum silage (SS) on feed intake, ruminal and apparent total tract digestibilities of organic matter (OM), neutral detergent fiber corrected for contaminant ash and protein (apNDF), and starch. Nellore rumen-cannulated bulls (n = 5; BW = 242 ± 5 kg) were used in a 5×5 Latin square design. The experimental treatments consisted of five concentrate levels (0, 200, 400, 600, and 800 g of concentrate/kg of diet DM) in SS-based diets. The concentrates used in the experimental diets were based on corn, soybean meal, sulfated urea, virginiamycin, and mineral supplement. The diets were formulated to provide approximately 120 g of crude protein per kg dietary DM. In the 0% concentrate diet, the protein level was adjusted with sulfated urea. All diets contained the same amount of virginiamycin and mineral supplement. Each experimental period lasted 24 d, with 17 d adaptation, 4 d of total feces collection, and 3 d collection to obtain omasal flow using a double marker technique (indigestible NDF and Co-EDTA). Data were analyzed using MIXED-SAS. Starch and OM intake linearly increased (P < 0.001) with increasing concentrate inclusion. Intake of apNDF decreased linearly (P = 0.018) and tended to be quadratically influenced (P = 0.022) with increasing concentrate inclusion (Table 1). Ruminal digestibility of OM increased linearly (P < 0.001) with increasing concentrate inclusion. Starch ruminal digestibility decreased linearly (P = 0.003) and tended to be influenced quadratically (P = 0.0015) with increasing concentrate inclusion. Ruminal digestibility of apNDF tended to decrease linearly (P = 0.057) with increasing concentrate inclusion. Total apparent digestibility of OM increased linearly (P < 0.001) and apNDF and starch total apparent digestibility decreased linearly (P = 0.002) with increasing concentrate inclusion. Increasing inclusion of concentrate in AGRI002E sorghum silage-based diets increased OM and starch intake, and ruminal and total apparent OM digestibility and decreased apNDF intake and ruminal and apNDF and starch total apparent digestibility. [ABSTRACT FROM AUTHOR]

Several methods to estimate the body weight (BW) of cattle have been proposed. Body measurements have proved to be useful in estimating the BW of cattle. However, there are multicollinearities between body measurements which could affect the accuracy of prediction models. Least absolute shrinkage and selection operator (LASSO regression), ridge regression, and more recently elastic net (EN) regularization has been suggested to handle multicollinearity better than simple regression. Elastic net is a regularization technique that combines LASSO and ridge regression. In this study, we modelled BW against some body measurements [calculated: volume (VL) 218 to 503 liters; frame score (FS) 2.1 to 7.5; surface area (SA) 4.02 to 7.1 m2], and direct body measurements [body length (BL) 89 to 136 cm; hip height (HH) 96 to 136 cm; hip width (HW) 33 to 52 cm; heart girth (HG) 149 to 191 cm; mid girth (MG) 177 to 234 cm; flank girth (FG) 156 to 239 cm] to examine which variable(s) predicts BW more accurately. Data from 300 heifers (9 breeds) collected over 4 years were used with year as a random effect to account for differences between years. We ran the EN model using the glmnet function of the R caret package. Ten-fold cross validation was used with 5 repeats. The EN model was trained using 206 observations and validated with 94 observations. The best model was selected based on the minimum root mean square error and median R-square (R2) values. Including FS in the prediction model resulted in the highest R2 (0.5754) and was a better predictor for BW compared with other models: VL (0.4271), SA (0.4130) and direct body measurements (0.4861). This suggests that calculated FS could be a better estimate for BW than direct body measurements and indicates that FS still accurately predicts size of heifers. [ABSTRACT FROM AUTHOR]

Dry matter intake (DMI) remains one of the most variable and significant factors contributing to cost of production in cow-calf systems. Body weight (BW) has been used to estimate DMI of individual cattle as an alternative to measuring DMI, which is expensive, labor intensive, and not practically feasible in production environments. The objective of this study was to evaluate if calculated body measurements [volume (VL) 218 to 503 liters; frame score (FS) 2.1 to 7.5; surface area (SA) 4.02 to 7.12 m2) and direct body measurements (DBM: body length (BL) 89 to 136 cm; hip height (HH) 96 to 136 cm; hip width (HW) 33 to 52 cm; heart girth (HG) 149 to 191 cm; mid girth (MG) 177 to 234 cm; and flank girth (FG) 156 to 239 cm] could be used to estimate DMI of heifers as accurately as using BW (267 to 506 kg). Data from 300 heifers (9 breeds) collected over 4 years were used. Year was included in the model as a random effect. An elastic net model using the glmnet function of the R caret package was used. There were 206 training and 94 testing observations. The models were cross validated 10-fold with 5 repetitions. Models with the least minimum root mean square error and greatest median R-square (R2) values were selected as the best models. Model R2 ranged from 0.19 (SA) to 0.63 (BW), where DBM (0.40) and FS (0.43) performed similarly. As prior studies have suggested, BW in this study accounts for the greatest variation in DMI. However, calculated FS and ABM also explained some variation in DMI and more so than VL (0.22) and SA. These data indicate that FS and ABM could be used as alternatives in cases where BW records are not available to estimate DMI of heifers. [ABSTRACT FROM AUTHOR]

Five essential oils (EO) were previously characterized in vitro and identified as candidates for the development of an intranasal EO spray to inhibit the colonization and proliferation of bovine respiratory disease (BRD) pathogens, especially at feedlot entry when cattle are most susceptible to BRD. In the present pilot study, these EO were evaluated for their potential to reduce BRD pathogens and to modulate nasopharyngeal microbiota in feedlot cattle. Angus-crossbred calves [n = 40; 7to 8 months old; initial BW = 284 ± 5 kg (SE)] received either an intranasal EO spray consisting of ajowan, thyme, fennel, cinnamon leaf, and citronella (0.025%, vol/vol per EO) suspended in PBS (3 mL per nostril) or PBS (Control) on day (d) 0. Deep nasopharyngeal swabs were collected on d -1 (24 h before EO administration), 1, 2, 7, 14, 28, and 42, and processed for microbiota characterization using 16S rRNA gene. The calves that received EO had similar feed intake (P = 0.62) and average daily gain (P = 0.37) than control calves. Overall bacterial concentration estimated by qPCR was greater in control (P =0.049) than EO group, with EO group having reduced bacterial concentration on d 2 (P = 0.01) and d 7 (P=0.07). Sequencing results revealed that overall community structure of nasopharyngeal microbiota was different between EO and control calves (PERMANOVA: R2 = 0.01, P = 0.02), and was strongly affected by time (R2 = 0.1, P = 0.001). Within individual sampling day, the effect of EO on community structure was only detected on d 1 (R2 = 0.05, P = 0.03). Microbial richness (observed ASVs) and diversity (Shannon and Inverse Simpson) were not different between the two groups (P = 0.17). The effect of EO on the most dominant phyla was observed (P = 0.05) with Proteobacteria (d14), Firmicutes (d1, 14), Actinobacteriota (d14), and Bacteroidota (d2, 14). Among the predominant genera: Moraxella, Ralstonia, Mycoplasma, Mannheimia, Filobacterium, Pseudomonas, Pasteurella, and Corynebacterium, the abundance of Mannheimia (4.34% vs. 10.4%) and Filobacterium (2.53% vs. 11.9%) were reduced (P < 0.05) by EO on d 2. In control calves, Mannheimia was enriched by 3.9-fold (P < 0.05) from d -1 (2.66%) to d 2 (10.4%), whereas it remained constant in EO calves (P > 0.05) between these days (2.23% and 4.34%). Corynebacterium was also decreased (P < 0.05) in EO calves on d 1 (1.06% vs. 2.58%). The BRD-associated Histophilus genus was low (mean 0.02%), so EO effect was not assessed. Overall, a single dose of intranasal EO spray modulated nasopharyngeal microbiota and reduced the abundance of Mannheimia within 48 h post administration while having no effect on feed intake and daily gain. Our study highlights that nasally dosing EO may modulate respiratory microbiota and potentially mitigate bovine respiratory disease in finishing cattle. [ABSTRACT FROM AUTHOR]

The objective was to determine if changes in DMI, time spent eating (TIME), and number of meals per day (MEALS) within interactions of frame score group (FSG) or primary ancestral breed type (PAB) with day relative to estrus (DRE) exist. We hypothesized that different FSG or PAB responses would vary between d -3 to d +3 surrounding estrus (d 0). Over four years, 295 crossbred heifers (347.03 ± 47.39 kg) were monitored. Using calculated frame score, heifers were classified as FSG small (< 4.00), moderately small (4.00 to 5.50), moderately large (5.50 to 6.50), and large (> 6.50). Admixture analysis classified heifers into five PAB (greatest proportion; Angus and Red Angus, American Aberdeen, Shorthorn, Simmental, and crossbred). Estrus was detected using visual checks [patches or chin ball markers, bull present (BP), year 1, n = 87] or heat detection devices (BP or absent, year 2 to 4, n = 208). The last 45 d of the feeding trial had BP. Conception date was estimated using ultrasound fetal size captured at pregnancy checks. Heifers were fed a forage-based diet using the Insentec feeding system. Software errors were removed; then estrus and feeding data were paired based on calendar date. A 7-d range was kept for each heifer using estrus categories (EC) of: 1) last without a BP (n = 195), 2) first with a BP (n = 285), and 3) at estimated conception date (n = 247). The statistical model included fixed effects of year, PAB, FSG, DRE, interactions of FSG x DRE (n = 28) and PAB x DRE (n = 42), and fixed covariate of calendar date. Repeated measures were modeled with unstructured covariance structure and heifer as experimental unit. Square root transformation for TIME and MEALS was used due to normality concerns. Across EC, no interactions for DMI were found (P = 0.5529). For TIME, differences existed within FSG x DRE (P = 0.0375; EC-3) suggesting large heifers responded differently than others. All EC showed DMI (P = 0.0083) and TIME (P = 0.0373) declined on d 0, with less reduction observed when BP (DMI, TIME: 1) -17.09%, -21.56%; 2) -9.01%, -15.02%; 3) -9.21%, -13.45%). A recovery surge occurred on d +1 (> 15%). For MEALS, PAB x DRE (P = 0.0495; EC-1,2) and FSG x DRE (P = 0.0494; EC-2,3) were different. A similar trend as DMI and TIME in response to estrus was observed in small heifers but no other FSG. Size did influence MEALS (P = 0.0024), where smaller heifers ate more MEALS than larger heifers. Results indicate differences in TIME and MEALS likely exist between small and large heifers in response to estrus, but all respond similarly in DMI. [ABSTRACT FROM AUTHOR]

To determine the effects of finishing system (conventional vs. natural), dietary adaptation length (14 vs. 28 d), and direct-fed microbial (DFM) supplementation (no DFM vs. DFM) on growth performance and feeding behavior, 120 yearling steers (390 ± 2.8 kg) were used in a completely randomized design with a 2 × 2 × 2 factorial arrangement of treatments. Feed intake was monitored using the Insentec feeding system. Blood samples were collected every 28 d. After 140 d on feed, steers were slaughtered and carcass characteristics collected. Conventionally fed steers had greater (P = 0.001) final BW, carcass weight, and dressing %. Dry matter intake was not influenced (P = 0.31) by treatment. Length of dietary adaptation period did not influence (P = 016) final BW, ADG, and G:F. There was a feeding system × DFM interaction (P = 0.02) for ADG and G:F with conventionally fed steers fed DFM having the greatest (P = 0.05) and naturally fed steers supplemented with DFM having the least (P = 0.05) ADG and G:F. Number of visits to the feed bunk and number of meals per day did not differ (P > 0.05) among treatments. Time eating per visit and per meal was greater (P = 0.05) in steers supplemented with DFM than in steers not supplemented with DFM. On day 56 and 140, plasma glucose concentration was greater (P = 0.03) in steers adapted in 14 d than in steers adapted in 28 d. On day 84, plasma glucose concentration was greater (P = 0.02) in naturally fed compared to conventionally fed steers. On day 112, there was a dietary adaptation period × DFM interaction (P = 0.004) for plasma glucose concentration with glucose concentration greatest (P = 0.05) in steers adapted in 14 d supplemented with DFM and in steers adapted in 28 d not supplemented with DFM, least for steers adapted in 28 d supplemented with DFM, with steers adapted in 14 d not supplemented with DFM intermediate (P = 0.05). On day 112 and 140, plasma urea N concentration was greater (P = 0.05) in steers adapted in 28 d than in steers adapted in 14 d. These data indicate that conventionally fed steers generally had improved growth performance compared to naturally fed steers. Length of dietary adaptation and DFM supplementation had minimal effects on growth performance but did interact with feeding system to influence feeding behavior and blood metabolite concentrations. [ABSTRACT FROM AUTHOR]

The hypothesis of this experiment was that increasing the inclusion level of distiller's dried grains with solubles (DDGS) in the diets would decrease semen quality but have no negative effects on growth performance. Following the removal of DDGS from the diet, it was hypothesized that the ram lambs would recover and become reproductively sound, independent of treatment. To test this hypothesis, Suffolk and Hampshire ram lambs (n = 112) were allocated to 4 treatments (n = 4 pens per treatment; 7 rams per pen) in a completely randomized design. Dietary treatments were 60% corn, 25% oats, and 15% commercial lamb pellet (CON), 15% of the ration as DDGS substituted for corn (% DM basis; 15DDGS), 30% of the ration as DDGS substituted for corn (% DM basis; 30DDGS), and 45% of the ration as DDGS substituted for corn (% DM basis; 45DDGS). Lambs were fed for 112 d on their respective treatment, after which they were placed on the CON ration until day 168. Lambs were weighed on consecutive d at the beginning (days 0 and 1) and end (days 167 and 168) of the study. Scrotal circumference was measured on all lambs on days 84, 112, 140, and 168. Semen samples were collected on a subset of 64 rams (4 rams per pen) to evaluate semen quality on days 84, 112, 140, and 168. Blood samples were collected on the same subset of rams every 14 d throughout the study. A quadratic effect on BW on day 112 and overall BW (P = 0.03 and P = 0.005, respectively), ADG on day 112 and overall ADG (P = 0.02 and P = 0.02, respectively), DMI (P = 0.007) on day 112, and a cubic effect (P = 0.05) for overall G:F were observed. Overall and day 168 scrotal circumference had a quadratic (P = 0.05) response. A linear increase in spermatozoa concentration on day 168 was observed (P = 0.03) as DDGS concentration increased in the treatment diets, although rams in this stage of the study were no longer receiving DDGS. Overall, testosterone concentrations exhibited a linear decrease (P = 0.005) as DDGS increased in the diet. The linear increase (P = 0.04) on day 168 in morphologically normal sperm as DDGS increased in the diets indicated that all rams, regardless of treatment, would have passed a reproductive soundness exam. In the current study, no negative effects were observed in lamb feedlot or reproductive traits due to increasing DDGS in the diet, indicating that DDGS may be included at levels up to 45% of growing lamb diets. [ABSTRACT FROM AUTHOR]

Cereal rye has been utilized in multiple ways within cropping systems in the northern Great Plains. Rye has traditionally not been utilized as a suitable grain for growing and finishing calves. Previously, recommendations have limited the use of rye due to the negative effects of ergot ingestion. Recent hybrid rye germplasms have shown increased yields with decreased incidence of ergot. The aim of this study was to determine the effects of ground hybrid rye inclusion rate on dry matter intake (DMI), growth performance, and feed efficiency in backgrounding beef steers. Two hundred crossbred steers were shipped to the Carrington Research Extension Center near Carrington, ND, stratified by weight, and assigned to one of twenty pens (n = 10 steers/pen). Four treatments were used in a completely randomized block design to evaluate animal performance during backgrounding when fed partial or complete replacement of corn with rye as the concentrate source. Ground hybrid rye was substituted for DRC as follows: a basal diet formulated with 20% DRC: 0% ground hybrid rye (CON), 13.5% DRC: 6.5% ground hybrid rye (RYE1), 6.5% DRC: 13.5% ground hybrid rye (RYE2), or 0% DRC:20% ground hybrid rye (RYE3) on a dry matter basis. Steers were fed for a total of 56 days beginning Oct. 25, 2021. Interim weights were taken on Nov. 22, 2021, and final weights were taken Dec. 20, 2021. At the conclusion of the feeding period, cattle were weighed on two consecutive days to determine final body weight. Performance data including animal live weights, ADG, DMI and G:F ratio were calculated. The use of rye within the diet did not influence steer weight throughout the study (P = 0.11). No differences in ADG were detected throughout the study (P = 0.68). Steers fed diets containing hybrid rye had higher DMI (P = 0.03) and higher F:G (P = 0.04) during the first month of the study. Increased DMI during the initial month of backgrounding may promote improved intake and growth. Results from the study suggest that steers fed rye as a partial or sole grain in a high forage backgrounding diet weighed similar to calves fed corn as the sole concentrate source. [ABSTRACT FROM AUTHOR]

Objectives were to evaluate the effects of feeding a vitamin and mineral (VTM) supplement to beef heifers during gestation on calf performance, body measurements, trace mineral status, and organ weights at 30 h after birth. We hypothesized that VTM supplementation during gestation would improve mineral status in the neonatal calf but not impact calf performance parameters and body and organ weights at 30 hours after birth. Fourteen Angus-based heifers [initial body weight (BW)] = 273.7 ± 1.10 kg) were randomly assigned to receive either a basal diet (CON; n = 7) or a basal diet plus a VTM supplement (VTM; n = 7; 113 g•heifer-1•d-1, targeting gain of 0.45 kg/day) from 60 d pre-breeding through gestation. Immediately after parturition, blood samples were collected from dams and calves, then calves were separated from their dams. Calves were fed one feeding of colostrum replacer, followed by milk replacer every 12 h, then euthanized at 30 h. Body weight and measurements were recorded, then organs and viscera were removed, weighed, and sampled. Dam serum and neonatal serum, liver, and blood were analyzed for concentrations of minerals. Data were analyzed using the GLM Procedure of SAS with individual animal as the experimental unit. Dietary treatments did not impact calf weight (0 h or 30 h), calf body measurements, or body weight of the dam at calving (P ≥ 0.32). Further, neonatal organ weights were not influenced (P ≥ 0.21) by maternal VTM treatment. Concentrations of Se and Co in calf serum and Se in calf liver were increased (P ≤ 0.02) by VTM treatment; however, concentrations of Cu, Mn, Mo, and Zn in calf muscle, liver, and serum were not impacted (P ≥ 0.07) by VTM treatment. Concentrations of Co in serum of the dam was the only mineral affected by dietary treatments, being greater (P = 0.001) in VTM than CON dams. In the current experiment providing trace mineral supplementation throughout gestation did not impact calf weight or body measurements at birth. However, the implications of altered mineral status of the neonatal calves at birth, and presumably throughout gestation, may have additional postnatal effects that warrant further investigation. [ABSTRACT FROM AUTHOR]

Insulin concentrations are variable in bovine colostrum (5 to 263 μg insulin/L) and its effects on gastrointestinal function in neonatal calves are unknown. The objective of this study was to determine if varying concentrations of insulin in colostrum would influence intestinal carbohydrases in neonatal Holstein bulls. Calves (n = 26; 49.11 kg, SD = 3.24) were removed from their dams after calving. They were fed 3 meals of colostrum (7% BW or 3.10 ± 0.02 L) at 2, 14 and 26 hours after birth containing one of 3 insulin concentrations: basal (16.8 μg/L; n = 8), or supplemental colostrum containing either a 5× (83.4 μg/L; n = 10) or 10× (167.5 μg/L; n = 8) increase in colostrum insulin respective to basal concentrations. At 30 hours, the animals were killed, and the gastrointestinal tract was removed for mucosal scrapings of the duodenum, proximal jejunum, and ileum. Intestinal mucosal scrapings were assayed for the following brush border carbohydrases: maltase, isomaltase, lactase and glucoamylase. Data were analyzed using the MIXED procedure of SAS with treatment and dam parity modeled as fixed effects. There was no treatment effect (P > 0.05) on intestinal maltase, isomaltase and glucoamylase concentrations. However, there was a linear increase (P < 0.05) in jejunal lactase activity (Unit/g of jejunum and U/g of protein) with increasing amount of insulin inclusion. These data indicate that insulin supplementation has minimal effects on activities of brush border starch degrading enzymes, but increases lactase activity in the proximal jejunum of neonatal calves. [ABSTRACT FROM AUTHOR]

Hempseed cake, a byproduct of industrial hemp and subsequent hempseed oil extraction processes, contains cannabinoids and fatty acids that could be potentially therapeutic for livestock, but little is known about the extent to which hempseed cake can influence immune response variables of cattle. An endotoxin challenge experiment using crossbred steers (n = 5; initial BW = 542 kg, SD = 40 kg) was conducted to evaluate the effects of hempseed cake treatment (HEMP) and dried corn distillers grains plus solubles treatment (DDGS; each included at 20% of diet DM in respective treatments) in comparison with a dryrolled corn-based negative control treatment (CON) on plasma glucose, non-esterified fatty acids (NEFA), urea nitrogen (PUN), rectal temperature, twelve cytokine (IFNγ, IL-1α, IL-6, IL-8, IL-10, IL-36RA, IP10, MCP-1, MIP-1α, MIP-1β, TNFα, and VEGF-A), and amino acid concentrations at five timepoints after administration of endotoxin (lipopolysaccharide; LPS). Steers were administered LPS at 0.25 μg/kg BW, and blood was collected via jugular venipuncture before and 1, 2, 4 and 6-hours post-bolus injection. Data were analyzed as repeated measures using the MIXED procedure of SAS, and pre-bolus values was used as a covariate. A treatment by hour interaction (P = 0.04) was observed for PUN, and pre-bolus PUN was greatest (P < 0.01) in steers fed the HEMP. Plasma IL-1α, IL-36RA, and TNF-α were least (P ≤ 0.02), while IL-10 and MIP-1α tended (P ≤ 0.10) to be less in steers fed the HEMP diet. Plasma isoleucine, leucine, tryptophan, and tyrosine concentrations were greatest (P ≤ 0.04) in steers fed the DDGS diet, plasma aspartic acid and glycine concentrations were greatest (P ≤ 0.02) for steers fed the DDGS and CON diets. Overall, these data suggest that hempseed cake has potential to reduce inflammation by influencing cytokine production, but more research is needed to further understand animal growth performance and health implications. [ABSTRACT FROM AUTHOR]

Feeding high-grain diets can result in reduced ruminal pH, inflammation of ruminal and other tissues, and subacute ruminal acidosis. Vasoactive intestinal polypeptide (VIP), a gut hormone with anti-inflammatory and other functions, could have a beneficial role in ruminants fed high-concentrate diets. To determine the effects of VIP injection on dry matter intake, average daily gain, gain:feed, and ruminal pH, wether lambs (n=16; BW=68.5 ±1.8 kg) were blocked by body weight and randomly assigned to VIP treatment (n=8) or control (n=8). All lambs were housed in individual pens, adapted to the same high concentrate diet (75% whole corn and 25% supplemental pellet; DM basis), and feed intake and average daily gain were measured from day 1 to 21 when lambs were placed in metabolism crates. Lambs in the treatment group were injected intraperitoneally with VIP (1.3 nmol/kg BW in 0.9% NaCl), whereas lambs in the control group were injected with 0.9% NaCl every second day over 28 days. Nutrient balance was measured over the final seven days (data will be reported elsewhere), and lambs then were slaughtered and ruminal fluid and tissues collected. The average daily gain was greater (p = 0.04) in VIP treated lambs than in control lambs. However, no difference (p > 0.05) in daily feed intake was observed between treatments. Ruminal fluid pH was not significantly influenced by treatment (5.2±0.11 vs 5.0±0.11 for the control and VIP treatments, respectively). These data indicate that VIP injection may increase ADG and gain:feed in lambs fed high concentrate diets. Further research is needed to verify these results and to delineate the mechanisms responsible for the observed increases in ADG and gain:feed. [ABSTRACT FROM AUTHOR]

A growing number of studies have investigated the viability of feeding hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake (HSC) on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers [19-months old; initial body weight (BW) = 494 ± 10 kg] were fed a corn-based finishing diet (10% forage) containing either 20% HSC (n = 15) or 20% corn distillers grains (Control, n = 16) for 111 days until slaughter. Individual feed intake, feeding behavior and BW were measured throughout the study. Rumen 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. HSC feeding resulted in reduced average daily gain (P = 0.05) without influencing feed intake and feeding behavior (P > 0.05) (reported elsewhere). Sampling time had a significant effect on both ruminal (PERMANOVA: R2 = 0.39; P < 0.001) and nasopharyngeal (R2 = 0.18; P < 0.001) microbial community structure. There was also a significant effect of diet on the ruminal (d7-98; 0.06 = R2 = 0.12; P < 0.05), nasopharyngeal (d 42; R2= 0.18; P < 0.001), and vaginal (R2 = 0.06; P < 0.01) microbiota. Although microbial richness in the rumen, nasopharynx, vagina, and uterus was not affected (P > 0.05) by HSC feeding, microbial diversity (Shannon diversity) was increased in the rumen (d42-98) but reduced in the uterus of HSC heifers (P < 0.05). The relative abundance of five ruminal genera was enriched, while five vaginal genera were reduced in HSC heifers (P < 0.05). Overall, the results of our longitudinal study suggest that feeding hemp by-products can alter the bovine gut, respiratory and reproductive microbiota. [ABSTRACT FROM AUTHOR]

There is interest in feeding industrial hemp production byproducts to livestock, but little is known about the digestibility and ruminal fermentation parameters associated with this feedstuff. A nutrient balance experiment using crossbred steers (n = 5; initial BW = 542 kg, SD = 40 kg) in a Youden square design was conducted to evaluate the effects of feeding hempseed cake (HEMP) or dried corn distillers grains plus solubles [DDGS; each included at 20% of diet dry matter (DM) in respective treatments] in comparison with a dry-rolled corn-based negative control treatment (CON) on ruminal fermentation parameters, nutrient digestibility, nutrient flow and nitrogen (N) balance. Organic matter (OM) tended (P = 0.07) to increase and OM total tract apparent digestibility decreased (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS and CON diets. Total tract apparent N digestibility was greatest (P < 0.01) in steers fed the HEMP diet, while total tract apparent digestibility in all other nutrients was not influenced (P = 0.13) by treatment. Furthermore, apparent ruminal digestibility of OM was greatest (P < 0.01) in steers fed the HEMP or CON diets, and neutral detergent fiber, acid detergent fiber (ADF), and true ruminal digestibility of N was greatest (P = 0.04) in steers fed the HEMP diet. Ruminal total amino acid degradation and total ruminal VFA concentration was greatest (P < 0.01) in steers fed the HEMP diet. A treatment by hour interaction (P = 0.01) was observed for ruminal ammonia concentration. Nitrogen retention was greatest (P < 0.01) in steers fed the HEMP diet, suggesting that feeding hempseed cake improved utilization of N. These results suggest that although ruminal digestibility of all nutrients is greater in steers fed the HEMP diet, greater ADF concentration in hempseed cake negatively influences total tract apparent OM digestibility when fed to finishing steers. [ABSTRACT FROM AUTHOR]

Average daily gain is one of the most important measures producers utilize to measure productivity of beef cattle. The objective was to examine how weather variables influence ADG. Data from 790 beef steers collected using an Insentec feeding system were utilized for this study. Intake data were condensed from daily data into weekly averages (n = 13,739 steer-weeks). The variables considered were ADG (-3.0 to 4.86 kg/d), DMI (2.50 to 21.77kg/d), BW (197.3 to 796.1 kg), dietary energy density (NEm; 1.2 to 2.5 Mcal/kg), average ambient temperature (-23.7 to 21.4 °C), range of temperature (2.8 to 19.4 °C), dew point (-27.8 to 14.3 °C), wind speed (2.08 to 6.49 km/h), solar radiation (30.8 to 297.1 W/m2), and two weeks lag (average of previous two weeks values) and monthly lag (average of previous four weeks values) of each weather variable. Relationship between weather variables were considered while developing the model, including controlling for confounding variables. Residuals of ADG generated after fitting week of year as a fixed effect were used in scatter plots with explanatory variables to identify if non-linear relationships existed. The MIXED procedure of SAS was used to assess the fit and regression parameters of explanatory variables as fixed covariates. Repeated measures were handled using the REPEATED statement and within-individual relationship was accounted for using the Toeplitz covariance structure. Body weight and energy density had linear and quadratic relationships with ADG (Table 1). Two weeks lag of wind speed and monthly lag of solar radiation had positive and negative associations with ADG, respectively, and there were several interactions between weather variables. These data indicate that weather variables influence ADG and should be considered in ADG prediction equations. [ABSTRACT FROM AUTHOR]