Orchardgrass Hay Research Articles

93 Red clover as a functional feed: Effects on rumen microbiota of finishing ram lambs

Abstract Red clover (RC) contains bioactive isoflavones. Supplementing RC as a functional feed (as little as 7.5% of the total diet) has been shown to alter ruminal fermentation and improve feed efficiency in ram lambs fed high-concentrate finishing diets. The objectives of this study were to determine if reduced RC inclusion will produce similar rumen microbiological effects. It was hypothesized that RC supplementation below 7.5% RC will alter rumen microbial community composition during the finishing period. Sixteen individually housed Polypay ram lambs (age; 134 ± 2.5 d; initial body weight: 31 ± 0.53 kg) were used in a complete block design and fed one of four isocaloric and isonitrogenous diets (85:15 concentrate:roughage ratio; n = 4 rams diet1): a control diet in which the roughage component (15.0% wt/wt of total diet) consisted of orchardgrass hay, 2.5%-RC (roughage: 2.5% RC; 12.5% orchardgrass wt/wt), 5.0%-RC (roughage: 5.0% RC; 10% orchardgrass wt/wt), and 7.5%-RC (roughage: 7.5% RC; 7.5% orchardgrass wt/wt). Rumen fluid was collected via oral intubation at 0, 2, 4, 6, and 8 h post-feeding at the end of the adaptation period (14 d; all rams on control diet) and at 21-d intervals during the trial. Rumen functional bacterial guilds, including hyper-ammonia-producing bacteria (HAB), amylolytic, lactate-utilizing (LU), and cellulolytic bacteria were enumerated via serial dilution at 4 h post-feeding. Data were analyzed using PROC MIXED with repeated measures in SAS (v.9.4, SAS inst. Inc., Cary, NC). There were no differences between diets on d 0 for any variable (P > 0.05). At d 21, all RC-containing diets exhibited a 10- to 100-fold reduction in ruminal HAB compared with the control (P < 0.05). While suppression of HAB was no longer apparent by d 42 in 2.5%-RC, HAB had decreased 100-fold (109 to 107) in lambs fed the 5.0%-RC and 7.5%-RC diets (P < 0.01). No differences in amylolytic bacteria were detected on d 21 (P > 0.05), but were 10-fold less in all diets containing RC by d 42 in comparison with control (109 to 108; P = 0.08). In contrast, LU increased by d 21 and were 100-fold greater (106 to 108) by d 42 when compared with the control for all levels of RC supplementation (P < 0.05). Cellulolytic bacteria also increased across the study period in all lambs fed RC diets, with 100-fold greater cellulolytics (106 to 108) by d 42 (P < 0.05). Consistent with the hypothesis, supplementing RC at levels as low as 2.5% wt/wt of the total diet decreased protein-wasting HAB and amylolytic bacteria while coincidingly increasing LU and cellulolytic bacteria in the rumen. These results indicate that adding red clover to finishing diets has the potential to increase lamb growth and feed efficiency through a functional feed action.

Supply of palmitic, stearic, and oleic acid changes rumen fiber digestibility and microbial composition

The concept that fat supplementation impairs total-tract fiber digestibility in ruminants has been widely accepted over the past decades. Nevertheless, the recent interest in the dietary fatty acid profile to dairy cows enlightened the possible beneficial effect of specific fatty acids (e.g., palmitic, stearic, and oleic acids) on total-tract fiber digestibility. Because palmitic, stearic, and oleic acids are the main fatty acids present in ruminal bacterial cells, we hypothesize that the dietary supply of these fatty acids will favor their incorporation into the bacterial cell membranes, which will support the growth and enrichment of fiber-digesting bacteria in the rumen. Our objective in this experiment was to investigate how dietary supply of palmitic, stearic, and oleic acid affect fiber digestion, bacterial membrane fatty acid profile, microbial growth, and composition of the rumen bacterial community. Diets were randomly assigned to 8 single-flow continuous culture fermenters arranged in a replicated 4 × 4 Latin square with four 11-d experimental periods. Treatments were (1) a control basal diet without supplemental fatty acids (CON); (2) the control diet plus palmitic acid (PA); (3) the control diet plus stearic acid (SA); and (4) the control diet plus oleic acid (OA). All fatty acid treatments were included in the diet at 1.5% of the diet (dry matter [DM] basis). The basal diet contained 50% orchardgrass hay and 50% concentrate (DM basis) and was supplied at a rate of 60 g of DM/d in 2 equal daily offers (0800 and 1600 h). Data were analyzed using a mixed model considering treatments as fixed effect and period and fermenter as random effects. Our results indicate that PA increased in vitro fiber digestibility by 6 percentage units compared with the CON, while SA had no effect and OA decreased fiber digestibility by 8 percentage units. Oleic acid decreased protein expression of the enzymes acetyl-CoA carboxylase compared with CON and PA, while fatty acid synthase was reduced by PA, SA, and OA. We observed that PA, but not SA or OA, altered the bacterial community composition by enhancing bacterial groups responsible for fiber digestion. Although the dietary fatty acids did not affect the total lipid content and the phospholipid fraction in the bacterial cell, PA increased the flow of anteiso C13:0 and anteiso C15:0 in the phospholipidic membrane compared to the other treatments. In addition, OA increased the flow of C18:1 cis-9 and decreased C18:2 cis-9,cis-12 in the bacterial phospholipidic membranes compared to the other treatments. Palmitic acid tended to increase bacterial growth compared to other treatments, whereas SA and OA did not affect bacterial growth compared with CON. To our knowledge, this is the first research providing evidence that palmitic acid supports ruminal fiber digestion through shifts in bacterial fatty acid metabolism that result in changes in growth and abundance of fiber-degrading bacteria in the microbial community.

Red clover supplementation modifies rumen fermentation and promotes feed efficiency in ram lambs.

Red clover produces isoflavones, including biochanin A, which have been shown to have microbiological effects on the rumen while also promoting growth in beef cattle. The objective was to determine if supplementation of biochanin A via red clover hay would produce similar effects on the rumen microbiota and improve growth performance of lambs. Twenty-four individually-housed Polypay ram lambs (initial age: 114 ± 1 d; initial weight: 38.1 ± 0.59 kg) were randomly assigned to one of three experimental diets (85:15 concentrate:roughage ratio; N = 8 rams/treatment): CON-control diet in which the roughage component (15.0%, w/w, of the total diet) consisted of orchardgrass hay; 7.5-RC-red clover hay substituted for half (7.5%, w/w, of the total diet) of the roughage component; and 15-RC-the entire roughage component (15.0%, w/w, of the total diet) consisted of red clover hay. Feed intake and weight gain were measured at 14-d intervals for the duration of the 56-d trial, and rumen microbiological measures were assessed on days 0, 28, and 56. Red clover supplementation impacted growth performance of ram lambs. Average daily gains (ADG) were greater in ram lambs supplemented with red clover hay (7.5-RC and 15-RC) than for those fed the CON diet (P < 0.05). Conversely, dry matter intake (DMI) was lower in 7.5-RC and 15-RC than for CON lambs (P = 0.03). Differences in ADG and DMI resulted in greater feed efficiency in ram lambs supplemented with red clover hay (both 7.5-RC and 15-RC) compared to CON (P < 0.01). Rumen microbiota were also altered by red clover supplementation. The total viable number of hyper-ammonia-producing bacteria in 7.5-RC and 15-RC decreased over the course of the experiment and were lower than CON by day 28 (P ≤ 0.04). Amylolytic bacteria were also lower in 15-RC than in CON (P = 0.03), with a trend for lower amylolytic bacteria in 7.5-RC (P = 0.08). In contrast, there was tendency for greater cellulolytic bacteria in red clover supplemented lambs than in CON (P = 0.06). Red clover supplementation also increased fiber utilization, with greater ex vivo dry matter digestibility of hay for both 7.5-RC and 15-RC compared to CON by day 28 (P < 0.03). Results of this study indicate that low levels of red clover hay can elicit production benefits in high-concentrate lamb finishing systems through alteration of the rumen microbiota.

Caecal microbiota in horses with trigeminal-mediated headshaking.

BackgroundTrigeminal‐mediated headshaking (TMHS) in horses is a form of neuropathic pain of undetermined cause that often results in euthanasia. The role of microbiota in TMHS has not been investigated in diseased horses.ObjectiveTo investigate if gastrointestinal microbiota in the cecum is different in horses with TMHS compared to a control population, during a summer season with clinical manifestations of disease.AnimalsTen castrated horses: five with TMHS and five neurologically normal controls.MethodsAll horses were sourced from our institution and kept under the same husbandry and dietary conditions. All horses were fed orchard grass hay for 30 days and then were euthanized due to chronic untreatable conditions including TMHS and orthopedic disease (control group). Caecal samples for microbiota analysis were collected within 20 min after euthanasia. Sequencing was performed using an Illumina MiSeq platform and the microbiome was analyzed.ResultsThe caecal microbiota of horses with TMHS was similar to control horses in terms of diversity but differed significantly with Methanocorpusculum spp. having higher abundance in horses with TMHS. Conclusions and clinical importance Methanocorpusculum spp. was more abundant in the cecum of horses with TMHS. However, its role in disease is unknown. Furthermore, it could also represent an incidental finding due to our small population size.

Effects of early high nutrition related to metabolic imprinting events on growth, carcass characteristics, and meat quality of grass-fed Wagyu (Japanese Black cattle).

The study was conducted to clarify how early high plane of nutrition related to metabolic imprinting affected growth, carcass characteristics, and meat quality of grass-fed Wagyu (Japanese Black cattle). Wagyu steers were allocated randomly into 2 dietary groups: (1) steers fed milk replacer (crude protein 26.0%, crude fat 25.5%; maximum intake 0.6 kg/d) until 3 mo of age and then fed roughage (orchard grass hay) ad libitum from 4 to 10 mo of age (roughage group, RG; n = 11); (2) steers fed milk replacer (maximum intake of 1.8 kg/d) until 3 mo of age and then fed a high-concentrate diet from 4 to 10 mo of age (early high nutrition, EHN; n = 12). After 11 mo of age, all steers were fed roughage ad libitum until 31 mo of age and then slaughtered. Growth performance, carcass traits, longissimus muscle (LM) meat quality and intramuscular fat (IMF) content, plasma insulin-like growth factor I (IGF-I) concentration, and bone mineral density were measured. Body weight was greater in EHN steers (571 kg) than RG steers (520 kg; P < 0.01). Plasma IGF-I levels were higher in EHN steers than in RG steers at 3, 10, and 14 mo of age (P < 0.01, P < 0.005, P < 0.001, respectively); however, plasma IGF-I levels were lower in EHN steers compared with RG steers at 30 mo of age (P < 0.01). The total weight of the muscles and bones of the left half of the carcass was not different between the 2 groups (P = 0.065). Five of the 19 muscles investigated (semimembranosus, P = 0.036; infraspinatus, P = 0.024; supraspinatus, P = 0.0019; serratus ventralis cervicis, P = 0.032; serratus ventralis thoracis, P = 0.027) were heavier in EHN steers. Total fat weight in the left half of the carcass was 30% greater (P = 0.025) in HNE carcasses. Subcutaneous and perirenal fat weights were 53% and 84% greater (P = 0.008, P = 0.002, respectively) in EHN carcasses. The LM IMF content was greater in EHN loins (13.2%) compared with RG loins (9.4%) at 31 mo of age (P = 0.038); however, no differences were found for shear force, tenderness, and cook loss. These results suggested early high-nutrition affected the growth and meat quality of livestock.

99 Determining dominance hierarchy of horses in an equine assisted services program

An ethogram was constructed as part of an undergraduate research course and used to determine the dominance hierarchy of a small (n = 4) herd of horses in a university-based equine-assisted services program. The herd consisted of one gelding and 3 mares ranging in age from 10 to 27 years. An ethogram of mutually exclusive agonistic behaviors was developed, with behaviors further defined and sub-categorized as either aggressive (approach, arched neck threat, bite, bite threat, boxing, circling, chase, ears pinned, following, grasping, head bowing, head threat, herding, interference, kick, kick threat, mount, neck wrestle, head on body, nip, push, rear stomp, strike, strike threat) or submissive (retreat/avoidance, balk, rump presentation, snapping). Horses had been group housed together during daytime hours for 22 mo before the study in a 23 by 38 m dry lot with ad libitum access to clean water and one round bale of mixed brome, timothy and orchardgrass hay. At approximately 4:30 p.m. daily horses were brought inside where they were maintained overnight in individual 3 by 3 m stalls with pine shavings and fed evening and morning grain meals with access to water and grass and/or alfalfa hay to meet their dietary requirements. When group housed, horses had access to shade in the morning hours, but no covered shelter. Horses were observed in June 2020 where the average temperature was 22°C, and ranged from 10 to 37°C and the average relative humidity was 61%, ranging from 18 to 100%. Horse behaviors were recorded in 1-h intervals between 9 a.m. and 4 p.m. on random days with 4 replicates of each hour for a total of 28 h of observation. All agonistic horse interactions were recorded as event behaviors. At the conclusion of the study, a score of +1 was assigned to all aggressive agonistic behaviors performed by a horse and –1 assigned to all submissive agonistic behaviors performed by a horse. The point value of all behaviors performed by each horse was added together. The hierarchy rank was then determined by the total scores, with more positive scores equaling a higher social ranking in the herd. Scores for horses from most dominant to least dominant were +168, +32, +20 and –52. These scores reflected a clearly dominant mare in the herd, as well as a dominance hierarchy that matched the hypothesized social structure based on informal observations. Awareness of social hierarchy among horses is essential for good herd management as well as human and equine safety, particularly in equine assisted services programs.

Effects of adding live Saccharomyces cerevisiae and Aspergillus-based enzyme extracts on ruminal fermentation, plasma polyamine concentrations, and fiber digestibility in beef steers fed a high-forage diet

We evaluated the effects of adding live Saccharomyces cerevisiae (SC) and Aspergillus -based extract (ABE) on rumen fermentation, plasma polyamine concentrations, and in vitro fiber digestibility in beef steers fed mixed red clover–orchardgrass hay. Eight rumen-cannulated Angus crossbred beef steers were assigned to 4 treatments arranged in a replicated 4 × 4 Latin square design with four 21-d periods. Dietary treatments were (1) control (CON; basal diet without additive), (2) SC (CON + 15 g/d of live SC), (3) ABE (5 g of ABE), and (4) SC+ABE (15 g/d of live SC + 5 g of ABE). On d 21, blood samples were collected before morning feeding for plasma metabolome analysis (including polyamines such as spermines, spermidine, and putrescine). Rumen fluid samples were collected 3, 6, and 9 h after feeding for analysis of VFA, ammonia-N concentrations, and in vitro DM and NDF digestibility. Compared with CON, neither SC nor ABE had effects ( P > 0.10) on rumen fermentation and in vitro digestibility. In contrast, SC+ABE increased ( P ≤ 0.05) the ruminal concentrations of acetate, butyrate, and total VFA and in vitro DM and NDF digestibilities. Both SC and SC+ABE increased ( P < 0.05) plasma concentrations of spermidine, spermine, and kynurenine. Supplementation of SC with or without ABE to forage-fed beef steers increased plasma concentrations of polyamines and kynurenine, a possible indication of improved immune function; however, combining SC and ABE, but not SC alone, improved the rumen fermentation and in vitro fiber digestibility.

PSIV-14 Fecal Microbiome of Horses Grazing Integrated Warm- and Cool-Season Grass Rotational Pasture Systems

Abstract The objective of this study was to characterize shifts in the fecal microbiota of horses grazing different forage types within integrated cool- and warm-season grass (CSG; WSG) pasture systems and to explore relationships between forage nutrients and microbial composition. Eight mares grazed integrated rotational systems containing mixed CSG and one of two WSG: bermudagrass or crabgrass. Fecal samples were collected after 2–3 weeks grazing WSG, CSG, and following an orchardgrass hay diet (HAY). Forage nutrients were determined by near-infrared spectroscopy and analyzed by two-way ANOVA in SAS (v.9.4). Following DNA extraction, 16S rRNA gene sequence analysis was conducted in QIIME 2 (v.2020.2) with Kruskall-Wallis tests for alpha diversity, Spearman correlation with forage nutrients, and taxonomic assignment with Greengenes. A random forest classifier and regressor determined ability to predict forage type and nutrients based upon bacterial composition. Statistical significance was set at p ≤ 0.05. Forage water-soluble carbohydrates (WSC) were greatest in CSG and lowest in WSG; neutral detergent fiber (NDF) was greater in HAY than CSG or WSG. Species richness and evenness (Shannon Index) was greater in horses adapted to WSG vs. CSG or HAY and was correlated with WSC (rs = -0.49) and ethanol-soluble carbohydrates (ESCrs = -0.62). The random forest classifier resulted in model accuracy of 1.0 and identified amplicon sequence variants (ASV) most important in prediction of forage type. Sixteen ASV were from the order Clostridiales including Lachnospiraceae, Ruminococcacceae, and Veillonellaceae families and the genus Coprococcus. Other important taxa included Prevotella spp., Streptococcus luteciae, and Fibrobacter succinogenes. The regressor accurately predicted WSC (r2 = 0.95) and ESC (r2 = 0.84), but not NDF (r2 = 0.09). These results suggest that the equine hindgut microbiome is impacted by forage type and soluble carbohydrate content; however, further research is required to determine functional and physiological significance in grazing horses.

Postprandial Blood Glucose and Insulin Responses of Horses to Feeds Differing in Soluble Fiber Concentration

In humans, the consumption of soluble fibers reduces glycemic response after a meal. We hypothesized high soluble fiber diets would reduce and delay postprandial glucose and insulin responses in horses. In a 4 × 4 Latin square design experiment, four Quarter Horse geldings were adapted to diets containing orchardgrass hay (ORCH) or ORCH with 1 of 3 treatment ingredients: molassed sugar beet pulp (BEET), almond hulls (HULL), or steam-crimped oats (OATS). Blood was serially sampled for 6 hours after feeding 0.15% body weight (BW) of the treatment ingredient (meal test) or 1.1 g starch/kg BW from oats plus the treatment ingredient (starch test) to evaluate glycemic and insulinemic responses. Glycemic response during the meal test peaked between 60 and 90 min after feeding (P < .05) and tended to be altered by diet (P = .071) and diet × time (P = .076). Serum insulin was affected by diet (P = .008), time (P < .001), and diet × time (P < .001) during the meal test, with concentrations lower in ORCH compared with BEET and OATS (P < .05). In the starch test, glucose was lower (P < .05) in ORCH and HULL compared with BEET and insulin was lower (P = .046) in ORCH compared with BEET. In both tests, horses took longer (P < .05) to consume HULL, likely influencing postprandial responses. Future research integrating the functional properties of feeds with physiological responses will be necessary to elucidate how soluble fiber affects postprandial glucose metabolism in horses.

Initial effects of supplemental forages and feedstuffs on bovine rumen ecology in vitro as determined by DNA-based molecular procedures

ABSTRACT This research aided in determining the impacts on rumen microbial ecology when supplemental forages and feedstuffs were added for 48 h after an initial 24-h in vitro rumen fermentation of orchardgrass (Dactylis glomerata L.) hay. Short-term shifts in bovine rumen community structure (bacteria, archea, protozoa, and fungi) resulting from each separate forage and feedstuff addition were measured using unique operational taxonomic units (OTU)s contained in terminal-restriction fragment length polymorphism (T-RFLP) profiles. The Tukey Vacuum Cleaner Analysis (TVCA) model of bacteria accounted for 66.3% of the treatment variance and OTUs clustered into 3 distinct groupings. The model developed for TVCA analysis of archaea accounted for 76.6% of the treatment variance and OTUs clustered into 2 distinct groupings. The TVCA treatment variance of protozoa accounted for 75.8% and OTUs clustered into 3 distinct groupings. Additions of various forages and feedstuffs did not result in shifts in fungal community structure in the short-term experiment. Our results demonstrate that the rumen ecology using initial T-RFLP profiles in vitro of bacteria, archaea, and protozoa and a TVCA analysis can identify pattern groupings of forages and feedstuffs. Groupings of forages and feedstuffs can help refine supplementation for improved nutritional management of ruminants.

Digestibility and Retention Time of Coastal Bermudagrass (Cynodon dactylon) Hay by Horses.

Simple SummaryLonger retention of forages with increased fiber concentrations may be a compensatory digestive strategy in horses. We investigated the digestive characteristics of bermudagrass hay, a prominent warm-season grass in the southeast United States that has greater fiber concentrations than other common forages fed to horses. The morphological structure and photosynthetic pathway of warm-season grasses differ from cool-season grasses and legumes which may have important impacts on equine digestion and digesta transit through the gastrointestinal tract. The retention time of Coastal bermudagrass was longer than alfalfa or orchardgrass hay. The digestibility of Coastal bermudagrass decreased with increasing maturity, but the fiber digestibility of alfalfa and orchardgrass was similar to the earliest maturity of Coastal bermudagrass hay. The chemical composition of the plant cell wall influences diet digestibility and is a major difference between warm-season and cool-season forages. The increased retention time of Coastal bermudagrass allows for microbial fermentation to occur longer, adapting to more difficult-to-digest plant cell walls in warm-season forages. The decrease in diet digestibility when horses consume warm-season forages can be reduced by feeding early maturity forage, by harvesting hay at an earlier stage of growth or managing pastures in a vegetative state.Bermudagrass (Cynodon dactylon) and other warm-season grasses are known for their increased fiber concentrations and reduced digestibility relative to cool-season grasses and legumes. This study investigated the digestive characteristics and passage kinetics of three maturities of Coastal bermudagrass hay. A 5 × 5 Latin square design experiment was used to compare the digestion of five hays: alfalfa (Medicago sativa, ALF), orchardgrass (Dactylis glomerata, ORCH), and Coastal bermudagrass harvested at 4 (CB 4), 6 (CB 6), and 8 weeks of regrowth (CB 8). Horses were fed cobalt-ethylenediaminetetraacetic acid (Co-EDTA) and ytterbium (Yb) labeled neutral detergent fiber (NDF) before an 84-h total fecal collection to determine digesta retention time. Dry matter digestibility was greatest for ALF (62.1%) and least for CB 6 (36.0%) and CB 8 diets (36.8%, SEM = 2.1; p < 0.05). Mean retention time was longer (p < 0.05) for Coastal bermudagrass (particulate 31.3 h, liquid 25.3 h) compared with ORCH and ALF (28.0 h, SEM = 0.88 h; 20.7 h, SEM = 0.70 h). Further evaluation of digesta passage kinetics through mathematical modeling indicated ALF had distinct parameters compared to the other diets. Differences in digestive variables between forage types are likely a consequence of fiber physiochemical properties, warranting further investigation on forage fiber and digestive health.

Effects of two equine digestive aid supplements on hindgut health.

Gastrointestinal disease is the number one killer of horses. Little is known about the maintenance of microbes in the equine hindgut and how to distinguish a healthy gut in a live horse. Utilization of internal and external digestibility markers and starch fermentation has been extensively studied in ruminants and is the basis for research conducted on horses. The aims of this study were to investigate the effects of two equine feed digestive aid supplements on hindgut health (HGH) as reflected in fecal pH and digestibility and to compare and validate DM digestibility measurements through the use of internal and external markers such as chromium oxide (CR), lignin (Lig), indigestible ADF (iADF), indigestible NDF (iNDF), and indigestible lignin (iLig). Nine mature Quarter horses (six geldings, three mares) were used in a crossover design, three feeding periods of 17 d (51 d total), using three treatments: control, no feed additive (CON), Smartpak (SP; Plymouth, MA), or Platinum Performance (PP; Buellton, CA). Both SP and PP contained a strain of Lactobacillus, whereas SP further supplied mannanoligosaccharides (MOS) and fructooligosaccharides (FOS) and PP supplied Saccharomyces boulardii. Within the 17-d period, horses were offered orchard grass hay and sweet cob grain and the assigned treatment daily and four CR cookies to deliver 8 g/d of CR for the last 7 d of each period. Total feces were collected from 15 to 17 d. Feed and fecal samples were dried, ground, and sent to ANALAB (Fulton, IL) for nutrient analysis. Duplicate samples of feed and feces were placed in ruminally cannulated cows for in situ determination of iADF, iNDF, and iLig to estimate digestibility. Estimated CR fecal output, CR DMI, and DM digestibilities were evaluated using the root mean square prediction error percentage of the observed mean (RMSPE), concordance correlation coefficient (CCC), and Nash–Sutcliffe efficiency methods. Marker predictive ability tests showed iADF to have the least amount of bias with the smallest RMSPE (4%), largest CCC (0.43), and the largest amount of random bias (error of dispersion = 0.45). Supplementation of PP decreased CR DM digestibility (P < 0.02). Smartpak increased fecal pH (P < 0.09), but PP had no effect on fecal pH. Therefore, SP had a beneficial effect on HGH that is believed to be due to MOS and FOS.

Effect of replacing calcium salts of palm oil with camelina seed at 2 dietary ether extract levels on digestion, ruminal fermentation, and nutrient flow in a dual-flow continuous culture system

Camelina is a drought- and salt-tolerant oil seed, which in total ether extract (EE) contains up to 74% polyunsaturated fatty acids. The objective of this study was to assess the effects of replacing calcium salts of palm oil (Megalac, Church & Dwight Co. Inc., Princeton, NJ) with camelina seed (CS) on ruminal fermentation, digestion, and flows of fatty acids (FA) and AA in a dual-flow continuous culture system when supplemented at 5 or 8% dietary EE. Diets were randomly assigned to 8 fermentors in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square design, with four 10-d experimental periods consisting of 7 d for diet adaptation and 3 d for sample collection. Treatments were (1) calcium salts of palm oil supplementation at 5% EE (MEG5); (2) calcium salts of palm oil supplementation at 8% EE (MEG8); (3) 7.7% CS supplementation at 5% EE (CS5); and (4) 17.7% CS supplementation at 8% EE (CS8). Diets contained 55% orchardgrass hay, and fermentors were fed 72 g of dry matter/d. On d 8, 9, and 10 of each period, digesta effluent samples were taken for ruminal NH3, volatile fatty acids, nitrogen metabolism analysis, and long-chain FA and AA flows. Statistical analysis was performed using the MIXED procedure (SAS Institute Inc., Cary, NC). We detected an interaction between FA source and dietary EE level for acetate, where MEG8 had the greatest molar proportion of acetate. Molar proportions of propionate were greater and total volatile fatty acids were lower on CS diets. Supplementation of CS decreased overall ruminal nutrient true digestibility, but dietary EE level did not affect it. Diets containing CS had greater biohydrogenation of 18:2 and 18:3; however, biohydrogenation of 18:1 was greater in MEG diets. Additionally, CS diets had greater ruminal concentrations of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid. Dietary EE level at 8% negatively affected flows of NH3-N (g/d), nonammonia N, and bacterial N as well as the overall AA outflow. However, treatments had minor effects on individual ruminal AA digestibility. The shift from acetate to propionate observed on diets containing CS may be advantageous from an energetic standpoint. Moreover, CS diets had greater ruminal outflow of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid than MEG diets, suggesting a better FA profile available for postruminal absorption. However, dietary EE at 8% was deleterious to overall N metabolism and AA outflow, indicating that CS can be fed at 5% EE without compromising N metabolism.

Nutritional evaluation and ruminal fermentation patterns of kochia compared with alfalfa and orchardgrass hays and ephedra and cheatgrass compared with orchardgrass hay as alternative arid-land forages for beef cattle in two dual-flow continuous culture system experiments.

The objective was to evaluate the ruminal fermentation patterns of forage kochia (FK) compared with alfalfa hay (AH) and orchardgrass hay (OH) (Exp. 1), and ephedra (EPH) and immature cheatgrass (CG) compared with OH (Exp. 2), using a dual-flow continuous culture system. Two in vitro experiments were conducted, and in each experiment, treatments were randomly assigned to six dual-flow fermenters (1,223 ± 21 mL) in a replicated 3 × 3 Latin square design, with three consecutive periods of 10 d each, consisting of 7 d for diet adaptation and 3 d for sample collection. Each fermenter was fed a total of 72 g/d (DM basis) and treatments were as follows: Exp. 1: 1) 100% OH, 2) 100% AH, and 3) 100% dried FK. Exp. 2: 1) 100% OH, 2) 100% dried CG, and 3) 100% dried EPH. On day 8, 9, and 10, samples of solid and liquid effluent from each fermenter were taken for digestibility analysis, and subsamples were collected for NH3-N, VFA, and bacterial N determinations. Data were analyzed using the MIXED procedure of SAS. In Exp. 1, treatments did not affect DM, OM, and NDF digestibilities, total VFA and molar proportions of acetate, propionate, butyrate, and branched-chain VFA. True CP digestibility, ruminal NH3-N concentration, and total N, NH3-N, NAN, and dietary N flows (g/d) were greater (P < 0.05) for FK compared with the other forages. However, treatments did not affect bacterial efficiency. In Exp. 2, DM, OM, and CP digestibilities were greater (P = 0.01) for EPH, and NDF digestibility was greater (P < 0.05) for EPH and CG compared with OH. Ephedra had the highest (P < 0.05) pH and acetate:propionate ratio and the lowest (P < 0.05) total VFA concentration. Total VFA, ruminal NH3-N concentration, and NH3-N flow (g/d) were highest (P < 0.05) for CG. Total N flow and bacterial efficiency were highest (P < 0.05) for OH and CG, while the flows (g/d) of NAN, bacterial N, and dietary N were greater (P < 0.05) for OH compared with the other forages. Results indicate that when compared with AH and OH (Exp. 1), FK has similar ruminal fermentation patterns and may be an adequate alternative for beef cattle producers. Furthermore, when compared with OH (Exp. 2), immature CG may also be an adequate forage alternative. This is especially important for areas in which conventional forages may not grow well such as the U.S. arid-land. However, EPH should not be used as the sole forage due to its poor ruminal fermentation as evidenced by the lowest total VFA concentration and propionate molar proportion.

Camelina Seed Supplementation at Two Dietary Fat Levels Change Ruminal Bacterial Community Composition in a Dual-Flow Continuous Culture System.

This experiment aimed to determine the effects of camelina seed (CS) supplementation at different dietary fat levels on ruminal bacterial community composition and how it relates to changes in ruminal fermentation in a dual-flow continuous culture system. Diets were randomly assigned to 8 fermenters (1,200–1,250 mL) in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square with four 10-day experimental periods that consisted of 7 days for diet adaptation and 3 days for sample collection. Treatments were: (1) no CS at 5% ether extract (EE, NCS5); (2) no CS at 8% EE (NCS8); (3) 7.7% CS at 5% EE (CS5); and (4) 17.7% CS at 8% EE (CS8). Megalac was used as a control to adjust EE levels. Diets contained 55% orchardgrass hay and 45% concentrate, and fermenters were equally fed a total of 72 g/day (DM basis) twice daily. The bacterial community was determined by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequencing data were analyzed using mothur and statistical analyses were performed in R and SAS. The most abundant phyla across treatments were the Bacteroidetes and Firmicutes, accounting for 49 and 39% of the total sequences, respectively. The bacterial community composition in both liquid and solid fractions of the effluent digesta changed with CS supplementation but not by dietary EE. Including CS in the diets decreased the relative abundances of Ruminococcus spp., Fibrobacter spp., and Butyrivibrio spp. The most abundant genus across treatments, Prevotella, was reduced by high dietary EE levels, while Megasphaera and Succinivibrio were increased by CS supplementation in the liquid fraction. Correlatively, the concentration of acetate was decreased while propionate increased; C18:0 was decreased and polyunsaturated fatty acids, especially C18:2 n-6 and C18:3 n-3, were increased by CS supplementation. Based on the correlation analysis between genera and fermentation end products, this study revealed that CS supplementation could be energetically beneficial to dairy cows by increasing propionate-producing bacteria and suppressing ruminal bacteria associated with biohydrogenation. However, attention should be given to avoid the effects of CS supplementation on suppressing cellulolytic bacteria.

Physiological Effect of Cutting Height and High Temperature on Regrowth Vigor in Orchardgrass.

Producers of orchardgrass (Dactylis glomerata L.) hay in the Mid-Atlantic US have experienced a reduction in regrowth vigor and a decline in the persistence of their swards. The common management practice for the region is to harvest the first growth of hay by cutting at 2.5–7.5 cm height in May or June. We hypothesize that high temperature and low cutting height interact to limit the regrowth rate. To test this, orchardgrass plants were cut to either 2.5 or 7.5 cm and then placed into environmentally controlled chambers with a constant temperature of 20 or 35°C. Stubble was harvested on days 0, 1, 3, and 11 following cutting and subjected to metabolite analysis. Photosynthetic parameters were measured in the regrown leaves on days 3 and 11, and regrowth biomass was recorded on day 11. Under optimal growth temperature (20°C), vegetative regrowth upon defoliation was significantly enhanced when more stubble tissue remained. However, this advantage was not observed under heat stress. Defoliation generally decreases the abundance of carbohydrate reserves in stubble. Interestingly, high temperature stimulated the accumulation of starch and ethanol-soluble carbohydrates in plants cut to 7.5 cm. The similar trends were also observed in protein, amino acids, nitrate, and ammonium. These responses were not pronounced in plants cut to 2.5 cm, presumably due to inhibited photosynthesis and photosystem II photochemistry. Overall, we anticipated that heat-activated metabolite accumulation is part of adaptive response to the stress. However, modified allocation of carbohydrate and nitrogen reserves leads to reduced vegetative regrowth upon defoliation. These data suggest that cutting height management for orchardgrass may be more effective for its regrowth vigor and productivity in cool seasons or when cool weather follows hay harvest.

Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems

Previous research indicated that there were significant differences in rumen-undegradable protein (RUP) among canola meals (CM), which could influence the nutritional value of CM. The objectives of this study were to (1) evaluate the effects of feeding CM with different RUP contents on ruminal fermentation, nutrient digestion, and microbial growth using a dual-flow continuous culture system (experiment 1) and (2) evaluate ruminal gas production kinetics, in vitro organic matter (OM) digestibility, and methane (CH4) production of soybean meal (SBM) and CM with low or high RUP in the diet or as a sole ingredient using a gas production system (experiments 2 and 3). In experiment 1, diets were randomly assigned to 6 fermentors in a replicated 3 × 3 Latin square. The only ingredient that differed among diets was the protein supplement. The treatments were (1) solvent-extracted SBM, (2) low-RUP solvent-extracted CM (38% RUP as a percentage of crude protein), and (3) high-RUP solvent-extracted CM (50% RUP). Diets were prepared as 3 concentrate mixtures that were combined with 25% orchardgrass hay and 15% wheat straw (dry matter basis). Experiments 2 and 3 had the same design with 24 bottles incubated 3 times for 48 h each. During the 48-h incubation, the cumulative pressure was recorded to determine gas production kinetics, in vitro OM digestibility, and CH4 production. In experiment 1, N flow (g/d), efficiency of N use, efficiency of bacterial N synthesis, total volatile fatty acids (mM), and molar proportion of acetate, propionate, and isobutyrate were not affected by treatments. There were tendencies for a decrease in ruminal NH3-N and an increase in molar proportion of butyrate for the SBM diet compared with both CM diets. The molar proportion of valerate was greater in both CM diets, whereas the molar proportion of isovalerate and total branched-chain volatile fatty acids was lower for the CM diets compared with the SBM diet. In experiments 2 and 3, the SBM diet had a greater gas pool size than both CM diets. The SBM diet increased in vitro OM digestibility; however, it also tended to increase CH4 production (mM and g/kg of DM) compared with both CM diets. Based on the results of this study, CM with RUP varying from 38 to 50% of crude protein does not affect ruminal fermentation, nutrient digestion, and microbial growth when CM is included at up to 34% of the diet.

Rumen-protected arginine alters blood flow parameters and luteinizing hormone concentration in cyclic beef cows consuming toxic endophyte-infected tall fescue seed.

The objective of this study was to determine the effect of rumen-protected arginine on median caudal artery blood flow and LH dynamics in cows fed toxic endophyte-infected tall fescue seed. Four ruminally cannulated nonlactating beef cows (539 ± 30 kg) were used in a 2 × 2 factorial arrangement of treatments utilizing a 4 × 4 Latin square design with 4 periods of 31 d each. Each cow was assigned to individual pens and fed orchardgrass hay (10.3% CP and 85% NDF; OM basis) during a 10-d adaptation period, followed by a 21-d collection period in which each cow was assigned 1 of 4 treatments: 1) rumen-protected Arg (180 mg/kg of BW) and 1.0 kg/d of toxic endophyte-infected fescue seed (AE+), 2) rumen-protected Arg (180 mg/kg of BW) and 1.0 kg/d of endophyte-free fescue seed (AE-), 3) 1.0 kg/d of toxic endophyte-infected fescue seed (E+) alone, or 4) 1.0 kg/d of endophyte-free fescue seed (E-) alone. In each period, Doppler ultrasound measurements for blood flow parameters were quantified on d 1, 5, 10, 15, and 20. On d 20 of each period, blood samples were collected every 10 min for 6 h and then once every hour for 12 h for LH response following exogenous GnRH. There was an Arg × fescue seed type interaction ( = 0.05) for median caudal artery blood flow due to an increase in blood flow in cows fed rumen-protected Arg with endophyte-free fescue seed. In addition, mean blood flow velocity in the artery was greater ( = 0.01) with the inclusion of rumen-protected Arg in the diet. Median caudal artery area ( = 0.03) and diameter ( = 0.01) were decreased in cows consuming E+ compared to those consuming E- with no effect ( ≥ 0.38) by Arg inclusion. Circulating nitric oxide (NO) concentrations tended to be influenced ( = 0.09) by the interaction of Arg × fescue seed type with E+ alone decreasing NO concentrations. Circulating NO concentrations were unaffected by rumen-protected Arg ( = 0.48). Mean serum LH concentration exhibited ( = 0.02) an Arg × fescue seed type interaction. Cows consuming E+ had decreased ( < 0.05) LH concentrations compared to all other treatments. However, cows consuming AE+ had ( ≥ 0.67) LH concentrations similar to those of cows consuming AE- and E-. Thus, supplementing rumen-protected Arg to cows consuming toxic endophyte-infected fescue seed has the potential to increase reproductive performance and peripheral blood flow.

Relationships Among Digestible Energy Intake, Body Weight, and Body Condition in Mature Idle Horses

The objective of this study was to evaluate the relationships among digestible energy (DE) intake, body weight (BW), and body condition score (BCS) in lean/moderate condition horses. The feed intake of 35 Quarter Horses (age 5.3 ± 1.2 years; BW 462 ± 39 kg; BCS 4.5 ± 0.5) was recorded daily over three, 42-day feeding trials. Horses were offered 1.75–2.00 kg DM/100 kg BW in Orchard grass hay and 0.2 kg/100 kg BW in whole oats. Body weight and BCS were recorded biweekly. Daily DE intake was calculated according to Pagan and recorded as the amount fed minus any refusal. The daily kilogram intake was multiplied by the DE (Mcal/kg) content of the feed to equal the total calories per day. The mean within-horse ΔBW and ΔBCS from 0 to 42 days of each trial were evaluated using paired t tests. Trial 1 horses consumed 24.5 Mcal/d and BW increased (P < .001) by 24 ± 3 kg; however, there was no significant change in BCS (0.0 ± 0.5). Trial 2 horses consumed 22.8 Mcal/d and BW increased (P = .009) by 8 ± 3 kg and BCS tended to increase (P = .06) by 0.5 ± 0.5. Trial 3 horses consumed 25.7 Mcal/d and BW and BCS increased (P < .001) by 22 ± 2 kg and 1.0 ± 0.5, respectively. According to trial, horses required approximately 19, 34, and 18 Mcal/kg of weight gain, respectively. Additional factors affecting weight gain are related to the individual.

Effect of Biochar Type and Size on&amp;lt;i&amp;gt; in Vitro &amp;lt;/i&amp;gt;Rumen Fermentation of Orchard Grass Hay

Biochar, a byproduct from the biofuels industry, may be a potential feed additive in ruminant diets due to possible improvements in microbial fermentation. Therefore, the objective of this study was to determine the nutritive value, in vitro digestibility, volatile fatty acid (VFA) production, and gas production of biochar inclusion to an orchard grass (Dactylis glomerata) basal diet. The study was designed as a 3 × 2 factorial arrangement with 3 different biochar sources and 2 biochar processed sizes as the main effects factors. Experimental treatments were biochar from 3 different tree types: 1) Chestnut Oak (Quercus prinus L.; CO), 2) Yellow Poplar (Liriodendron tulipifera; YP), or 3) White Pine (Pinus strobus L.; WP), and processed at 2 different biochar particle sizes: a) 178 μm (Coarse). Biochar was added to the basal diet of orchard grass hay (872.35 g/kg of DM, 98.31 g/kg of CP, and 704.02 g/kg of aNDF, DM basis) at a rate of 81 g/kg DM. Biochar residual ash content was greater (P P P = 0.01) with lower aNDF content in both WP sizes compared with their respective biochar type and size. Gas production was not influenced (P = 0.23) by biochar tree type; however, gas production was increased (P = 0.05) by Fine particle size compared with Coarse biochar. The in vitro true digestibility (IVTD) of orchard grass hay was increased (P = 0.01) by the inclusion of Fine biochar particle size compared with Coarse particle size. Additionally, in vitro CP true digestibility (DCP) exhibited a type × size interaction (P = 0.01). Crude protein digestibility was lower for Fine particle-sized CO and WP biochar sources compared with Coarse particle-sized CO and WP (P ≤ 0.004). However, DCP was not different between Coarse and Fine particle-sized YP biochar (P = 0.70). Volatile fatty acids (acetate, propionate, and butyrate) were not altered by biochar type (P ≥ 0.66) or particle size (P ≥ 0.19). These results indicate that both tree type and particle size of biochar may need to be carefully considered before incorporating into a ruminant diet. Furthermore, Fine particle-sized biochar may be the most effective to incorporate as a feed additive in a ruminant diet based on digestibility parameters.