Fed Bermudagrass Hay Research Articles

Impact of orange essential oil on enteric methane emissions of heifers fed bermudagrass hay.

In this study, the effects of orange essential oil (OEO) on the rumen fermentation, nutrient utilization, and methane (CH4) emissions of beef heifers fed a diet of bermudagrass (Cynodon dactylon) were examined. In addition, in vitro and in situ experiments were conducted. The in vitro experiment consisted of three treatments: control (CTL, no OEO), OEO1 (0.25% OEO), and OEO2 (0.5% OEO). The forage to concentrate ratio was 70:30 (dry matter [DM] basis) in all treatments. No changes in pH, proportions of volatile fatty acids, and the acetate:propionate ratio were observed (P > 0.05). The addition of 0.25% OEO resulted in a reduction in CH4 production (mL/g) relative to the control (P < 0.05). In the in situ experiment, 5 g of total mixed ration (CTL, OEO1, and OEO2) were incubated for 6, 12, 24, 48, and 72 h. Potential and effective degradability were not affected by OEO supplementation (P > 0.05). In the in vivo study, six crossbred beef heifers (Bos indicus × Bos taurus), fitted with rumen cannulas, were assigned to three different treatments: no additive (CTL), 0.25% OEO (OEO1), and 0.5% OEO (OEO2) in a replicated 3 × 3 Latin square (21-day periods). Heifers were fed at 2.8% body weight. In vivo CH4 production was measured in open-circuit respiration chambers. Reductions in gross energy consumption, apparent total tract digestibility, and rumen valerate concentration were observed for OEO2 compared to the control (P < 0.05). Additionally, decreases in CH4 emissions (g/day; P < 0.05) and CH4 (MJ gross energy intake/day; P < 0.05) were observed in response to supplementation of 0.5% OEO as compared to the CTL treatment. Thus, supplementation of 0.5% OEO reduced CH4 emissions (g/day) by 12% without impacting the DM intake of heifers fed bermudagrass hay as a basal ration.

54 Evaluation of gastric health in cribbing horses fed a digestive support supplement

Cribbing is a stereotypic oral behavior whereby the horse places its incisors on a fixed object, arches its neck, pulls against the object, and emits an audible grunt. Cribbing behavior (CB) has been associated with gastrointestinal (GI) dysfunction and gastric ulceration. This randomized crossover study tested the hypothesis that dietary inclusion of a commercially available equine GI support supplement (Legends Gastrocare, Cargill, Wayzata, MN) would alter the GI environment and gastric ulcer severity in normal and cribbing horses. Mature Quarter Horses with CB (n = 4) and sex-matched non-cribbing controls (NCB; n = 4) were randomly assigned to receive either a GI support supplement (TRT) or placebo for 21 d, followed by a 2-wk washout period. Treatment groups were then switched and horses were treated for an additional 21 d. Before and after each treatment period, gastric and fecal pH were measured, and gastric ulcer severity was evaluated via endoscopic examination using an established grading system for squamous (0–4) and glandular gastric ulceration (0–1). Horses were acclimated for 2 wk before the start of the study, and throughout the study were individually stalled 16 h/d and fed bermudagrass hay (1.2% BW, DM basis) and concentrate (0.5% BW) and turned out in pairs in paddocks 8 h/d. Data were analyzed by mixed-model ANOVA with treatment, cribbing status (CB or NCB) and period included as fixed effects, and horse as a random effect. Data are presented as means ± SD. Fecal pH (6.5 ± 0.1) and gastric pH (2.9 ± 0.5) were similar between CB and NCB horses and were unaffected by TRT. Squamous mucosa ulcer scores did not differ between CB and NCB, and were unaffected by TRT. However, within CB horses, squamous ulcer severity scores were greater (indicating more severe ulceration) ( P = 0.003) with TRT (3.9 ± 0.6) than placebo (1.4 ± 0.3). Based on this pilot study, administration of a commercial GI support supplement did not alter gastric or fecal pH in normal or CB horses. Ongoing serum cortisol, serum gastrin, and microbiome analyses may help to explain the differences in gastric ulceration severity noted in CB horses when receiving TRT versus placebo. Collectively, these findings add to the growing body of literature regarding GI environment and pathophysiology in horses exhibiting CB.

184 President Oral Presentation Pick: Supplementation of Angus crossbred steers with avian-derived polyclonal antibody preparations against ruminal methanogenic Archaea alters ruminal fermentation and decreases ex situ methane production

Abstract An experiment was conducted to evaluate the effect of supplementing fourteen ruminally cannulated Angus crossbred steers with polyclonal antibody preparations (PAP) from avian origin against ruminal methanogens Methanobrevibacter gottschalkii Ho (PAP-Ho) and M. ruminantium M1 (PAP-M1). Steers were fed bermudagrass hay ad libitum and 2 kg d-1 of corn gluten feed. A randomized block design was used, with a 3 × 2 + 1 factorial arrangement, replicated in three periods. Factors were proportions of PAP against Ho and M1 in the mixture (100:0, 50:50, and 0:100 Ho:M1) and level of supplementation of each mixture (3 or 6 mL d-1). Control steers had no PAP supplementation. Steers were adapted to the feeding regimen for 14 d, with no PAP supplementation, followed by a 21-d treatment period. Ruminal fluid (RF) from each steer (experimental unit) was collected before PAP supplementation (h 0) and every 4 h (for a 24-h period) on d 0, 14, and 21 of treatment period for the determination of ruminal fermentation profile. In addition, RF collected at h 0 was individually mixed with McDougall’s Buffer (1:3 ratio) to inoculate serum bottles and polycarbonate tubes for the determination of methane production and in vitro fermentation profile. Treatment means were evaluated by preplanned, non-orthogonal, single-degree-of-freedom contrasts. There was no effect (P ≥ 0.48) of level of inclusion on ex situ methane production (ESMP). When PAP-M1 was used either alone or in combination with PAP-Ho, ESMP decreased (P ≤ 0.05) compared to control. Ex situ ruminal fermentation profile was not different (P ≥ 0.12) across treatments. In vivo molar proportion of propionate tended to be greater (P = 0.10) with supplementation of PAP-M1, alone or combined, compared with control. Polyclonal antibody preparations against ruminal methanogens have the potential to decrease enteric methane emissions.

Comparison of acid-detergent lignin, alkaline-peroxide lignin, and acid-detergent insoluble ash as internal markers for predicting fecal output and digestibility by cattle offered bermudagrass hays of varying nutrient composition

BackgroundThe potential for acid-detergent insoluble ash (ADIA), alkaline-peroxide lignin (APL), and acid-detergent lignin (ADL) to predict fecal output (FO) and dry matter digestibility (DMD) by cattle offered bermudagrass [Cynodon dactylon (L.) Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 hay diets: low (L), medium low (ML), medium high (MH), and high (H) crude protein (CP) concentration (79, 111, 131, and 164 g CP/kg on a DM basis, respectively). Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08:00 and 16:00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake (DMI), DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD.ResultsForage DMI was affected by diet (P = 0.02), and DMI from MH and H was greater (P < 0.05) than from L. Apparent DMD tended (P = 0.08) to differ among diets while FO (P = 0.20) was not affected by diet treatments. Average ADL recovery (1.16) was greater (P < 0.05) than that of ADIA (1.03) and APL (1.06), but ADIA and APL did not differ (P = 0.42). Estimates of FO and DMD derived using APL and ADIA were not different (P ≥ 0.05) from total fecal collection while those using ADL differed (P < 0.05). There was no diet by marker interaction (P ≥ 0.22) for either FO or DMD.ConclusionAcid-detergent insoluble ash and APL accurately predicted FO and DMD of cattle fed bermudagrass hay of varying nutrient composition. These internal markers may facilitate studies involving large numbers of animals and forages. Results from such studies may be used to develop improved equations to predict energy values of forages based on the relationship of dietary components to digestibility across a wide range of forages.

Grazing activity and ruminal bacterial population associated with frothy bloat in steers grazing winter wheat

<h2>ABSTRACT</h2> Two grazing experiments were designed to elucidate the shifts in rumen bacterial populations (Exp. 1) and grazing activities (Exp. 2) in wheat forage diet between bloated and nonbloated steers. In Exp. 1, the bacterial DNA density was greatest for Ruminococcus flavefaciens, Streptococcus bovis, and Eubacterium ruminantium among tested strains when steers were fed bermudagrass hay (d 0). Steers that grazed wheat forage, however, increased the bacterial density of 6 major rumen bacterial populations in bloated steers, indicating that frothy bloat may be associated with a species-specific bacterial population. In Exp. 2, overall time, total grazing, and ruminating time did not differ between bloated and nonbloated steers. In contrast, idling time was greater for bloated (P < 0.01) than for nonbloated steers (10.9 vs. 7.9 h/d, respectively). Bloated steers did not differ in total grazing activity patterns; however, grazing activity in bloated steers decreased (P < 0.05) from 0400 to 0700h and 1400 to 1800h. Ruminating activity in nonbloated steers peaked from 0200 to 0500h and 1900 to 2200h but was lower (P < 0.05) for bloated than for nonbloated steers from 0100 to 0600h and 0700 to 1200h. The data suggest that rumen bacterial populations and grazing activities changed when steers experienced frothy bloat.

Flavor Compounds and Quality Parameters of Chevon As Influenced by Sericea Lespedeza Hay

This research assessed the utilization of sericea lespedeza (SL, Lespedeza cuneata ) hay, a highly condensed tannin (CT) forage (87-181 g CT/kg), as a dietary regimen of meat goats, and thereby the effects on physicochemical properties of goat meat (chevon) and flavor compounds in cooked chevon chops were evaluated. Although it is commonly believed that higher amounts of CT can have deleterious effects on animal performance due to low digestibility and low voluntary intakes in ruminants, feeding meat goats with SL hay increased the body weight compared to goats fed bermudagrass hay without altering the chemical composition and meat quality of chevon. Feeding SL hay to meat goats also did not significantly influence the flavor volatiles in cooked chevon chops. The findings indicate that SL hay can be used as a low-input forage to replace expensive forages.

Using copper oxide wire particles or sericea lespedeza to prevent peri-parturient gastrointestinal nematode infection in sheep and goats

Gastrointestinal nematodes (GIN) continue to plague the small ruminant industry, especially in parts of the world with warm, humid climates. Alternatives to chemicals are needed for GIN control because of anthelmintic resistance and a desire to reduce chemical residues in meat products. Three experiments using peri-parturient does or ewes addressed the objective: 1) in Arkansas, meat goats were untreated ( n = 20) or fed copper oxide wire particles (COWP; 2 g each) in pelleted sericea lespedeza ( Lespedeza cuneata; n = 22) before kidding while consuming sericea lespedeza hay, 2) in Arkansas, 42 Katahdin ewes were randomly assigned to remain untreated or were fed COWP (2 g each) before lambing within groups fed bermudagrass ( Cynodon dactylon) or sericea lespedeza hay in a 2 × 2 factorial design, 3) in Louisiana, Gulf Coast Native ewes were randomly assigned to remain untreated or were fed COWP (4 g each) in a pelleted ration ( n = 10 each) after lambing began. Fecal egg counts (FEC) and blood packed cell volume (PCV) were determined weekly in all experiments, and coproculture to examine GIN species was conducted in the first two experiments. Haemonchus contortus is typically the predominant GIN in the southeastern U.S., even during cooler months. However, Trichostrongylus spp. was the predominant GIN in Arkansas during these experiments. In all of the experiments, feeding COWP led to a reduction in FEC, but no change in PCV. The sericea lespedeza hay fed to ewes in Experiment 2 was associated with a reduction in FEC compared with ewes fed bermudagrass hay. Kids and lambs from COWP-treated dams in two experiments were lighter than those from untreated dams. Sericea lespedeza aided in the control of GIN infection, and while feeding COWP to peri-parturient ewes and does offered some reduction in GIN infection, body weight of offspring at birth and 60 or 90 days of age may be reduced.

Rumen Bacterial Diversity Dynamics Associated with Changing from Bermudagrass Hay to Grazed Winter Wheat Diets

Rumen bacterial communities in forage-fed and grazing cattle continually adapt to a wide range of changing dietary composition, nutrient density, and environmental conditions. We hypothesized that very distinct community assemblages would develop between the fiber and liquid fractions of rumen contents in animals transitioned from bermudagrass hay diet to a grazed wheat diet. To address this hypothesis, we designed an experiment utilizing a 16S-based bTEFAP pyrosequencing technique to characterize and elucidate changes in bacterial diversity among the fiber and liquid rumen fractions and whole rumen contents of 14 (Angus x Hereford) ruminally cannulated steers sequentially fed bermudagrass hay (Cynodon dactylon; 34 days) and grazing wheat forage (28 days). Bermudagrass hay was a conserved C4 perennial grass lower in protein and higher in fiber (11% and 67%, respectively) content than grazed winter wheat (Triticum aestivum), a C3 annual grass with higher protein (20%) and a large (66%) soluble fraction.Significant differences in the OTU estimates (Chao1, Ace,and Rarefaction) were detected between fractions of both diets, with bermudagrass hay supporting greater diversity than wheat forage. Sequences were compared with a 16S database using BLASTn and assigned sequences to respective genera and genera-like units based on the similarity value to known sequences in the database. Predominant genera were Prevotella (up to 33%) and Rikenella-like (upto 28%) genera on the bermudagrass diet and Prevotella (upto 56%) genus on the wheat diet irrespective of the fractions. Principle component analyses accounted for over 95% of variation in 16S estimated bacterial community composition in all three fractions and clearly differentiated communities associated with each diet. Overall, bermudagrass hay diets clustered more clearly than wheat diets.These data are the first to explore bacterial diversity dynamics in a common population of animals in response to contrasting grass forage diets.

Evaluation of Whole, In-Shell Peanuts as a Supplemental Feed for Beef Cows

<h2>ABSTRACT</h2> Two trials were conducted to evaluate the suitability of whole, in-shell peanuts (WP) as an energy and protein supplement feed for beef cattle. A digestion trial used 18 steers (265kg average BW). The steers were fed bermudagrass hay plus 1 of 3 supplement treatments: 1) corn and cottonseed meal (50:50; CCSM), 2) corn and WP (50:50; CWP), or 3) WP. The supplements were fed at 1.4 kg/d per head. Hay and diet DM consumption, and apparent digestibility of DM, ADF, and NDF were reduced (P < 0.03) for the WP treatment compared with CCSM and CWP; CCSM and CWP were similar. Digestibility of CP for the WP treatment was similar to CCSM. A cow trial used 80 mature cows (573kg BW) to determine the effects of feeding WP on performance of the cows and their progeny. The cows were fed free-choice bermudagrass hay and either CCSM (50:50) or WP 3 times weekly to provide an average of 1.1 kg/d per head. The trial was conducted for 2yr (40 cows/yr) and lasted for 84 d each year. Supplement treatment did not affect BCS, but BW gain tended to be lower for WP compared with CCSM (P = 0.09). Subsequent calf birth weight, survival rate, and weaning weight, and subsequent cow AI conception rate were not affected by treatment. The WP used in the cow trial averaged (n = 4) 93% DM, 22% CP, 41% ether extract, 25% ADF, and 34% NDF. Results indicate that WP may have potential as an energy and protein supplement for mature beef cows.

Effects of dietary n-6:n-3 fatty acid ratio on feed intake, digestibility, and fatty acid profiles of the ruminal contents, liver, and muscle of growing lambs

This study investigated the effect of modifying the n-6:n-3 fatty acid ratio (FAR) of diets using linseed, soybean, and cottonseed oils on apparent digestibility, ruminal fermentation characteristics, growth performance, key circulating hormones, and the fatty acid profile of ruminal digesta, liver, and fore-shank muscle of growing lambs fed a high concentrate diet. Forty individually housed Katadhin Dorper lambs (average of 20.0 kg of BW) were fed Bermudagrass hay in ad libitum amounts and concentrates at 3.7% of BW daily. The concentrate contained 68.9% corn, 23.8% soybean meal, 3.3% limestone, and 4.0% oil supplements (DM basis). The treatments consisted of dietary n-6:n-3 FAR of 2.3:1, 8.8:1, 12.8:1, and 15.6:1. After feeding for 35 d in metabolism crates, lambs were slaughtered 15 h after feeding, and samples of ruminal digesta, blood, liver, and foreshank tissue were collected. Increasing dietary n-6:n-3 FAR did not affect the intake of DM nor the apparent digestibility of DM, ether extract, NDF, or ADF, but did increase apparent digestibility of CP (linear, P < 0.05). Concentrations of ruminal butyrate increased linearly (P < 0.05) with increasing dietary n-6:n-3 FAR, whereas the valerate concentration decreased linearly (P < 0.001). Concentrations of plasma insulin and IGF-I were not affected by dietary n-6:n-3 FAR. Concentrations of C18:3n-3 increased linearly (P < 0.001), whereas that of C18:2n-6 decreased linearly (P < 0.001) in ruminal digesta with decreasing dietary n-6:n-3 FAR. Concentrations of transisomers of fatty acids in ruminal digesta did not change. Proportions of C18:0 in liver and foreshank muscle were unchanged by diet. The proportion of trans11 C18:1 and cis-9 trans11 CLA decreased (P < 0.05) in liver but increased (P < 0.05) in foreshank muscle as dietary n-6:n-3 FAR decreased. Proportions of all measured n-3 fatty acids were greater in liver when diets contained more C18:3n-3 from linseed oil. By decreasing the dietary n-6:n-3 FAR, the proportions of n-6 fatty acids in foreshank muscle decreased dramatically; specifically, C18:2n-6 decreased linearly (P < 0.001) from 28.0 to 16.5% and C20:4n-6 decreased linearly (P < 0.001) from 14.7 to 8.6%. Although feeding a diet that contained more n-3 fatty acids increased the n-3 fatty acid concentration of muscle, the ratio of PUFA to SFA was decreased.

Effect of lasalocid on growth, blood gases, and nutrient utilization in dairy goats fed a high forage, low protein diet.

This study investigated the effect of lasalocid on weight gain, blood gases, nutrient digestibility, and nitrogen utilization in growing dairy goats. In a growth experiment, 24 crossbred dairy does were assigned to diets without or with lasalocid (approximately 30 mg per head per day) for 12 wk. Goats were group fed bermudagrass hay for free choice plus concentrate at a fixed level (approximately 0.264 kg DM per head per d). Goats grew faster when fed lasalocid than those fed the control diet. Jugular blood partial pressure of O2 was lower when goats were supplemented with lasalocid. In contrast, goats fed lasalocid tended to have a higher partial pressure of CO2 than control goats. Percent O2 saturation tended to increase, and concentrations of total CO2 tended to decrease in goats fed lasalocid. Serum glucose and urea N did not differ between treatments. In a metabolism experiment, 8 castrated male goats were fed hay and concentrate identical to those of the growth experiment to determine whole tract nutrient digestibility and N utilization. Lasalocid did not affect feed intake or nutrient digestion coefficients. Daily urinary N output was reduced by lasalocid supplementation. In spite of this, N retention was not significantly affected. With use of ionophore, the proportion of urinary N relative to digested N tended to decrease, and the retained N as a proportion of digested N tended to increase.

Digestibility and dry matter intake of diets containing alfalfa and kenaf.

Two experiments were conducted to determine the dietary value of pellets containing kenaf (Hibiscus cannabinus cv. 'Everglade 41') hay. Averaged across both experiments, kenaf pellets contained 82.6% kenaf hay, 16.6% liquid molasses, and 0.8% mineral oil. The chemical composition of the kenaf pellet was 12.6% crude protein (CP), 41.2% neutral detergent fiber (NDF), and 14.4% acid detergent fiber (ADF). In Exp. 1 (digestion and N balance trial), 18 lambs (body weight [BW] = 36.4 kg) were blocked by BW. Lambs were randomly assigned within a block to Diet 1 (59.5% corn and 40.5% alfalfa pellet), Diet 2 (59.7% corn, 28.4% alfalfa pellets, and 11.9% kenaf pellets), or Diet 3 (59.6% corn, 16.5% alfalfa pellets, and 23.9% kenaf pellets). Diets were formulated so that CP was the first-limiting nutrient. Each diet was limit-fed at 2.4% of BW. Replacing alfalfa pellets with kenaf pellets tended to decrease (P = 0.10) CP and ADF intakes, but increased (P = 0.01) DM digestibility. Diet had no effect (P = 0.33) on N balance. In Exp. 2 (dry matter [DM] intake trial), 32 lambs (BW = 30.4 kg) were blocked by gender and BW. Within a block, lambs were randomly assigned to one of four diets in a 2 x 2 factorial arrangement. Main effects were hay (bermudagrass or fescue) and supplemental protein source (kenaf or alfalfa pellets). Lambs were housed in individual pens with ad libitum access to the assigned hay. Supplemental protein was fed (185 g of DM) once daily. Hay intake was measured weekly for 8 wk. Lambs consumed more (P = 0.002) fescue than bermudagrass hay (743 vs 621 g/ d). Lambs fed fescue hay gained weight more rapidly (P = 0.001) than lambs fed bermudagrass hay (120 vs 72 g/d). Hay intake and ADG were similar (P = 0.90) for lambs fed alfalfa or kenaf pellets. Kenaf hay mixed with molasses and mineral oil can be formed into a pellet. In the diets used in this experiments, kenaf pellets can replace alfalfa pellets in diets fed to lambs without altering forage intake, gain, or N retention.

Growth performance of stocker calves backgrounded on sod-seeded winter annuals or hay and grain.

Economically viable options for retaining ownership of spring-born calves through a winter backgrounding program are somewhat limited in the southeastern United States. Although sod-seeded winter annual forages produce less forage than those same forages planted using conventional tillage practices, sod-seeded winter annual forages have the potential to provide a low-cost, rapid-gain, ecologically and economically viable option for retaining ownership of fall-weaned calves. A study was conducted during the winters of 1998, 1999, and 2000 using 180 crossbred calves (261 +/- 2.8 kg initial BW; n = 60 each year) to compare sod-seeded winter annual forages with conventional hay and supplement backgrounding programs in southeast Arkansas. Calves were provided bermudagrass hay (ad libitum) and a grain sorghum-based supplement (2.7 kg/d) on 1-ha dormant bermudagrass pastures or were grazed on 2-ha pastures of bermudagrass/dallisgrass overseeded with 1) annual ryegrass, 2) wheat plus annual ryegrass, or 3) rye plus annual ryegrass at a set stocking rate of 2.5 calves/ha. Calves grazed from mid-December until mid-April but were fed bermudagrass hay during times of low forage mass. Mean CP and IVDMD concentrations were 19.0 and 71.1%, respectively, across sampling dates and winter annual forages, but three-way interactions among forage treatments, year, and sampling date were detected (P < 0.01) for forage mass, concentrations of CP, and IVDMD. The IVDMD of rye plus ryegrass was greater (P < 0.05) than that of ryegrass in yr 2. A forage treatment x sampling date interaction was detected for forage CP in yr 1 (P < 0.05) and 2 (P = 0.05) but not in yr 3 (P = 0.40). Forage mass did not differ (P > or = 0.22) among winter annual treatments on any sampling date. During the first 2 yr, calves fed hay plus supplement gained less (P < 0.05) BW than calves that grazed winter annual forages; gains did not differ (P > or = 0.23) among winter annual treatments. During the 3rd yr, undesirable environmental conditions limited growth of the winter annual forages; total gain did not differ (P = 0.66) among the four treatments. Winter annual forages offer potential to provide high-quality forage for calves retained until spring, but consistent forage production and quality are a concern when sod-seeding techniques are used.

The Immune Response and Performance of Calves Supplemented with Zinc from an Organic and an Inorganic Source11Published with the approval of the director of the Arkansas Agricultural Experiment Station, manuscript no. 00075.

Abstract Two experiments were conducted to determine the effects of supplemental zinc (Zn) from an organic and an inorganic source on growth performance, serum Zn concentrations, and immune response of beef calves. Treatments consisted of: i) control (no supplemental Zn), ii) Zn sulfate, or iii) Zn-amino acid complex. Zinc sources were supplemented to provide 360 mg of Zn/d. Experiment 1 was a 28-d study using 84 steers (240 ± 1.5 kg) fed bermudagrass hay (21 mg Zn/kg DM) with 1.8 kg/d of the appropriate corn-based supplement. In Exp. 2, 75 heifers (176 ± 2.5 kg) were fed bermudagrass hay (38 mg Zn/kg DM) and the supplements for 140 d. In Exp. 1, ADG was greater (P 0.10) among treatments for the entire 28-d study. In Exp. 2, there was no effect (P>0.10) on ADG as a result of Zn supplementation. In Exp. 2, Zn-supplemented heifers had a greater response (P=0.06) tophytohemagglutinin 24 h after an intradermal injection. In Exp. 2, calves supplemented with Zn-amino acid complex had a greater antibody response to a second vaccination for bovine respiratory syncytial virus than did control or Zn sulfate-supplemented calves (treatment by day interaction, P=0.06). There was not a consistent benefit of supplemental Zn on growth of calves, but there was a positive impact of supplemental Zn on some immune response measurements.

Induction and maintenance of gastric ulceration in horses in simulated race training.

Gastric ulceration is a prevalent condition of racehorses. A number of models of gastric ulceration have been described, but none mimic the conditions of a horse in training. The objectives of this study were to determine whether gastric ulcers could be induced and maintained in a group of horses in simulated race training. In addition, serum cortisol was measured on a weekly basis to investigate the possibility that stress may be important in the pathogenesis of gastric ulceration. Thirty horses used in the trial were fed Bermuda grass hay and 6 kg of a concentrate diet, and exercised 6 days/week at speed over a distance of 1.6-2.4 km. Serum was collected and gastroendoscopic examinations performed on a weekly basis for the duration of the trial. All horses developed moderate to severe ulceration, and ulcers were maintained for the 56 day period of the trial. Only one horse had signs of abdominal discomfort, which resolved with minimal symptomatic treatment and without the use of anti-ulcer medications. Serum cortisol remained within reference ranges for the duration of the trial. Although there was some variation between the weekly examinations, serum cortisol concentrations were decreased from values obtained at the start of the trial. In this study ulcers developed without the administration of nonsteroidal anti-inflammatory agents or withholding of feed. This model provides a method to study the condition, and to investigate the effects of medications on the healing of ulcers in racehorses.

Dietary protein and(or) energy restriction in mares: plasma glucose, insulin, nonesterified fatty acid, and urea nitrogen responses to feeding, glucose, and epinephrine.

Sixteen light horse mares (8 to 9 yr of age; 457 to 579 kg BW) were fed Bermudagrass hay and a corn/cottonseed hull-based supplement formulated to contain either 100% (control) or 50% (restricted) of the protein and(or) energy requirements for maintenance in a 2 x 2 factorial arrangement of treatments. Daily measurements of intake, BW, and plasma hormones and metabolites were made for 33 d. Plasma glucose, insulin, NEFA, and urea N were measured in hourly samples drawn on d 27, and parallel with an i.v. glucose tolerance test (IVGTT) and epinephrine challenge on d 29. Energy restriction increased daily NEFA concentrations (P < .001) and urea N (P = .013), whereas protein restriction decreased (P = .002) urea N concentrations. These effects of protein and energy restriction occurred within 24 h and were consistent (day effect, P > .1) throughout the remaining 24 d. Normal meal consumption elevated plasma glucose, insulin, and urea N concentrations (time effect, P < .08). Plasma NEFA concentrations did not change after feeding in mares fed control energy, but decreased in mares fed restricted energy (energy x time interaction, P = .005). After IVGTT, areas under the curve for plasma glucose and insulin were smaller in mares fed restricted protein (P < .05), whereas glucose area was larger in mares fed restricted energy (P = .009). After epinephrine injection, energy restriction increased the initial magnitude of the NEFA response, but after 50 min, reduced plasma NEFA below pre-injection concentrations (energy x time interaction, P = .06).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of protein level and source in molasses slurries on the performance of growing cattle fed hay during winter.

Four molasses slurries of varying protein level and source were fed in two performance trials (Year 1, 105 d; Year 2, 92 d) to growing cattle (Year 1, 230 kg; Year 2, 247 kg). Treatments were CONTROL (hay only), MOL (molasses-corn meal), MOL-UREA (molasses-urea-corn meal), MOL-SBM (molasses-soybean meal), and MOL-BF (molasses-urea-corn meal blood meal-hydrolyzed feather meal). Animals on all treatments were offered bermudagrass hay (Year 1: 12.8% CP, 50% TDN; Year 2: 12.8% CP, 54% TDN) and a complete mineral mixture free choice. Each treatment was fed to three pens each year with seven animals/pen. Slurries were offered at 2.1 kg/d (DM) and effects on forage intake, ADG, condition score (1 to 9), hip height, and plasma urea nitrogen were monitored. Treatment effects for Years 1 and 2 were analyzed separately due to treatment x year interactions (P < .15) with respect to ADG, hip height change, condition score change, and feed cost of gain. Supplementation increased (P < .001) ADG over CONTROL in Year 1 (.41 vs .06 kg/d) and Year 2 (.69 vs .25 kg/d), increased hip height change by .02 cm/d (P < .001) in Year 1 and by .01 cm/d (P = .012) in Year 2, and decreased (P < .001) loss of body condition in Years 1 and 2. Molasses-urea showed no advantage over MOL in Years 1 and 2. Natural protein (MOL-SBM and MOL-BF) increased ADG by .10 kg/d in Year 1 (P = .001) and by .06 kg/d in Year 2 (P = .077) compared with MOL-UREA. Daily gain was improved by MOL- BF by .05 kg/d (P = .109) in Year 1 and by .08 kg/d (P = .063) in Year 2 compared with MOL-SBM. Results indicate that growing cattle fed bermudagrass hay during winter respond positively to energy supplementation in the form of molasses. The addition of animal source protein enhanced this response.

Effects of supplementing growing steers with high levels of partially hydrogenated tallow on feed intake, digestibility, live weight gain, and carcass characteristics.

Effects of supplementing growing steers consuming forage-based diets with high levels of partially hydrogenated tallow on feed intake, digestibility, live weight gain, and carcass characteristics were determined in this study. In Exp. 1, Holstein steer calves were fed bermudagrass hay alone (Control) and with a ground corn-based concentrate at .95% BW (DM basis) plus partially hydrogenated tallow at 0 (Basal), .33 (low fat; LF), or .67% BW (high fat; HF) in a Latin square. Total DMI was increased by concentrate supplementation and was lower for HF than for LF (P < .05; 3.18, 3.83, 4.25, and 3.17 kg/d for Control, Basal, LF, and HF, respectively). In Exp. 2, grazing Angus x Hereford steers (270 kg +/- .4 initial shrunk BW) were fed the same supplements as in Exp. 1 for 84 or 98 d and slaughtered. Live weight gain was increased (P < .05) by concentrate supplementation (1.01, 1.34, 1.41, and 1.30 kg/d for Control, Basal, Low, and High, respectively). The concentration of total lipids in longissimus muscle was 2.51, 2.53, 3.05, and 3.03% of wet tissue for Control, Basal, LF, and HF, respectively (Basal > the mean of LF and HF; P < .07); the proportion of palmitic acid in total fatty acids was similar among treatments. Fat supplementation did not markedly affect sensory, taste, or tenderness characteristics of longissimus muscle. In conclusion, supplementing grazing beef steers with high levels of partially hydrogenated tallow, with slaughter at approximately 400-kg shrunk BW, tended to increase fat in longissimus muscle without altering the palmitic acid level in fatty acids, although sensory, taste, and tenderness characteristics were not modified.

Digestion, feed intake, and live weight gain by cattle consuming bermudagrass hay supplemented with whey.

Three experiments were conducted with cattle consuming bermudagrass hay to determine whether low-level supplements of whey alone, corn alone, or whey plus corn affect feed intake, digestion, and(or) BW gain. Six ruminally and duodenally cannulated beef cows (574 kg), used in a Latin-square trial (Exp. 1), were fed bermudagrass hay without supplementation (control) or with 2.8% whey (low whey, LW), 5.6% whey (high whey, HW), 17.4% ground corn (C), 2.8% whey plus 14.9% corn (C-LW), or 5.6% whey plus 12.4% corn (C-HW). Supplementing with whey and(or) corn increased ruminal butyrate (8.8, 9.4, 10.0, 9.6, 10.5, and 11.0 mol/100 mol of total VFA for control, LW, HW, C, C-LW, and C-HW, respectively; SE = .20). Supplements did not affect microbial N flow at the duodenum. Six Holstein steer calves (158 kg) in a Latin square (Exp. 2) consumed bermudagrass hay ad libitum alone (control) or with .075 or .15% BW whey (LW and HW, respectively), .5% BW ground corn (C), or corn-whey mixes made by substituting whey for corn (C-LW and C-HW). Substituting .15% BW of whey for corn increased (P less than .05) total OM intake slightly (3.99, 3.84, 3.75, 4.11, 4.28, and 4.47 kg for control, LW, HW, C, C-LW, and C-HW, respectively; SE = .10). In an 84-d randomized block experiment (Exp. 3), 96 beef calves (194 kg) consumed (ad libitum) low-quality bermudagrass hay alone or with C, LW, HW, C-LW, or C-HW supplements.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of starch on ruminal fermentation and detergent fibre digestion in lambs fed bermudagrass hay

Twelve cannulated Suffolk wether lambs (30.1 kg) were used in a randomised complete block design experiment to determine the effects of increasing dietary concentrate (corn starch-based) on ruminal digestive kinetics and fermentation characteristics and digestion of bermudagrass hay (BGH) fibre in lambs. Treatments consisted of as-fed concentrate:BGH ratios (C:F) of 10:90, 40:60 and 70:30. Ruminal digestion of neutral detergent fibre (NDF) and hemicellulose (HC) declined linearly ( P < 0.01) with increasing C:F. Quadratic responses to post-ruminal ( P < 0.10) and total tract ( P < 0.05) digestion of HC were obtained with increasing C:F. Total tract digestion of NDF declined linearly ( P < 0.05) with increasing C:F. Extent of acid detergent fibre (ADF) digestion was not affected ( P > 0.10) by C:F at any digestive site. Integrated pH-hours below pH 6.7 declined linearly ( P < 0.01) with increasing C:F and was correlated with ruminal digestion of NDF ( r = −0.75, P = 0.005) and HC ( r = −0.67, P = 0.018). Ruminal volatile fatty acid (VFA) concentrations increased linearly ( P < 0.01) with increasing C:F and were correlated with ruminal digestion of NDF ( r = −0.88, P = 0.001) and HC ( r = −0.82, P = 0.001). Ruminal liquid turnover was not affected ( P > 0.10) by C:F. Ruminal forage particulate passage rate tended ( P = 0.12) to increase with increasing C:F and was correlated with the ruminal digestion of both NDF ( r = −0.67, P = 0.023) and HC ( r = −0.57, P = 0.063). While virtually all potentially digestible ADF (cellulose) was digested in the rumen, ruminal escape of HC increased with increasing C:F. Data suggest that HC is the cell wall fraction of BGH that is the most sensitive to dietary starch level.