Digestibility Of Hay Research Articles

PSVII-35 Fecal innocula from horses fed DigestaWell® Fiber improves in-vitro dry matter digestibility of commercial hays in horses

Abstract Enhanced microbial activity in the equine hindgut increases nutrient availability, reduces fecal waste, and adds value to low quality forages. The encapsulated dietary supplement DigestaWell® Fiber (DF; fibrolytic cofactors, methionine, B vitamins) has been shown to improve in-vitro digestibility measures of common hays fed to horses. However, its in-vivo effect on dry matter (DMd) and ADF digestibility (ADFd) is unknown. The objectives of this study were to test whether fecal innocula from horses fed DF would result in improved DMd or ADFd relative to innocula from unsupplemented horses consuming alfalfa or coastal bermudagrass hays. Utilizing a crossover design, four Quarter Horse mares were fed 2% BW daily alfalfa hay (AF; 32.8% NDF, 27.1% ADF) or coastal bermudagrass hay (CB; 63.2% NDF, 35.4% ADF), with or without oral DF supplementation (32 g/d), for 14d. Fresh feces were collected to serve as inoculum in an ANKOM Daisy II incubator at 37.5°C to determine in-vitro DMd and ADFd at 48h or 72h. Forage samples were run in triplicate. Data were transformed to approximate normality, then analyzed using a repeated measures mixed model in SAS with main effects of forage, treatment, incubation time, feeding period, and significant interactions. Across forages and incubation times, in-vivo DF supplementation improved DMd (P < 0.01). Across incubation times, DF improved ADFd of both AF (P < 0.0001) and CB (P = 0.04), but not DMd. Across forages, DF improved both DMd and ADFd at 48h (P < 0.001 and P = 0.003, respectively) but not at 72h (P = 0.29 and P = 0.27, respectively). Taken together, and combined with previous findings, these results provide further evidence that DF improves forage digestibility, presumably due to improved microbial fermentation in the equine hindgut.

Economic Injury Level for Bermudagrass Stem Maggot (Diptera: Muscidae) in Bermudagrass Forage Production in Texas.

The bermudagrass stem maggot, Atherigona reversura Villeneuve (Diptera: Muscidae), was first reported damaging bermudagrass Cynodon dactylon (L.) Pers grown for forage in 2010 in the southeastern United States. Injury results from individual larvae feeding internally on the vascular tissue just above the terminal node of the grass stem. Injury slows plant growth and reduces forage accumulation. To address the need for economic guidelines to manage this new pest, the relationship between the percent of stems damaged by bermudagrass stem maggot and forage yield was measured in commercial bermudagrass hay fields in northcentral Texas. Yield loss was estimated to be 9.97 kg/ha (8.90 lbs /acre) for each percentage of stems with bermudagrass stem maggot damage. This relationship was used to calculate economic injury levels for a range of hay market values and control costs. The impact of stem damage on protein content, energy, and digestibility of bermudagrass hay was also investigated. Although there was a significant trend for declining forage quality with increasing stem damage, stem damage explained very little of the model's variability.

Effect of growth stage and method of conservation of H. filipendula and H. dissoluta on nutrient composition and digestibility

<p class="Default">Native species such <em>Hyparrhenia filipendula</em> and <em>Hyperthelia dissoluta </em>have great potential in livestock production but not much has been done to improve their contribution to that sector. This factorial study examined 2 grass species (<em>H. filipendula</em> and <em>H. dissoluta)</em> × 2 conservation methods (drying and ensiling) × 3 different growth stages, namely: elongation stage (January), early flowering (February) and late flowering stage (March) of <em>H. filipendula</em> and <em>H. dissoluta </em>during growing season in terms of nutritional composition and digestibility. There was no difference (P>0.05) in nutritional composition between the two-grass species. The method of conservation had an effect (P<0.05) on nutritive value, with silage having more phosphorus (P), neutral detergent fibre (NDF) and crude protein (CP) than hay. Stage of growth had an effect (P<0.05) on all nutritional properties of both hay and silage. Phosphorus, Calcium, NDF, CP concentrations and digestibility of hay and silage decreased with maturity, while acid detergent fibre (ADF) concentration increased. Silage pH value was significantly higher at elongation 5.1 and 4.9 for <em>H. filipendula</em> and <em>H. dissoluta</em>,<em> </em>respectively. Silage pH for early flowering stage was within the recommended ranges from 4.1 to 4.4 on the pH scale, with higher than the recommended range for the late flowering growth stages (4.8 and 4.5) for <em>H. filipendula</em> and <em>H. dissoluta</em>, respectively. Dry matter digestibility of the conserved material reached levels as high as 80% for silage made at the elongation stage with all values at least 60%. The study results reveal that<em> H. filipendula</em> and <em>H. dissoluta </em>can be conserved as both silage and hay to produce a good quality feed. Harvesting at the early flowering stage provide a good compromise between quantity and quality of harvested forage. Further studies are necessary to assess the acceptability of the forage by livestock as well as to determine dry matter yields in different areas and a range of seasonal conditions.</p>

Effect of different sources of non-fiber carbohydrate on ruminal pH and in vitro digestibility of tropical forage

The present study aimed to evaluate non-fiber carbohydrates (NFC) in sugarcane-based diets on rumen pH, and forage digestibility, and to describe NFC degradation curves. The study consisted of two trials. For the first trial, three rumen cannulated steers, BW of 350 ± 15 kg (mean ± SE), were assigned in a 3×3 Latin Square (LS) design. They were fed diets containing finely-ground (0.9 mm average particle size) corn (GC), steam-rolled corn (SRC), or pelleted citrus pulp (PCP). Each period had 14 d, with the first 12 for adaptation. The 13th d was for serial measurement of rumen pH, and the14th for rumen fluid collection and in vitro incubation for DM and NDF digestibility (IVDMD and IVNDFD) of bermudagrass hay (Hay), corn (CS), and sugarcane (SS) silages. In the second trial, rumen fluid of a cannulated bull, fed corn silage and a regular concentrate, was collected for in vitro digestion of NFC for multiple time points. The incubation results were used to adjust the NFC degradation curves, and calculate lag-time, feed fractions, and degradation rate. Data from first trial was analyzed in a 3×3 LS. The model for the digestibility parameters included fixed effects of forage (Feed), diets with NFC (Diet), and their interaction (Feed × Diet), and random effect of animal and period. The model for rumen pH included fixed effect of diet, time as repeated measures, animal and period as random effects. The significance was considered at probability ≤ 5% (α = 0.05). The NFC degradation curves were adjusted using the PROC NLIN procedure from SAS, and equation parameters compared using confidence intervals. There was a Diet × Time interaction on rumen pH (P = 0.04), where SRC decreased pH compared to PCP and GC diets at the time 6 h, only. There was no Feed × Diet interaction effect (P > 0.05) for any digestibility parameter. There was a Feed effect on both IVDMD and IVNDFD, either after 30 or 48 h incubation (P < 0.01). The CS had the greatest IVDMD, followed by SS and Hay, after 30 and 48 h of incubation. The CS had the greatest IVNDFD after 30 h, compared to SS and Hay. However, for IVNDFD after 48 h, CS presented the greatest mean, followed by SS and Hay. The rumen fluid from animals fed SRC decreased both IVDMD and IVNDFD (P < 0.05) of all roughages after 48 h. Results from the second trial showed that the PCP had lower Lag Time, B fraction and greater kd compared to both corn sources, and SRC had greater kd than GC. In conclusion, the SRC diet decreased rumen pH 6 h after feeding and, consequently, decreased fiber digestibility of the tropical forage sources evaluated. Although the PCP had lower lag time, and faster rate of degradation of B fraction, it did not negatively affect rumen pH or fiber digestibility of forage.

Effect of Natuzyme Enzyme on Fecal Digestion and Fermentation of Wheat Straw and Alfalfa Hay in Arabian Horses

The aim of this study was to evaluate the effect of Natuzyme enzyme mixture (0, 3, and 6 g/kg dry matter [DM]) on microbial digestion as well as fermentation of wheat straw and alfalfa hay in Arabian horse. Four female Arabian horses (3–4 years, average body weight 400 kg) were fed with diet containing 35% commercial concentrate +65% forage (wheat straw and alfalfa hay) for 2 weeks. The fermentation and gas production of wheat straw and alfalfa hay with different levels of Natuzyme enzyme were determined using standard in vitro gas production protocol (6 replicates). The DM and neutral detergent fiber (NDF) digestibility were determined using specific media (four replicates per time). Addition of enzyme had no effect on gas production rate of alfalfa hay (P > .05), but the potential of gas production was increased with alfalfa hay at 3 and 6 g/kg DM of enzyme compared with control. The addition of enzyme to alfalfa did not affect partitioning factor, microbial biomass, microbial biomass efficiency, and cell wall degradability (P > .05). DM digestibility of alfalfa hay after 24, 48, and 72 hours of incubation with mixed cecum contents was not affected by enzyme (P > .05), but NDF digestibility at 24, 48, and 72 hours was increased (P < .05). The enzyme supplementation decreased microbial biomass efficiency and increased potential of gas production, DM, and NDF digestibility at 24 hours for straw. The highest value was obtained for straw treated with 3 and 6 g/kg DM of enzyme. Gas production parameters, DM, and NDF digestibility of straw at 48 and 72 hours of incubation were not influenced by enzyme addition. In conclusion, addition of Natuzyme enzyme mixture caused the proper fermentation, gas production, and digestibility of alfalfa hay and straw without affecting the DM digestibility by cecal microorganisms, thereby suggesting the additive role of this enzyme in Arabian horse nutrition.

Effect of biochanin A on corn grain (Zea mays) fermentation by bovine rumen amylolytic bacteria.

The objective was to determine the effect of biochanin A (BCA), an isoflavone produced by red clover (Trifolium pratense L.), on corn fermentation by rumen micro-organisms. When bovine rumen bacterial cell suspensions (n=3) were incubated (24h, 39°C) with ground corn, amylolytic bacteria including group D Gram-positive cocci (GPC; Streptococcus bovis; enterococci) proliferated, cellulolytic bacteria were inhibited, lactate accumulated and pH declined. Addition of BCA (30μgml-1 ) inhibited lactate production, and pH decline. BCA had no effect on total amylolytics, but increased lactobacilli and decreased GPC. The initial rate and total starch disappearance was decreased by BCA addition. BCA with added Strep. bovis HC5 supernatant (containing bacteriocins) inhibited the amylolytic bacteria tested (Strep. bovis JB1; Strep. bovis HC5; Lactobacillus reuteri, Selenemonas ruminatium) to a greater extent than either addition alone. BCA increased cellulolytics and dry matter digestibility of hay with corn starch. These results indicate that BCA mitigates changes associated with corn fermentation by bovine rumen bacteria exvivo. BCA could serve as an effective mitigation strategy for rumen acidosis. Future research is needed to evaluate the effect of BCA on mitigating rumen acidosis invivo.

Methane emissions by beef cattle consuming hay of varying quality in the dry forest ecosystem of Costa Rica

In livestock production systems, methane (CH4) is produced and released during the digestive process, representing a loss of energy that can be as high as 12% of total intake. In Costa Rica there are not actual in vivo measurements of methane produced from enteric fermentation in the livestock sector. This research represents the first effort to quantify the CH4 emitted by growing beef steers fed three different diets during the dry season in the Dry Tropics ecosystem of Costa Rica, using the SF6 tracer technique. Three diets were evaluated, all of them offered at libitum: 1) Good quality hay of transvala (Digitaria decumbens; GOOD). 2) Low quality Brachiaria tanner hay (POOR). 3) Low quality hay (B. tanner) plus a supplement of 1kg/d of sugar cane molasses mixed with 46g/d of urea (POOR+MU). Nine Brahman steers (329±38kg of body weight) were utilized in a triplicated 3×3 Latin square for a total of 9 replicates/treatment. Variables measured were in vivo CH4 emissions, feed intake, and apparent total tract digestibility of nutrients using indigestible neutral detergent fiber (NDF) as an internal indigestible marker. Dry matter intake (DMI) was greater in GOOD (7.9kg/d) compared to the remaining two diets (3.6 and 4.2kg/d for POOR and POOR+MU, respectively). Enteric CH4 emission (g/d) was similar (P>0.05) for POOR (110.4) and POOR+MU (125.8) but lower (P<0.0001) than that of GOOD (181.5); when the methane emitted was reported as g of CH4/kg of DMI, greatest (P<0.0001) emissions were detected with POOR (31.0) and POOR+MU (29.8), and lesser in diet 1 (23.0±1.9). Estimated methane yield (Ym) for GOOD (6.9) was similar to that suggested by the Intergovernmental Panel on Climate Change (IPCC); however, greater values than those reported by the IPCC were obtained for POOR (9.3) and POOR+MU (9.0). In conclusion, CH4 emitted by growing Brahman steers fed hay of varying quality was closely related to daily DMI. Furthermore, when CH4 emission was expressed per unit of DMI, poor quality hay increased emissions intensity, regardless of supplementation with urea and molasses. Supplementing poor quality B. tanner hay with urea and molasses increased hay digestibility but did not alter methane emissions. Feeding good quality D. decumbens hay decreased CH4 emissions (in g/kg of DMI) by 30% relative to those by steers receiving poor quality B. tanner hay during the dry season in Costa Rica.

Neglected grass species of Southern Africa: Nutritive value of conservedHyperthelia dissolutaharvested at different growth stages

Native species like Hyperthelia dissoluta have great potential in livestock production but not much has been done to improve their contribution to that sector. This study examined 2 conservation methods (drying and ensiling) and 3 different growth stages, namely: elongation stage (January), early flowering (February) and late flowering stage (March) of H. dissoluta in terms of nutritional composition and digestibility. The method of conservation had a significant effect (P<0.05) on nutritive value, with silage having more P and CP than hay. Stage of growth had an effect (P<0.05) on all nutritional properties of both hay and silage: Phosphorus, Ca and CP concentrations and digestibility of hay and silage decreased with maturity, while NDF and ADF concentrations increased. Silage pH value was significantly higher at elongation (5.2) and late flowering growth stages (5.7) than at early flowering (4.4). Dry matter digestibility of the conserved material reached levels as high as 82% for silage made at the elongation stage with all values at least 60%. We conclude that H. dissoluta can be conserved as both silage and hay to produce a good quality feed. Harvesting at the early flowering stage would seem to provide a good compromise between quantity (not measured in this study) and quality of harvested forage. Further studies seem warranted to determine the acceptability and intake of the material by livestock, the advantages of adding fermentable carbohydrates during ensiling and DM yields in different areas and a range of seasonal conditions. Keywords : Air drying, hay, perennial native grasses, plastic bag silo, quality silage. DOI: 10.17138/TGFT(4)179-184

SOME ENGINEERING FACTORS AFFECTING THE PREPARATION OF MORINGA RESIDUES FOR ANIMAL DIETS

Moringa oleifera, a rapid growing tree found in a different climatic condition, the moringa is a promising tree and has the potential to become a new source of fresh forage material per unit area compared to other forage crops high productivity. Moringa produce a large amount of the residues consisting of branches and stalks which lefts over after getting moringa leaves for human use, causing environmental problems. Therefore, the main objectives of this research are to prepare moringa residues to be used as a dietary supplement for animals feed due to it's content of many nutrients, protein sources and vitamins, to decrease the cost of the feed. Meanwhile the essential factor is preventing the accumulation of these quantities and environment pollution. Some physical, mechanical properties and chemical composition of moringa residues were investigated at moisture content (8%). In order to determine engineering treatments to get the most appropriate lengths for cutting of moringa residues to be used as appropriate residues roughage for animal diets. A local manufacture hammer mill machine was used for crushing and milling the moringa residues, three different types of hammer were used in this machine to cut the right lengths. The current research focus on machine noise levels and air pollution dust particle due to crushing and milling the moringa residues for human safety. The quantity of fine particles inhaled and produced from a local hammer mill machine operator was recorded. The microbiological analysis showed the presence of microorganisms such as Bacteria, Fungi, Actinomyces and Yeasts in the moringa dust particles. The nutritional characteristics of stems (stalks) of Moringa oleifera plant with two levels of grinding (fine and coarse Moringa oleifera stems) _______________________________________ 1 Researcher, Agricultural Engineering Research Institute (AEnRI), Agricultural Research Center (ARC), Dokki. Egypt. 2Prof., Animal Production Research Institute, (ARC), Dokki. Egypt. (Fine MOS; from > 0.6 mm to 1.4 mm and Coarse MOS; from >1.4 mm to 6.7 mm) and clover hay (CH) were studied in a completely randomize design using: chemical composition In-vivo digestibility coefficients and feeding values determination. Results revealed that crude protein (CP) content was 12.81, 12.24 and 13.08% for (Fine MOS and Coarse MOS) and clover (CH), respectively. The MOS had high crude fiber (CF) content than CH, while recorded high ether extract (EE) 3.12% content while stems recorded low EE 1.03 and 0.94% content. The fiber fraction (NDF, ADF, ADL, cellulose and hemicellulose) of MOS content were higher than those in CH content. Fine MOS) with highest nutrient digestibility, TDN (50.72%) and DCP (8.39%), followed by coarse MOS (TDN, 48.46% and DCP, 7.12%). Meantime, intermediate values of nutrients digestibility of clover hay led to intermediate TDN and DCP values (45.41and 8.14%) respectively. The results revealed that fine grinded Moringa oleifera stalks had great potential as livestock feed for small ruminants holder, especially during dry season and it consider a good quality roughage compare to clover hay.

Evaluation of methodological aspects of digestibility measurements in ponies fed different grass hays.

Methodological aspects of digestibility measurements of feedstuffs for equines were studied in four Welsh pony geldings consuming four grass-hay diets in a 4 × 4 Latin square design. Diets contained either a low (L), medium (M), high (H), or very high (VH) ADF content (264, 314, 375, or 396 g·kg DM, respectively). Diets were supplemented with minerals, vitamins, and TiO (3.9 g Ti·d). Daily feces excreted were collected quantitatively over 10 consecutive days and analyzed for moisture, ash, ADL, AIA, and titanium (Ti). Minimum duration of total fecal collection (TFC) required for an accurate estimation of apparent organic matter digestibility (OMD) of grass hay was assessed. Based on literature and the calculated cumulative OMD assessed over 10 consecutive days of TFC, a minimum duration of at least 5 consecutive days of fecal collection is recommended for accurate estimation of dry matter digestibility (DMD) and OMD in ponies. The 5-d collection should be preceded by a 14-d adaptation period to allow the animals to adapt to the diets and become accustomed to the collection procedures. Mean fecal recovery over 10 d across diets for ADL, AIA, and Ti was 93.1% (SE 1.9), 98.9% (SE 5.5), and 97.1% (SE 1.8), respectively. Evaluation of CV of mean fecal recoveries obtained by ADL, AIA, and Ti showed that variation in fecal Ti (6.8) and ADL excretion (7.0) was relatively low compared to AIA (12.3). In conclusion, the use of internal ADL and externally supplemented Ti are preferred as markers to be used in digestibility trials in equine fed grass-hay diets.

Chemical Composition, In vivo Digestibility and Metabolizable Energy Values of Caramba (Lolium multiflorum cv. caramba) Fresh, Silage and Hay.

The experiment was conducted to determine nutritive values of caramba (Lolium multiflorum cv. caramba) fresh, silage and hay by in vivo and in vitro methods. There was a statistically significant difference (p<0.01) in crude protein content value between fresh caramba (12.83%) and silage (8.91%) and hay (6.35%). According to results of experiment, the crude fiber, neutral detergent fiber, acid detergent fiber (ADF), acid detergent lignin contents of the three forms of caramba varied between 30.22% to 35.06%, 57.41% to 63.70%, 35.32% to 43.29%, and 5.55% to 8.86% respectively. There were no significant differences between the three forms of caramba in digestibility of nutrients and in vivo metabolizable energy (ME) values (p>0.05). However, the highest MECN (ME was estimated using crude nutrients) and MEADF values were found in fresh caramba (p<0.01). As a result, it could be said that, there were no differences between the three forms of caramba in nutrient composition, digestibility and ME value, besides drying and ensiling did not affect digestibility of hay. Consequently, caramba either as fresh, silage or hay is a good alternative source of forage for ruminants.

Steam explosion pretreatment for enhancing biogas production of late harvested hay.

Grasslands are often abandoned due to lack of profitability. Extensively cultivating grassland for utilization in a biogas-based biorefinery concept could mend this problem. Efficient bioconversion of this lignocellulosic biomass requires a pretreatment step. In this study the effect of different steam explosion conditions on hay digestibility have been investigated. Increasing severity in the pretreatment induced degradation of the hemicellulose, which at the same time led to the production of inhibitors and formation of pseudo-lignin. Enzymatic hydrolysis showed that the maximum glucose yields were obtained under pretreatment at 220 °C for 15 min, while higher xylose yields were obtained at 175 °C for 10 min. Pretreatment of hay by steam explosion enhanced 15.9% the methane yield in comparison to the untreated hay. Results indicate that hay can be effectively converted to methane after steam explosion pretreatment.

Effects of including saponins (Micro-Aid®) in a protein supplement on performance of growing steers and spring-calving cows

Three experiments were conducted to evaluate the use of Micro-Aid® (MA; DPI Global, Porterville, CA, USA) on the performance of stocker steers and spring-calving cows. In Experiment 1, fall-born crossbred steers (n=68; 289±34kg initial body weight; BW) were randomly allotted to one of four supplement treatments: (1) soybean hulls: 130g dry matter (DM)/d (C; control), (2) cottonseed meal and wheat middlings: 410g DM/d (PC; positive control), (3) MA added to PC to supply 1g MA/d (MA1), and (4) MA added to PC to supply 2g MA/d (MA2). Experiment 2, utilized Angus and Angus x Hereford beef cows (n=93) stratified by age and body weight and randomly assigned to one of two supplement treatments: (1) cottonseed meal and wheat middlings: 820g DM/d during gestation and 1,550g DM/d during lactation (PC) and (2) MA added to PC to supply 1g MA/d (MA). Supplements were delivered 3 days per week during gestation and 4 days per week during lactation. All cattle were individually fed in either a 32 animal stall barn or an individual pen. Experiment 2 evaluated the use of MA on the performance of spring-calving cows, its effect on forage intake and digestibility, milk yield and milk composition during early and late lactation. In Experiment 1, protein supplementation improved average daily gain (ADG) as compared to C, but providing MA to stocker steers had no impact on total BW gain or ADG (P>0.21) compared to PC. In Experiment 2, Cow BW and body condition score (BCS) was increased during gestation for MA cows, but to a lesser extent than PC (P=0.03). At the end of supplementation, cow BW and BCS was similar across treatments (P=0.70), but calves from cows fed MA were heavier (P<0.001) than calves from PC cows. Dietary MA did not impact milk yield and composition during early lactation when consuming supplement or residual milk yield and composition at weaning. Hay DM intake (DMI), or digestibility was also not affected by MA. These data are interpreted to indicate that MA has no impact beyond PC on growing steer performance during late summer or spring-calving cow performance and total tract apparent hay digestibility. Supplementing cows MA may be effective at improving suckling calf performance; however this weight advantage was not maintained through weaning.

Fibre digestibility, abundance of faecal bacteria and plasma acetate concentrations in overweight adult mares.

The purpose of the present study was to compare digestibility of grass hay, faecal and plasma volatile fatty acid (VFA) concentrations, and faecal bacterial abundance in overweight and moderate-condition mares. Five overweight adult mixed-breed mares and five adult mixed-breed mares in moderate condition were housed individually and limit-fed orchard grass (Dactylis glomerata) hay at 20g/kg body weight (as fed) daily for 14 d. Forage DM and fibre digestibility were determined using AOAC methods; digestible energy was measured using bomb calorimetry; plasma and faecal VFA concentrations were determined by use of GC and MS; faecal Firmicutes, Bacteroidetes, Fibrobacter succinogenes, Ruminococcus flavefaciens and total bacteria abundance was determined by quantitative real-time PCR using previously designed phylum-specific 16S ribosomal RNA gene primers. No differences in hay digestibility, faecal VFA concentrations or faecal bacterial abundance were detected between overweight and moderate-condition mares. Mean plasma acetate concentrations were higher (P=0·03) in overweight (1·55 (range 1·43-1·65) mmol/l) v. moderate-condition (1·39 (range 1·22-1·47) mmol/l) mares. We conclude that the higher plasma acetate in overweight mares should be further investigated as a potential link between gut microbes and obesity in horses.

Fibrolytic enzymes and a ferulic acid esterase‐producing bacterial additive applied to alfalfa hay at baling: effects on fibre digestibility, chemical composition and conservation characteristics

AbstractThis study evaluated the effect of two fibrolytic enzyme products, applied at baling, on the chemical composition and digestibility of alfalfa hay. Three replicate bales of alfalfa hay (82% dry matter) were produced with the application of one of five treatments including an untreated control and one of two fibrolytic enzyme products (DYC and ECO), either applied alone or in combination with a ferulic acid esterase‐producing bacterial additive. The enzyme products were applied on the basis of endoglucanase activity. The neutral detergent fibre (NDF) concentration and accumulated temperature after storage of hay produced using DYC‐ or ECO‐based treatments were greater (P &lt; 0·05) than untreated hay, except for hay bales produced using ECO alone. Bales produced using ECO‐based treatments had a greater (P &lt; 0·05) in vitro NDF digestibility compared with untreated bales. The application of fibrolytic enzymes at baling may potentially improve NDF digestibility without negatively affecting chemical composition or increasing aerobic deterioration. However, the effects of fibrolytic enzymes varied depending on the product applied. Combining ferulic acid esterase‐producing bacterial additives with fibrolytic enzymes did not improve the nutritive value of hay after storage.

Intake and digestibility by sheep, in situ disappearance in cannulated cows, and chemical composition of crabgrass hayed at two moisture concentrations and treated with a non-viable Lactobacillus–lactic acid additive

Crabgrass (Digitaria ciliaris [Retz.] Koel.) is a high-quality warm-season annual that can be used as hay, but field curing time may be lengthy compared with other forages. A 1.6-ha field of common crabgrass was divided into 12 plots (8.25m×50m) that were used in a randomized complete block design with a 2×2 factorial treatment arrangement to determine the effects of a non-viable Lactobacillus–lactic acid additive and moisture concentration at baling on heating characteristics and pre- and post-storage chemical composition. Half of the plots within each block were treated with 0.081ml/mg dry matter (DM) of a solution containing 110g lactic acid/kg and non-viable Lactobacillus acidophilus at the time of mowing (T) and half were not treated (U). Within T and U plots, half were baled in small square bales at 163g moisture/kg DM (L) and half at 251g moisture/kg DM (H) of moisture. Six bales per plot were selected at random, weighed, and stored in separate insulated 6-bale stacks. Core samples were taken from 3 bales initially and 3 bales post-storage. Initial bale moisture concentrations were greater (P<0.05) and initial neutral-detergent fiber (NDF) concentrations were lower (P<0.05) from H vs. L. Post-storage concentrations of NDF and acid-detergent insoluble N (ADIN; g/kg DM and g/kg N), were greater (P<0.05) from H vs. L. Dry matter intake in sheep was unaffected (P>0.05) by either treatment, but DM digestibility and digestible DM intake were both positively affected (P<0.05) by the spray treatment. In addition, DM digestibility was also affected (P<0.05) by moisture, with H>L. In situ DM disappearance was largely affected by spray treatment×moisture interactions (P<0.05). The immediate soluble fraction and effective ruminal disappearance were greater (P<0.05), and the undegraded portion in the rumen was less (P<0.05) for HT compared to HU, indicating a positive relationship between applied spray treatment and digestibility of high-moisture crabgrass. Treating crabgrass with the additive at mowing may not affect forage chemical composition, but may improve digestibility in hay baled at elevated moisture levels.

Comparative digestibility of low‐quality grass hay by two breeds of cattle differing in mature live weight

The digestive capacity of the Portuguese native breed of Barrosão cattle and the Holstein-Friesian breed was measured when fed meadow hay (72-74 g CP and 641-671 g NDF/kg dry matter), offered either alone or supplemented with soya bean meal (150 g/kg dry matter), at maintenance level. Four mature cows of each breed were used. Average initial live weight (LW) was 457 and 635 kg for the Barrosão and the Holstein-Friesian cows respectively. The organic matter digestibility (OMD) of the meadow hay was higher in Holstein-Friesian than in Barrosão cows (p < 0.08) whether supplemented or not. The neutral detergent fibre digestibility of the hay was also higher in Holstein-Frisian when the hay was fed alone (p < 0.08). The soya bean meal supplementation increased the OMD and the NDFD digestibility of the total diet (p < 0.05), but not the OMD digestibility of the hay (p > 0.05). The results obtained in this study suggest a higher ability to digest fibre in the large dairy breed than in the small native breed. This suggestion is also supported by previous findings with sheep breeds largely differing in mature live weight.

Steer Intake, Digestion, and Ingestive Behavior of Switchgrass and Alfalfa Hays

ABSTRACTPerennial, warm‐season grasses cut for hay frequently have inadequate crude protein (CP) concentrations for acceptable ruminant performance. This study determined the influence of alfalfa (Medicago sativa L.) as a CP supplement to steers (Bos taurus) fed switchgrass (Panicum virgatum L.) hay harvested at the early‐heading stage. Diets of 100% switchgrass (SG) and 100% alfalfa (AL) were included along with 25, 50, and 75% mixtures of the hays making five treatments. Steer dry matter intake (DMI), whole tract dry matter digestibility (DMD), eating behavior, and masticate characteristics were estimated. Steer DMI averaged 1.35 kg 100 kg−1 body weight (BW) for 100% SG and increased linearly (P &lt; 0.01) to 2.93 kg 100 kg−1 BW for 100% AL. Also, DMD increased linearly (P &lt; 0.01) from 484 g kg−1 for 100% SG to 653 g kg−1 for 100% AL. Concentration of CP was 51 g kg−1 for SG and increased quadratically (P &lt; 0.01) to 241 g kg−1 with increasing AL while neutral detergent fiber (NDF) decreased quadratically (P &lt; 0.01) from 792 g kg−1 for SG to 407 g kg−1 for AL. Masticate in vitro dry matter disappearance (IVDMD) increased quadratically (P &lt; 0.01) from 509 g kg−1 for SG to 660 g kg−1 in AL whereas CP increased linearly (P &lt; 0.01) from 60 g kg−1 for SG to 230 g kg−1 in AL. Increasing AL of the as‐fed hay linearly decreased (P &lt; 0.01) chews per gram of dry matter, IVDMD, and CP but increased quadratically (P &lt; 0.01) chews per gram of NDF. Steers readily ate the SG:AL combinations; AL could thus provide a source of CP for SG based diets.

Prediction of Energy Digestibility of Hays in Horses

Difficulties in applying in vivo methods encourage the prediction of energy values of feeds in horses from alternative methods. Previous attempts to predict energy values from chemical composition have ignored differences among experiments. The current evaluation aimed to find the most reliable predictors (chemical composition and nutrient digestibilities) of apparent total tract energy digestibility of hays. Prediction was done with treatment means from a diverse collection of studies conducted worldwide. Experiment was included as a random effect in models to control for differences among experiments, and treatments means were weighted to account for unequal variances of the means across experiments. Organic matter digestibility (OMD; %) proved to be the most reliable (root mean square error [RMSE] = 1.6486; R2 = 0.8871) predictor of gross energy digestibility (GED; %) when calculated from 44 treatment means (n) obtained from 28 experiments conducted in 16 different studies (GED = 5.527 + 0.8124 OMD). Neutral detergent fiber (NDF; g/kg dry matter) presented a single chemical entity that was preferred over any multipredictor equation (GED = 70.4638−0.0360 NDF; RMSE = 2.9462; R2 = 0.6309; n = 58). However, the obtained equations should be validated against observed values, whereas alternative methods should be explored to predict OMD.

Comparison of indigestible markers from in situ and in vivo incubation to predict apparent digestibility in hay- and corn-fed horses

Four castrated crossbred horses were used in a randomized block design to study the use of indigestible internal markers iNDF and iADF obtained in situ (from bovines) or in vivo (from equines). Treatments consisted of determining digestibility by the direct method comprising total feces collection (TC) and by the indirect method comprising internal markers iNDF and iADF obtained by in situ incubation in bovine rumen or in vivo by the mobile nylon bag (MNB) technique with horses. iNDF-IV and iADF-IV resulted in better marker recovery rate (RR) (91.50%), similar to TC. The in situ technique resulted in lower RR values for the two indigestible markers, averaging 86.50% (p < 0.05). Estimates of the nutrient coefficient of digestibility (CD) were adequately predicted by iADF-IV, for horses fed on hay exclusively, with rates 46.41, 48.16, 47.92 and 45.51% for dry matter (DM), organic matter (OM), FDN and gross energy, respectively. Results show that MNB may be used to obtain iADF in horses fed on coast-cross hay exclusively, whereas NDFi and ADFi were selected for horses fed on mixed diets to predict the coefficient of nutrient digestibility