Control Hay Research Articles

The feeding of heather (Calluna vulgaris) to Teladorsagia circumcincta infected lambs reduces parasitism but can detrimentally impact performance

Gastrointestinal nematode (GIN) infections impact small ruminant health, welfare, and production across farming systems. Rising anthelmintic resistance and regulation of synthetic drug use in organic farming is driving research and development of sustainable alternatives for GIN control. One alternative is the feeding of plants that contain secondary metabolites (PSMs) e.g., proanthocyanidins (PA, syn. condensed tannins) that have shown anthelmintic potential. However, PSMs can potentially impair performance, arising from reduced palatability and thus intake, digestibility or even toxicity effects. In this study, we tested the trade-off between the antiparasitic and anti-nutritional effects of heather consumption by lambs. The impact of additional feeding of a nematophagous fungus (Duddingtonia flagrans) on larval development was also explored. Lambs infected with Teladorsagia circumcincta or uninfected controls, were offered ad libitum heather, or a control chopped hay for 22 days during the infection patent period. Eight days into the patent period, parasitised lambs were supplemented (or remained unsupplemented) with D. flagrans for a 5-day period. Performance and infection metrics were recorded, and polyphenol levels in the heather and control hay were measured to investigate their association with activity.The lambs consumed heather at approximately 20% of their dry matter intake, which was sufficient to exhibit significant anthelmintic effects via a reduction in total egg output (P = 0.007), compared to hay-fed lambs; the magnitude of the reduction over time in heather fed lambs was almost 10-fold compared to control lambs. Negative effects on production were shown, as heather-fed lambs weighed 6% less than hay-fed lambs (P < 0.001), even though dry matter intake (DMI) of heather increased over time. D. flagrans supplementation lowered larval recovery in the faeces of infected lambs by 31.8% (P = 0.003), although no interactions between feeding heather and D. flagrans were observed (P = 0.337). There was no significant correlation between PA, or other polyphenol subgroups in the diet and egg output, which suggests that any association between heather feeding and anthelmintic effect is not simply and directly attributable to the measured polyphenols. The level of heather intake in this study showed no antagonistic effects on D. flagrans, demonstrating the methods can be used in combination, but provide no additive effect on overall anthelmintic efficacies. In conclusion, heather feeding can assist to reduce egg outputs in infected sheep, but at 20% of DMI negative effects on lamb performance can be expected which may outweigh any antiparasitic benefits.

Anaerobic Digestion of Hemp and Flax Straw and Shives and Rapeseed Straw by the Ruminal Microbiota

To mitigate greenhouse gas emissions and improve energy supply security, there is an increasing effort toward the use of non-fossil energy sources. Crop residues have a great potential to be exploited as biomass for biogas production. However, due to their lignocellulosic structures they are difficult to degrade and do not reach competitive performance. A feasible option to mine these substrates is present in the forestomach of ruminants. Therefore, the aim of the present study was to use rumen microorganisms to improve anaerobic digestion (AD) of crop residues. For this purpose, hemp straw, mechanically pre-treated hemp fibers and shives, flax straw, flax shives, and aged and fresh rapeseed straw were evaluated using the rumen simulation technique. The AD of the substrates was divided into three batches. In two batches, hay was added as a control substrate. In summary, none of the analyzed substrates had an equivalent performance as the control hay, but pre-treated hemp fibers and shives had better AD parameters compared to all other alternative substrates, with the lowest pH (mean: 6.81), highest short chain fatty acid (20.0 mmol/day) and H2 production (25.6 mM) and highest degradability (25.2%). Flax straw had the second-best performance (6.81, 17.4 mmol/day, 20.6 mM and 22.2%, respectively), followed by fresh rapeseed straw, hemp straw, aged rapeseed straw and flax shives. Therefore, hemp fibers and shives demonstrated to be the most suitable substrates for AD. However, since pre-treatment can represent significant additional costs for biogas production, flax straw also demonstrated to be a good alternative.

Hydrodynamics affect plant traits in estuarine ecotones with impact on carbon sequestration potentials

Estuaries are highly productive ecosystems that play an important role in carbon fixing. The amount of carbon fixed by temperate brackish marshes depends, among others, on the biomass produced, its decomposition and the organic carbon stored in the soil. Here, we assumed that the functional trait composition of the vegetation both responded to environmental drivers and affected production, decomposition rate of native biomass and soil organic carbon, in addition to direct links between environmental drivers and these ecosystem properties. We tested a set of detailed hypotheses with a partial least squares structural equation model and quantified wave height, inundation period, salinity, soil nutrients, species abundances and as traits the leaf area, specific leaf area, stem bending properties and investment per plant organ, as well as above-ground standing biomass, decomposition rates of native and control biomass (hay) and soil organic carbon (SOC).There was no direct relationship between environmental drivers and ecosystem properties, except with the decomposition of control hay. All other linkages involved the functional composition of the vegetation. Increasing inundation period simultaneously decreased plants traits like stem stiffness, leaf area, specific leaf area and mass fraction of stems and leaves, which were aggregated in a new trait ‘aboveground module’. Total plant biomass decreased in communities on higher elevations with reduced wave height. Here, increased investment in the aboveground trait module resulted in higher aboveground community biomass and SOC but decreased the decomposition of native plant material, which in turn was higher in the low lying vegetation zones. Increasing total plant biomass also increased SOC, but not aboveground community biomass. Both the aboveground trait module and total plant biomass were response and effect traits, by responding to the environmental drivers and affecting carbon related ecosystem properties.At lower elevation with higher inundation and higher wave height, SOC was lower than the product of standing biomass and decomposition rate, which could be a proxy of the expected SOC. This may indicate an export of dead plant material to higher elevations or further downstream.Due to sea level rise, the area of estuarine vegetation may decrease because a fixed dike line along the river prevents landward migration, which can reduce the amount of biomass produced and with it the potential to store SOC. Restoration of the tidal marshes or realignment of the dikes may be necessary to protect the ecosystem properties and services of estuarine vegetation.

The use of an impeller mowing conditioner during haymaking had no effects on feeding behavior, feed intake or performance of organic dairy cows

AbstractImpeller mowing conditioners are commonly used to speed up the drying process on the field, making forage preservation (haying, ensiling) less dependent on weather conditions. However, the effects of this technique on the nutritive value of the forage and dairy cows' responses have not been investigated yet. Each half of two fields of grass-dominated swards, first regrowth, was cut either with or without the use of an impeller mowing conditioner (experimental hay and control hay, respectively).Ceteris paribusconditions were guaranteed by the same cutting and wilting times (roughly 48 h), number of teddings, field pickup technique and barn-drying method. At the beginning of the feeding trial, 19 lactating Holstein cows were allocated to one of two groups, one control (nine cows) and one experimental group (10 cows) and were fed the respective forage plus a fixed amount of concentrate [3.6 kg d−1; dry matter (DM) basis]. After a 14-d adaptation period, data were collected over 21 consecutive days. Covariate data of cows were collected prior to the experimental feeding period, over a time span of 9 d, and included in the statistical model. Results revealed that control and experimental hay showed significant (P&lt; 0.05) differences in the nutrient profile. However, the magnitude of these differences was not enough to affect intakes of hay (18.4 ± 0.29 kg DM d−1), total dietary energy or chewing activity, but did lead to a decreased intake of water-soluble carbohydrates and an increased crude protein intake, thus affecting ruminal nitrogen balance (P&lt; 0.01). This resulted in a higher milk urea content [23.3vs17.9 mg (100 mL)−1;P&lt; 0.01] in cows fed the experimental hay, whereas other milk performance parameters remained unaffected. In conclusion, the use of the impeller mowing conditioner did not affect the overall forage utilization by cows when the diet contained about 16% concentrate (DM basis). As this is the first study dealing with the effects of an impeller mowing conditioner on cows' responses, future research should consider investigating the effects of mowing conditioners when cows are fed only forage or diets with lower concentrate amounts.

Microwave Heat Treatment Induced Changes in Forage Hay Digestibility and Cell Microstructure

To investigate the effects of microwave (MW) treatment on hays nutritive value, five types of hay (50 g) were treated with MW for 0 (control), 20, 40, 60, and 80 s (0, 440, 880, 1320, and 1760 kJ kg−1 of MW energy, respectively) and analyzed for nutritive value prior to scanning by an electron microscope to observe microstructure changes. The dry matter (DM) % of hays were increased with increasing treatment time (p &lt; 0.001). The improved DM and digestible organic matter in the DM were recorded from MW treated lucerne (60 s), wheat (40 s), and canola (20 s) (p &lt; 0.001), which might have been due to the MW ruptured cell wall. The MW energy required for maximal DM digestibility improvement was linearly related to control hay crude protein content (r2 = 0.79; p &lt; 0.001). Overall, the study showed MW treatment can increase some hays’ digestibility. In addition, the crude protein content from control hay may be a proxy to indicate DM digestibility improvement.

Effect of birdsfoot trefoil cultivars on exsheathment of Haemonchus contortus in fistulated sheep

Proanthocyanidin (PAC, condensed tannin) containing forages have well-documented anti-parasitic effects against gastrointestinal nematodes (GIN) of small ruminants. Although extensive research has been conducted on the inhibition of exsheathment of the L3 stage of Haemonchus contortus by in vitro exposure to the extracts of PAC containing plants, only one study has previously attempted to replicate this process in vivo and it was found that consumption of fresh sainfoin slowed the exsheathment rate. No similar studies have explored the effect of feeding condensed tannin forages in the form of hay on in vivo exsheathment of GIN. Another PAC containing forage, birdsfoot trefoil (Lotus corniculatus, BFT), has a large area of adaptation globally and feeding BFT has been shown to reduce fecal egg counts and total worm burdens. However, its effect on the in vivo exsheathment of H. contortus in the rumen is unknown. Recent work from this laboratory showed that BFT populations differ in the ability of aqueous extracts of freeze-dried plants to reduce exsheathment of H. contortus in vitro, and that the reduced exsheathment caused by BFT populations did not directly correlate with PAC content. Therefore, the objective of this study was twofold: 1) to evaluate the ability of birdsfoot trefoil hay to impair ruminal exsheathment of H. contortus in vivo and 2) to measure the difference in exsheathment between three commercially available cultivars of birdsfoot trefoil representing a broad range of in vitro efficacy against H. contortus. Four rumen fistulated ewes were fed three cultivars of birdsfoot trefoil (cv. Bruce, Empire, and Pardee) hay or a control hay (alfalfa/grass hay) in a Latin 4 × 4 design. The effect of consumption of birdsfoot trefoil on the exsheathment of H. contortus larvae in vivo was evaluated. For each exsheathment test, two capsules with 2000 ensheathed third-stage larvae per capsule were placed in the rumen of each ewe for eight hours. Larval containment capsules were made by capping each end of a short piece of Tygon® tubing (ID 9.5 mm, OD 14.3 mm) with an 8 μm NuncTM Cell Culture Insert. Larval exsheathment and motility were examined pre and post rumen exposure. Three exsheathment tests were run per diet cycle. Consumption of BFT hay did not significantly alter larval exsheathment. These results highlight the importance of further in vivo testing on the role of condensed tannins and other plant secondary compounds on larval exsheathment in the rumen.

Effect of age and dietary carbohydrate profiles on glucose and insulin dynamics in horses.

Glucose and insulin dynamics may be different in adult and aged horses. To determine the effects of age and dietary carbohydrates on glucose and insulin dynamics in healthy horses. Balanced Latin square with four isocaloric diets: CONTROL (hay plus restricted-starch-and-sugar fortified pellets), STARCH (control plus kibbled corn), FIBER (control plus unmolassed sugar beet pulp/soybean hull pellets) and SUGAR (control plus dextrose powder). A total of 16 healthy Thoroughbreds and Standardbreds divided into two age groups: ADULT (8.8±2.9years; n=8) and AGED (20.6±2.1years; n=8). Following dietary adaptation, horses underwent an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGTT), modified oral sugar test (OST) and dietary meal challenge. Outcome variables included: insulin sensitivity (SI), disposition index (DI), glucose effectiveness (Sg) and acute insulin response to glucose (AIRg) from the FSIGTT; peak glucose, peak insulin, time to peak, area under the curve for glucose (AUCg) and insulin (AUCi) from the OST and dietary meal challenge. Data were analyzed using multivariable linear mixed regression modelling. AIRg was higher in AGED (mean [95% confidence interval]; 582.0 [455.0-709.0]) vs. ADULT (358.0 [224.0-491.0]; P=0.03). ADULT and AGED horses had a higher SI on STARCH (adult: 3.3 [2.3-4.2]; aged: 2.8 [1.9-3.7]) and SUGAR (adult: 3.4 [2.5-4.3]; aged: 4.0 [3.1-4.9]) diets compared with CONTROL (adult: 2.0 [1.1-2.9], P=0.029 (starch), P=0.009 (sugar); aged: 1.4 [0.5-2.2], P=0.009 (starch), P < 0.001 (sugar)). Feeding a STARCH (adult: 21581.0 [15029.0-28133.0]; aged: 35205.0 [29194.0-41216.0]) or SUGAR (adult: 26050.0 [19885.0-32215.0]; aged: 25720.0 [19770.0-31670.0]) meal resulted in postprandial hyperinsulinaemia (AUCi). Study cohort contained two insulin-sensitive breeds and no insulin-resistant breeds. Age and diet should be considered when evaluating glucose and insulin dynamics.

Inoculation and co-inoculation of alfalfa seedlings with root growth promoting microorganisms (Piriformospora indica, Glomus intraradices and Sinorhizobium meliloti) affect molecular structures, nutrient profiles and availability of hay for ruminants.

Inoculation of alfalfa seedlings with root growth promoting microorganisms under semi-arid climate condition may improve biomass production and nutritive value. The current study aimed to investigate the effect of inoculation of alfalfa seedlings with Piriformospora indica (Pi) and co-inoculating Pi with Glomus intraradices (Gi + Pi) or Sinorhizobium meliloti (Sm + Pi) on hay yield, chemical composition, molecular structures by Fourier transformed infrared (FTIR) spectroscopy, in situ ruminal degradability and in vitro gas production. Seedlings were grown in experimental pots in a greenhouse until first cut and then transferred outside and cut a further 4 times. Biomass yield was similar across the treatments. Acid detergent fiber (ADF) concentration was higher in Pi than in control hay, and ADF decreased further with co-inoculation (P < 0.05). The ether extract (EE) concentration was lower for Pi and Gi + Pi compared with control hay, and control, Pi and Gi + Pi hays had lower EE concentration compared with Sm + Pi (P < 0.05). The FTIR spectroscopic vibration peak height ratio related to proteins (amide 1 + amide 2): total carbohydrate ratio was lower for the inoculation treatments compared with control hay (P < 0.05). In situ ruminal degradability of dry matter and organic matter were higher for hay of inoculated and co-inoculated seedlings than for control hay (P < 0.05). In conclusion, hay of alfalfa seedlings inoculated and co-inoculated with root growth promoting microorganisms had improved nutritional value compared with hay from non-treated alfalfa seedlings, and co-inoculation was the most effective, however, changes were relatively minor.

Fodder quality and intake by dairy cows. 1. Preference for oaten hays

This work was undertaken to determine whether measurement of preference 30 min after alternative hays are offered to lactating dairy cows adequately predicts preference over a 3-day period and to determine the influence of the concentrations of water-soluble carbon (WSC) and neutral detergent fibre (NDF) of hays on preference. Eleven test hays were chosen to provide an NDF concentration of between 45% and 60% and a WSC concentration of between 10% and 30%. The test hays were each offered to lactating dairy cows as an alternative choice, with two control hays with NDF concentrations of 49% and 54%. A replicated Latin-square design was used to determine the preference of cows for the test hays, using three cows for each test hay versus control-hay comparison. Preference measured 30 min after hays were offered to cows was highly correlated with measures of preference made after 24 h and again for the same measures on the third day of the hays being offered. However, preference measures with the two different control hays were not well related, thus indicating that preference values are control-hay specific. Total hay intake was unchanged with the low-NDF control hay but declined with increasing NDF concentration of the test hays with the higher-NDF control hay. WSC did not influence preference at any one level of NDF of the test hays when the control hay had a low NDF concentration, but there was a small rise in preference at each NDF level when the control hay had a higher NDF concentration. This may have been a result of a contribution of WSC to digestibility as much as to taste response. With the low-NDF control hay, drivers of preference were the NDF concentration and the digestibility of the hay, but with the higher-NDF control hay, the drivers were the NDF concentration and fibre characteristics (shear and potential fibre digestibility). Calculation of the NDF concentration of the total hay consumed, test plus control hays, suggested that a change in drivers of selection is likely at the point where the NDF concentration of the test hay equals that of the control hay. Unless models identifying selection drivers handle non-linear data, misleading results may be obtained.

Digestibility and growth performance of sheep fed alfalfa hay treated with fibrolytic enzymes and a ferulic acid esterase producing bacterial additive

This study was conducted to determine the effects of fibrolytic enzymes applied at baling, with or without ferulic acid esterase (FAE) producing bacterial inoculant, or to hay at feeding on digestibility and growth performance of lambs. Prior to starting the animal studies, two runs of replicated 24- and 48-h batch culture in vitro incubations were conducted using control alfalfa hay to select a suitable enzyme and dose. Eleven replicate bales of alfalfa-grass (93.8:6.2) hay (∼500kg) were produced with the application of one of three treatments: control (water), enzyme applied at baling (Eb; Econase RDE-L, AB Vista, Wiltshire, UK) and enzyme plus ferulic acid esterase producing bacterial additive applied at baling (EIb; 11 GFT, Pioneer HI-Bred Ltd., Chathan, ON, Canada). The mean internal bale temperature after 50 days of storage was greater (P<0.001) for Eb than control and EIb, as was the post-storage hemicellulose concentration (P<0.05). Two animal experiments using lambs were conducted after bales were stored for at least 90 days. The digestibility study was a replicated 4×4 Latin square design with 16 lambs and the animal performance study consisted of 32 lambs (8 per treatment) in a randomized complete block design. In both studies lambs received one of four treatments: control, Eb, EIb and enzymes added to control hay at feeding (Ef). In the digestibility study, total tract apparent organic matter (OM) (P=0.07) digestibility tended to be affected by treatment, with OM digestibilities greater for lambs fed Ef compared with lambs fed the other treatments, although differences were small (Ef vs. others; OM, 0.658 vs. 0.646). However, neutral detergent fiber (aNDF) and hemicellulose digestibilities were greatest (P<0.05) for lambs fed Eb, with no differences among the other treatments (aNDF, Eb=0.480, control=0.437, Ef=0.430, EIb=0.430; hemicellulose, Eb=0.524, control=0.460, Ef=0.458, EIb=0.446). In both studies there was no effect (P>0.05) of treatment on OM intakes. Average daily gain (ADG, g/d) of lambs in the performance study was greater (P=0.048) for EIb (233) than control (192) and Ef (202), and intermediate for Eb (206). Feed efficiency tended to be affected (P=0.07) by treatment; gain:feed for EIb was 18% greater than control and Eb and Ef were similar to the control. This study showed that applying enzymes to alfalfa hay at baling decreased aerobic stability, and increased fiber content and its digestibility, but ADG and gain:feed of lambs were not improved. Adding FAE producing bacterial inoculant with enzymes at baling improved aerobic stability of hay and ADG and gain:feed of lambs were increased relative to lambs fed control and enzymes applied at feeding. Applying enzymes at feeding increased apparent OM digestibilities but not fiber digestibilities, and had no effect on animal performance. We conclude that fibrolytic enzyme application with FAE producing bacterial inoculant at baling was the most promising method for enhancing performance of lambs fed baled alfalfa hay.

&lt;b&gt;Correlation between chemical composition, kinetics of fermentation and methane production of eight pasture grasses

Eight different grasses collected from pastures of the Kermanshah province (Kermanshah, Iran), at mid-vegetative stage were used to study the relationships between their chemical compositions, kinetic parameters of in vitro gas production and rumen methane production. There was a positive correlation (r = 0.62, p < 0.05) between crude protein (CP) content of grasses and total gas production (A) at 96h incubation. Negative correlations were also observed between acid detergent fiber (ADF) content and total gas production (r = -0.60, p < 0.05). Amongst the nutrients, neutral detergent fiber (NDF) and ADF were positively correlated with methane concentration, (r = 0.75 and 0.77, p < 0.01). The methane reduction potential (MRP) was negative for Trachyspermum copticum indicating higher methane production than the control hay for this grass. The MRP of Chamaemelum nobile was more than 25%, indicating plants that reduce methane production more than 20 percent methane in comparison with control actually have ingredients to reduce methane.

Effects of rotational infrastructure within pasture-raised pig operations on ground cover, soil nutrient distribution, and bulk density

Interest in pasture-based pork products has increased significantly in recent years. However, nitrogen (N) losses resulting from these systems are common due to importation of feed, high stocking rates, and pig behavior. This study was conducted to evaluate soil inorganic N, soil-test phosphorus (STP), ground cover, and compaction changes as impacted by rotational shade, water, and feed structures in a pasture-raised pig operation over two 12-week pig occupations. Shade and watering structures were rotated weekly for 12 weeks within a rotational (mobile) scheme; data were compared to a stationary structure system as well as to a managed hay operation with no pigs. Soil samples were acquired from subplots and analyzed for distribution of inorganic N concentrations among main plot treatments, including nitrate (NO3), ammonium (NH4), and STP values. Soil inorganic N concentrations were higher in exterior subplot positions than in interior positions. This pattern was not maintained after a second pig group occupied the plots. Soil test phosphorus was unaffected by either pig occupation. Ground cover percentages were higher in control (hay) treatments than for pig treatments, however no difference was found between mobile and stationary structure treatments in either pig occupation. Soil compaction, as measured by soil bulk density, was found to be higher under permanent shade structure locations as compared to mobile and control treatments. Mobile and control compaction levels were not different for the second occupation, utilizing a more intensive sampling scheme, suggesting a benefit to the rotation of shade, water and feed infrastructure. The weekly rotation of infrastructure performed during both occupations was both labor intensive and time consuming. The observed lack of improvement in nutrient distribution to a rotational infrastructure may limit its utility in pastured-pig systems. However, further options are available that would allow the production of pasture-raised pigs while minimizing associated nutrient loading and pasture degradation.

Intake in cattle of a ground switchgrass and alfalfa hay mixture blended with various levels of sucrose or citric acid

Palatability of feed affects voluntary intake. The objectives were to evaluate preference by bovine for sweet (sucrose) or sour (citric acid) blended with a mixture of ground switchgrass (42g crude protein/kg dry matter) and alfalfa hay (176g crude protein/kg dry matter). Flavors were dissolved in 50mL deionized water per kg of hay for blending. In Experiment 1, sucrose hay (S100) had 100g sucrose added per kg hay. Citric acid hay (CA50) had 50g citric acid added per kg hay. Control hay (CON) had 50mL deionized water added per kg hay. In Experiment 2, treatments were CON, sucrose added at 25g per kg hay (S25), S100, 150g per kg hay (S150). Citric acid added at 25g per kg hay (CA25), and CA50. Hays were mixed in a horizontal mixer 3d prior to each experimental period. Twelve beef cattle (initial BW=283±25kg) were housed under a roof on expanded metal flooring with access to six feed locations designated I through VI, west to east. Cattle consumed 1kg/day of supplement (corn, soybean hulls, and trace mineralized salt) that was fed daily, after hay orts were removed and weighed at 0800. Cattle were offered treatment hay equal to 6g per kg BW at each feed slot and treatments were randomly assigned to two of the six locations at 0830. Cattle were given a 14-d adaptation to CON followed by a 7-d offer of treatments. In Experiment 1, cattle preferred S100 (3.42±0.04kg/d) over CON (2.8±0.04kg/d, P<0.01) and CA50 (0.32±0.04kg/d, P<0.01) and preferred CON over CA50 (P<0.01). In Experiment 2, cattle preferred CA10 over CON (P<0.02) and CA25 (P<0.02), and S100 was preferred over S150 (P<0.02) and S25 (P<0.02). Compared with control, cattle preferred hay flavored with sucrose up to 100g per kg of hay, and preferred hay flavored with citric acid up to 10g per kg of hay. Flavored feeds that are nutritionally adequate can be used to provide variety in the diet of cattle, where total intake increases when different feeds are presented together. Adding sugar may increase intake of undesirable feeds, or citric acid may be added at greater than 10g per kg hay to limit intake of desirable feeds.

Zinc-enriched and zinc-biofortified feed as a possible animal remedy in pastoral agriculture: Animal health and environmental benefits

Zinc is used in New Zealand agriculture to protect livestock against fungal infection (facial eczema), and supplementation can improve growth performance and feed efficiency. Zinc is commonly administered via a drench or bolus, but most is excreted in faeces. Mass balance calculations indicate that excreta is increasing the average Zn concentration in some NZ pastoral soils at a rate of 0.78mg/kg/ha/yr. This represents an unsustainable level of Zn increase that threatens environmental quality guidelines. To determine whether current supplements could be replaced by naturally Zn-enriched or biofortified fodder, 20 sheep were administered one of four Zn treatments over seven days (drench, control hay, biofortified (Zn) hay and willow with a naturally elevated concentration of Zn; Salix purpurea, clone Pohangina). Blood and faeces were sampled regularly and analysed for Zn. Drench rapidly increased blood serum and whole blood Zn concentrations to above the established threshold for protection. The plant treatments also increased blood Zn relative to the control, but there was insufficient Zn in the fodder to reach the threshold level. The concentration of Zn in faeces was significantly increased by drench and willow. For animals fed willow, the faeces Zn concentration remained elevated for longer than for those that were drenched. This was despite the animals on the willow treatment receiving only 11% of the Zn given to the drenched animals. We propose that willow, grown on soil elevated in Zn to yield a higher concentration of Zn in fodder, may represent a biogeochemical system for Zn supplementation where the trace element is cycled from soil, to plant, to animal, and back to soil. Such a system could reduce the flux of trace elements entering the pastoral environment from animal remedies, mitigate future environmental risk that may become apparent due to current farming practices, and potentially lead to increased livestock production.

Do sheep use umami and bitter tastes as cues of post-ingestive consequences when selecting their diet?

Grazing herbivores use their senses to select their diet. As tastes could reveal certain plant properties, we investigated whether sheep use them as cues to anticipate post-ingestive consequences. We focused on umami and bitter tastes reported to be associated with protein and toxin contents, respectively. We aimed to determine (1) lambs’ preferences for umami and bitter tastes offered together or with a control, and (2) lambs’ efficiency in learning positive and negative post-ingestive consequences associated with tastes coherently (i.e. umami taste → positive, bitter → negative) or incoherently (i.e. bitter → positive, umami → negative). The umami taste was induced by either 15 ( MSG1) or 25 (MSG2) g monosodium glutamate per kg DM hay, whereas the bitter taste was induced by 2 (Quin1) or 3 (Quin2) g quinine per kg DM hay that were sprayed on an orchard grass hay. In the first experiment, 24 ewe lambs were tested on eight two-choice types: MSG1-Quin1, MSG1-Quin2, MSG2-Quin1, MSG2-Quin2, MSG1-Control, MSG2-Control, Quin1-Control, and Quin2-Control, in a Latin-square design. They always preferred the umami-tasting hay to the control and the bitter-tasting hay ( P < 0.01) while they were indifferent to the bitter-tasting hay compared to control hay. After having checked that the lambs perceived the bitter taste induced by quinine (experiment 2) and that none of the substances used to modify the tastes induced their own post-ingestive consequences (experiment 3), we conducted the fourth experiment. Then, both coherent and incoherent groups decreased their preference for the taste associated with negative consequences compared to the taste associated with positive consequences, and aversion was greater in the coherent than in the incoherent group (0.04 ± 0.02 and 0.19 ± 0.08, respectively, P < 0.05). This difference could however be a residual effect of the large difference between initial preferences. After conditionings, to assess changes in individual tastes values, we re-tested the lambs’ preferences between umami- or bitter-tasting hay and control hay, and compared them with the initial preference patterns recorded in experiment 1. Preference for umami-tasting hay logically varied according to whether post-ingestive consequences were positive or negative, contrary to preference for bitter tasting-hay which was unaffected and close to umami value once negatively conditioned. Umami taste thus appears to have a positive value that can decrease after aversive conditionings, while bitter taste appears to have a negative value that made sheep suspicious about it even when associated with positive consequences.

Evidence for the inhibition of the terminal step of ruminal α-linolenic acid biohydrogenation by condensed tannins

Effects of condensed tannins (CT), either via extract or plant-bound, and saponin extract on ruminal biohydrogenation of α-linolenic acid (ALA) were investigated in vitro. Grass-clover hay served as basal diet (control). The control hay was supplemented with extracts contributing either CT from Acacia mearnsii [7.9% of dietary dry matter (DM)] or saponins from Yucca schidigera (1.1% of DM). The fourth treatment consisted of dried sainfoin (Onobrychis viciifolia), a CT-containing forage legume, in an amount also providing 7.9% CT in dietary DM. All diets were supplemented with linseed oil at a level contributing 60% of total dietary ALA in all treatments. Diets were incubated for 10 d (n=4) in the rumen simulation technique system, using the last 5 d for statistical evaluation. Fatty acids were analyzed in feed, feed residues, incubation fluid, and its effluent. Data were subjected to ANOVA considering diet and experimental run as main effects. Both CT treatments reduced ruminal fiber and crude protein degradation, and lowered incubation fluid ammonia concentration. Only the CT extract suppressed methane formation and shifted microbial populations toward bacteria at cost of protozoa. The saponin extract remained without clear effects on fermentation characteristics except for increased protozoal counts. The extent of ALA biohydrogenation was 20% less with the CT plant, but this probably resulted from reduced organic matter degradability rather than from an inhibition of biohydrogenation. After incubation analysis of incubation fluid effluent and feed residues showed a considerable proportion of the 3 biohydrogenation intermediates, cis-9, trans-11, cis-15 C18:3, trans-11, cis-15 C18:2, and trans-11 C18:1, which did not occur in the initial feeds. Only the CT-extract diet led to a different profile in the effluent compared with the control diet with trans-11 C18:1 being considerably increased at cost of C18:0. This could have been achieved by suppressing protozoa and enhancing the bacterial population, thus removing potential microbes involved in biohydrogenation and increasing competition between bacteria involved in biohydrogenation and others. The elevation of trans-11 C18:1 as the precursor of cis-9, trans-11 conjugated linoleic acid formed in body tissue and mammary gland is probably favorable from a human health point of view.

Tannins determined by various methods as predictors of methane production reduction potential of plants by an in vitro rumen fermentation system

Relationships between chemical constituents, including values obtained with tannin assays ( i.e., total phenols, total tannins, condensed tannins and tannin activity using a tannin bioassay) for plant materials ( n = 17), and methane production parameters at 24 h of incubation in the in vitro Hohenheim gas method were established. The methane production reduction potential (MRP) was calculated by assuming net methane concentration for the control hay as 100%. The MRP of Bergenia crassifolia leaves and roots, and Peltiphyllum peltatum leaves, was >40%. Amongst the chemical constituents, neutral detergent fibre had a high correlation ( r = 0.86) with methane concentration. There was negative relationship between total phenol, total tannins or tannin activity and methane concentration. However, a positive relationship existed between these tannin assays and the MRP, with r-values ranging from 0.54 to 0.79 ( P<0.05). A very weak relationship ( r = 0.09) occurred between condensed tannins and MRP. Similar results to those with MRP were obtained with the percent increase in methane on addition of polyethylene glycol. The highest correlations, 0.79 and 0.92 ( P<0.001), were between tannin activity determined using the tannin bioassay and the MRP, or the percent increase in methane on addition of polyethylene glycol, respectively, suggesting that this tannin assay could be used to identify plants possessing antimethanogenic properties. Leaves of Rheum undulatum, Vaccinium vitis-idaea, B. crassifolia, Rhus typhina and P. peltatum, and roots of B. crassifolia have considerable potential ( i.e., >25%) to decrease enteric methane production from ruminants.

Effect of method of applying fibrolytic enzymes or ammonia to Bermudagrass hay on feed intake, digestion, and growth of beef steers1

This study examined how different methods of applying a fibrolytic enzyme or ammonia affect the nutritive value of Bermudagrass hay and the performance of beef cattle. Fifty Angus x Brangus crossbred steers (mean initial BW 244 +/- 26 kg) were individually fed for ad libitum intake of a 5-wk regrowth of a mixture of Florakirk and Tifton 44 Bermudagrass [Cynodon dactylon (L.) Pers] hay for 84 d with a concentrate supplement (77% soybean hull pellets, 23% cottonseed meal (DM basis) fed at 1% of BW daily. The Bermudagrass was conserved as hay without treatment (control), with NH(3) (30 g/kg of DM), or with a fibrolytic enzyme (16.5 g/t, air-dry basis) that was applied immediately after cutting (Ec), at baling (Eb), or at feeding. Chromic oxide was dosed to steers for 10 consecutive days, and fecal Cr concentrations from the last 5 d were used to estimate apparent total tract digestibility. In situ ruminal DM degradability was measured by incubating ground (4-mm) hay samples in duplicate in each of 2 ruminally cannulated cows having ad libitum access to Bermudagrass hay and 500 g/d of soybean meal. Unlike the enzyme treatment, ammoniation increased (P < 0.001) the CP concentration and reduced (P < 0.001) NDF, hemicellulose, and lignin concentrations of hay. Total DMI was greater (P < 0.05) for steers fed hays treated with Ec or NH(3) than for those fed control hays. All additive treatments increased (P < 0.05) DM digestibility, and NH(3), Ec, and Eb treatments also increased (P < 0.01) NDF digestibility. The initial and final BW, ADG, BCS, G:F, and hip height of the steers were not affected (P > 0.05) by treatment. The wash loss fractions in hays treated with Ec and Eb were lower than that in the control hay, but the potentially degradable fraction, total degradable fraction, and the effective degradability were increased (P < 0.01) by NH(3) treatment. Application at cutting was the most promising method of enzyme treatment, and this treatment was almost as effective as ammonia for enhancing forage quality.

Effect of sainfoin ( Onobrychis viciifolia) silage and hay on established populations of Haemonchus contortus and Cooperia curticei in lambs

The objective of the study was to examine the effect of dried and ensiled sainfoin ( Onobrychis viciifolia) on established populations of Haemonchus contortus (abomasum) and Cooperia curticei (small intestine) in lambs under controlled conditions. Twenty-four parasite naïve lambs were inoculated with a single dose of infective larvae of these parasites 28 days prior to the start of the feeding experiment. Twenty-four days post-infection, 4 days prior to the start of the feeding experiment, animals were allocated to four groups according to egg excretion, live weight and sex. Groups A and B received sainfoin hay and control hay, respectively, for 16 days. Groups C and D were fed on sainfoin silage or control silage for the same period. Feeds were offered ad libitum and on the basis of daily refusals were supplemented with concentrate in order to make them isoproteic and isoenergetic. Individual faecal egg counts on a dry matter basis (FECDM) were performed every 3–4 days and faecal cultures and packed cell volume (PCV) measurements were done weekly. After 16 days of experimental feeding, all animals were slaughtered and adult worm populations were determined. The consumption of conserved sainfoin was associated with a reduction of adult H. contortus (47% in the case of hay, P < 0.05; 49% in the case of silage, P = 0.075) but had little effect on adult C. curticei. Compared to the controls, H. contortus specific FECDM was reduced by 58% ( P < 0.01) in the sainfoin hay group and by 48% ( P = 0.075) in the sainfoin silage group. For both sainfoin feeds FECDM specific to C. curticei were significantly decreased when compared to the control feeds (hay 81% and silage 74%, both tests P < 0.001). Our data suggest that different mechanisms were responsible for the reduction in FECDM in response to feeding tanniferous fodder. For H. contortus, the decrease seemed to be due to a nematocidal effect towards adult H. contortus. In contrast for C. curticei, the reduction in FECDM appeared to be a result of a reduced per capita fecundity. For both, hay and silage, an antiparasitic effect could be shown, offering promising perspectives for the use of conserved tanniferous fodder as a complementary control approach against GIN.

Effects of Tasco (a seaweed extract) and heat stress on N metabolism and meat fatty acids in wether lambs fed hays containing endophyte-infected fescue

Wether lambs ( n = 27, average BW = 40 kg) were used to test response to forage treated with Tasco-Forage (an extract of the brown kelp Ascophyllum nodosum) prior to conserving, or to direct feeding of the extract (Tasco-EX). Hays made from endophyte ( Neoyphodium coenophialum)-infested tall fescue ( Festuca arundinacea)-based pasture received 0 or 3 kg of Tasco/ha prior to harvest. Lambs, blocked by weight, were randomly allotted to three diets: (1) control hay, (2) treated hay, and (3) #1 + Tasco-EX fed at 1% of the diet. Hays were low in CP (<7%) so all lambs were fed soybean meal (12% of the diet) in addition to trace mineralized salt. Diets were fed at 1.5% BW to prevent refusals. Total collections (7 d) were made during periods without or with applied heat stress. After each period, rumen contents were obtained to determine pH, NH 3 and VFA. Lambs were sacrificed post-trial. A subset was used to evaluate sensory traits and muscle fatty acids. Lambs were in negative N balance during the study and Tasco treatments did not affect N metabolism. Fecal N tended ( P < 0.10) to increase with short duration heat stress causing a concomitant decrease ( P < 0.05) in apparent N digestibility (58.6 versus 56.1%; S.E. = 0.7). Urinary N loss decreased ( P < 0.001) with heat stress (8.0 versus 5.9 g/d; S.E. = 0.2), resulting in increased ( P < 0.001) N retention (−2.1 versus −0.3 g/d; S.E. = 0.2). Apparent OM digestibility was not affected by heat stress but was greater ( P < 0.05) for lambs fed Tasco-EX treatment than those fed treated hay. Treatment diets decreased ( P < 0.05) ruminal butyrate. Heat stress increased ( P < 0.05) acetate and total VFA and decreased ( P < 0.01) ruminal pH. A tendency ( P < 0.11) of increased 14:1ω5, decreased ( P < 0.05) 18:0 and total saturated fatty acids in muscle was observed with Tasco diets. Meat sensory characteristics were not affected by treatment. Tasco may alter some aspects of rumen or lipid metabolism but has no effect on N metabolism or meat sensory characteristics of sheep fed restricted, low-quality diets.