Search

Medusahead [Taeniatherum caput-medusae (L.) Nevski] is an invasive annual grass spreading into rangelands throughout the western United States. We tested cattle (Bos taurus L.) utilization of T. caput-medusae following treatment with glyphosate in two forms of its salt (potassium salt and isopropylamine salt) at three different rates of application; low (236 g ae ha−1), medium (394 g ae ha−1), and high rates (788 g ae ha−1) in eastern Washington. The herbicide was applied on April 26, 2016. A second location, northern Utah, was treated with glyphosate in the form of its isopropylamine salt at the high rate. The herbicide was applied on June 5, 2019. Cattle were allowed to start grazing T. caput-medusae 15 d after glyphosate treatment and had unlimited access to the glyphosate-treated plots for more than 85 d. The greatest utilization of T. caput-medusae occurred at the highest glyphosate application rate (P < 0.05), in Washington, with no difference between forms of glyphosate salt. Cattle also consumed T. caput-medusae at the Utah site (P < 0.05). Glyphosate treatment preserved the water-soluble carbohydrate content of T. caput-medusae at levels greater than the nontreated controls (P < 0.05) at both locations. The glyphosate treatment assisted in the increased utilization of T. caput-medusae by cattle and is a viable option for the reduction of T. caput-medusae while increasing the forage value of the weed.

Ruminants would suffer from gastric distension (bloat) when feeding on alfalfa (Medicago sativa L.; Alf), while tannins can relieve this problem. Thus, this study aimed to evaluate the effect of Alf mixed with paper mulberry (Broussonetia papyrifera) leaves (PML) or condensed tannins (CT) extracted from PML on in vitro fermentation performance. Seven experimental treatments based on the mass ratios of Alf and PML were set up: Alf, PML, 3A1P (Alf:PML = 3:1), 1A1P (Alf:PML = 1:1), 1A3P (Alf:PML = 1:3), A1P (Alf with 1% CT extracted from PML), A2P (Alf with 2% CT extracted from PML), and a blank. The results after fermentation were as follows. (1) The degradable dry matter (DDM) and degradable organic matter (DOM) contents increased simultaneously with the increase in the proportion of PML (p .05), propionic, and butyric acids compared to Alf alone. Adding CT improved the concentrations of propionic and butyric acids over the Alf treatment (p

Medusahead [Taeniatherum caput-medusae (L.) Nevski] is one of the most detrimental invasive annual grasses impacting the sustainability and function of rangeland in the western United States. This annual grass possesses high concentrations of tissue silicon (Si) that may facilitate invasion through key plant characteristics such as increased plant fitness, structure, and antinutritive qualities. These characteristics may affect known invasive processes such as increased plant productivity, slow litter decomposition, and decreased herbivory, facilitating a positive feedback cycle of invasion. However, Si is not considered an essential element and is often overlooked as a factor of T. caput-medusae invasion. Thus, this article provides a synthesis of plant Si, T. caput-medusae, and the self-reinforcing feedback cycle of invasion. We also discuss how current control strategies address plant characteristics determined by Si and suggest research avenues that may aid in novel or improved control strategies that target the T. caput-medusae–silica relationship.

Medusahead is an aggressive, winter annual that is of dire concern for the health and sustainability of western rangelands in the United States. Medusahead reduces plant diversity, alters ecosystem function, and reduces carrying capacities for both livestock and wildlife. The species has competitive advantages over cheatgrass and native grasses that causes an increased amount of fine fuels deposited on western rangelands. The Channeled Scablands of eastern Washington in the United States represent a typical example of a region being challenged by the expansion of this weed. The costs of the invasion are high and financial constraints can limit successful management. Managers need the ability to identify medusahead across entire landscapes, so they can work towards effective and efficient management approaches. Remote sensing offers the ability to measure vegetation cover at large spatial scales, which can lead to a better understanding of the invasive characteristics of problematic species like medusahead. For instance, research has been successful in creating large-scale distribution maps of cheatgrass over western rangelands. Many applications rely on the phenological characteristics of a target plant which can present problems in separating two species with similar phenologies (i.e. cheatgrass & medusahead). A medusahead-specific map gives managers the flexibility to prioritize and direct management needs when attempting to control the spread of medusahead into non-invaded areas. This study integrated GPS acquired field locations from three study sites (Sites S, C, & N) and imagery from two remote sensing platforms (1-m aerial imagery & 30-m Landsat), to model and predict fractional cover of medusahead over 37,000+ ha of rangelands in the Channeled Scabland region of eastern Washington. Using a multi-scaled approach, this research showed that regression tree algorithms can model the complex spectral response of senesced medusahead using late summer Landsat scenes. The predictive performances resulted in a R2 of 0.80 near the model's training site (Site S) and an average R2 of 0.68 away from the training site (Sites C & N). This research provides a non-phenological approach to produce accurate large-scale, distribution maps of medusahead which can aid land managers who are challenged by its invasion.

A diversity of forages with different types and concentrations of nutrients and plant secondary compounds may lead to complementary relationships that enhance cattle performance and welfare. We determined whether grazing combinations of tanniferous legumes (Lotus corniculatus, birdsfoot trefoil [BFT], Onobrychis viciifolia, sainfoin [SF]), and alfalfa [ALF] (Medicago sativa) influence foraging behavior, performance, and hair cortisol concentration in beef cattle compared with grazing the same legumes as monocultures. Twenty-one pairs of heifers grazed three spatial replications of seven treatments: monocultures of BFT, SF, or ALF, and all possible two- and three-way choices among strips of these legumes: SF-BFT, ALF-BFT, ALF-SF, and ALF-SF-BFT in two periods of 25 d each (adaptation phase + experimental period) during two consecutive years. The lowest incidence of grazing events occurred in the BFT treatment (42.0% of the total scans recorded; P < 0.10), with the rest of the treatments ranging between 47.8% (SF-BFT) and 52.6% (ALF-SF) of the total scans recorded. Heifers selected a varied diet, preferring SF over BFT or ALF in a 46:27:27 ratio for the three-way choice, and in a 70:30 ratio for both two-way choices. Heifers preferred BFT over ALF (62:38 ratio) in a two-way choice. All treatments followed similar daily grazing patterns (P > 0.10), with two major grazing events (1 h after sunrise and 3 h before dark). No differences among treatments were observed for the number of steps taken by heifers on a daily basis, motion index, or the percentage of time heifers spent standing (1,599, 5,356, and 45.3%, respectively; P > 0.10), suggesting that heifers on choice treatments did not invest extra time in walking, searching, or patch switching activities relative to heifers grazing monocultures. Heifers grazing the three-way choice gained more body weight (1.27 kg/d) than the average gains observed for animals grazing in all legume monocultures (1.00 kg/d; P = 0.014) or two-way choices (0.97 kg/d; P = 0.007), suggesting a synergism among pasture species for the treatment with the highest diversity. No differences in hair cortisol concentration were observed among treatments, with values ranging between 1.4 (BFT) and 2.12 ng/g (three-way choice; P > 0.10). Thus, forage diversity has the potential to enhance animal performance without affecting grazing efficiency, likely explained by the spatial arrangement of the forage species presented in the study.

Intake of medusahead (Taeniatherum caput-medusae (L.) Nevski) by livestock is typically low given the poor nutritional quality of the weed, but utilization may increase through the provision of supplemental nutrients. This study compared cattle that initially grazed on a supplemented pasture (SUP) of established cool-season perennial grasses and forbs to nonsupplemented cattle that grazed only medusahead-infested rangeland (NSUP) in order to determine whether supplemental nutrients could increase use of medusahead. The quality of different forage types in the plant community and grazing events on these forage types were assessed. Supplemented animals grazed medusahead to a greater extent than NSUP animals in the medusahead-infested pastures (P = 0.003). Thus, grazing of improved pastures in close temporal proximity to grazing of medusahead-infested rangeland may represent a management tool that contributes to enhancing medusahead utilization by cattle. However, future long-term studies need to be conducted in order to examine whether medusahead use by cattle can be used as a practical, low-cost tool for medusahead management.

Diverse combinations of forages with different nutrient profiles and plant secondary compounds may improve intake and nutrient utilization by ruminants. We tested the influence of diverse dietary combinations of tannin- (sainfoin-Onobrichis viciifolia; birdsfoot trefoil-Lotus corniculatus) and non-tannin- (alfalfa-Medicago sativa L.) containing legumes on intake and diet digestibility in lambs. Freshly cut birdsfoot trefoil, alfalfa, and sainfoin were offered in ad libitum amounts to 42 lambs in individual pens assigned to 7 treatments (6 animals/treatment): 1) single forage species (sainfoin [SF], birdsfoot trefoil [BFT], and alfalfa [ALF]), 2) all possible 2-way choices of the 3 forage species (alfalfa-sainfoin [ALF-SF], alfalfa-birdsfoot trefoil [ALF-BFT], and sainfoin-birdsfoot trefoil [SF-BFT]), or 3) a choice of all 3 forages (alfalfa-sainfoin-birdsfoot trefoil [ALF-SF-BFT]). Dry matter intake (DMI) was greater in ALF than in BFT (P = 0.002), and DMI in SF tended to be greater than in BFT (P = 0.053). However, when alfalfa was offered in a choice with either of the tannin-containing legumes (ALF-SF; ALF-BFT), DMI did not differ from ALF, whereas DMI in SF-BFT did not differ from SF (P > 0.10). When lambs were allowed to choose between 2 or 3 legume species, DMI was greater (36.6 vs. 33.2 g/kg BW; P = 0.038) or tended to be greater (37.4 vs. 33.2 g/kg BW; P = 0.067) than when lambs were fed single species, respectively. Intake did not differ between 2- or 3-way choice treatments (P = 0.723). Lambs preferred alfalfa over the tannin-containing legumes in a 70:30 ratio for 2-way choices, and alfalfa > sainfoin > birdsfoot trefoil in a 53:33:14 ratio for the 3-way choice. In vivo digestibility (DMD) was SF > BFT (72.0% vs. 67.7%; P = 0.012) and DMD in BFT tended to be greater than in ALF (64.6%; P = 0.061). Nevertheless, when alfalfa was offered in a choice with either sainfoin or birdsfoot trefoil (ALF-SF; ALF-BFT), DMD was greater than ALF (P < 0.001 and P = 0.007, respectively), suggesting positive associative effects. The SF treatment had lower blood urea nitrogen and greater fecal N/N intake ratios than the ALF, BFT, or ALF-BFT treatments (P < 0.05), implying a shift in the site of N excretion from urine to feces. In conclusion, offering diverse combinations of legumes to sheep enhanced intake and diet digestibility relative to feeding single species, while allowing for the incorporation of beneficial bioactive compounds like condensed tannins into the diet.

The objective of this study was to determine whether feeding tannin-containing hays to heifers and mature beef cows influences enteric methane (CH4) emissions and nitrogen (N) excretion relative to feeding traditional legume and grass hays. Fifteen mature beef cows (Exp. 1) and 9 yearling heifers (Exp. 2) were each randomly assigned to treatment groups in an incomplete bock design with 2 periods and 6 types of hays with 3 hays fed each period (n = 5 cows and 3 heifers per treatment). Groups were fed tannin-containing [birdsfoot trefoil (BFT), sainfoin (SAN), small burnet (SML)] or non-tannin-containing [alfalfa (ALF), cicer milkvetch (CMV), meadow bromegrass (MB)] hays. Each period consisted of 14 d of adjustment followed by 5 d of sample collection. Nine cows and 9 heifers were selected for the measurement of enteric CH4 emissions (sulfur hexafluoride tracer gas technique), and excretion of feces and urine, while dry matter intake (DMI) was measured for all animals. The concentration of condensed tannins in SAN and BFT was 2.5 ± 0.50% and 0.6 ± 0.09% of dry matter (DM), respectively, while SML contained hydrolyzable tannins (4.5 ± 0.55% of DM). Cows and heifers fed tannin-containing hays excreted less urinary urea N (g/d; P < 0.001) and showed lower concentrations of blood urea N (mg/dL; P < 0.001) than animals fed ALF or CMV, indicating that tannins led to a shift in route of N excretion from urine to feces. Additionally, cows fed either BFT or CMV showed the greatest percentage of retained N (P < 0.001). Enteric CH4 yield (g/kg of DMI) from heifers (P = 0.089) was greatest for MB, while daily CH4 production (g/d) from heifers (P = 0.054) was least for SML. However, digestibility of crude protein was reduced for cows (P < 0.001) and heifers (P < 0.001) consuming SML. The results suggest that tannin-containing hays have the potential to reduce urinary urea N excretion, increase N retention, and reduce enteric CH4 emissions from beef cattle. The non-bloating tannin-free legume CMV may also reduce environmental impacts relative to ALF and MB hays by reducing N excretion in urine and increasing N retention.

Ruminant livestock-production systems are between a rock and a hard place; they are experiencing increasing societal pressure to reduce environmental impacts in a world that demands increased food supply. Recent improvements in the understanding of the nutritional ecology of livestock by scientists may help livestock producers respond to these seemingly contradictory demands. Forages are nutrition and pharmacy centers with primary (nutrients) and plant secondary compounds (PSC; pharmaceuticals, nutraceuticals), which can provide multiple services for the proper functioning of agroecosystems. Legumes with lower contents of fiber and higher contents of nonstructural carbohydrates, coupled with different types and concentrations of PSC (e.g., condensed tannins, terpenes), create a diverse array of chemicals in the landscape (i.e., the “chemoscape”) with the potential to enhance livestock nutrition, health and welfare relative to foodscapes dominated by grasses and other conventional feeds. These PSC-containing plants may reduce methane emissions and nitrogen (N) excretion from animals while increasing animal growth rate compared with swards dominated by grasses, and provide meat quality that appeals to consumers. Condensed tannins from sainfoin and saponins from alfalfa and manure of cattle consuming these forages also reduce N mobilization in soils, reduce nutrient leaching, and increase plant-available N stores for future use. The challenge for future pastoral production systems is to design multifunctional spatiotemporal arrangements of forages with “ideal” chemical diversity for specific ecoregions, aiming to achieve sustainability while increasing production goals and improving ecosystem services. Thus, the objective of this review is to stimulate the quest for chemically and taxonomically diverse pastoral feeding systems that optimize overall productivity; reduce environmental impacts; and enhance livestock, soil, and human health.

The aim of this study was to determine in vitro ruminal degradability and gas production kinetics of sainfoin (Onobrichis viciifolia; SF), birdsfoot trefoil (Lotus corniculatus; BFT), alfalfa (Medicago sativa L.; ALF) and their binary or trinary mixtures using the gas production technique. The proportions in the mixtures represented: (1) those selected by lambs in a free-choice experiment (70:30 and 50:35:15 ratios for binary and trinary combinations, respectively), or (2) equal proportions (50:50 or 33:33:33 ratios for binary or trinary mixtures, respectively). Organic matter digestibility was greater in ALF and BFT than in SF (0.791 and 0.796 vs 0.751; P SF (198.3 ml) > BFT (187.6 ml) (P

Herbivores satiate on single foods ingested too frequently or in excess. We hypothesized that exposure to the same unpalatable food too frequently or in excess causes satiety, which in turn would reduce subsequent use and preference for this food when alternatives become available. In each of three experiments, twenty-four lambs were randomly assigned to three treatment groups (8 lambs/group), where they received high (Ad libitum), intermediate (100–200 g/d) or low exposure (20–40 g/d) to three unpalatable foods: The invasive weed medusahead (Experiment 1), an alfalfa:quebracho tannin ration (70:30; QT) (Experiment 2), or wheat straw (Experiment 3). After exposure, all groups in Experiments 1 and 3 received a simultaneous offer of the unpalatable food and a novel food that changed across four consecutive preference tests: Grape pomace (Test 1), barley straw (Test 2), tall fescue hay (Test 3), and beet pulp (Test 4). Lambs in Experiment 2 received a simultaneous offer of each of these novel foods and the same novel food containing 30% quebracho tannins. During exposure, lambs in Experiment 1 showed a low and cyclic pattern of medusahead intake, and the group with intermediate level of medusahead exposure showed greater intake values than the Ad libitum group, followed by the group with the lowest level of exposure (P < 0.05). For the rest of the experiments, intake was Ad libitum > intermediate > low level of exposure (P < 0.05). During preference tests, lambs with the least level of exposure to the unpalatable foods tended to consume more medusahead (35% to 37%; P = 0.11) or wheat straw (15 to 30%; P = 0.10) than lambs that received greater levels of exposure. In contrast, differential exposure to QT did not influence subsequent preference for tannin-containing foods (P = 0.33), but animals with the greatest level of exposure to QT consumed 24% more alternatives (i.e., non-tannin containing foods) than lambs that had received the lowest level of QT exposure (P < 0.05). Intake of alternative novel foods during preference tests increased with increments in nutritional quality from grape pomace and barley straw to tall fescue hay and beet pulp (P < 0.05), suggesting that lambs discriminated the nutritional value of the novel foods. In conclusion, repeated exposure to unpalatable foods has the potential to further reduce their utilization when alternatives –even when novel– become available. This effect appeared to be influenced by the chemical characteristics of the unpalatable food and it has implications for the coexistence of plant species in grazed communities.

International audience; Plant secondary metabolites (PSM) are one of the promising options to control gastrointestinal nematodes in sheep and goats. The objective of this study was to assess the abilities of sheep and goats to self-medicate with tannin-rich sainfoin (Onobrychis viciifolia) (SF) when infected with gastrointestinal nematodes, using a cafeteria and an operant conditioning trial. Hypotheses were that parasitized (P) lambs and goat kids would show greater intake and preference for SF than their non-parasitized (NP) counterparts, that kids would eat more SF than lambs (due to their lower resistance against parasites and their greater ability to consume PSM), and that SF intake would increase over time for P animals. We used 20 female kids and 20 ewe lambs aged 3 months. Half of the animals per species (n = 10) were experimentally infected with 170 L3 larvae of Haemonchus contortus/kg of BW (P). The other half were free from parasites throughout the study (NP). Five weeks after infection, animals were exposed to a 24-day cafeteria trial (three 8-day periods) offering a free choice between two legume pellets: SF (3.8% condensed tannins) and alfalfa (ALF, Medicago sativa; no tannin). Subsequently, animals were involved in an operant conditioning trial of two 4-day long sessions, to assess in short-term tests their motivation to walk for a SF reward when offered in choice with freely available ALF. In the cafeteria trial, SF preference was greater in kids than in lambs, particularly in the first two periods. We did not observe a greater preference for SF in P animals, which was even greater in NP animals for periods 1 and 2. Sainfoin intake increased through periods for P animals, which led to similar SF preferences for all groups during period 3. In the operant-conditioning trial, motivation to get the SF reward was similar between P and NP animals. These results support the hypotheses that goats are more willing to consume tanniferous feeds than sheep, and that P animals increased SF intake through time. However, the emergence of a curative self-medicative behaviour was not supported, as P individuals did not show greater SF intake, preference, nor a greater motivation to get SF than NP animals, regardless of animal species. These findings are discussed with previous results and some explanations are presented.

Forages can provide a complete diet for ruminant animals, increasing the sustainability of beef production systems worldwide while reducing competition with humans for agricultural land or grain crops. Much of the emphasis on the nutritional characteristics of forages has been on the fiber, sugars, starch, and protein they supply to the rumen, despite the fact that other less-explored constituents, i.e., neutral detergent soluble fiber (NDSF) and other non-structural or non-fiber carbohydrates (NFC) also play a key role in the nutrition of ruminants. This paper explores the less investigated potential of temperate legumes to accumulate levels of NFC comparable to corn silage or beet pulp in cool, dry environments under irrigation, and its implications for forage-based beef production systems. We conclude that genetic or managerial interventions (i.e., breeding programs, defoliation frequency) or ecological conditions (i.e., climate, elevation) that increase concentrations of NFC in legumes can enhance beef production, meat quality, and the efficiency of nitrogen utilization by ruminants while reducing environmental impacts.

Incorporation of legumes into forage systems has been a widely adopted strategy to increase pasture productivity and forage nutritive value, while reducing N inputs. In addition, some legumes contain beneficial chemicals like condensed tannins (CT), which could enhance the efficiency of energy and protein use in ruminants relative to other forages. We assessed (i) animal performance, (ii) methane emissions (SF6 technique), and (iii) concentration of nitrogen in urine and blood in cattle grazing a CT-containing legume (birdsfoot trefoil; BFT), a legume without tannins (cicer milkvetch; CMV), a grass (meadow brome; MB), or in cattle fed a total mixed ration (TMR). Fifteen Angus heifers were randomly assigned to one of three treatment pastures: (1) BFT, (2) CMV, and (3) MB. Each treatment had 5 spatial replications, randomly divided into three paddocks (64 × 57m), seeded with BFT, CMV or MB, and one heifer was assigned to each paddock. Five Angus heifers were randomly assigned to individual adjacent pens and received a TMR ration (25% of alfalfa hay, 25% corn silage and 50% chopped barley) during the same period. Response variables were analyzed as a split-plot design, with experimental units as the random factor and treatment as a fixed factor with day as the repeated measure. Cows grazing BFT (1.9% condensed tannins) or fed the TMR showed greater weight gains than cows grazing CMV or MB (P = 0.0006). Methane emissions did not differ among treatments (P > 0.05; Table 1). Blood urea nitrogen concentrations were similar in cows grazing BFT or CMV (P = 0.1202), but greater than in animals grazing MB or fed TMR (P < .0001). Urinary nitrogen concentrations were similar among treatments (P = 0.5266). These results suggest grazing tanniferous legumes enhanced BW gains with similar methane and urinary nitrogen emissions to grass and confinement alternatives and greater levels of production than grass or CMV.

We determined whether sheep discriminate among different mineral supplements containing P and Mg and if they modify their selection as a function of the basal diet received. Forty lambs were offered four-way choices among inorganic sources of P and Mg: magnesium oxide in its coarse 1) C-MgO and granular 2) MgO forms and magnesium phosphate: 3) Mag33 (33% Mg and 2.7% P), and 4) MGP (25% Mg and 15% P), and two-way choices between MGP and each of the other minerals, and between MgO and C-MgO (baseline). Subsequently, lambs were randomly assigned to four groups (10 lambs/group) and fed rations such that the levels of Mg and P were low (LMg_LP), adequate (NMg_NP), low in Mg and adequate in P (LMg_NP), or adequate in Mg and low in P (NMg_LP). After 29 d, choice tests (post-deficiency) were repeated. During baseline, lambs ate and preferred Mag33 > C-MgO = MGP > MgO (P < 0.05). This pattern remained during post-deficiency tests, but lambs in LMg_LP and LMg_NP increased their preference for MGP and C-MgO, respectively, whereas lambs in NMg_LP increased their preference for C-MgO and MGP relative to baseline (P < 0.05). The serum concentrations of P and Mg increased after preference tests, and preference for MgO and MGP in low-Mg groups increased as the serum concentration of Mg declined (P < 0.05). Thus, lambs discriminated among different minerals and some groups modified their preferences based on the basal diets received, which rectified mineral imbalances.

Our objective was to explore diet selection and productive performance by sheep during peripartum. Pregnant Saint-Croix and Katahdin ewes were housed in individual pens from 100 days of gestation to 60 days of lactation and assigned to two groups: Free-choice-FC and Mixed-ration-MR (n = 12/group). Sheep in FC received ad-libitum amounts of soybean meal, sorghum grain, alfalfa and oat hays, presented in individual troughs. Animals in MR received a total-mixed-ration with these feeds, balanced for gestation or lactation according to NRC. Dry matter (and nutrient) intake/kg BW was measured daily, whereas BW and BCS were measured every 7 and 14 d, respectively. Data was analyzed as a Linear Mixed Model with repeated measures; group, breed, litter size (single, twins) and parity (primiparous, multiparous) were the fixed factors and sheep (random factor) was nested within group. Overall dry matter and ME intake did not differ between groups (P > 0.05), without breed, litter size or parity effects (P > 0.05), but protein intake was greater and NDF and ADF intakes were lower in FC than in MR (P < 0.001). During gestation, FC sheep consumed soy=alfalfa >sorghum >oats, and during lactation they increased (2X) soy intake (P < 0.001). Body weight was similar between groups (73.3±1.3, and 70.6±1.3 kg, for FC and MR, respectively; P=0.148), whereas BCS was greater for FC than for MR (3.9±0.2 vs. 3.3 ±0.1; P = 0.01). During lactation, ewe BW (67.3±1.3 vs. 61.92±1.3 kg; P = 0.01) and BCS (3.83±0.1 vs. 3.03±0.1; P < 0.001) were greater for FC than for MR. Offspring BW was similar between groups (11.5±0.6, and 11.4±0.5 kg, for FC and MR, respectively; P = 0.804). In conclusion, the free-choice treatment enhanced ewe nutrition, reducing BW and BCS losses during lactation without influencing offspring growth. Free-choice may enable ewes to meet their individual nutrient needs, with benefits to their welfare and postpartum ovarian activity.

We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle performance, methane (CH4) emissions and nitrogen (N) balance. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of 7 treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design of two 15-d periods during 2 consecutive years. Average daily gains (ADG) of heifers grazing the tanniferous legumes (1.05 kg/d) were 40% greater (P < 0.10) than of heifers grazing ALF (0.74 kg/d) during the first year. Heifers grazing the 3-way choice had greater intakes (10.4 vs 7.8 kg/d; P = 0.064) and ADG (1.21 vs. 0.95 kg/d, P = 0.054) than those grazing monocultures, suggesting a nutritional synergism among legumes. The average CH4 emissions for legume monocultures vs. 2- and 3-way choices was 222 vs. 202 and 162 g/kg BW gain (P > 0.10), respectively. For heifers grazing SF and BFT compared with ALF, blood urea N was less (14.3 and 16.8 vs 20.8 mg/dL; P < 0.05) as were urinary N concentrations (3.7 and 3.5 vs 6.0 g/L; P < 0.05), but fecal N concentrations were greater (34.5 and 35.5 vs 30.5 g/kg, respectively; P < 0.05). Combining both tanniferous legumes (SF-BFT) led to the greatest declines in urinary N (2.24 g/L) and urea-N (1.71 g/L) concentration, suggesting that different types of tannins in different legume species result in associative effects that enhance N economy. In addition, heifers grazing 3-way choices partitioned less N into urine (40.7 vs 50.6%; P = 0.037) and retained more N (36.1 vs 25.2%, P = 0.046) than heifers grazing monocultures. In summary, combinations of tanniferous legumes with alfalfa improved animal performance and reduced environmental impacts relative to monocultures, resulting in a more sustainable approach to beef production in pasture-based finishing systems.

The objective of this study was to explore the influence of prior dietary experiences on intake and selection of novel feeds by lambs. Twenty lambs housed in individual pens were assigned to two groups (10lambs/group): Negative (NE) and Positive (PE) Experiences, in a split-plot design. Lambs were offered a nutritive novel feed followed by intra-ruminal infusions of lithium chloride-LiCl (150 mg/kg BW), a toxicant that causes food aversions (NE), or vehicle (water; PE). The feed was offered daily and infusions were delivered only when intake was ≥50g, when the protocol was repeated with another novel feed until 4 feeds (oats, wheat bran, corn, beep pulp) were offered. After exposure, all lambs were tested for their acceptance of single novel feeds, each offered during 2 consecutive days: sorghum grain, rice bran, Calfmanna® pellets and soybean meal. Subsequently, all lambs were offered a 5-way choice among these feeds and alfalfa (familiar feed). Intake data, preference and Shannon’s diversity index (5-way choices) were analyzed with a Mann-Whiney U test. During exposure, the NE group ate less of the 4 feeds than the PE group (P < 0.05). Moreover, as exposure progressed, it took more days for NE lambs to reach the 50 g intake threshold, suggesting that neophobia in this group increased with negative experiences. During testing, NE lambs ate less (P < 0.05) of the novel feeds, except soybean meal, than the PE lambs. During the 5-way-choice test, preference for alfalfa was 63.6±3.5% for NE and 45.2±2.6% for PE (P < 0.001). The Shannon’s index was 0.85±0.05 for NE and 1.24±0.03 for PE (P < 0.001), suggesting that lambs in NE selected a less diverse diet. Thus, prior experience influenced neophobia and dietary diversity, an outcome that could impact the nutrition and welfare of grazing animals introduced to novel environments and the diversity of plant communities.

The objective of this study was to determine the influence of biochar obtained from exothermic production of lodgepole pine (Pinus contorta) and quaking aspen (Populus tremuloides) on sheep performance and diet digestibility and on preference for a ration enriched with this carbon-based material. Twenty-four lambs were housed in individual pens and assigned to one of three treatment groups (eight animals per group), where they received: 1) a 60:40 ration of alfalfa:barley (Control), 2) an isoenergetic and isonitrogenous ration with alfalfa, barley, and 2% biochar (BC), and 3) a simultaneous offer of the Control and BC rations (Choice). Lambs were exposed to two consecutive feeding periods (Period 1: 13 d and Period 2: 21 d), representing time intervals where the evolution of intake, animal performance, and rumen parameters were assessed; in vivo digestibility was determined during the last 5 d of the study. Ration intake did not differ among groups of lambs (P > 0.10), although during some days in Period 2, intake was greater for the BC and Choice groups than for the Control group (P < 0.05). Lambs in Choice had a lower preference for BC than for the Control ration (Period 1: P < 0.05; Period 2: P < 0.10), although they incorporated a substantial amount of BC (39 and 40%, for Periods 1 and 2, respectively) into their diets. No differences in body weight gains (ADG) or gain-to-feed ratios were found among groups of animals (P > 0.10), although dry matter digestibility and digestible dry matter intake was greater for lambs in the BC group than for lambs in Control group (P < 0.05). The ruminal concentration of the volatile acid acetate in Period 2 was greater for BC than for Choice (P < 0.05). During the same period, the concentration of valerate and ruminal pH values were greater in BC than in Control (P < 0.05). Thus, the addition of biochar to grain-based diets enhanced diet digestibility and influenced some ruminal parameters in lambs. Nevertheless, these positive effects were not reflected in significant improvements on ADG or feed conversion efficiencies. Lambs offered choices between Control and BC rations formed a diet with concentrations of biochar of ~1.2%, suggesting that these animals would tolerate such levels without reductions in ration palatability.

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L3 stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L3 (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.

The efficiency of grazing ruminant production systems is directly associated to the animals' ingestive behavior, and to structural characteristics of the pastures. The objective of this study was to evaluate the ingestive behavior of young lambs grazing three different heights of Capim Aruana (Panicum maximum). The experiment was carried out in two consecutive years, in which 30 tester lambs (4–5 months old) were equally divided into three paddocks (treatments) corresponding to different average sward heights of Aruana grass: (1) Tall-75 cm; (2) Medium-50 cm; and (3) Short-25 cm in a randomized block design. Ingestive behavior assessments were carried out every 28 days through 10-min observations of the main activities of the animals (grazing, ruminating, idling) and biting rate, from sunrise to sunset. In addition, the productive and qualitative characteristics of the pastures were assessed. Despite differences in pasture structure, grazing time (GT) and idling time were similar among treatments (P = 0.4266 and P = 0.2939, respectively). The shortest ruminating time (RT, P = 0.0181) was recorded in the treatment of lowest sward height. Lambs grazing on this treatment also showed 23% more bites per minute (P= < 0.0001) than animals in the Tall and Medium treatments. A Decision Tree analysis was performed for GT, identifying in a hierarchical order that the initial weight of the animals and sward height explained 62% (R2 = 0.621) of the variation, representing the variables with the greatest influence on GT. Initial body weight explained 48% of the model. Thus, our research shows that the different sward heights of Capim Aruana mainly alter the lamb's RT and biting rate, and that the animals' initial body weight is a key factor influencing GT, given that this variable makes lambs more susceptible to changes in sward height.

We hypothesized that ruminants discriminate among different mineral supplements and modify their selection as a function of need. Forty lambs were offered four-way choices among P, Ca, and Mg sources: monosodium phosphate (MSP), Magnesium phosphate (MGP), Monocalcium phosphate (MCP), and Dicalcium phosphate (DCP); and two-way choices between DCP and the other mineral sources (Baseline). Subsequently, lambs were randomly assigned to four groups (10 lambs/group) and fed rations such that levels of Ca and P were low (LCa_LP), adequate (NCa_NP), low in Ca and adequate in P (LCa_NP), or adequate in Ca and low in P (NCa_LP). Four- and two-way choice tests were repeated (Post-deficiency). During Baseline, lambs ate and preferred MSP > MGP>DCP = MCP (p

Background Perennial legumes cultivated under irrigation in the Mountain West USA have non-fibrous carbohydrate (NFC) concentrations exceeding 400 g kg-1 , a level commonly found in concentrate-based ruminant diets. Our objective was to determine the influence of NFC concentration and plant secondary compounds on in vitro rumen digestion of grass, legume and forb forages compared with digestion of their isolated neutral detergent fiber (NDF) fraction. Forages were composited from ungrazed paddocks of rotationally stocked, irrigated monoculture pastures between May and August 2016, frozen in the field, freeze-dried, and ground. Results The maximum rate (RMax ) of gas production was greater for the legumes alfalfa (ALF; Medicago sativa L.) and birdsfoot trefoil (BFT; Lotus corniculatus L.) than for the legume cicer milkvetch (CMV; Astragalus cicer L.) the grass meadow brome (MBG; Bromus riparius Rehm.) and the non-legume forb small burnet (SMB; Sanguisorba minor Scop.), and intermediate for the legume sainfoin (SNF; Onobrychis viciifolia Scop.). The RMax of isolated NDF was greatest for BFT and CMV, intermediate for ALF, SNF and SMB and least for MBG. Conclusions More than 900 g of organic matter kg-1 dry matter of legumes was digested after 96 h. Across forages, the extent of whole-plant digestion increased with NFC and crude protein concentrations, decreased with NDF concentrations, and was modulated by secondary compounds. The extent of digestion of isolated NDF decreased with concentration of lignin and residual tannins. © 2020 Society of Chemical Industry.

Detailed representation of ingesta inflow to and digesta outflow from the rumen is critical for improving the modelling of rumen function and herbage intake of grazing ruminants. The objective of the current work was to extend a mechanistic model of a grazing ruminant, MINDY, to simulate the dynamic links between ingestive and digestive processes as affected by forage and sward features (e.g. sward structure, herbage chemical composition) as well as the internal state of the animal. The work integrates existing aspects of forage ingestion, oral physiology and rumen digestion that influence ingesta characteristics and digesta outflows from the rumen, respectively. The paper describes the structure and function of the new development, assessing the new model in terms of dynamic changes of oral processing of ingesta and rumen dilution rate under different grazing contexts. MINDY reproduces characteristics of ingesta inflow to and digesta outflow from the rumen of grazing ruminants, achieving temporal patterns of occurrence within and between meals, similar to those for grazing animals reported in the literature. The model realistically simulates changes in particle size distribution of the ingestive bolus, bolus weight and rumen dilution rate in response to contrasting grazing management regimes. The new concepts encoded in MINDY capture the underlying biological mechanisms that drive the dynamic link between ingestion and digestion patterns. This development advances in the understanding and modelling of grazing and digestive behaviour patterns of free-ranging ruminants.

The foraging ecology of mammalian herbivores is determined by plant secondary compounds (PSC) that defend plants against herbivory, by nutrients that are required for maintenance, growth, and reproduction, and by the interaction between these variables. In this study, we explored the influence of an herbivore’s nutritional state and experience on intake of aspen (Populus tremuloides) leaves with contrasting concentrations of a PSC, phenolic glycosides (PG). Thirty-two lambs were randomly assigned to two groups (N = 16). Each group received aspen leaves with either higher (21.2%) or lower (16.3%) concentrations of PG throughout the study. In Experiment 1, half of the lambs within each group received rations with a high (22.2% crude protein [CP]; 3.13 Mcals/kg) or low (11.9% CP; 3.13 Mcals/kg) concentration of CP. During Experiment 2, half of the lambs within each group received rations with a high (3.45 Mcals/kg; 16.1% CP) or low (2.52 Mcals/kg; 18.5% CP) concentration of energy. During Experiment 3, all lambs received a simultaneous offer of aspen leaves containing higher (20.6%) and lower (14.8%) concentrations of PG. Aspen intake was greater when lambs received the high-protein or the low-energy rations (P

We determined whether sheep discriminate among mineral supplements containing P and Mg and if they modify their selection as a function of need. During 3 consecutive days, 40 lambs under a basal diet of alfalfa pellets and barley grain were offered 4-way choices among= (1) MgO-powder form (MgO-82% Mg), (2)MgO-coarse form (C-MgO-82% Mg), (3) Magnesium Phosphate (Bolifor® Mag33-33% Mg, 2.7% P), and (4)Magnesium Phosphate (Bolifor® MGP-25% Mg, 15% P), and 2-way choices between MGP and each of the other minerals, and between MgO and C-MgO (Baseline). Subsequently, lambs were randomly assigned to 4 groups (10 lambs/group) and fed rations such that the levels of Mg and P were low (LMg-LP), adequate (NMg-NP), low in Mg and adequate in P (LMg-NP), or adequate in Mg and low in P (NMg-LP). After 29 d, groups received again the described choices (post-deficiency). Intake and preference indexes during choice tests were analyzed as a split-plot design with lambs nested within group and day as the repeated measure. During Baseline, lambs ate and preferred Mag33 > C-MgO = MGP > MgO (P < 0.05). This pattern remained during post-deficiency, but lambs in LMg showed the greatest preference for Mag33 (P < 0.05). All lambs preferred C-MgO over MgO or MGP (P < 0.05), but lambs in LMg-NP showed the greatest preference for C-MgO (P < 0.05) and the lowest preference for MGP (P < 0.05). Serum concentrations of P (7.1 to 8.4±0.2 mg/dL) and Mg (3.0 to 3.9±0.1 mg/dL) increased after post-deficiency tests relative to Baseline (P < 0.05). Lambs discriminated among different mineral sources and the physical form of MgO influenced preference. Groups in low Mg diets favored sources of Mg with no or low concentration of P, and when P was adequate (LMg-NP), they reduced their preference for the source with the greatest concentration of P (MGP).

Measurement of water consumption and urinary nitrogen (UN) excretion of individual grazing ruminants is difficult, time-consuming and expensive. Therefore, prediction and modelling are critical for research to improve N and water use efficiency. The objective of the current work was to use a mechanistic model of a grazing ruminant, MINDY, to represent drinking and urination diurnal patterns, and the resulting pattern of UN excretion. This work is primarily an integration of existing knowledge of basic urination physiology and water dynamics in ruminants. MINDY reproduces observed patterns of urination achieving the correct temporal occurrence, relative volumes and nitrogen (N) concentration of individual urination events for a grazing dairy cow, comparable with those reported in the literature. The model simulates daily water imbibed and UN realistically, as well as ingestion rates for herbages with different protein content and contrasting grazing managements. Results of a cross-validation indicate that the root mean square prediction error and mean absolute error as % of the observed mean, respectively, were 26 and 23% for daily water imbibed, 26 and 27% for urination volume, and 25 and 19% for the frequency of urination. Although further parameterization and validation are needed, for a new development in an exploratory model like MINDY, these numbers are encouraging and reflect that the concepts encoded capture many of the underlying biological mechanisms that drive the diurnal pattern and daily UN excretion, as well as thirst, acceptable.

Nutritional requirements at the end of gestation in ewes carrying multiple fetuses are rarely fully met in pasture production systems. Thus, concentrate feeds entail an alternative for increasing herd productivity. However, daily offer of complementary feed in extensive livestock production systems is not always possible due to climatic or geographic constraints or to labor shortages. One alternative is to offer large amounts of concentrate feed with the addition of NaCl that limits voluntary consumption, eliminating the need for daily supplement delivery. Our objective was to evaluate the effect of high salt levels added to concentrate feed on pre- and post-lambing twin-gestating ewes and their responses on feed intake, colostrum and milk production and composition, plasma biochemical profile variation and lamb growth. Twenty-four adult Corriedale females were housed in individual stalls and divided into four treatments: S13: ad libitum concentrate feed plus 13 % of salt; C13: the same amount of concentrate feed consumed by S13 ewes the day before, but without salt; S17: ad libitum concentrate feed with 17 % of salt, and C17: the same amount of concentrate feed consumed by S17 ewes the day before, but without salt. Fresh water and forage were offered in ad libitum amounts. Treatments were applied in the period of highest ewe nutrient demand, from day 123 of pregnancy to day 21 of lactation. The four percentage points in salt content resulted in a decrease of organic matter daily intake of concentrate (23 % of reduction in pre-lambing and 35 % of reduction in post-lambing for S17 relative to S13; P = 0.0134 and P = 0.0164, respectively). Lamb birth weights were similar between S13 and C13 (P = 0.1002) and between S17 and C17 (P = 0.8449) treatments. Colostrum and milk production did not differ between S13 and C13 (P = 0.9776 and P = 0.8928, respectively) or between S17 and C17 groups (P = 0.4943 and P = 0.7705, respectively). Plasma insulin, hematocrit and total protein levels were not influenced by the treatments and these parameters remained within normal physiological limits. Thus, the addition of 13 or 17 % of salt to concentrate feed did not affect the reproductive capacity of ewes or offspring growth, showing that ewes are able to withstand high doses of NaCl and supporting the potential of salt as a limiter of voluntary intake in pre- and post-lambing diets.

Nutrients and plant secondary compounds in aspen (Populus tremuloides) may interact with nutrients in the surrounding vegetation to influence aspen use by herbivores. Thus, this study aimed to determine aspen intake and preference by sheep in response to supplementary nutrients or plant secondary compounds (PSC) present in aspen trees. Thirty-two lambs were randomly assigned to one of four molasses-based supplementary feeds to a basal diet of tall fescue hay (N = 8) during three experiments. The supplements were as follows: (1) high-protein (60% canola meal), (2) a PSC (6% quebracho tannins), (3) 25% aspen bark, and (4) control (100% molasses). Supplements were fed from 0700 to 0900, then lambs were fed fresh aspen leaves collected from stands containing high (Experiment 1, 2) or low (Experiment 3) concentrations of phenolic glycosides (PG). In Experiment 2, lambs were simultaneously offered aspen, a forb (Lathyrus pauciflorus), and a grass (Bromus inermis) collected from the aspen understory. Animals supplemented with high protein or tannins showed greater intake of aspen leaves than animals supplemented with bark or the control diet (P

Theories suggest that incorporating alfalfa (Medicago sativa L.; Alf) or birdsfoot trefoil (Lotus corniculatus L.; BFT) into endophyte-infected tall fescue (Festuca arundinaceas Schreb.; E+TF) pasturelands may improve livestock production. We investigated how planting configuration might influence plant secondary metabolites (PSM) and nitrogen concentration in these forages. Total nitrogen (N), in addition to condensed tannins (CT), saponins and ergovaline (EV), was compared in BFT, Alf and E+TF, respectively, when forages grew in monocultures and all possible two-way “mixtures” using a block design with repeated measures in three blocks. Ergovaline (p .10). We conducted an in vitro trial to determine whether CT or saponins isolated from BFT and Alf, respectively, would bind to EV in water. Ergovaline bound to saponins to a greater extent (39%; SE = 0.25) than CT (5.1%; SE = 5.13; p

Vegetation on the Channeled Scablands of eastern Washington has been altered to a community dominated by medusahead (Taeniatherum caput-medusae [L.] Nevski). Medusahead is used by livestock but becomes unpalatable as the plant matures and seed heads develop, thus decreasing carrying capacity. The objective of this study was to determine if improved cool-season grasses could establish and persist on medusahead-infested rangelands in the region. A split-plot randomized complete block design consisting of four blocks was established at three different locations. Plots were treated with herbicides to remove all vegetation and seeded in 2010. Seeded species included introduced cool-season grass cultivars: Hycrest II crested wheatgrass (Agropyron cristatum [L.] Gaertn.), Vavilov II Siberian wheatgrass (Agropyron fragile [Roth] P. Candargy), Bozoisky II Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski), and a native cool-season grass mix composed of Sherman big bluegrass (Poa secunda J. Presl), Secar Snake River wheatgrass (Elymus wawawaiensis J. Carlson & Barkworth), Bannock Thickspike wheatgrass (Elymus lanceolatus [Scribn. & J. G. Sm.] Gould), and Recovery Western wheatgrass (Pascopyrum smithii [Rydb.] A Love). Sherman big bluegrass was the only native species that established, and frequency was 65% at the end of the study. Hycrest II frequency was 48% at the end of the study. Vavilov II frequency was 50% at the end of the study. Sherman big bluegrass matured early in the season and had greater biomass production than Hycrest II and Vavilov II in May. The later-maturing Hycrest II and Vavilov II were similar in biomass production to Sherman big bluegrass in July. Bozoisky II had poor stand establishment and did not persist. Hycrest II, Vavilov II, and Sherman big bluegrass are forages that can be used for revegetation on the Channeled Scablands of eastern Washington.

Medusahead is an annual weed that invades millions of acres in the western United States. This study explored the effect of energy supplementation on use of this unpalatable weed by ewes and their lambs. Thirty-six ewes with their lambs (2–3 mo old) were randomly assigned to 12 groups (3 ewes with their lambs per group), and half of the groups received 2.5 kg group d-1 of an energy-based supplement (beet pulp—barley—Ca-propionate, 66:30:4; as-fed basis). After supplementation, all groups grazed plots with medusahead infestation for 15 d. Lambs were then weaned, kept in the same groups but without supplementation, and allowed to graze medusahead-infested plots for 3 d. Grazing events were recorded daily at 5-min intervals, and defoliation of medusahead tillers was measured in all plots. The proportion of grazing events recorded on medusahead and the proportion of defoliated medusahead tillers were not affected by supplementation in either ewes or lambs (P > 0.05). All ewe-lamb groups presented a g...