Cool-season Forage Research Articles

PSXII-10 Concordance between a Time-of-Flight Sensor and Plate Meter Method for Estimating Forage Mass

Abstract This project explored the use of a time-of-flight sensor (ToF) as an alternative to the plate meter (PM) for estimating forage mass. The ToF configuration included a single beam TFmini Plus LiDAR Module (Benewake Co., Haidian District, Beijing, China), an Arduino Uno (manufactured by Arduino S.r.l., Torino, Italy), and either a PC or cellular phone for datalogging transmitted serial values sent over a USB connection. The ToF configuration was attached to a utility vehicle drawn sled with a ground to sensor distance of 84cm. A reflective mat was attached to the sled that floated atop the forage canopy to create a height area to compensate for the narrow field of view of the sensor beam (≤ 5cm). Six comparisons were conducted between the ToF and PM including warm-season and cool-season forage stands. Both the ToF and PM were calibrated by clipping 10, 14, or 20 calibration squares each to a 5cm residual forage height followed by drying clipped forage at 55C. Calibration coefficient of determination ranged from 0.86 to 0.95 and 0.86 to 0.96 for ToF and PM, respectively. Pearson’s correlation and Lin’s concordance coefficients ranged from 0.45 to 0.95 and 0.36 to 0.92, respectively. While both the ToF and PM demonstrated a predictable relationship between their respective height measurements and clipped area forage mass, the concordance between the two methods was weak for some comparisons, likely due to within field sample point variation between the two methods. Further research is needed to better understand mat density, sampling intensity, and plant density and height on the potential use of the ToF as an alternative to the PM.

Genome-wide identification and functional analyses of heat shock transcription factors involved in heat and drought stresses in ryegrass

Italian ryegrass ( Lolium multiflorum ) is one of the most important and widely cultivated cool-season forage and turfgrass around the world. Heat and drought are two key factors limiting its growth and distribution. Heat shock transcription factors ( Hsfs ) are important regulators involved in various abiotic stresses; however, how the Hsf family responds to heat and drought stresses and the roles of LmHsfs in heat and drought tolerance remain to be determined in Italian ryegrass . In the present study, 16 putative Hsf genes were identified by whole-genome bioinformatics analysis, including eight HsfAs , five HsfBs , and three HsfCs . The subcellular localization, physiological and biochemical characteristics, conserved domains, gene structure, and phylogenetic relationship of the Hsf family were systematically analyzed in silico. Gene expression profiling analyses revealed that all Hsfs were responsive to heat and drought stresses. Most Hsfs , including LmHsfA2 , LmHsfA3 , LmHsfA4 , LmHsfA5 , LmHsfA6 , LmHsfA7 , LmHsfA8 , LmHsfB1 , and LmHsfB2 , were induced to the highest expression levels at 1 h of heat stress treatment, while the majority of LmHsfs were up-regulated with a peak at 10 d of drought stress treatment. Subsequently, the biological function of LmHsfA5 which was induced by both heat and drought stresses was analyzed. Heterologous overexpression of LmHsfA5 improved heat and drought tolerance in transgenic Arabidopsis . The qRT-PCR analysis showed that the expression of APX2 and HSP18.2 were significantly induced in LmHsfA5- overexpressing lines under both normal and heat stress conditions. What’s more, yeast one-hybrid, dual-luciferase assay, and electrophoretic mobility shift assay exhibited that LmHsfA5 could bind to the promoters of LmHSP18.2 and LmAPX2 and induce their expression, indicating that LmHsfA5 may positively regulate heat and drought tolerance via directly activating the expression of LmHSP18.2 and LmAPX2 in ryegrass. This study provides a basis for further research on LmHsfs functions in abiotic stress. • 16 LpHsfs were identified by whole-genome bioinformatics analysis. • All LmHsfs were responsive to heat and drought stresses. • Heterologous expression of LmHsfA5 improved heat and drought tolerance in Arabidopsis. • LmHsfA5 directly activates the expression of LmHSP18.2 and LmAPX2 .

Pastures and Climate Extremes: Impacts of Cool Season Warming and Drought on the Productivity of Key Pasture Species in a Field Experiment.

Shifts in the timing, intensity and/or frequency of climate extremes, such as severe drought and heatwaves, can generate sustained shifts in ecosystem function with important ecological and economic impacts for rangelands and managed pastures. The Pastures and Climate Extremes experiment (PACE) in Southeast Australia was designed to investigate the impacts of a severe winter/spring drought (60% rainfall reduction) and, for a subset of species, a factorial combination of drought and elevated temperature (ambient +3°C) on pasture productivity. The experiment included nine common pasture and Australian rangeland species from three plant functional groups (C3 grasses, C4 grasses and legumes) planted in monoculture. Winter/spring drought resulted in productivity declines of 45% on average and up to 74% for the most affected species (Digitaria eriantha) during the 6-month treatment period, with eight of the nine species exhibiting significant yield reductions. Despite considerable variation in species’ sensitivity to drought, C4 grasses were more strongly affected by this treatment than C3 grasses or legumes. Warming also had negative effects on cool-season productivity, associated at least partially with exceedance of optimum growth temperatures in spring and indirect effects on soil water content. The combination of winter/spring drought and year-round warming resulted in the greatest yield reductions. We identified responses that were either additive (Festuca), or less-than-additive (Medicago), where warming reduced the magnitude of drought effects. Results from this study highlight the sensitivity of diverse pasture species to increases in winter and spring drought severity similar to those predicted for this region, and that anticipated benefits of cool-season warming are unlikely to be realized. Overall, the substantial negative impacts on productivity suggest that future, warmer, drier climates will result in shortfalls in cool-season forage availability, with profound implications for the livestock industry and natural grazer communities.

Poultry Litter and Inorganic Fertilization: Effects on Biomass Yield, Metal and Nutrient Concentration of Three Mixed-Season Perennial Forages

Poultry litter and fertilizers are normally added as soil amendments. The effects of poultry litter and inorganic fertilizers on three mixed-season perennial forages were studied for two years in the field to understand growth dynamics, metals, and nutrient uptake. The primary objective was to investigate the heavy metal and nutrient concentrations, biomass yield and forage potential of a cool-season forage, stinging nettle (Urtica dioica L.), relative to warm-season forages, bermudagrass (Cynodon dactylon (L.) Pers.) and switchgrass (Panicum virgatum L.). Forage cuttings and soil samples were analyzed for heavy metals and nutrients using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Total biomass yield was higher by 66% and 50% in switchgrass and bermudagrass, respectively, compared with stinging nettle for the first year. While the warm-season forages yielded more biomass over the cool-season forage, metal concentrations were significantly higher for all elements in the cool-season forage. Stinging nettle showed greater macro-nutrient uptake with 103.20 kg ha−1, 0.87 kg ha−1, 27.49 kg ha−1 and 32.08 kg ha−1 for Ca, Fe, Mg, and P, except for K with 223.51 kg ha−1 compared with 267.29 kg ha−1 and 283.96 kg ha−1 for switchgrass and bermudagrass, respectively. Heavy metals were also higher in stinging nettle but were within the allowable limits for forages, indicating its potential as a resource for forages and nutrient cycling, particularly when double-cropped with warm-season forages.

Forage yield and profitability of grain‐type intermediate wheatgrass under different harvest schedules

AbstractIntermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & Dewey] (IWG) is a perennial forage grass being domesticated to function as a perennial grain crop. Grain yield of improved, grain‐type IWG cultivars decline by the third year of production and managing aging stands for forage production presents economic opportunities. Limited research is available on the response of second‐ and third‐year grain‐type IWG to different forage harvest schedules. We measured forage yield and nutritive value of grain‐type IWG in the second and third year of production under nine forage harvest schedules varying in the timing of the first harvest (at boot, anthesis, or soft dough stage) and the number of fall harvests (none, one [Sept.], or two [Sept. and Nov.]). As timing of the first harvest was delayed and IWG maturity increased from boot to soft dough, yield increased from 2.4 to 3.7 Mg ha–1 and relative feed value decreased from 113 to 82. Yield at subsequent September and November harvests averaged 30% and 12% of the initial harvest yield, respectively. Total annual forage yield was not affected by the timing of the first harvest but was predictably greater for two or three harvests compared with one harvest; however, additional harvests in September and November decreased net returns. Grain‐type IWG stands harvested in the third year after peak grain production have potential to provide forage similar to common perennial cool season forage grasses. Tradeoffs between forage yield and nutritive value should be considered when selecting the timing of the initial spring forage harvest.

Do High-Magnesium Cool-Season Grasses Contemplate Grass Tetany Risk?

Economic losses associated with grass tetany either of death or poor growth performance of livestock are a growing concern. Breeding of high magnesium (high-Mg) cool-season forage grass (C3) has been a challenging process to minimize the hazards of grass tetany. For appraising the breeding of high Mg-containing cultivars in Japanese Andisol, agronomic properties and grass tetany risk of high-Mg cultivars were compared with commercial cultivars. The high-Mg cultivars of Italian ryegrass (Lolium multiflorum L.), tall fescue (Festuca arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.) were “Magnet”, “HiMag” and “Mgwell”, respectively. The commercial cultivars were viz., Ace, Tachiwase, and Waseyutaka of Italian ryegrass, Hokuryo, Kentucky-31 (Ky-31), and Fawn of tall fescue, and Akimidori and Okamidori of orchardgrass, respectively. Grasses were grown in temperate Andisol under field conditions with standard management practices and were harvested four times during the year. The average plant heights of the high-Mg containing cultivars were lower than the commercial cultivars with the relative range of −7.4%, −3.7%, and −1.5% for Italian ryegrass, tall fescue, and orchard grass species, respectively. The seasonal yield of high-Mg cultivars was ranked as Magnet > HiMag > Mgwell. The Mgwell orchard grass had lower potassium (K) content compared with their respective commercial cultivars with a relative range of −2.2%. Across four harvests, a significantly higher calcium (Ca) and magnesium (Mg) content, and lower grass tetany potential were recorded in high-Mg cultivars when compared to commercial cultivars, irrespective of species. Across four harvests, the lowest grass tetany index, [K/(Ca + Mg)] of 1.36 was recorded in Mgwell orchard grass. The high-Mg cultivars showed the lowest [K/(Ca + Mg)] across four harvests compared to commercial cultivars, promoting the effectiveness of breeding cool-season grass species to control grass tetany in temperate regions (Andisol) and climatic conditions.

Endophyte Infected Tall Fescue: Plant Symbiosis to Animal Toxicosis.

Endophyte-infected fescue is a major cool season forage used for livestock production in the United States and through other areas of the world. A unique aspect of this forage resource is the symbiotic relationship with an endophytic fungus (Epichloë coenophiala) that has detrimental impact on herbivores due to toxic ergot alkaloids. Research over the past 50 years has unveiled details regarding this symbiotic relationship. This review focuses on the origin of tall fescue in the United States and the consequences of its wide-spread utilization as a livestock forage, along with the discovery and toxicodynamics of ergot alkaloids produced by E. coenophiala. The majority of past ergot alkaloid research has focused on observing phenotypic changes that occur in livestock affected by ergot alkaloids, but recent investigation of the metabolome, transcriptome, and proteome have shown that fescue toxicity-related illnesses are much more complex than previous research suggests.

Evaluation of Barley (Hordeum vulgare) and Wheat (Triticum aestivum) for Resistance to Hessian Fly, Mayetiola destructor, in a Controlled Environment

Small grains are widely grown as a cool-season forage crop for beef cattle and dairy industries in Texas. Small grains such as wheat (Triticum aestivum L.) for grazing are typically planted early in the fall and hence are more vulnerable to infestation by Hessian fly, Mayetiola destructor (Say). Although delaying planting until cooler weather can reduce pressure, Texas does not have a “fly free” date like many northern states. However, other small grains such as barley (Hordeum vulgare L.) might be less prone to damage by Hessian fly. An experiment in a controlled environment was used to determine resistance of winter barley, hard red winter wheat, and hard red spring wheat lines to Hessian fly and compare infestations among species. Infested tillers of winter wheat were collected and put with barley and wheat lines at Feekes growth stage 1.1 in a growth chamber. Approximately 2 weeks later, plants were dissected and numbers of Hessian fly larvae and pupae were counted. Hessian fly infestations significantly greater than zero using Fisher's LSD (P < 0.1) were considered susceptible while those not significantly different were resistant. Results showed that 42 of 136 (30.9%) winter barley, 31 of 40 (77.5%) winter wheat, and eight of 24 (33.3%) spring wheat genotypes were susceptible to the biotype of Hessian fly. The average numbers of Hessian flies per tiller were 2.2, 4.8, and 7.6 for barley, spring wheat, and winter wheat lines, respectively. Barley was a less preferred host than wheat and might be better suited in areas with abundant Hessian flies.

A Walk on the Wild Side: 2021 Cool-Season Forage Recommendations for Wildlife Food Plots in North Florida

The list of cool-season forage recommendations for wildlife in this publication includes varieties that have been tested and are known to perform well in Florida. Written by M. Wallau, A. R. Blount, J. M. Campos-Krauer, M. A. Lashley, E. Rios, J. M. B. Vendramini, J. C. B. Dubeux, Md. A. Babar, C. L. Mackowiak, and K. H. Quesenberry, and published by the UF/IFAS Agronomy Department, revised October 2021.

PSIII-19 Soil nutrient profile from cool-season forages fertilized with manure from steers supplemented with titrated levels of dried distillers grains

Abstract Dried distillers grains with solubles (DDGS) is commonly used as supplemental feed in cattle rations. However, the systemic effects of overfeeding DDGS, especially to potential fertilizer benefits of pass-through nitrogen, are widely unknown. Therefore, our objective was to evaluate plant and soil response to fertilization with manure from steers supplemented with titrated levels of DDGS. Manure utilized was collected from steers supplemented with DDGS (0%, 0.25%, 0.5%, and 1% BW) during a 2-yr experiment. The experimental design was a randomized complete block design with an augmented factorial treatment structure wherein benches represented blocks. The factorial was made up of manure treatment (0, 0.25, 0.5, or 1% BW DDGS, chemical fertilizer, or none) soil type (Windthorst or Purves), and plant species (none, crimson clover, or rye). Pots were sown (5 seeds/pot) and grown in a greenhouse for 35 d. Water was applied daily at 90% evapotranspiration. After harvest, soils were sifted, dried for 72 h at 55°C, then assayed for C, N, NO3-N, P, K, Ca, Mg, Na, and S. There was an interaction of manure and soil type for soil C (P &amp;lt; 0.01). Purves soils amended with any manure had a greater (P &amp;lt; 0.05) concentration of C (1.8%) than did the negative control (1.3%). From Windthorst, soil C was greatest from 1% BW DDGS manure (1.9%), and least from 0% DDGS manure (1.5%), with 0.25 and 0.5% manures and the negative control intermediate. There was an interaction of manure, soil type, and forage for soil N (P &amp;lt; 0.01). Manures with higher levels of supplementation had greater (P &amp;lt; 0.05) soil N than lower levels of supplementation or the negative control. Legumes had greater soil N than grasses. Results are interpreted to mean that moderate supplementation of steers with DDGS may yield soil nutrient benefits through nutrient deposition.

Partitioning of Forage Mass and Nutritive Value in Sunn Hemp Leaf and Stem Components

Sunn hemp (SH; Crotalaria juncea L.) is a fast-growing, annual, warm-season tropical legume that could complement less productive cool-season forages such as tall fescue during summer. Little is known about seasonal forage mass and nutritive value partitioning in SH plant components when SH is managed for forage. We determined partitioning of forage mass and nutritive value (crude protein (CP), in vitro true digestibility (IVTD), neutral detergent fiber (NDF), acid detergent fiber (ADF), and neutral detergent fiber digestibility (NDFD)) concentrations in SH leaves and stems harvested 35, 45, and 55 days after planting (DAP) at Bradford Research Center, Columbia, MO, in a 2-year field study. Leaf and stem mass increased with increasing DAP and was greatest ( P ≤ 0.05 ) at 55 DAP followed by 45 and 35 DAP. Stems contributed most to the total forage mass beyond 45 DAP. Across years, CP was greatest ( P ≤ 0.05 ) in leaves (281 g kg−1 DM) and lowest for stems (81 g kg−1 DM) at 55 DAP. The lowest NDF ( P ≤ 0.05 ) was observed in leaves (251 g kg−1 DM) and stems (585 g kg−1 DM) at 35 DAP. Acid detergent fiber was lowest ( P ≤ 0.05 ) for SH leaves (178 g kg−1 DM) and stems (484 g kg−1 DM) at 35 DAP. Digestibility of leaves was greater than that of stems and generally decreased with maturity. The nutritive value of leaves was consistently greater than that of stems and decreased with maturity, except for CP of leaves, which was maintained throughout the season. Results suggested that SH leaves can maintain forage mass and greater quality than its stem throughout the growing season.

Transcriptomic resources for prairie grass (Bromus catharticus): expressed transcripts, tissue-specific genes, and identification and validation of EST-SSR markers

BackgroundPrairie grass (Bromus catharticus) is a typical cool-season forage crop with high biomass production and fast growth rate during winter and spring. However, its genetic research and breeding has remained stagnant due to limited available genomic resources. The aim of this study was to generate large-scale genomic data using high-throughput transcriptome sequencing, and perform a preliminary validation of EST-SSR markers of B. catharticus.ResultsEleven tissue samples including seeds, leaves, and stems were collected from a new high-yield strain of prairie grass BCS1103. A total of 257,773 unigenes were obtained, of which 193,082 (74.90%) were annotated. Comparison analysis between tissues identified 1803, 3030, and 1570 genes specifically and highly expressed in seed, leaf, and stem, respectively. A total of 37,288 EST-SSRs were identified from unigene sequences, and more than 80,000 primer pairs were designed. We synthesized 420 primer pairs and selected 52 ones with high polymorphisms to estimate genetic diversity and population structure in 24 B. catharticus accessions worldwide. Despite low diversity indicated by an average genetic distance of 0.364, the accessions from South America and Asia and wild accessions showed higher genetic diversity. Moreover, South American accessions showed a pure ancestry, while Asian accessions demonstrated mixed internal relationships, which indicated a different probability of gene flow. Phylogenetic analysis clustered the studied accessions into four clades, being consistent with phenotypic clustering results. Finally, Mantel analysis suggested the total phenotypic variation was mostly contributed by genetic component. Stem diameter, plant height, leaf width, and biomass yield were significantly correlated with genetic data (r > 0.6, P < 0.001), and might be used in the future selection and breeding.ConclusionA genomic resource was generated that could benefit genetic and taxonomic studies, as well as molecular breeding for B. catharticus and its relatives in the future.

Influence of amount and frequency of protein supplementation to ruminants consuming low-quality cool-season forages: efficiency of nitrogen utilization in lambs and performance of gestating beef cows.

We evaluated the influence of amount and crude protein (CP) supplementation frequency (SF) on nitrogen (N) use by wethers and the performance of late-gestation beef cows. In exp. 1, seven Western whiteface wethers (31.8 ± 1.4 kg) were used in an incomplete 7 × 4 Latin square to evaluate intake and N use. Wethers received one of the seven treatments in a 2 × 3 factorial design containing two levels of supplemental soybean meal offered at a rate of 100% (F) or 50% (H; 50% of F) of the estimated CP requirement daily, once every 5, or once every 10 d, plus a non-supplemented control (CON). Low-quality cool-season forage (4.9 % CP; dry matter [DM] basis) was provided daily for ad libitum intake. Experimental periods lasted 30 d. In exp. 2, 84 Angus × Hereford cows (560 ± 35 kg) were stratified by age, body condition score (BCS), and expected calving date and allocated to 1 of the 21 feedlot pens (three pens per treatment). Pens were randomly assigned to receive the same treatments as in exp. 1 and cows had free access to low-quality cool-season forage (2.9% CP; DM basis). Cow body weight (BW) and BCS were measured every 14 d until calving and within 24 h after calving. In exp. 1, supplementation did not alter total DM and organic matter (OM) intake (P ≥ 0.26), but both parameters linearly decreased as SF decreased (P = 0.02). Supplementation increased DM, OM, and neutral detergent fiber (NDF) digestibility (P ≤ 0.02). Additionally, F feeding linearly increased DM, OM, and NDF digestibility as SF decreased (P ≤ 0.04). Digestibility of N, N balance, and digested N retained were greater with supplementation (P < 0.01), and N digestibility linearly increased as SF decreased (P = 0.01). Mean plasma urea-N concentration was not only greater (P < 0.01) for supplemented vs. CON wethers but also greater (P = 0.03) for F vs. H. In exp. 2, pre-calving BCS change was greater (P = 0.03) for supplemented cows. A linear effect of SF × supplementation rate for pre-calving BCS change was noted (P = 0.05), as F-supplemented cows lost more BCS compared with H as SF decreased. When considering supplementation intervals greater than 5 d, reducing the quantity of supplement provided, compared with daily supplementation, may be a feasible management strategy to maintain acceptable nutrient use and animal performance while reducing supplement and labor costs.

Influence of amount and frequency of protein supplementation to steers consuming low-quality, cool-season forage: intake, nutrient digestibility, and ruminal fermentation

This experiment evaluated the influence of protein supplementation frequency (SF) and amount offered on intake, nutrient digestibility, and ruminal fermentation by rumen-fistulated beef steers consuming low-quality [2.9% crude protein (CP); dry matter (DM) basis], cool-season forage. Seven Angus × Hereford steers (300 ± 27 kg) fitted with ruminal cannulas were randomly assigned to 1 of 7 treatments in an incomplete 7 × 4 Latin square. Treatments, in a 2 × 3 factorial design plus a non-supplemented control (CON), consisted of 2 levels of supplemental soybean meal, 100% (F) or 50% (H) of the estimated rumen-degradable protein requirement, provided daily (D), once every 5 d (5D), or once every 10 d (10D). Experimental periods were 30 d and dry matter intake (DMI) was measured from days 19 to 28. On days 21 (all supplements provided) and 30 (only daily supplements provided; day immediately prior to supplementation for 5D and 10D treatments) ruminal fluid was collected for ruminal pH, ammonia-N (NH3), volatile fatty acids (VFA), and determination of ruminal fermentation variables. Forage and total DM, organic matter (OM), and nitrogen (N) intake increased with supplementation (P ≤ 0.04). However, a linear effect of SF × amount of supplement interaction was observed for forage and total DM, OM, and N intake (P ≤ 0.04), with each variable decreasing as SF decreased, but the decrease being greater with F vs. H. Apparent total tract DM, OM, and neutral detergent fiber digestibility was not affected by supplementation or amount of supplement provided (P ≥ 0.10). In contrast, N digestibility increased with supplementation and for F vs. H (P < 0.01). Digestibility of DM, OM, and N increased linearly as SF decreased (P ≤ 0.03). When all supplements were provided, ruminal NH3, total VFA, and molar proportions of all individual VFA increased with supplementation (P ≤ 0.04), whereas acetate:propionate ratio decreased (P < 0.01). When only daily supplements were provided, none of the aforementioned fermentation parameters were affected (P ≥ 0.09). In summary, reducing the amount of supplemental CP provided to ruminants consuming low-quality forages, when supplementation intervals are >5 d, can be a management tool to maintain acceptable levels of DMI, nutrient digestibility, and ruminal fermentation while reducing supplementation cost.

Factors Affecting Sugar Accumulation and Fluxes in Warm- and Cool-Season Forages Grown in a Silvopastoral System

Forage management and environmental conditions affect water soluble carbohydrate (WSC) storage, and, in turn, influence ruminant forage utilization in silvopastoral systems. The objective was to determine effects of four dependent variables: forage species [(non-native, C3 (orchardgrass (Dactylis glomerata L.)) and native C4 mix (8:1:1 big bluestem (Andropogon gerardii Vitman), little bluestem (Schizachyrium scoparium Michx. Nash) and indiangrass (Sorghastrum nutans L.))]; fertility (poultry litter and an unfertilized control); forage sampling date (mid-May, late-May, early-June, mid-June, and late-June); and hour of day (0800, 1100, 1400, and 1700 h) on WSC accumulation in a silvopasture. Concentrations of WSC (g kg DM−1) were greater (p ≤ 0.05) for C3 forages, with poultry litter not impacting WSC accumulation. Overall, WSC was greatest in mid-June, with the lowest WSC concentration observed at 0800 compared to 1100, 1400, and 1700 h (p ≤ 0.05). Therefore, harvesting forages later in the day resulted in greater WSC. A stepwise regression model indicated acid detergent fiber, ash, and forage P concentration were the best predictors (R2 = 0.85, p ≤ 0.05) of forage WSC. These results may be useful in future studies aimed at explaining diurnal cattle grazing preference and optimum forage harvest timing in silvopastoral systems.

Opportunities for Increased Nitrogen Use Efficiency in Wheat for Forage Use.

Wheat is a major cool-season forage crop in the southern United States. The objective of this study is to understand the effect of nitrogen (N) fertilization on wheat biomass yield, quality, nitrogen use efficiency (NUE), and nitrogen nutrition index (NNI). The experiments were conducted in a greenhouse and a hoop house in a split-plot design, with three replications. Twenty wheat cultivars/lines were evaluated at four N rates (0, 75, 150, and 300 mg N.kg−1 soil) in the greenhouse and (0, 50, 100, and 200 mg N.kg−1 soil) in the hoop house. In general, high-NUE lines had lower crude protein content than the low-NUE lines. None of the cultivars/lines reached a plateau for biomass production or crude protein at the highest N rate. The line × N rate interaction for NUE was not significant in the greenhouse (p = 0.854) but was highly significant in the hoop house (p < 0.001). NNI had a negative correlation with NUE and biomass. NUE had strong positive correlations with shoot biomass and total biomass but low to moderate correlations with root biomass. NUE also had a strong positive correlation with N uptake efficiency. Lines with high NUE can be used in breeding programs to enhance NUE in wheat for forage use.

PSI-19 Preference grazing evaluation of new forage varieties, and the effect of animal temperament on grazing behaviour

Abstract In Canada, new forage varieties need not undergo grazing trials before registration and sale. As such, little is known about forage performance under grazing, or how animal preference and temperament affect grazing behaviour. To determine these effects, 6 cool-season forage species including meadow bromegrass (Bromus bieberseinii), orchardgrass (Dactylis glomerate L.), sainfoin (Onobrychis viciifoila ssp. Viciifolia) and three alfalfa varieties (Medicago sativa L.) were established in monoculture and grass-legume binary mixtures (14 treatments) at the Livestock and Forage Centre of Excellence (Saskatchewan, Canada). Forages were seeded in randomized adjacent 0.3 ha (21 × 125 m) strips within each of three, 5 ha paddocks. Sixty-nine Bos taurus crossbred steers (396 ± 34 kg BW) were homogenously allocated to the 3 paddocks for grazing observations. Individual steer temperament was characterized via novel object and corridor tests prior to grazing. The 9 steers showing the most bold or shy temperaments were labelled for identification while grazing. The grazing period length was 19 d, from July 27 to August 15, 2019, with observations made during the first six days. Observers determined forage preference based upon the number of animals grazing each forage type every 30 min for 2 h in the morning and 2 h in the evening. Animal preference did not differ (P &amp;gt; 0.05) between the forage treatments. Yield of grass and legume components did not differ (P &amp;gt; 0.05) between monocultures or binary mixtures (1255 kg ha-1 ± 277 kg ha-1). Steer temperament affected (P &amp;lt; 0.0001) animal distribution, with bold steers traveling further from the center of the paddock than shy steers or average herd animals (P &amp;lt; 0.05). These preliminary results indicate that differences in grazing behaviour were due to individual animal temperament rather than forage preference or performance.

141 Reproductive characteristics of post-pubertal lambs after being rendered short scrotum

Abstract A follow-up study was conducted to validate observations from an earlier trial on reproductive function in ram lambs following short scrotum castration. Again, East Friesian x Lacaune male dairy lambs from a commercial sheep dairy born in February and March were either left intact (IN, n=25), rendered short-scrotum (SS; n=18), or completely banded (WE; n=25) within 10 d of birth. At a mean age of 65 d, lambs were moved to the study site and managed as one group on cool season forages and supplemented with grain at 2–3% BW. At a mean age of 172 d, lambs were tested for libido in a 5 min pen test, and semen was collected from 7 IN and 7 SS lambs. Four estrus-induced teaser ewes were used for libido testing and semen collection by artificial vagina. Lambs were harvested the day after testing/collection, and reproductive tracts were recovered from 5 IN and 5 SS lambs at random. Differences between male lamb types were analyzed using PROC GLM. No statistical differences (P &amp;gt;0.05) in reproductive behaviors were observed between IN and SS, though number of services and kicks were numerically higher in IN than SS (1.3 vs. 0.45; 1.6 vs. 0.73). No reproductive behaviors was observed in WE. Ejaculate volume was not different between IN and SS (0.56 vs. 0.49 ml), but percent motile sperm (45 vs. 6 %; P&amp;lt; 0.01) and sperm concentration (1.52 vs. 0.05 billion/ml; P&amp;lt; 0.05) were higher in IN then SS lambs. Total testis and epididymis weight were also higher (P&amp;lt; 0.01) in IN than SS lambs (291 vs. 109 g; 53.8 g vs. 17.7 g). Additionally, epididymal sperm reserves were higher (P&amp;lt; 0.05) in IN than SS (9.42 vs. 0.89 billion) lambs. Results confirm our earlier findings that reproductive function was greatly reduced, but did not cease in short scrotum ram lambs.

192 Towards Year-Round Grazing in the Southeastern U.S

Abstract Winter feeds costs for small ruminants exceeds 50% of the total cost of most small ruminant production systems in the Southeastern U.S. Keeping these feed costs low is one of the most effective and time-tested ways to improve farm profitability. While maintaining an appropriate stocking rate will be critical for sustaining long-term farm productivity, a suite of other management practices is available to assist in this objective. Installing appropriate fence and watering system infrastructure for managing grazing will be critical for improving harvest efficiency and stockpiling forages for utilization when forage growth is limited. Filling gaps in forage production may also be achieved through the strategic use of a number of forage species, including warm-season or cool-season forages and annual or perennial forages. Managing stored forages appropriately during storing and feeding will help minimize feed losses, while producing quality hay will reduce the need for supplementary feeds. With the adoption of these proven practices, sheep and goat production may be optimized by allowing them to harvest their own feed almost year-round in the Southeastern U.S.

113 Mineral Supplementation Effects in Stocker Cattle Performance Grazed on Wheat Seeded Native Pastures

Abstract One way to extend the grazing season in the southeast United States is to plant cool-season forages into native pastures to provide additional forages for the winter and spring grazing. The objective of this study was to evaluate the effects of two different medicated (Monensin) supplementation types, with or without protein, on stocker calves grazing native pasture overseeded with wheat through the months of February to May. Cross-bred steers (n = 36; BW = 291.76 kg ± 29.92) and heifers (n = 29; BW = 288.17 kg ± 25.22), sired primarily by Hereford bulls, were assigned to two treatment groups at two locations blocked by sex and weight. All mineral supplementation was provided ad libitum. The first supplementation consisted of a commercial loose mineral (Advanced Mineral Performance Technology (AMPT); ADM; Quincy, Illinois), and the second was a commercial protein block (MoorMan’s, Mintrate Blonde Block RU; ADM; Quincy, IL) containing 42.0% Crude Protein. Average Daily Gain was compared using PROC MIX with the main effects: treatment, pasture, gender, and their interactions. The starting weights of the treatment groups were not different (P = 0.996). No significant interactions (P &amp;lt; 0.05) were detected and only the main effects will be reported. Steers gained more (P &amp;lt; 0.0001) than heifers (1.25 kg ± 0.025 kg vs. 0.96 kg ± 0.029 kg, respectively). ADG for the mineral was 1.14 kg ± 0.027 kg, compared to 1.06 kg ± 0.028 kg for the protein block (P &amp;lt; 0.05). Differences in ADG was observed between pastures (P &amp;lt; 0.07). At 124 days the final body weight of heifers averaged 119.56 kg and the steers averaged 154.70 kg. These results indicate that the mineral improved ADG over the block supplementation.