Forage Mass Research Articles

Potassium Fertilization Alters the Morphogenetic, Structural, and Productive Characteristics of Panicum maximum Cultivars

The objective was to evaluate the effects of potassium fertilization on the morphogenetic, structural, and productive characteristics of Panicum maximum (cvs. Tanzania, Quênia, Mombaça, Zuri, Massai, and Tamani). The design was in randomized blocks with four doses of potassium (K) 0, 205, 410, and 820 mg dm−3, divided into 5 applications. The analyzed variables were leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), leaf senescence rate (LSR), leaf life span (LLS), phyllochron (PC), number of live leaves (NLL), final leaf length (FLL), tiller population density (TPD), and forage mass (FM). LAR increased by 0.00216 leaves tiller on day-1 (p = 0.0354) and LER increased by 0.00980 cm tiller on day-1 for each milligram of K (p = 0.0402). There was an increase in FLL of 0.16, 0.08, and 0.07 days for the cultivars Mombaça, Massai, and Tamani, respectively, for each milligram of K applied (p = 0.0034). The TPD of the cultivar Tamani increased linearly by 0.074 tillers/pot for each milligram of K (p = 0.0226), and the cultivar Massai showed a quadratic behavior. The TPD of the other cultivars was not influenced by the increase in the K doses. For forage mass (FM), the cultivars Mombaça and Quênia increased by 0.16 and 0.39 g DM/pot for each milligram of K added to the soil. The cultivars Tanzânia, Zuri, Massai, and Tamani showed maximum point at doses of 261.35, 279.45, 300.57, and 275.86 mg dm−3 K, respectively. Potassium fertilization linearly increased leaf appearance and elongation, with maximum productivity reached at a K dose of 430 mg dm−3, except for the cultivars Mombaça and Quênia, which responded up to a K dose of 820 mg dm−3.

The Performance of an Alfalfa–Sainfoin Mixture in the Semiarid Southern High Plains of the USA

While alfalfa (Medicago sativa) is widely used as forage because of its many positive attributes, there are concerns regarding bloat in grazing ruminants, but tannin-containing legumes, such as sainfoin (Onobrychis viciifolia), are non-bloating. Based on interest elsewhere for growing alfalfa–sainfoin mixtures to address bloat concerns, the objectives of a study conducted at Tucumcari, NM, USA, were to compare an alfalfa–sainfoin mixture to the respective monocultures for stand persistence and dry matter yield over three production years in three randomized complete blocks. The onset of drought limited irrigation water availability shortly after the study’s initiation, which limited sainfoin persistence to the second year after seeding. The resulting percentage decline in forage mass in June from year 1 to year 2 was alfalfa > alfalfa–sainfoin > sainfoin. That said, the alfalfa mass was considerably greater than the sainfoin mass, and the June mass of both monocultures was consistent with that in previous studies in the region when fully irrigated (5.57 vs. 2.00 Mg ha−1 for monoculture alfalfa and sainfoin, respectively; p < 0.0004). Alfalfa persistence was greater than that of sainfoin after 3 years. Alfalfa–sainfoin mixtures may have value in the Southern High Plains of the USA and similar semiarid environments when fully irrigated. Additional studies should evaluate mixture seeding ratios and stand performance under fully irrigated conditions with sainfoin reseeding.

Addition of Tannin-Containing Legumes to Native Grasslands: Effects on Enteric Methane Emissions, Nitrogen Losses and Animal Performance of Beef Cattle

Extensive cattle production on native grasslands is vital to the sustainability of the South American Pampas, and the inclusion of tannin-containing legumes can increase farm profitability, improve nitrogen (N) use and reduce greenhouse gas (GHG) emissions. This study quantified the effects of adding tannin-containing legumes to native grasslands on enteric methane (CH4) emissions, animal performance and N balance in cattle. A crossover design trial was conducted with 22 beef heifers under two treatments: native grassland (NG) and native grassland with the addition of Lotus uliginosus and L. angustissimus (NG+L). The results showed that forage mass disappearance was similar between treatments; however, 54% of the forage disappearance in the NG+L corresponded with legumes, indicating that the heifers in this treatment consumed a better-quality diet. While individual CH4 emissions were similar between treatments, heifers grazing the NG+L showed a higher average daily gain (ADG) and lower emissions intensity than heifers grazing NGs (0.25 vs. 0.58 g CH4/g ADG, p < 0.05). Additionally, they also ingested 20% more N and were more efficient in its utilization. Incorporating tannin-containing legumes into native grasslands can improve animal productivity and N use efficiency while reducing the intensity of enteric CH4 emissions.

Canopy Characteristics of Gamba Grass Cultivars and Their Effects on the Weight Gain of Beef Cattle under Grazing

Gamba grass (Andropogon gayanus Kunth) is a tussock-forming forage species adapted to acid soils of Brazilian savannas and cultivated for grazing pastures. Four decades since its release, Planaltina prevails as the most commercialized cultivar of the species, even though the new cultivar BRS Sarandi could be a better alternative for Gamba-grass-based farms by presenting a greater leaf:stem ratio. The objective of this study was to evaluate the average daily live weight gain (ADG) of Nellore bulls (Bos indicus) for two Gamba grass cultivars—Planaltina and Sarandi. The experiment was conducted in Planaltina, Federal District, Brazil, for 3 years, namely 2018, 2018–2019, and 2020. The experimental design was a completely randomized block design with two treatments and three replicates, each one continuously stocked at three stocking rates (SR)—1.3, 2.6, and 4 young bulls/ha. Canopy height (CH), forage mass (FM), plant-part proportion (green leaf, stem, and dead material), and nutritive value were evaluated. In 2018, mean ADG for Sarandi pastures was greater (0.690 kg/bull/d) than that of Planaltina (0.490 kg/bull/d) (p < 0.10). In the subsequent year (2018–2019), there was no effect of cultivar (p > 0.10), while in 2020 the ADG was again affected by cultivar (p < 0.10), confirming the advantage of Sarandi (0.790 kg/bull/d) over Planaltina (0.650 kg/bull/d). In 2018 and 2020, the percentage of stems for Sarandi was about 3–6 pp less than for Planaltina (p < 0.10). As well as for stems, Sarandi pastures presented a shorter CH in 2028 and 2020 (6–7%) (p < 0.10). The positive high correlation of leaf:stem ratio with ADG (r = 0.70) probably predisposed the superiority of Sarandi over Planaltina. The distinguishing plant-part composition of Sarandi canopy promotes increasing weight gain of beef cattle when compared to cv. Planaltina.

Native Forbs Provide Pollinator Resources and Improve Forage Nutrient Composition, Animal Performance, and Pasture Productivity

Pollinator declines and expectations for more sustainable agriculture, including pasture-based enterprises, bring attention to strategies to enhance the habitat value of grazing lands. We evaluated native warm-season grass (NWSG) pastures with (FORB) and without (CONT) interseeded native forbs in 2021–2023. An analysis was conducted using R with the significance set at p ≤ 0.05. The grass appeared to be weakened predominantly by grazing management practices. Forb density and mass had an inverse relationship in seasons two and three. Total forage mass declined in response to increased grazing days and weakened stands. The forage nutritive compositions differed, with more stable, season-long crude protein and lower fiber concentrations in late-season FORB, which supported higher bodyweight gains and season-long average daily gain. Black-eyed Susan (Rudbeckia hirta; BESU), lanceleaf coreopsis (Coreopsis lanceolata; LCOR), and showy ticktrefoil (Desmodium canadensis; STTF) were the most abundant forbs, and BESU, LCOR, and purple coneflower (Echinacea purpurea; PURC) produced long flowering windows. Cattle grazed STTF, cup plant (Silphium perfoliatum; CUPP), and oxeye sunflower (Helopsis helianthoides) the most. Under continuous stocking, a blend of BESU, LCOR, PURC, STTF, and CUPP produced acceptable cattle gains and provided pollinator resources, suggesting that this model may be a viable means to enhance the sustainability of pastures.

THE STUDY OF MAIZE HYBRIDS (ZEA MAYS SPECIES L.) IN DIMAL MUNICIPALITY, BERAT

Maize is one of the most important crops in world agriculture and has a very important place in the planted area. It is cultivated for various purposes: Bread, Livestock (silage), the beer industry, the oil industry, and for bioenergy. More than five hundred different food items, dishes and drinks are produced from the maize plant. The production of hybrid seed has greatly influenced the increase in the yield of maize, both for grain and forage mass. For the conditions of Albania, the study of maize hybrids is very important, since the hybrid seed is imported and not produced in the country. The experiment involved eleven hybrids imported by the companies: ARLI International and Huqi, which respectively import from Zemun Polje and from Dekalb and KWS. Eleven hybrids were included in the study, namely: 477, 6263, 388, 735, 606, 555, 5601, 707, 666,553 B from Zemun Polje and Kulmos from KWS, Germany. The experiment was set up according to a randomized block design with eleven variants and four replications. Ten plants were determined for each replicate and variant on which biometric measurements and production indicators were made. The data was subjected to mathematical data processing to determine the best hybrid, which is adapted to the conditions of the area and gives the highest yield.

218 Comparison between vegetation indices to estimate biomass in cereal rye

Abstract Accurate forage mass estimation can lead to improved pasture management, but it requires a significant investment of time on the ground sampling. The use of satellite images has potential to reduce the time needed and thus, expediting decision-making processes. Satellite measure various spectral wavelengths of light reflected by plants (i.e., reflectance), and using satellite images, various vegetation indices (VI) can be calculated, such as the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), the Green Normalized Difference Vegetation Index (GNDVI), and the Spectral Feature Depth Vegetation Index (SFDVI). Each of these indices shows different vegetation properties via mathematical combinations of reflectance in two or more spectral wavelengths. For example, NDVI is calculated by reflectance in red and near infrared wavelengths, which is an effective VI to quantify vegetation greenness and vigor. This study aimed to compare the mentioned VI to evaluate their ability in estimating cereal rye (Secala cereale) mass and to compare them with a traditional method of biomass measurement, which relies on the standing height of the forage. From May 2 to 23, 2023, forage mass was measured in 18 paddocks (1.6 ha/paddock). Mass in the paddock was estimated by clipping four randomly located frames (0.49 m2) to ground level. The standing height of the forage was collected from 20 random points, measured in 0.625 cm increments, within each paddock. The forage mass of the paddocks measured from the clipped forage ranged from 212 to 3,382 kg/ha. PlanetScope satellite images from the day of forage mass sampling were obtained using the Planet Explorer platform. This satellite data was chosen due to its high spatial resolution (3 x 3 m2/pixel) and highly available data (theoretically daily). The four VI were calculated from images in QGIS software. A linear regression of each index against the forage mass estimated from the average of the clipped forage, was conducted in SAS using PROC REG. There was a significant (P < 0.01) correlation between each VI with the forage mass. The adjusted R2 was 0.60, 0.58, 0.41, 0.78 and 0.76 for NDVI, EVI, GNDVI, SFDVI and standing height, respectively. The root mean square error (RMSE) was 518, 528, 629, 379, and 396 for NDVI, EVI, GNDVI, SFDVI, and standing height, respectively. All VI exhibited moderately promising results in cereal rye mass estimation. In particular, SFDVI proved to be superior with the greatest adjusted R² and least RMSE, followed by the traditional method of estimating forage mass by standing height. This comparable result between the use of SFDVI from satellite images and traditional ground measurement indicates that the use of VI, SFDVI, specifically in our study, from satellite images can be an effective means for a fast cereal rye mass estimation.

396 Effects of allocation timing on cattle performance and forage utilization when swath grazing a sorghum-sudangrass hybrid in eastern Nebraska

Abstract Swath, or windrow, grazing is the process of cutting hay, leaving it in windrows, and allowing cattle to graze these windrows in the winter. This grazing system reduces winter feeding costs by mitigating the need to bale and transport hay, while having the potential for increased utilization compared with grazing the forage standing. This study aimed to determine the effect of varying allocation timing on cattle performance and forage utilization. A sorghum-sudangrass hybrid (Sorghum× drummondii) was planted in June 2023, cut in early November, and grazed from mid-November 2023 to mid-January 2024. A 16-ha field was divided based on seeding rate with one-half seeded at the recommended rate of 39.2 kg/ha (REC) and one-half with a double rate of 78.4 kg/ha (DOU). The field was subdivided into a total of 8 paddocks (4 per seeding rate) with either 10 (n = 4) or 11 (n = 4) windrows. Forage was cut and windrows were gathered from a 4.57 m width in the field. Prior to grazing, a 0.30 m length of three swaths in each paddock was sampled to determine initial forage mass. A total of 60 steers [initial body weight (BW) = 240 ± 8.3 kg] were stratified by BW and assigned to one of 8 paddocks (n = 7 or 8 calves) to result in equal BW per swathed area. Allocations were offered in full once-per week (1X) or, one-half of the total forage was allocated twice weekly (2X). Post-graze samples were collected to estimate utilization and allocation amount was adjusted as needed based on visual appraisal of post grazing biomass. Cattle were pulled from the field due to snow cover after a 64-d grazing period. The area grazed was used to calculate the animal unit months/ha (AUM) achieved for each paddock. Pre-grazing forage mass did not differ between allocation timing (P = 0.89) or among seeding rates (P = 0.10; REC = 6,720 ± 545 kg/ha, DOU = 8,534.0 ± 545 kg/ha). There was an allocation timing by seeding rate interaction (P < 0.01) for forage offered with 1X (10.62 kgּ steer-1ּ d-1) being offered more (P < 0.01) than 2X (8.43 kg/steer/d) within REC, but no difference (P = 0.31) in forage offered due to allocation within DOU (8.31 kgּ steer-1ּ d-1). However, post grazing biomass (P = 0.35) and utilization (59 ± 8%) were not affected by allocation timing (P = 0.48). Average daily gain (ADG) also did not differ (P = 0.93) due to allocation timing (0.20 ± 0.07 kg). Most notably, there was a significant allocation effect (P = 0.05) on AUM/ha with 1X (14.51 ± 1.00) being lesser than 2X (16.82 ± 1.00). However, there was no significant difference (P = 0.30) in forage disappearance (291 ± 61 kg/AUM) due to allocation timing. This indicates that more frequent allocations can lead to increased carrying capacity. Increasing the frequency of allocation is a simple management practice producers can implement when swath grazing sorghum-sudangrass to increase carrying capacity.

Effect of Time of Nitrogen Fertilization on Use of Root Reserves in Megathyrsus maximus Cultivars

Nitrogen is a very important nutrient in grass maintenance fertilization and therefore must be applied at the appropriate moment. The objective of this study was to identify the most responsive moment to nitrogen fertilization and to verify if root mass and the content of carbohydrates and nitrogen in roots influence the moment of fertilization in cultivars of Megathyrsus maximus (syn. Panicum maximum). This study was carried out simultaneously in a greenhouse using a completely randomized design, with sixteen treatments and five replications, in a 4×4 factorial design. The treatments consisted of four intervals between cultivar defoliation and nitrogen fertilization (0, 3, 6 and 9 days) and four Megathyrsus maximus cultivars, Mombasa, BRS Zuri, BRS Quenia and BRS Tamani, which were evaluated in five regrowth cycles. No difference in forage mass was observed among cultivars when fertilization was performed on days zero, three and nine after harvesting. On day nine, Mombasa showed a higher forage mass compared to BRS Tamani. Nitrogen content in the roots of Zuri decreased when fertilization was performed on the third day after defoliation, remaining constant in the other fertilization intervals. A linear reduction in root starch in BRS Zuri was observed, while in Mombasa cultivars, a linear increase was observed when fertilization was performed nine days after harvesting. Thus, nitrogen fertilization of BRS Tamani should be carried out closer to defoliation, while Mombasa, BRS Zuri and BRS Quenia can be fertilized up to nine days after harvesting, which results in greater flexibility regarding the moment of nitrogen fertilization.

Evaluating the effects of cotton intercropping on cool‐season perennial forage persistence, forage mass, and nutritive value in the southeastern United States

AbstractIntegrated forage–row cropping systems provide important agronomic and economic benefits to producers. However, little attention has been given to incorporating forages into row crop systems unique to the southeastern United States. This study assessed the viability of intercropping cotton (Gossypium hirsutum L.) on perennial, cool‐season legumes during the summer months in the Southeast Coastal Plain over two production years. Treatments included a weedy fallow, annual ryegrass (ARG; Lolium multiflorum Lam.) monoculture, a red clover (RC; Trifolium pratense L.) and white clover (WC; Trifolium repens L.) mixture, and a three‐species mixture of ARG, RC, and WC. Plots were established in fall 2020 with forage grown until May 2021 and 2022, when plots were strip‐tilled and planted with cotton. Cotton was managed with minimal herbicide use to preserve perennial clovers. Results indicated WC was more persistent than RC (>40 plants m−2 vs. <40 plants m−2), and the presence of perennial clovers suppressed weeds at similar levels to the ARG monoculture (35 weeds m−2) during the second spring. Perennial clovers grew taller (4–5 cm) when mixed with ARG. The presence of clovers mixed with ARG during the second spring reduced acid detergent fiber (ADF) concentration and increased crude protein (CP) concentration (280 g ADF kg−1; 167 g CP kg−1) compared to the ARG monoculture (315 g ADF kg−1; 126 g CP kg−1). Benefits of intercropping perennial forages with cotton were maximized during the second year of growth, but future work is necessary to improve stand survival.

Urea fertilization for potentializing beef cattle performance in agroforestry systems in the humid tropics

AbstractThis study hypothesized that urea fertilization could optimize animal performance in an agroforestry system. This study evaluated how increasing rates of N fertilization (0, 100, 200, and 400 kg N ha−1 year−1) using urea (CH4N2O) affected forage mass, nutritive value, and beef cattle (Bos indicus) performance in an agroforestry system with Massai grass (Megathyrsus maximus Jacq. cv. Massai) and legume tree (Mimosa caesalpiniifolia Benth.), in the humid tropic region of Brazil, over 2‐year period. The experiment was carried out in a randomized complete block design with four treatments (N fertilizer rates) and three replications. Forage mass was positive and linearly affected by N fertilization (p = .0236, R2 = 0.92), ranging from 1297 to 1583 kg DM ha−1 under 0 and 400 kg N ha−1 year−1, respectively. There was greater average forage mass during the rainy period (1826 kg ha−1) (p < .05). Crude protein in green forage mass increased linearly (p = .0041, R2 = 0.91) in function of the N applied. Cattle average daily gain showed a positive quadratic response to the rates of N applied (p = .0298, R2 = 0.97), ranging from 0.46 kg to 0.68 kg animal day−1; and the gain per area increased linearly from 1.84 to 2.68 kg LW ha−1 day−1 (p = .0640, R2 = 0.96). The findings indicate that applying 200 kg N ha−1 year−1, split‐applied during the rainy season, would yield acceptable outcomes in terms of forage mass, nutritive value, and animal performance for this type of agroforestry system.

Soil aggregation and surface‐soil properties under grazed pastures and other conservation land uses in Virginia

AbstractGrazed pastures supporting ruminant livestock have not been well characterized for soil health condition. However, growing interest in holistic management of compromised watersheds suggests that grazing lands deserve more attention for their capacity to provide ecosystem services. Relatively little is known about how grazing management affects soil aggregation and other surface‐soil properties on private lands in the eastern United States. This study investigated the effects of land use (conventional‐till cropland, no‐till cropland, grassland, and woodland) and pasture management characteristics on soil aggregation, bulk density, sieved soil density, total soil N, and soil‐test biological activity on 31 private farms distributed across the western half of Virginia. Soil stability index followed the order (p < 0.05): conventional‐till cropland (0.60 mm mm−1) < no‐till cropland (0.78 mm mm−1) < woodland (0.85 mm mm−1) = grassland (0.89 mm mm−1). Surface soil characteristics improved with pasture age due to organic matter recycling from residual forage mass and animal excreta. Increases in total soil N and soil‐test biological activity helped create water‐stable aggregation and reduce soil bulk density. Soil stability index was optimized with moderate stocking rate of 0.5–1.1 Mg live weight ha−1. Stocking method did not affect soil aggregation or bulk density. Soil stability index declined with increasing N fertilization rate. Soil aggregation characteristics were generally not affected by organic amendment, quantity of hay fed on farm, or occasional hay harvest from pastures, likely because aggregation was high across management variables. Well‐managed grazed pastures in Virginia are creating desirable conservation agricultural land uses to protect watershed quality.

Forage accumulation and nutritive value in extensive, intensive, and integrated pasture-based beef cattle production systems

Context A challenge for the livestock sector is to improve the production and nutritive value of forage grasses through sustainable management strategies. Aims This study evaluated the impact of management on the productive and nutritive value of five pasture-based production systems: irrigated pasture with 600 kg nitrogen (N) ha−1 (IP600); rainfed pasture with 400 kg N ha−1 (RP400); rainfed pasture with 200 kg N ha−1 (RP200); silvopastoral with 200 kg N ha−1 (SP200); and degraded pasture without N fertilisation (DP0). Methods During two experimental years, samples were collected pre- and post-grazing to determine forage and nutritional parameters. Land-saving effects and efficiencies of N fertilisation and water use were calculated. Key results For C4 grasses, forage mass accumulation was greater for IP600 and RP400. IP600 also presented the greatest leaf area index and crude protein concentration, whereas DP0 presented the lowest values of both. For C3 grasses in the IP600 treatment, greater forage mass accumulation and leaf area index were found in winter than in autumn; all nutritional characteristics were not affected by season of the year. For land-saving effect, and N- and water-use efficiencies, IP600, RP400 and RP200 presented higher values than DP0 and SP200. Conclusions More intensified systems with proper management allowed better productive and nutritional characteristics than degraded pasture or silvopasture, especially during seasons with greater precipitation or when irrigated. Implications Intensification practices make better use of natural resources (water and land) and agricultural inputs (N fertiliser) to ameliorate the effects of seasonality and improve quality and productivity of tropical grasses in pasture-based livestock production systems.

Panicum maximum cultivars for use in integrated agricultural production systems in Cerrado biome soils

AbstractIntegrated production systems have been an alternative for diversifying agricultural production, and therefore, it is necessary to study tropical forage grasses that can impact both straw production and soil organic matter, as well as benefit animal production. The objective of this work was to evaluate the productive characteristics and accumulation of nutrients in the biomass of grasses of the genus Panicum grown in the off‐season, in Cerrado biome soil as cover plants for use in integrated production systems. It evaluated different grasses of Panicum maximum: Aruana, Tamani, and Massai guinea grasses, distributed in a randomized block design with four replications of each grass. The productive characteristics, mineral accumulation, and carbon/nitrogen (C/N) ratio in the biomass of the cultivars were evaluated. No cultivar effect was observed for forage mass (3997.4 kg/ha DM). However, the largest (p = 0.0077) leaf blade masses were observed in the Massai and Tamani guinea grasses. On the contrary, the Aruana guinea grass exhibited the highest value (p = 0.0001) for stem mass, reflected in a higher (p = 0.0001) leaf/stalk ratio in the Massai and Tamani guinea grasses. No effect (p > 0.05) of the cultivar on micronutrients, magnesium, and phosphorus concentrations was observed. However, the Aruana guinea grass presented higher concentrations of calcium and sulfur; on the other hand, potassium values were higher in the Massai and Tamani guinea grasses. The Massai guinea grass exhibited a higher (p = 0.0214) C/N ratio, while the Aruana guinea grass recorded lower values, with no significant differences between these cultivars and Tamani guinea grass. The Tamani and Massai guinea grasses stand out as recommended choices for cultivation during the off‐season in Cerrado biome soils as cover crops in integrated production systems.

PSIV-A-2 Comparison of rising plate meter and total collection methods for forage mass determination of tall fescue

Abstract The objective was to compare estimates of forage mass (FM) determined with a rising plate meter (RPM) with forage mass determined by total collection method. Estimates of FM impact management decisions and give the producer a greater understanding of forage availability for their herd. Traditional methods of FM estimation using a forage ring or quadrat and total collection are labor intensive and time consuming. The RPM tool aims to provide a quicker method of FM estimation without sacrificing accuracy. The reliability of this tool can be impacted by season, species composition, plant growth state, and pasture management. Forage samples were collected from six random locations within both continuous and rotationally grazed systems. The predominant forage species was endophyte-infected tall fescue. A 0.25 m2 forage ring was randomly thrown, then two RPM (Jenquip Manual Platemeter) measurements were collected in the ring, followed by five measurements adjacent to the ring. The RPM determined the compressed sward height (CSH). Subsequently, forage within the ring was hand-clipped at ground level and collected. Samples were dried for 120 h at 55° C to determine forage availability (kg/ha). This process was repeated weekly for 6 wk. Rising plate meter FM was estimated using the equation: kg dry matter (DM)/ha = CSH × 158 + 200. Data were analyzed using the CORR procedure of SAS 9.4. Forage mass estimates from total ring collection method and RPM were weakly correlated in the rotational grazing system (r = 0.26; P = 0.13) and in the continuous grazing system (r = 0.20; P = 0.24). It is important to note that certain sample collection dates had stronger correlations than others. In the rotationally grazed paddocks, FM from RPM were strongly correlated (r ≥ 0.89, P ≤ 0.02) with FM from total ring collection on 6/23/23 and 7/26/23. In the continuously grazed paddocks, FM estimations from RPM were strongly correlated (r ≥ 0.73, P ≤ 0.10) with forage mass from total collection on 7/20/23 and 7/26/23. Variation among the seven RPM readings at each collection site could have contributed to variability. Coefficient of variation ranged from 9 to 48% and averaged 18% for all samples. The inconsistencies in relationship of forage mass determination methods suggests that more variables need to be considered when determining the accuracy of RPM-derived estimates of forage mass of tall fescue.

61 Effects of botanical composition on grazing system management, forage quality, forage availability, and ewe performance

Abstract The objective was to compare the effects of two forage mixtures utilized in a rotational grazing system on ewe performance, forage quality, and forage availability. Dorset-Suffolk crossbred ewes [n = 48; body weight (BW) = 187 ± 20 kg] were stratified by BW, body condition score (BCS), and age, then allotted to six groups. Groups were randomly assigned to one of two treatments: forage mixture 1 (FM1; 47% orchard grass, 30% white clover, 14% brome grass, and 9% ryegrass) and forage mixture 2 (FM2; 44% ryegrass, 33% white clover, and 23% red clover). There were 18 paddocks (30.5 m x 22 m) for each treatment, each group was rotated between one of six paddocks; the rotation of each group was determined by the reduction of forage height to approximately 10 cm. Ewe BW and BCS were collected on d 0, 14, and 28. Forage heights were measured using meter sticks upon the groups entering and exiting each paddock. Forage heights were used to calculate forage availability, and the difference between pre-grazing and post-grazing forage availability was assumed to be forage disappearance. Five pre-grazing forage samples from each paddock were clipped at 10 cm using the forage square (0.0625 m²) to determine fiber content. Data were analyzed using the GLM procedure of SAS 9.4. No effects on ewe BW or BCS were observed (P = 0.4134) between treatments. Ewes grazing FM2 spent more time grazing each paddock (P < 0.01) compared with ewes grazing FM1. Pre-grazing forage ground cover (P < 0.01) was greater in FM2 compared with FM1; however, grazed forage mass disappearance was not different (P = 0.44) between treatments. The NDF and ADF values were greater for FM1 than FM2 (P < 0.01 and P = 0.02, respectively) indicating that more forage is needed to meet ewe energy requirements. Results suggest that neither forage mixture had a significant impact on ewe BW or BCS; however, ewes grazing FM2 maintained themselves on a smaller land area during growing season, making it a more feasible option for rotational grazing management.

Using sentinel-2 satellite images and machine learning algorithms to predict tropical pasture forage mass, crude protein, and fiber content.

Grasslands cover approximately 24% of the Earth's surface and are the main feed source for cattle and other ruminants. Sustainable and efficient grazing systems require regular monitoring of the quantity and nutritive value of pastures. This study demonstrates the potential of estimating pasture leaf forage mass (FM), crude protein (CP) and fiber content of tropical pastures using Sentinel-2 satellite images and machine learning algorithms. Field datasets and satellite images were assessed from an experimental area of Marandu palisade grass (Urochloa brizantha sny. Brachiaria brizantha) pastures, with or without nitrogen fertilization, and managed under continuous stocking during the pasture growing season from 2016 to 2020. Models based on support vector regression (SVR) and random forest (RF) machine-learning algorithms were developed using meteorological data, spectral reflectance, and vegetation indices (VI) as input features. In general, SVR slightly outperformed the RF models. The best predictive models to estimate FM were those with VI combined with meteorological data. For CP and fiber content, the best predictions were achieved using a combination of spectral bands and meteorological data, resulting in R2 of 0.66 and 0.57, and RMSPE of 0.03 and 0.04g/g dry matter. Our results have promising potential to improve precision feeding technologies and decision support tools for efficient grazing management.

The Characterization of Pastures by Grazing Cycle and Evaluation of Supplementation with Agro-Industry Co-Products on the Performance of Buffaloes in the Humid Tropics.

The objective was to characterize the pastures by grazing cycle, as well as to evaluate the performance of buffaloes in intensive rotational grazing in a silvopastoral system in the eastern Amazon supplemented with agro-industry co-products in order to characterize the grazing cycles, the composition of the fractions, and the carcass yield. Fifteen non-castrated, crossbred water buffaloes (Murrah × Mediterranean) were used. All animals used in the study were clinically healthy and weighed approximately 458 kg. The animals were grazed in a single group, and supplementation (1% of live weight-LW/day) was divided into three treatments: control (control-conventional ingredients); Cocos nucifera coconut cake (Cocos nucifera) (coconut cake-70%); and palm kernel cake (Guinean elaeis) (palm kernel cake-70% palm kernel cake). The chemical composition of the forage is different in each part of the plant, with higher protein values in the leaves (11.40%) and higher acid detergent fiber (ADF) values in the stems (50.03%). Among the ingredients of the supplement, corn has the highest percentage of indigestible protein (35.57%), most of the protein in palm kernel cake is B3 (49.11%), and in Coco, B2 (51.52%). Mombasa grass has a higher percentage of B3 and B2 proteins; the indigestible fraction is lower in the leaves (17.16%). The leaf/stem ratio also varied between grazing cycles, being better in the second cycle (2.11%) and with an overall average of 1.71. Supplement consumption varied between cycles and was higher in the control treatment, with an overall mean of 4.74. There was no difference in daily weight gain and carcass yield, with an average of 1 kg/day and 49.23%, respectively. Therefore, it can be concluded that including supplements based on by-products from the coconut and palm oil agro-industries promotes performance and carcass yields compatible with conventional supplements. Their use reduces production costs, optimizes the utilization of forage mass, enhances the sustainability of the production chain, and, therefore, is recommended.

165 Does supplementation of beef cattle impact the agronomy performance of tall fescue and bermudagrass pastures?

Abstract In forage-based beef cattle systems, bermudagrass [Cynodon dactylon (L.) Pers.] and tall fescue (Festuca arundinacea Schreb.) stand as widely used forage species. The strategic supplementation of animals may reduce forage intake, thereby potentially affecting the agronomic performance of these grasses. Our objective was to evaluate the impact of beef cattle supplemental feeding on forage accumulation, forage mass, and nutritive value in tall fescue and bermudagrass pastures. Two studies were conducted where pregnant beef cows were supplemental fed 1% of BW on DM basis of corn silage daily (SUP) or received no supplemental feeding (free-choice mineral; NON). Trial 1: conducted on bermudagrass pastures (BERM) grazed from late May to early October. Experimental design for BERM was completely randomized design with 4 pastures per treatment (n = 3 cows/pasture; average 5 years of age; 550 ± 72 kg initial BW). Trial 2: conducted on fescue pastures (FES) with an experimental design of a 2 x 2 factorial arrangement. The two factors evaluated were fescue type [TOXIC (507 ppm ± 0.82 SEM ergot alkaloids; 92.5% endophyte infection)] or non-toxin-producing (NT; 5 ppm ± 2.50 SEM ergot alkaloids; 38.6% endophyte infection) and two levels of supplemental feeding (NON or SUP). There were 3 or 4 replications per fescue x supplemental feeding treatment (n = 15 pastures), stocked with 3 cows/pasture (average age 4.75 years; 558 ± 73 kg initial BW) and grazed from early May through November. Forage accumulation (FA) was estimated every 28 d using the paired-cage method (4 exclosure cages/pasture). On each exclusion period, the forage mass (FM) was estimated both inside and outside the cages through destructive sampling method and samples analyzed for forage quality. Pasture was experimental unit and repeated measures were included in analysis. Bermudagrass FM tended to be increased by 31% with SUP (P = 0.09; 774 kg/ha greater). Forage accumulation tended (P = 0.07) to be affected by feeding method x month. There was greater FA in June for SUP; however, there was greater FA for NON in July. SUP pastures had greater ADF (1% more; P = 0.01) and reduced TDN (1.5%; P < 0.01) than NON. Forage mass tended to be 10% greater for TOXIC pastures (P = 0.09; 409 kg/ha more forage mass). Supplemental feeding on fescue did not impact FM (P = 0.74). Forage accumulation was not impacted by fescue type, feeding method, nor the interaction (P > 0.30). Cows generally do not consume as much toxic fescue, thus more forage is available in pastures and supplemental feeding did not alter forage parameters. However, on a warm-season grass that is growing while supplemental feeding, forage availability was increased and maybe useful as method to increase stocking rates or as mitigation tool during drought.

164 Effect of distillers grains supplementation and fertilization rate on performance of stocker cattle grazing wheat pasture and stand performance

Abstract Within this study, the objectives were to determine how varied Nitrogen (N) fertilization rates and inclusion of dried distiller’s grains plus solubles (DDGS) impacted stocker and wheat stand performance within a no-till (NT) production system. A total of twenty-four 1.62-ha pastures were split between 3 unsupplemented treatments with urea spread at fixed rates of 50.44, 67.25, 84.06 kg N/ha in autumn and again in spring along with an additional 6 pastures fertilized with 50.44 kg N/ha each growing season plus supplemented with DDGS. From fall of 2021 to Spring of 2023, 576 beef steers (286.62 ± 36.67 kg) were randomly allocated at fixed stocking rates of 2.47 steers/ha (4 steers/pasture) in the fall, and 4.94 steers/ha (8 steers/pasture) in the spring. Steers were weighed upon arrival, at turnout, every 28 d, and when pulled off pasture. Steers were pulled off pasture when forage mass (FM) became insufficient, temperatures became too cold to support regrowth, or forage entered reproductive phase. Sampling dates to determine forage mass and quality coincided with weigh dates, where 20 plate meter readings were taken in every field and were recorded with a 0.25m2 plate meter, and 0.25m2 grass clippings were obtained from 15 fields every sampling date to estimate FM. Pairwise comparisons using the Mixed Model procedure in JMP were used to analyze data, with N rates with and without supplementation as a single fixed categorical variable, and year modeled as a random effect. In the fall, supplemented pastures produced greater ADG than 67.25 and 84.06 kg N/ha pastures (P < 0.05), along with greater total costs of supplemented pastures compared with all unsupplemented treatments (P < 0.0001). In the spring, supplemented pastures produced greater end weights, gain per hectare, forage mass and ADG than all unsupplemented treatments (P < 0.0001), and supplementation provided more grazing days (P < 0.05). While total sale income for supplemented pastures were greater than all unsupplemented treatments (P < 0.05), total costs of supplemented pastures were all increased (P < 0.0001), resulting in less income after variable costs (P < 0.0002). Response changes to supplementation were more pronounced than responses to increased fertilization. In conclusion, these results indicate that DDGS supplementation provided greater performance benefits to stocker cattle grazing wheat pasture than increased N fertilization rate, but the added costs associated with feeding resulted in lower profitability. However, the addition of DDGS supplementation may provide an opportunity to increase stocking rates to potentially improve profitability.