Forage Nutrient Research Articles

Seasonal monitoring of forage C:N:ADF ratio in natural rangeland using remote sensing data

In recent decades, natural rangelands have emerged as vital sources of livelihood and ecological services, particularly in Southern Africa, supporting communities in developing regions. However, the escalating global demand for food, driven by a growing human population, has led to the extensive expansion of cultivated areas, resulting in continuous nutrient leaching in rangelands. To ensure the long-term viability of these ecosystems, there is a need to develop effective approaches for managing and monitoring the seasonality of forage quality. This study aims to achieve this by utilizing multispectral Sentinel-1 (S1) and Sentinel-2 (S2) data to monitor the seasonal distribution and occurrence of carbon (C), nitrogen (N), acid detergent fiber (ADF), and the (C:N:ADF) ratio in mesic rangelands. Six sites were randomly selected from Welgevonden and Hoogland private game reserves in Limpopo, South Africa, representing varying vegetation cover and standing biomass. Transects, each with ten fixed sample sites (30 × 30 m) characterized by homogeneous vegetation, were established. The grass samples and aboveground biomass were collected during each season and analyzed for biochemical parameters using a near-infrared spectroscopy (NIRS) machine. S1 and S2 data from Google Earth Engine (GEE) were employed, and the random forest (RF) modelling algorithm revealed significant seasonality impacts on the distribution of forage C:N:ADF ratios. The study demonstrates that integrating S1 and S2 data enhances the estimation of forage nutrients. This study offers valuable insights for a diverse range of stakeholders, including ecologists, resource managers, farmers, and park managers. By giving an understanding of nutrient limitations and facilitating a deeper understanding of resource availability and animal distribution in rangelands, this research serves as a crucial tool for informed decision-making and sustainable management practices.

The effect of nitrogen-fixing bacteria in the plant Rhizosphere on the quality of forage nutrient

The presence of soil microbes around plant roots (Rhizosphere) plays a role in providing nutrients needed by plants. Research to determine the effect of nitrogen-fixing bacteria population in the plant Rhizosphere on the quality of forage nutrient. Sampling in the plant Rhizosphere: NR = Non Rhizosphere, RG = Rhizosphere Gliricidia sepium, RL= Rhizosphere Leucaena leucocephala, and RI = Rhizosphere Indigofera zollingeriana, and each treatment was repeated 7 times. Observed variables include: soil nutrient content, population microbes, nitrogen-fixing bacteria, and quality of forage nutrient. The results showed that the C-organic content of the soil in the Rhizosphere Indigofera zollingeriana (RI) treatment was 4.16% (very high) and total Nitrogen was 0.34% (moderate). The highest total microbes and nitrogen-fixing bacteria populations of 6.0 x 106 and 2.5 x 105 Cfu/g soil were found in the Rhizosphere Gliricidia sepium (RG) treatment, and the lowest results were 2.6 x 105 and 2.0 x 105 Cfu/g soil in the Non Rhizosphere (NR). The quality of forage nutrient in the Rhizosphere Gliricidia sepium (RG) treatment, produced the highest crude protein (28.56%) and the lowest crude fiber (14.41%). It can be concluded that the population nitrogen-fixing bacteria in the Rhizosphere ​​Gliricidia sepium (RG) is able to improve the quality of forage nutrient produced.

The nutritional feed gap: Seasonal variations in ruminant nutrition and knowledge gaps in relation to food security in Southern Africa

AbstractLivestock production is critical to food security and rural livelihoods across Southern Africa. Despite progress in livestock science research in recent years, the seasonal availability and quality of feed remains one of the key challenges to livestock productivity in Southern Africa. In particular, dry weather conditions, the lack of rain and lower temperatures in the dry season cause herbaceous plants to die back and browse species to defoliate, limiting the abundance, quality, and variety of feed available. This creates a ‘Nutritional Feed Gap’, defined here as the combined effect of the sharp reduction in both forage quantity and quality from the wet to the dry season and the risk that it poses to ruminant production systems and the food security of the people and communities reliant on them. Understanding the nature and extent of how seasonality impacts ruminant production potential can thus contribute towards mitigating negative impacts of extreme weather and climate change on food systems. In this review, we characterise this nutritional feed gap in terms of forage abundance and nutrition as well as discussing how climate change may shape the future nutritional landscape. Whilst some forage nutrient concentrations varied little by season, crude protein and phosphorus were consistently found to decrease from the wet season to the dry season. We also identify a shortfall in primary research that assess both forage quality and quantity simultaneously, which forms part of a broader knowledge gap of our limited understanding of the impact of limiting factors to ruminant production on short and long-term food security across Southern Africa.

Screening Suitable Ecological Grasses and the Seeding Rate in the Muli Mining Area

To target the lack of suitable grass species in the ecological restoration process of the Muli mining area, nine ecological grass species of Gramineae, Gentianaceae, Scrophulariaceae, and Ranunculaceae were selected as experimental materials to simulate the external alkaline environment for a seed germination test, which could be used to explore the response of seed germination to the environment. At the same time, Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, Koeleria cristata, and Elymus tangutorum were used as test materials to carry out a variety of comparison and screening tests of suitable seeding rates. The effects of the seeding rate on plant coverage, biomass, forage nutrients, and soil properties were analyzed by a variety of comparison and seeding rate tests. The results showed the following: (1) The relative germination rate of Koeleria cristata, Elymus tangutorum, Deschampsia cespitosa, and Poa pratensis L. ‘Qinghai’ was more than 70%, and the coverage in the returning green period was more than 60%, which was significantly higher than that of other treatments (p < 0.05) and can better adapt to the environment of the Muli mining area compared to other grass species. Meanwhile, the adaptability of Pedicularis kansuensis, Gentiana macrophylla, and Aconitum pendulum was weak. (2) It was found that when the seeding rate was 9 g·m−2, the biomass of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos, and Koeleria cristata was the highest, which was 296.45 g·m−2, 224.32 g·m−2, and 236.35 g·m−2, which was significantly higher than that of other treatments (p < 0.05); the aboveground biomass was 356.24 g·m−2 when the seeding rate of Elymus tangutorum was 18 g·m−2, which was significantly higher than that of other treatments (p < 0.05). The membership function showed that the comprehensive evaluation value was 0.701, 0.576, 0.610, and 0.673 when the seeding rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos, and Koeleria cristata was 9 g·m−2 and the seeding rate of Elymus tangutorum was 18 g·m−2. To sum up, it is recommended that the four ecological grass species of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, Koeleria cristata, and Elymus tangutorum can be used as the main grass species for ecological restoration in high-altitude and alpine areas such as the Muli mining area, which is affected by an alpine climate and fragile habitats. The optimum sowing rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, and Koeleria cristata is 9 g·m−2, and that of Elymus tangutorum is 18 g·m−2. This cultivation method can effectively promote plant growth and development, improve the physicochemical properties of soil, and is conducive to improving the stability and sustainability of artificial grassland in alpine mining areas.

Integrating Nitrogen, Water, and Other Management Practices to Improve Grain and Ratoon Forage Yields in Perennial Rice.

Perennial rice has recently garnered global attention due to its potential to save on seeds and labor costs and its high production efficiency. The "mid-season rice-ratoon forage" mode is a new planting system that has emerged in recent years. However, detailed information is still lacking on the regenerative characteristics, grain and ratoon forage yields, and forage nutrient content of perennial rice under different planting densities, nitrogen (N) rates, stubble heights, and water management practices. Four experiments with perennial rice were conducted in Sichuan Province, Southwest China, from 2017 to 2022. The results show that the rice grain and ratoon forage yields were significantly affected by year, planting density, and N. The grain yield was 28.18% and 60.81% lower in 2018F and 2019F, respectively, than in 2017F; similarly, the ratoon forage yield was 29.01% and 52.74% lower in 2018S and 2019S, respectively, than in 2017S. The low grain yield was mainly associated with lower numbers of spikelets per panicle and panicles per m2, which resulted from a lower regrowth rate, and the low ratoon forage yield was mainly attributed to the lower regrowth rate. The rice grain and ratoon forage yields increased with an increase in the N rate and planting density. The ratoon forage was found to be rich in crude protein, crude fat, crude fiber, calcium, nitrogen, phosphorus, potassium, and other nutrients. Moreover, the content of these nutrients increased significantly with an increase in the N rate. The regrowth rate and maximum tillers showed trends of first increasing and then decreasing with an increase in the stubble height under dry and wet alternation irrigation during the winter season. When the relative soil moisture decreased to below 80% during the winter season, the regrowth rate and seedling development index could reach more than 99% and 84%, respectively. Our results suggest that integrating N, water, and other management practices (including the combination of a 150 kg ha-1 N rate, 18.0 hills per m2, 10-20 cm rice stubble height, and alternating dry and wet irrigation during the winter season) is a feasible approach for achieving high grain and ratoon forage yields in perennial rice systems.

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.

PSLBII-5 Impacts of residual feed intake measured as a heifer in drylot on mature cows and calves grazing native pasture

Abstract Selection for feed efficiency is crucial for improving economic and environmental sustainability in beef cattle production. Residual feed intake (RFIfat) is a commonly used measure of feed efficiency and is determined in a drylot setting by calculating the difference between observed and expected dry matter intake (DMI), where expected feed intake is adjusted for metabolic body weight (BW), average daily gain (ADG) and body fatness. Lower RFIfat cattle are more efficient animals as they eat less than predicted for the same growth, body size and body fatness. Limited studies have been conducted evaluating the role of RFIfat on the subsequent performance of cow-calf pairs on native range. Kinsella Composite cows and calves (n = 120) grazed native pasture from July 11 to Sept 12 (summer) and from Sept 13 to Nov 2 (fall) of 2023 were included in this study. All dams had previously been evaluated for RFIfat as a heifer (8 to 12 mo of age) using the GrowSafe Feed Intake System (Vytelle, Canada). Cow and calf ADG were subjected to an analysis of covariance using lm function from stats R core package (R Core Team, 2024), with cow age (2 to 8 yr of age) as the fixed effect and RFIfat as the covariate, analyzing separately by season. An unbalanced Tukey HDS post-hoc were applied for age and p-values < 0.05 were considered significant. Weight gain was assessed on cows with an initial BW on pasture of 598.4 ± 68.4 kg, and 2 to 8 yr of age, and on calves having an initial on pasture BW of 106 ± 21.5 kg, and 65 ± 14 d of age. Cow age affected (P < 0.01) cow ADG during summer, with the youngest dams (2 yr old) gaining more weight than older animals (7 yr old; Figure 1A). No effect of RFIfat was found on cow weight gain during summer grazing. However, during fall grazing, RFIfat affected (P < 0.01) cow ADG (Figure 1B). Low-RFIfat cows (efficient) had increased weight gain during fall grazing as compared with high-RFIfat cows (inefficient: Figure 1B). Calf ADG was not affected (P > 0.1) by cow age, cow RFIfat and cow ADG during summer and fall. We conclude that cows with low RFIfat exhibited superior body weight gain, during fall grazing on native range when forage nutrient quality and quantity become limiting.

Comparative Analysis of Feature Importance Algorithms for Grassland Aboveground Biomass and Nutrient Prediction Using Hyperspectral Data

Estimating forage yield and nutrient composition using hyperspectral remote sensing is a major challenge. However, there is still a lack of comprehensive research on the optimal wavelength for the analysis of various nutrients in pasture. In this research, conducted in Hailar District, Hulunber City, Inner Mongolia Autonomous Region, China, 126 sets of hyperspectral data were collected, covering a spectral range of 350 to 1800 nanometers. The primary objective was to identify key spectral bands for estimating forage dry matter yield (DMY), nitrogen content (NC), neutral detergent fiber (NDF), and acid detergent fiber (ADF) using principal component analysis (PCA), random forests (RF), and SHapley Additive exPlanations (SHAP) analysis methods, and then the RF and Extra-Trees algorithm (ERT) model was used to predict aboveground biomass (AGB) and nutrient parameters using the optimized spectral bands and vegetation indices. Our approach effectively minimizes redundancy in hyperspectral data by selectively employing crucial spectral bands, thus improving the accuracy of forage nutrient estimation. PCA identified the most variable bands at 400 nm, 520–550 nm, 670–720 nm, and 930–950 nm, reflecting their general spectral significance rather than a link to specific forage nutrients. Further analysis using RF feature importance pinpointed influential bands, predominantly within 930–940 nm and 700–730 nm. SHAP analysis confirmed critical bands for DMY (965 nm, 712 nm, and 1652 nm), NC (1390 nm and 713 nm), ADF (1390 nm and 715–725 nm), and NDF (400 nm, 983 nm, 1350 nm, and 1800 nm). The fitting accuracy for ADF estimated using RF was lower (R2 = 0.58), while the fitting accuracy for other indicators was higher (R2 ≥ 0.59). The performance and prediction accuracy of ERT (R2 = 0.63) were noticeably superior to those of RF. In conclusion, our method effectively identifies influential bands, optimizing forage yield and quality estimation.

Analysis of rotational grazing management for sheep in mixed grassland.

Sown mixed grassland is rarely used for livestock raising and grazing; however, different forages can provide various nutrients for livestock, which may be beneficial to animal health and welfare. We established a sown mixed grassland and adopted a rotational grazing system, monitored the changes in aboveground biomass and sheep weights during the summer grazing period, measured the nutrients of forage by near-infrared spectroscopy, tested the contents of medium- and long-chain fatty acids by gas chromatography, and explored an efficient sheep fattening system that is suitable for agro-pastoral interlacing areas. The results showed that the maximum forage supply in a single grazing paddock was 4.6 kg DM/d, the highest dry matter intake (DMI) was 1.80 kg DM/ewe/d, the average daily weight gain (ADG) was 193.3 g, the DMI and ADG were significantly correlated (P<0.05), and the average feed weight gain ratio (F/G) reached 8.02. The average crude protein and metabolizable energy intake by sheep were 286 g/ewe/d and 18.5 MJ/ewe/d respectively, and the n-6/n-3 ratio of polyunsaturated fatty acids in mutton was 2.84. The results indicated that the sheep fattening system had high feed conversion efficiency, could improve the yield and quality of sheep, and could be promoted in suitable regions.

315 Awardee Talk: Late Gestational Nutrient Restriction Alters Postnatal Nutrient Delivery and Calf pre-Weaning Growth in the Primiparous Beef Female

Abstract Nutrient requirements increase dramatically in the late gestation beef female to allow for proper growth and function of the uteroplacenta, fetus, and mammary gland. In fall- and spring-calving systems, late gestation grazing beef cattle often have limited forage nutrient availability. Late gestational nutrient restriction research generally associates decreased prenatal nutrient delivery with programming fetal growth and development, resulting in poor postnatal outcomes. However, the effects gestational nutrient partitioning may have on programming the mammary gland to decrease postnatal nutrient delivery is far less understood. In a fall-calving experiment, primiparous females were individually fed either 100% or 70% of energy and protein requirements from d 160 of gestation until parturition. Nutrient restricted females lost body weight and condition and had less nutrients in maternal circulation during late pregnancy. Calf birth weight was not affected, but nutrient restricted dams had less vigorous calves and 40% less colostrum yield. Colostrum of nutrient restricted females was more concentrated with IgG, and calf 48-h serum IgG indicated that offspring of both treatments had successful passive transfer of immunity. Colostrum of nutrient restricted females had less total lactose, but similar total protein and triglycerides compared with control females. Even when females were fed to meet their energy and protein requirements during lactation, late gestational nutrient restriction reduced milk yield by 15% and decreased milk protein concentration during the first 150 d of lactation. Reduced milk production was partially explained by a 19% reduction in blood flow supplying the mammary gland during this time. Less total lactose, protein, and triglycerides provided by the milk resulted in calf body weight diverging by 42 d of age, and calves born to nutrient restricted dams were 13% smaller at weaning. Interestingly, calf metabolic status pre-weaning was not as severely altered as expected considering milk nutrient and calf growth differences. By d 21 of lactation, metabolic status of previously nutrient restricted dams had returned to concentrations similar to control dams. During lactation, previously nutrient restricted females gained maternal weight faster and increased body condition, but had still not fully recovered to that of control females by weaning. Females were managed together and followed through their second parity to examine effects during the subsequent parity. Previously nutrient restricted dams still weighed less, were in thinner body condition, and had less mammary blood flow during their second lactation. Lactational performance and second parity calf growth were similar between treatments. While late gestational nutrient restriction may not always reduce fetal growth, our results illustrate that impaired postnatal nutrient delivery mechanisms in the cow and calf deserve continued consideration. Additionally, persisting effects in the second parity on maternal size, fleshing ability, and mammary blood flow demonstrate the possibility of long-term programming effects on the dam.

Неточности и необходимость унификации методов анализов качества кормов

Fodder laboratories make analysis specifically using different methods, devices and equipment. Thesearticle is devoted fundamental principle in work of laboratories on fodder quality evaluation — to maximally exact fulfillment of the standardized procedures of estimation of the forage nutrients and antinutrients content. It is necessary to consider as the important problem unification of methods of estimation of the nutrients content in forages, preliminarily having carried out objective comparative researches on purpose to find out, how much adequate the methods of analysis reflect a true quality of forages.

Analysis of leaf forage value and screening of different populations of Pteroceltis tatarinowii, a rare and endemic species in China.

To fully exploit the economic value of the Chinese endemic species Pteroceltis tatarinowii and provide new resources for forage production, the forage nutritional value of P. tatarinowii leaves from different populations was analyzed and evaluated. The results were as follows: 1) There were significant differences in the forage nutrient indices of leaves from different populations. The crude protein content was 10.77%-18.65%, with an average of 14.58%, and the SDJN population had the highest crude protein content. The average crude fat, crude fiber content was 7.62%; the average neutral detergent fiber content was 25.33%; and the average acid detergent fiber contents were 6.79%, 7.62%, 25.33%, and 17.52%, respectively. The average phosphorus and calcium content in the leaves was 0.785 g·kg-1 and 58.01 g·kg-1, respectively. The tannin content was much lower than the antifeedant standard, at an average of 4.97 g·kg-1. The average total amounts of hydrolyzed and free amino acids in the leaves were 108.20 mg·g-1 and 47.87 mg·g-1, respectively. Thus, P. tatarinowii leaves have high crude protein, crude fat, and calcium contents, and low fiber, tannin contents, and are protein-rich. These results provide evidence that this species can be developed into an excellent woody forage tree. 2) There were significant differences in the forage quality evaluation indices among the populations. The forage indices of NDP, ADP, DMI, DDM, and RFV of 21 populations all met the super standard of the American Grass and Grassland Association (AFGC) for hay, two crude protein indices met the grade 1 standard, and 12 crude protein indices met the grade 2 standard. Four high-protein and high-RFV forage populations (SDJN, SDZZ, SXLQ, and AHXX) were selected. 3) The results of the correlation analysis showed that there was no significant correlation between the forage characteristics of P. tatarinowii leaves and latitude and longitude, indicating no significant geographical variation. However, the forage characteristics were strongly correlated with elevation, average annual temperature, and annual precipitation. Thus, high elevation, low temperatures, and rainy weather can improve the forage value of the leaves. P. tatarinowii can be planted to provide leaf forage in cold and wet areas at a specific elevation. Moreover, the forage value of P. tatarinowii leaves can be further improved by increasing nitrogen fertilizer and reducing K and Ca fertilizers during cultivation. 4) Cluster analysis revealed obvious regionalism. Taking the Yangtze River Basin as the limit, cluster analysis divided the species into four population groups: the Yangtze River Basin and northern, southwestern, and eastern coastal populations.

Mapping the forage nitrogen, phosphorus, and potassium contents of alpine grasslands by integrating Sentinel-2 and Tiangong-2 data

Nitrogen (N), phosphorus (P), and potassium (K) contents are crucial quality indicators for forage in alpine natural grasslands and are closely related to plant growth and reproduction. One of the greatest challenges for the sustainable utilization of grassland resources and the development of high-quality animal husbandry is to efficiently and accurately obtain information about the distribution and dynamic changes in N, P, and K contents in alpine grasslands. A new generation of multispectral sensors, the Sentinel-2 multispectral instrument (MSI) and Tiangong-2 moderate-resolution wide-wavelength imager (MWI), is equipped with several spectral bands suitable for specific applications, showing great potential for mapping forage nutrients at the regional scale. This study aims to achieve high-accuracy spatial mapping of the N, P, and K contents in alpine grasslands at the regional scale on the eastern Qinghai-Tibet Plateau. The Sentinel-2 MSI and Tiangong-2 MWI data, coupled with multiple feature selection algorithms and machine learning models, are applied to develop forage N, P, and K estimation models from data collected at 92 sample sites ranging from the vigorous growth stage to the senescent stage. The results show that the spectral bands of both the Sentinel-2 MSI and Tiangong-2 MWI have an excellent performance in estimating the forage N, P, and K contents (the R2 values are 0.68–0.76, 0.54–0.73, and 0.74–0.82 for forage N, P, and K estimations, respectively). Moreover, the model integrating the spectral bands of these two sensors explains 78%, 74%, and 84% of the variations in the forage N, P, and K contents, respectively. These results indicate that the estimation ability of forage nutrients can be further improved by integrating Tiangong-2 MWI and Sentinel-2 MSI data. In conclusion, integration of the spectral bands of multiple sensors is a promising approach to map the forage N, P, and K contents in alpine grasslands with high accuracy at the regional scale. This study offers valuable information for growth monitoring and real-time determination of forage quality in alpine grasslands.

Correlation and determination of the Metabolizable Energy (ME) of tropical forage with nutrient content for ruminants

The metabolizable energy (ME) of tropical forages measured by in vivo method in ruminants had a high degree of accuracy but requires a long time and is expensive. One method that can be done is the ME estimation model. The objectives of the present study were carried out to investigate the relationship between tropical forage nutrient content and ME for ruminants as well as determine and validate a model for estimating ME of tropical forage based on nutrient content. A total of 26 forage samples consisting of 14 types of grass and 12 legumes were obtained after data pre-processing or data cleaning and data normalization. Forage samples will be grouped into 3, Grass + Legume (G+L=26), grass (R=14), and legume (L=12). The database used is Crude Protein (CP), Extract Ether (EE), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), and hemicellulose as well as ME with in vivo experiments. The initial stage is preprocessing data. Nutrient content and ME were analyzed using Pearson Correlation and followed by multiple linear regression to determine the ME estimation model. However, validated used the mean absolute deviation (MAD), root means square error (RMSE), and mean absolute percentage error (MAPE). The results showed that there was a significant and highly significantly correlated between nutrient composition and ME in the Grass + Legume, Grass, and Legume groups so it could be used to determine ME. There are 9 regression equations with significance and have high R2 and after being validated with the lowest MAD, RMSE, and MAPE values, three regression equations are obtained with one each for each group Grass + Legume (G+L), Grass (R), and Legumes (L). It is concluded that the regression equation of ME of tropical forage is MER+L = 12.429 – 0.122 ADF for Grass + Legume, EMR = 15.609 – 0.115 NDF for Grass, and EML = 3.726 – 0.186 CP for Legume.

118 Nutrient Cycling Potential from Manure from Heifers Fed Four Bermudagrass Cultivars

Abstract Maintenance of pastures for grazing accounts for $132.50/animal in the United States (23% of operating costs), and pasture nutrient input represents the single greatest influence in productivity per unit area. Cultivar differences in the forage offered to cattle have the potential to manifest differences in digestive efficiency, resulting in different nutrient excretion profiles. The objective of this study was to assess the growth potential and incorporation of N, P, and K into forage material from manure from cattle fed one of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars. Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal, Russell, Tifton 44, or Tifton 85) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 23, total fecal collections were subsampled from each heifer. As a hierarchical addition, a controlled greenhouse experiment was conducted for each period [15 pots per period; 5 manure treatments (four bermudagrass diets plus a negative control) × 3 replications]. Manure was added to 4.58 L pots based on stocking rate estimates for Central Alabama (1,110 kg/ha). The pots were seeded with bermudagrass (cv. Giant) as an indicator for forage nutrient uptake. At harvest (d 70), herbage, root, and soil samples were collected. Herbage and root samples were assayed for CP. Soil samples were assayed for pH, N, P, K, Mg, and Ca. Data were analyzed using SAS v. 9.4. There was no effect of manure treatment on herbage (P = 0.88) or root DM yield (P =.00;.54 and.73 g/pot, respectively). Similarly, there was no effect of manure treatment on soil pH (P = 0.18; 5.5), P (P = 0.78; 24.2 kg/ha), or K (P = 0.42;56.7 kg/ha). Results are interpreted to mean that, regardless of the cultivar effects on ruminal digestive dynamics, there is little to no effect of the resulting manure on subsequent forage production and nutrient uptake.

105 Botanical composition, yield, horse preference, and forage and soil nutrient values of grass pastures treated with different soil amendments

Forage is the foundation of a horse's diet, therefore, pasture management is critical to improve horse health and pasture productivity. The objective of this study was to evaluate botanical composition, horse preference, yield, and forage and soil nutrient values of pasture treated with horse manure, horse compost, commercial urea fertilizer, and a no amendment control. Researchers hypothesized soil amendments would increase soil nutrients and yield with minimal effects on botanical composition, preference and forage nutrient value. Replicated (n = 3) plots of established cool-season mixed grass pasture were 3 × 6 m and located in St. Paul, Minnesota. The soil was a Waukegan silt loam with a pH of 6.4 and 47 g kg–1 organic matter. Urea was applied based on initial soil test recommendations, 0.64 cm of compost was applied based on common recommendations, and manure was applied at a rate to represent horse manure deposition in May 2022. Sample collection and grazing periods occurred in May, June, July, August, and October 2022, each over a 2-d period. Botanical composition, average forage height and maturity, soil samples, forage samples, and forage yield were taken immediately before grazing. Horses were allowed to graze all plots for 4 h with preference visuallyassessed at 2- and 4 h post-grazing based on percent removal. Data were analyzed as a randomized complete block design using PROC MIXED in SAS with significance set at P ≤ 0.05. Season-long yield ranged from 2,690 to 3,363 kg DM ha-1 and did not differ across treatments (P > 0.05). Botanical composition differed across treatments with the control having the most weeds (32%) and the least amount of grass (62%) while manure treatments resulted in the most bare ground (11%; P ≤ 0.05). The soil nutrients magnesium and phosphate were highest in compost-treated plots and nitrate-nitrogen and sodium were highest in manure-treated plots (P ≤ 0.05). Forage nutrient content did not differ across treatments (P > 0.05). Horses did not prefer pasture treated with manure and only 15 and 33% of forage was consumed after 2 and 4 h, respectively (P ≤ 0.001). All other treatments averaged 53 and 78% removal after 2 and 4 h, respectively. Based on differences observed in botanical composition and horse preference, commercial fertilizer and compost appear to be the most beneficial soil amendments for horse pastures.

Nutritive value and net return of forage crop rotations in the central Great Plains

AbstractSustainable forage‐based rotations with greater forage nutritive values and efficient resource utilization are needed to increase forage availability in the central Great Plains. The objectives of the study were to quantify nutritive value and net return from individual crops and overall crop rotation sequence of winter triticale, forage sorghum, and spring oat. The study was conducted near Garden City, KS, from 2013–2020. There were six treatments in the study, that is, continuous sorghum [Sorghum bicolor (L.) Moench] (S‐S) no‐till (NT), triticale (×Triticosecale Wittm. ex A. Camus [Secale × Triticum])/sorghum‐sorghum‐oat (Avena sativa L.) (T/S‐S‐O) reduced till (RT) and NT, triticale/sorghum‐sorghum‐sorghum‐oat (T/S‐S‐S‐O) RT and NT, and triticale‐sorghum‐oat (T‐S‐O) NT. Crude protein concentration was 23%–31% greater for T‐S‐O and T/S‐S‐O compared with S‐S. The S‐S treatment had greater fiber content and least digestibility, calcium, and phosphorus concentrations compared with the remaining forage rotations. Annualized cost of production was 11%–32% greater for forage sorghum dominated NT systems (T/S‐S‐O, T/S‐S‐S‐O, S‐S [NT]) compared with T‐S‐O or T/S‐S‐S‐O (RT) rotation. T/S‐S‐S‐O (RT) was among the top in net return due to a combination of greater forage biomass production and forage nutrient value. The cost of production for forage sorghum and triticale were more economical compared to purchasing commercial feedstuffs. We concluded forage producers should consider productivity and market value, in addition to nutritive value and cost of production in selecting crops for a profitable forage‐based rotation system.

Fecal Microbiota, Forage Nutrients, and Metabolic Responses of Horses Grazing Warm- and Cool-Season Grass Pastures

Integrating warm-season grasses into cool-season equine grazing systems can increase pasture availability during summer months. The objective of this study was to evaluate effects of this management strategy on the fecal microbiome and relationships between fecal microbiota, forage nutrients, and metabolic responses of grazing horses. Fecal samples were collected from 8 mares after grazing cool-season pasture in spring, warm-season pasture in summer, and cool-season pasture in fall as well as after adaptation to standardized hay diets prior to spring grazing and at the end of the grazing season. Random forest classification was able to predict forage type based on microbial composition (accuracy: 0.90 ± 0.09); regression predicted forage crude protein (CP) and non-structural carbohydrate (NSC) concentrations (p < 0.0001). Akkermansia and Clostridium butyricum were enriched in horses grazing warm-season pasture and were positively correlated with CP and negatively with NSC; Clostridum butyricum was negatively correlated with peak plasma glucose concentrations following oral sugar tests (p ≤ 0.05). These results indicate that distinct shifts in the equine fecal microbiota occur in response different forages. Based on relationships identified between the microbiota, forage nutrients, and metabolic responses, further research should focus on the roles of Akkermansia spp. and Clostridium butyricum within the equine hindgut.

Relevance of sward structure and forage nutrient contents in explaining methane emissions from grazing beef cattle and sheep

Forage nutrient contents are an important factor explaining the dry matter intake (DMI), average daily gain (ADG), and methane emissions (CH4) of ruminants fed indoors. However, for grazing animals, the forage nutrient contents might be limited in explaining such response variables. We aimed to verify the explanatory power of forage nutrient contents and sward structure on daily intake, performance, and CH4 emissions by sheep and beef cattle grazing different grassland types in southern Brazil. We analyzed data from five grazing trials using sheep and beef cattle grazing on Italian ryegrass (Lolium multiflorum), mixed Italian ryegrass and black oat (Lolium multiflorum + Avena strigosa), pearl millet (Pennisetum americanum), and multispecies native grassland. We used mixed models, including the forage nutrient contents [crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF)], sward structure (sward height and herbage mass) and their interactions, as fixed effects and trial, season, methodologies, animal species, grassland type, and paddock, as random effects. The model for DMI (kg DM/LW0.75) had an adjusted coefficient of determination (R2adj) of 71.6 %, where 11.3, 23.1, and 37.2 % of the R2adj were explained by the forage nutrient contents, sward structure, and their interaction, respectively. The ADG (kg/LW0.75) model presented an R2adj of 74.2 %, with 12.5 % explained by forage nutrient contents, 29.3 % by sward structure, and 32.4 % by their interaction. The daily CH4 emission (g/LW0.75) model had a lower adjusted coefficient of determination (R2adj = 47.6 %), with 16.8 % explained by forage nutrient contents and 30.8 % explained by sward structure, but no effect of the interaction. Our results show that in grazing ecosystems, the forage nutrient contents explain a small fraction, and the greater explanatory power for DMI, ADG, and CH4 emissions models is related to sward structure descriptors, such as sward height and herbage mass. Moreover, the interaction between these variables explains most of the variation. In conclusion, forage nutrient contents and sward structure have different influences on DMI, ADG, and CH4 emissions by grazing ruminants. Because of its relevance to daily CH4 emissions, offering an optimal sward structure to grazing animals is a major climate-smart strategy to improve animal production and mitigate CH4 emissions in pastoral ecosystems.

Nitrogen utilisation, energy utilisation and methane emissions of sheep grazing in two types of pasture

Livestock grazing plays a significant role in maintaining grasslands and promoting animal production globally. To understand the livestock performance in sown pasture (SP) vs native pasture (NP) is important to ensure more effective grassland-livestock interactions with minimal environmental impact. A 2 (treatment) * 2 (period) Latin Square design experiment was conducted with 10 growing Hu sheep ♂ × thin-tailed Han sheep ♀ rams grazed perennially SP vs NP in an inland arid region of China. The objectives were to evaluate the effects of grazing management on nutrient digestibility, nitrogen (N) and energy utilisation and methane (CH4) emission. The N intake, N retained and energy intake (gross energy (GE), and digestible and metabolisable energy) of sheep grazing in SP were significantly increased compared with those grazing in NP. There were significant linear relationships between DM intake (DMI) (g/kg BW or g/kg BW0.75) or CH4 (g/kg BW or g/kg BW0.75) emissions and forage nutrient and GE concentrations within each grassland type. The linear regression analysis indicated that forage CP or ether extract concentration was a good predictor for DMI (g/kg BW or g/kg BW0.75) (R2 = 0.756 or 0.752), and CH4 emission could be predicted using forage nutrient and GE concentrations (R2 = 0.381–0.503). These results suggest that DMI and CH4 emissions per unit metabolic BW were accurately predicted by multiple-factor combinations of forage nutrients, including ether extract and CP paired with GE. The present output could provide useful information for the development of sustainable sheep grazing systems in the inland arid regions of the world.