Grazing Season Research Articles

Influence of Grazing Season, Residual Herbage, and Precipitation on Rumen Extrusa Diet Quality

While considerable research has quantified effects of grazing management and precipitation on plant communities, less is known about how seasonal effects influence extrusa diet quality selected by grazing ruminants. We tested effects of cattle grazing to two residual herbages (600 kg [moderate] or 300 kg [low] animal unit mo [AUM]/ha) and two grazing seasons (summer and fall) on 20 indicators of ruminant extrusa diet quality over a 6-yr period. We found no effect of residual herbage on 13 indicators of diet extrusa quality (P ≥ 0.13) and no effect of season on 4 indicators of extrusa diet quality (P ≥ 0.0773). We did, however, detect effects of yr on extrusa diet quality metrics and nutrients, likely due to variation in annual precipitation, which ranged from 63.9% to 138.6% of the long-term average. Most noticeably, the mineral Mn in extrusa was substantially lower in yrs with higher precipitation (P < 0.0001). While grazing intensity had divergent effects on forage quality in the summer versus fall, annual precipitation was often important. Crude protein was lowest in fall of 2013 (6.5%) and 2018 (7.78%), two high-precipitation yrs, but it was also low in fall of 2015 (7.30%), a low-precipitation yr (P < 0.0001). Forage extrusa Cu, an important catalyst in ruminant metabolism, exhibited a yr × season interaction. Copper in fall of 2018 was greater compared with all other yrs and seasons in the study (P < 0.0001), 35.7% greater than summer of 2018, a high-precipitation yr, and 82.9% and 43.5% greater than summer and fall of 2013, another high-precipitation yr. Seasonal variation in diet nutrients and quality indicators were complex and complicated by yr effects, which sometimes related to precipitation amounts.

Integrative biology defines novel biomarkers of resistance to strongylid infection in horses

The widespread failure of anthelmintic drugs against nematodes of veterinary interest requires novel control strategies. Selective treatment of the most susceptible individuals could reduce drug selection pressure but requires appropriate biomarkers of the intrinsic susceptibility potential. To date, this has been missing in livestock species. Here, we selected Welsh ponies with divergent intrinsic susceptibility (measured by their egg excretion levels) to cyathostomin infection and found that their divergence was sustained across a 10-year time window. Using this unique set of individuals, we monitored variations in their blood cell populations, plasma metabolites and faecal microbiota over a grazing season to isolate core differences between their respective responses under worm-free or natural infection conditions. Our analyses identified the concomitant rise in plasma phenylalanine level and faecal Prevotella abundance and the reduction in circulating monocyte counts as biomarkers of the need for drug treatment (egg excretion above 200 eggs/g). This biological signal was replicated in other independent populations. We also unravelled an immunometabolic network encompassing plasma beta-hydroxybutyrate level, short-chain fatty acid producing bacteria and circulating neutrophils that forms the discriminant baseline between susceptible and resistant individuals. Altogether our observations open new perspectives on the susceptibility of equids to strongylid infection and leave scope for both new biomarkers of infection and nutritional intervention.

Forest degradation and short-term seasonal exclosure effects on biotic and abiotic factors linked to rangeland rehabilitation in semiarid Chaco, Argentina

In semiarid Chaco, wet season grazing exclosures allow a rapid grass recovery in mature and secondary forest patches, but not in the most degraded patches dominated by shrublands. In order to understand the causes of their dissimilar rehabilitation dynamics, we analyzed the effects of the forest-patch type (mature forest = MF, secondary forest = SF, and shrubland = S) and 4-year seasonal exclosures (vs continuous grazing) on biotic and abiotic factors (vegetation structure, incident radiation, grass seed bank, litter and soil traits) that could affect grass recovery. We found that vegetation structure, through determining litter quantity, controlled soil chemical traits. As forest degradation level increased, litter mass (MF = 6260, SF = 5410, S = 1220 kg DM/ha), total soil organic matter (MF = 5.1%, SF = 4.1%, S = 3.5%) and nitrogen (MF = 0.25%, SF = 0.22%, S = 0.18%) decreased, and the incident radiation at soil level rose (MF = 28%, SF = 41%, S = 52%). After 4 years of seasonal grazing rest, we found reduced soil bulk density (from 1.13 to 1.07 and 1.07 to 1 g/cm3) and increased total porosity (from 57 to 60 and 60 to 62%) at 0–10 and 10–30 cm depth, respectively, in all forest patch types. Exclosure also increased soil seed bank density (from 28 to 251 grass seeds/m2) both in the forests (with grass) and in the shrublands (even before grass recovery), which would receive seeds from the adjacent forest patches, which coexist in the same landscape matrix. Our results suggest that the low tree cover, litter, and soil chemical traits related to lower availability of water and nutrient in shrublands, could hamper grass recovery in recently established exclosures. However, improvements in the grass seed bank and soil physical traits related to higher water infiltration could favor its late recovery, which is triggered by an extremely wet cycle after several years of the seasonal exclosure. Exclosure is a promising management strategy for degraded areas involving intermingled patches of forests and shrublands.

Effects of rotation grazing time on the characteristics of soil seed bank in desert steppe.

Exploring the characteristics of soil seed bank under seasonal grazing plays an important role in the reasonable use of desert steppe. We examined seed bank species composition, density, vertical distribution, diversity in the soil of 0-5, 5-10, 10-15 cm soil layers and the relationship with vegetation and soil environmental factors in Ningxia desert steppe. The treatments included enclosure (FY), traditional time rotation grazing (FG), delayed to start rotation grazing (YG), early to end rotation grazing (TG), delayed to start and early to end rotation grazing (YT) and free grazing (ZY). The results showed that there were nine families and 21 species in the soil seed bank in the study area. The species composition of soil seed bank in TG seed bank with 13 species was the largest, while FY and ZY soil seed banks had the least, with 8 species, respectively. The den-sity of ZY soil seed bank was significantly higher than that of FY, YG, TG and YT. The number of perennial species seeds in the soil seed bank of FY was the largest, reaching 32.0%, while that in the ZY was the least, only 12.4%, mainly with sexually reproduced annual weeds. Soil seed bank was mainly concentrated in the 0-5 cm surface layer. With increasing soil depth, the size of soil seed bank decreased. The dominance and diversity of soil seed bank were the highest in FY, while the dominance, diversity and uniformity were the lowest in ZY. The similarity between soil seed bank and aboveground vegetation was generally low. In contrast, the FG and ZY seed banks had higher similarity with vegetation, and the FY was the lowest. Soil moisture, organic matter, total nitrogen concentration, total phosphorus concentration, and soil bulk density were the main soil factors affecting soil seed bank. Compared with traditional whole year free grazing, seasonal four-zone rotation grazing could increase species richness and abundance of perennial plants in soil seed bank of desert steppe, as well as the total species richness, diversity and uniformity of the seed bank. Although the effect sof seasonal four-zone rotation grazing on seed bank was not as good as the long-term enclosure grassland, it was of great significance to the utilization and protection of desert steppe.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Cheese quality from cows given a tannin extract in 2 different grazing seasons

The aim of the present study was to compare the effect of dietary tannins on cow cheese quality in 2 different grazing seasons in the Mediterranean. Two experiments were performed on 14 dairy cows reared in an extensive system. The first experiment took place in the wet season (WS), and the second experiment took place in the dry season (DS). In the WS and DS experiments, cows freely grazed green pasture or dry stubbles, respectively, and the diet was supplemented with pelleted concentrate and hay. In both experiments, the cows were divided into 2 balanced groups: a control group and a group (TAN) receiving 150 g of tannin extract/head per day. After 23 d of dietary treatment, individual milk was collected, processed into individual cheeses, and aged 25 d. Milk was analyzed for chemical composition, color parameters, and cheesemaking aptitude (laboratory cheese yield and milk coagulation properties). Cheese was analyzed for chemical composition, proteolysis, color parameters, rheological parameters, fatty acid profile, and odor-active volatile compounds. Data from the WS and DS experiments were statistically analyzed separately with an analysis of covariance model. In the WS experiment, dietary tannin supplementation had no effect on milk and cheese parameters except for a reduced concentration of 2-heptanone in cheese. In the DS experiment, TAN milk showed lower urea N, and TAN cheese had lower C18:1 trans-10 concentration and n-6:n-3 polyunsaturated fatty acid ratio compared with the control group. These differences are likely due to the effect of tannins on rumen N metabolism and fatty acid biohydrogenation. Dietary tannins may differently affect the quality of cheese from Mediterranean grazing cows according to the grazing season. Indeed, tannin bioactivity on rumen metabolism seems to be enhanced during the dry season, when diet is low in protein and rich in acid detergent fiber and lignin. The supplementation dose used in this study (1% of estimated dry matter intake) had no detrimental effects on cheese yield or cheesemaking parameters. Also, it is unlikely that sensorial characteristics would be affected by this kind of dietary tannin supplementation.

Soil physical properties in a natural highland grassland in southern Brazil subjected to a range of grazing heights

Natural grasslands in southern Brazil are ecosystems that are naturally adapted to grazing. Despite the productivity and ecological relevance of these ecosystems, the effects of grazing intensity on their soil quality are still underexplored. This work aimed to determine whether increasing the grazing intensity would jeopardize the soil structure in a natural highland grassland in southern Brazil. Pastures were evaluated at four pregrazing canopy heights, 0.12, 0.20, 0.28 and 0.36 m, with Andropogon lateralis Nees as the reference species, and in one ungrazed control area. The pastures were intermittently stocked, and the postgrazing heights corresponded to 60% of the pregrazing targets (i.e., the postgrazing heights were 0.072, 0.12, 0.168 and 0.216 m). The experiment started in 2015 and was conducted for three years, with evaluations of soil physical properties performed in the final year. Forage growth and grazing were concentrated from October to May; during the winter, no grazing occurred for a period of approximately 4 months. The soil structure was evaluated at two points: after the end of the 2017/2018 grazing season, in June, and after the winter period, in October. Regardless of the canopy height, the presence of grazing animals increased the degree of compaction at the soil surface (0.0–0.05 m) to an intermediate level immediately after grazing, did not disaggregate the soil or change its carbon and nitrogen stocks, and increased soil macroporosity and water infiltration compared to those in the exclusion area (control). Increasing the grazing intensity (i.e., increasing the grazing frequency, corresponding to lower pregrazing canopy heights) increased the soil macroporosity and water infiltration rate, decreased the soil moisture and increased the soil penetration resistance. Except at the 0.12 m canopy height, the exclusion of grazing for 4 months allowed the soil water infiltration in the grazed plots to return to a level similar to that in the exclusion area. We conclude that there are a wide range of grazing intensities (corresponding to canopy heights of 0.12–0.36 m) that do not jeopardize the soil structural quality in highland grasslands. Furthermore, it was not possible to determine whether canopy heights below 0.12 m would disrupt the synergism at the soil-plant-animal interface in these natural ecosystems.

Life cycle assessment of pasture-based suckler steer weanling-to-beef production systems: Effect of breed and slaughter age

Demand for beef produced from pasture-based diets is rising as it is perceived to be healthier, animal friendly and good for the environment. Animals reared on a solely grass forage diet, however, have a lower growth rate than cereal-fed animals and consequently are slaughtered at an older age. This study focused on the former by conducting life cycle assessments of beef production systems offering only fresh or conserved grass, and comparing them to a conventional pasture-based beef production system offering concentrate feeding during housing. The four suckler weanling-to-beef production systems simulated were: (i) Steers produced to slaughter entirely on a grass forage diet at 20 months (GO-20); (ii) Steers produced to slaughter entirely on a grass forage diet at 24 months (GO-24); (iii) Steers produced to slaughter on a grass forage diet with concentrate supplementation during housing (GC-24), and (iv) Steers produced to slaughter entirely on a grass forage diet at 28 months (GO-28). Two breed types were evaluated: early-maturing and late-maturing (LM). The environmental impacts assessed were global warming potential (GWP), non-renewable energy (NRE), acidification potential (AP), eutrophication potential (marine (MEP) and freshwater) were expressed per animal, per kg live weight gain (LWG), kg carcass weight gain, and kg meat weight gain (MWG). The GO-20 production system had the lowest environmental impact across all categories and functional units for both breeds. Extending age at slaughter increased environmental impact across all categories per animal. The LWG response of EM steers to concentrate feed supplementation in GC-24 was greater than the increase in total environmental impact resulting in GC-24 having a lower environmental impact across categories per kg product than GO-24. Concentrate feed supplementation had a similar effect on LM steers with the exception of NRE and AP. The increase in daily LWG in the third grazing season in comparison to the second grazing and housing resulted in GO-28 having lower GWP, NRE, AP, and MEP per kg product than GO-24. Early-maturing steers had lower environmental impact than LM when expressed per kg LWG. However the opposite occurred when impacts were expressed per kg MWG, despite LM steers producing the least LWG. The LM steers compensated for poor LWG performance by having superior carcass traits, which caused the breed to have the lowest environmental impact per kg MWG. The results reaffirms the importance of functional unit and suggests reducing the environmental impact of LWG does not always translate into improvements in the environmental performance of meat.

The Impact of Herbage Mass on Perennial Ryegrass Swards in Autumn on Autumn and over Winter Production and Characteristics

Accumulating herbage mass to facilitate the extension of the grazing season in autumn is commonly practised. The objective of the current study was to investigate the effect of accumulating varying target herbage masses (THM) in autumn and imposing different defoliation dates (DD), on herbage mass, sward quality and water-soluble carbohydrates in autumn and the subsequent spring. A 4 × 3 factorial split plot design was assigned with four THM (Low ≈ 500 kg·DM·ha−1, Medium ≈ 1500 kg·DM·ha−1, High ≈ 2000 kg·DM·ha−1 and Very high ≈ 3000 kg·DM·ha−1) and three DD (DD1—15 October, DD2—7 November and DD3—21 November), across two years. Measurements were carried out at each DD and in spring. Differences in sward quality were found between each THM on different DD. Sward quality reduced from DD2 to DD3 in the high THM (−13 g·kg−1 DM CP, p &lt; 0.001). The very high THM had the lowest sward quality from DD1 (206 g·kg−1 DM CP, p &lt; 0.001 and 787 g·kg−1 DM DMD, p &lt; 0.05). This study has identified the defoliation date of THM in autumn as key to improving autumn management strategies for increased utilisation and sward quality.

Comparative Pasture Management on Canadian Cattle Ranches With and Without Adaptive Multipaddock Grazing

Significant interest exists in the potential for specialized grazing systems, including adaptive multipaddock (AMP) grazing, to enhance grassland health and function. However, specific pasture management practices associated with AMP grazing at the ranch level remain poorly understood in comparison with more regionally representative management systems. As part of a larger study examining grazing effects on soil carbon, greenhouse gases, and other ecosystem attributes, here we report on differences in disturbance history and grazing management practices on a sample of AMP operators and their neighboring (n-AMP) ranches at 32 paired sites across the prairie provinces of western Canada. Most ranches studied (77.5%) relied on pastures composed of introduced (seeded) forage. On average, the AMP ranches surveyed were larger in size, supported greater animal numbers, and were more likely to use seeded forages comprising diverse mixes. Relative to n-AMP ranches, AMP ranches used 18.6-fold higher average stock densities in smaller paddocks (22.3 vs. 120.7 ha) while grazing over a grazing season that was 76 d longer, although computed stocking rates remained similar (P ≥ 0.10). AMP operators specifically used much shorter grazing periods (2.8 d) during the early growing season (i.e., before August 1) that were followed by a prolonged rest period (69 d) and could be used to compute a rest-to-grazing ratio for the first half of the grazing season for all ranches. This ratio, along with cattle stock density computed at the pasture scale, exhibited the greatest potential to differentiate the two groups of ranchers. Finally, both groups, and in particular ranchers within the AMP group, demonstrated high variability in management practices among individual operators, highlighting the importance of using specific management metrics rather than generalized descriptors of “grazing system type” to interpret their influence.

Seasonal patterns of endozoochory by cattle in subtropical grassland in southern Brazil

AbstractSeed dispersal influences plant community dynamics and regeneration. Zoochory by cattle is a particularly important type of dispersal in grasslands, but still poorly understood in subtropical grasslands. We studied endozoochory in a native grassland area with different grazing intensities, defined by distinct forage allowance levels. On one day in each of the four seasons of the year, dung samples were collected and kept in a greenhouse for germination over one full year. At each dung collection date, a survey of reproducing plants was conducted to relate the species composition of seed within dung to the community in dispersal phase. We used randomisation tests to compare grazing intensities and seasons in terms of dung community richness, abundance and composition. We recorded 93 species in the dung samples, with 65 species in the spring samples, 61 in summer samples, 45 in the autumn samples and 37 in the winter samples. Of the 90 species identified in the vegetation, almost 50% (43 species) also occurred in dung samples. Graminoid herbs presented the largest number of species in all samples. Grazing had no effect on overall seed and species number, but was related to compositional differences in the cattle dung communities. Grazing also influenced the species composition in relation to life cycle, by the increase of annual species at the extremes of our grazing gradient (very high or very low grazing intensities). We conclude that endozoochory by cattle is an important process for the dispersal of native species in the studied system, with potential applications in grassland management and restoration. A better understanding of the strategies involved in seed dispersal is essential to improve knowledge about grassland vegetation regeneration and maintenance.

Grassland grazing management altered soil properties and microbial β-diversity but not α-diversity on the Qinghai-Tibetan Plateau

Grazing management can alter soil properties and microbial communities that are critical to maintaining grasslands' long-term productivity and function, but information relevant to such influences operating on the Qinghai-Tibetan Plateau (QTP) of China is scarce. The present study was undertaken to examine the impact of different grazing management approaches [e.g., seasonal grazing (SG), continuous grazing (CG), and exclosure grazing (EG)] on soil properties and microbial communities on the QTP. Soil properties from two depths (0 to 0.15 m and 0.15 to 0.30 m) and microbial communities from topsoil (0 to 0.15 m) were measured in plots representative of each grazing type. Several soil properties were of greater magnitude in SG vs. CG sites: aboveground biomass, 838 vs. 46 g/m2; soil organic carbon 20.73 vs. 8.07 g/kg; total soil nitrogen 1.74 vs. 1.07 g/kg; total soil phosphorus 0.20 vs. 0.16 g/kg. Soil property values at the EG site were intermediate to those at the SG and CG sites. While no significant difference in richness and the α-diversity of soil bacteria and soil fungi occurred among grazing types, the β-diversity of soil fungi differed significantly, and the β-diversity of soil bacteria under EG was significantly different from that under SG or CG. Results from the present study suggest that grazing management can alter soil conditions and microbial β-diversity, and EG might prove a useful long-term option for grassland recovery.

Effects of grazing disturbance of spatial distribution pattern and interspecies relationship of two desert shrubs

Grazing significantly affects the distribution, growth, and productivity of shrubs. In this study, we evaluated the effects of grazing disturbance on the spatial distribution patterns and interspecific relationships of two desert shrubs, Ammopiptanthus mongolicus and Sarcozygium xanthoxylon. Three types of grazing conditions were considered, including enclosed area (EA), seasonal rotational grazing area (SRGA), and grazing area (GA) (100 m × 100 m), in the West Ordos Nature Reserve of Inner Mongolia, China. The results showed that A. mongolicus and S. xanthoxylon populations were uniformly distributed at a small scale, and the distribution in EA and SRGA became gradually random. In GA, A. mongolicus population showed aggregated distribution but S. xanthoxylon population showed random distribution at a small scale. Moreover, both A. mongolicus and S. xanthoxylon populations at the 5–7 m scale showed random distribution. At the small and intermediate scales, the two species showed positive interspecific relationships of GA. However, no interspecific relationship was noted between the two species in EA and SRGA. A significant positive relationship (P < 0.01) was noted between the two species at 2–9 m and a negative relationship (P < 0.01) at 13–17 m scales in GA. Positive relationship (P < 0.01) was noted between the two species at 6–13 m scales and a significant negative relationship (P < 0.01) at 14–24 m scales in SRGA. The two species of desert shrubs showed positive interspecific relationships at the small scale, and they showed negative relationships as the interspecific competition intensified in the presence of grazing disturbance. When the grazing intensity exceeds a certain threshold, the interspecific relationships become weak. Therefore, moderate grazing would facilitate interspecific competition and species succession, whereas excessive grazing would disrupt natural competition causing desertification ultimately.

Responses of calcareous grassland plant communities to changed seasonal grazing management: Results of a 31 year study

Calcareous grasslands are of high conservation importance and have been maintained by livestock grazing over many centuries. Following the reduction in traditional livestock grazing (cattle and sheep) of semi-natural grassland during the twentieth century, conservation-based grazing management was introduced in order to conserve remaining grasslands. In UK semi-natural grasslands, grazing pressure has fluctuated over time due to changes in conservation funding and stock availability, whilst the time of year at which stock graze has also shifted. There is little quantitative data available to demonstrate the details of changed grazing patterns, or their long-term effects on the vegetation, thus the full impacts of these changes are not well understood. This study examines the response of a diverse calcareous grassland community to changes in grazing management between 1979 and 2010 at Martin Down National Nature Reserve, southern England, using historical vegetation surveys and grazing records collected and recorded by reserve staff. Historical data showed a shift in grazing regime, whereby grazing occurred across all seasons in the early period, but switched to predominately the autumn and winter in the present century. Despite this significant shift in management over time, the vegetation community did not change dramatically over this period, although small increases in species richness and diversity were detected. The richness of calcareous grassland indicator species remained largely consistent, suggesting the conservation value of the grassland persisted, and the community types also stayed fairly constant over the 31 years. Furthermore, weak evidence was found for impacts of grazing in particular seasons on vegetation community measures; species richness, species diversity, indicator richness, indicator abundance, grass abundance and forb abundance. This study suggests that these vegetation communities are robust to changes in grazing seasonality providing that sufficient grazing pressure is provided within the year. The compartmentalised grazing employed at Martin Down may be a useful method for ensuring this outcome. However more research is required, preferably using controlled field experiments before more reliable recommendations can be prescribed.

Forage Characteristics and Grazing Preference of Cover Crops in Equine Pasture Systems

Cover crops are commonly used to provide environmental benefits and can extend the grazing season, but have not been explored in horse pastures. The objectives of this research were to evaluate forage mass, forage nutrient composition, and preference of annual ryegrass, winter rye, berseem clover, purple top turnip, and daikon radish under horse grazing. Cover crops were seeded in monoculture and mixtures in August 2018 and 2019 as a randomized complete block with four replicates and grazed by four adult horses. Prior to grazing, forages were sampled to determine herbage and root mass and nutrient composition. After grazing, forages were visually assessed for the percentage of removal on a scale of 0 to 100% to estimate preference. Data was analyzed using an analysis of variance and linear regression; significance was set at P ≤ .05. Berseem clover was the lowest producing forage (590 to 1,869 kg ha−1 dry matter; P ≤.001), while minimal differences in herbage mass were observed among the other cover crops. All forages met digestible energy (>2.17 Mcal kg−1) and crude protein (>19%) requirements for idle, adult horses. Berseem clover was most preferred (>73% removal) while turnip and radish were the least preferred (<19% removal; P ≤.001). Winter rye and annual ryegrass in monoculture and when seeded with berseem clover were moderately preferred (20%–68% removal). Placing a priority on preference, berseem clover, annual ryegrass, and winter rye appear to be suitable cover crops to extend the grazing season in horse pastures.

Multipurpose simulation model for pasture-based mobile Automated Milking and Marketing System, Part-I: Pasture, milk yield, and milk marketing characteristics

It is essential to promote sustainable dairy farming which could lead to improved animal welfare, economic benefits, biodiversity and environmental benefits, milk quality, and customer satisfaction. In this regard, a mobile automated milking system (AMS) could contribute a lot. However, mobile AMS is a new innovative system which is not investigated well. Therefore, a simplified and integrated management approach should be introduced. The main objective of this study was to develop a multipurpose simulation model (DigiMilk model) specific to pasture-based mobile AMS. The model comprises five major subsystems: Pasture yield as dry matter (DM) and grazing characteristics; AMS Milking and milk yield characteristics; Milk handling and marketing; Resource consumption; and Economic assessment. This paper (Part-I) focuses on the first three components while the remaining two subsystems would be addressed in Part-II of this paper. DigiMilk model was built in MATLAB-Simulink environment. It was tested and evaluated using mainly secondary data and limited primary information acquired from a dairy farm in central Sweden. In this initial analysis, a continuous stocking system on pasture was assumed to be implemented from May 15 till September 15. Multiple sensitivity analyses were successfully conducted to get more insights. The results indicated that, considering maximum pasture growth rate of 77 kgDM day−1ha−1, the accumulated average pasture yield, over the grazing season, was estimated to be 6928 kgDM ha−1. For cows with average grazing rate of 16–18 kgDM day−1cow−1, the stocking rate of 3 cow ha−1 could lead to good performance of grazing management. When stocking rate and grazing rate of 3 cow ha−1 and 16 kgDM day−1cow−1 were considered respectively, the cumulative milk yield values (excluding amount consumed by calves) over the grazing season were estimated to be 2101 L cow−1 and 6303 L ha−1. Out of this 6303 L ha−1, 2952 L ha−1was estimated to be sold on-site, using milk vending machine (MVM), while 3351 L ha−1 was to be delivered to super market. The accuracy of results from the the simulation model could be improved with future work with more real data from actual demonstration of mobile AMS over the entire grazing season. In addition to its capacity to serve as an integrated decision making tool, DigiMilk model enables to have organized digital data that could be useful for future researches to evaluate the environmental and/or economic performances of pasture-based dairy systems with mobile AMS.

Incorporating Alfalfa into Warm-season Grass Systems in the Southeast

Abstract Bermudagrass is the primary warm season perennial forage crop grown in the Southeast (~20 million acres) for livestock and forage operations. While prominent in the region, bermudagrass requires large amounts of fertility and forage quality is moderate relative to other options. There has been great success and a growing interest in interseeding alfalfa into existing bermudagrass stands in the region. This combination eliminates the need for nitrogen fertilization, increases relative forage quality (RFQ) better meeting the nutritional needs of livestock, and decreases the need for supplemental feed. In recent years, research evaluations have been conducted across the Southeast to evaluate the use of alfalfa when incorporated into warm-season grass forage systems under various management strategies. Three projects conducted from 2016–2020 at the University of Georgia Tifton campus evaluated ‘Bulldog 805’ alfalfa interseeded into Tifton-85 bermudagrass (1) when harvested as baleage, (2) under grazing management and(3) in a clipping study to better define defoliation management recommendations. Overall findings from this work observed that alfalfa-bermudagrass mixtures provide greater seasonal herbage accumulation, extend the growing season by three to four months annually, and increase forage DM digestibility and CP compared to bermudagrass alone. Steers on ABG managed under rotational stocking had greater total gain/ha (~%33 increase) due to a higher stocking density throughout the growing season than a bermudagrass monoculture. Results indicate that interseeding alfalfa into bermudagrass is a viable option for southeastern forage systems and can be an effective way to improve forage quality, extend the grazing season, and reduce the need for additional supplementation when fed to livestock.

BioWorma as an Aid for Controlling Ruminant Nematode Parasites

Abstract Nematode-trapping fungi are biological control agents used against the larval stages of gastrointestinal nematodes in livestock feces. These fungi are normal soil inhabitants where they feed on a variety of non-parasitic soil nematodes. Of the various fungi tested, Duddingtonia flagrans spores (BioWorma, International Animal Health Products, Australia) have been shown to survive passage through the gastrointestinal tract of ruminants. After defecation, the spores germinate and grow in the feces to form sticky, sophisticated traps/loops which are able to trap the developing larval stages in the fecal environment. This form of control has been successfully applied under field conditions and is an environmentally safe biological approach for forage-based feeding systems. BioWorma has recently been approved for use in the United States. The primary delivery system is mixing BioWorma into supplement feedstuffs daily where each animal has the opportunity to consume an adequate amount of the mixture. To achieve optimum control of larvae during the transmission season (May–October), BioWorma needs to be fed for a period of no shorter than 60 days, starting at the beginning of the grazing season (especially young after weaning). Feeding BioWorma to dams during late pregnancy and lactation will also help to reduce pasture contamination, especially for growing young that will graze the same pasture. Another delivery system is mixing BioWorma into loose mineral supplement where animals will consume it free choice. The mineral needs to be kept covered and dry. The spores cannot be incorporated into pellets as the heat of the pelleting process will kill the spores. One drawback in using BioWorma is the relatively high cost. Research is being conducted to evaluate other delivery schemes that could be more cost effective. This product is the only control method that targets nematodes on pasture, where a majority of the total population reside.

Profitability of Supplementing Dried Distillers’ Grains Cubes to Improve Animal Performance and Replace N Fertilizer for Steers Grazing Introduced Pastures

Abstract During the summer grazing season, steers grazing introduced forages are oftentimes provided supplemental protein and energy to improve animal performance. However, it is important to determine if the additional supplementation is economically beneficial. Therefore, the objective was to evaluate the profitability of supplementing dried distillers’ grains cubes (DDGS) to improve animal performance or replace the use of N fertilizer (112 kg N/ha from urea) for steers (n = 149; BW = 238 ± 13.8 kg) grazing mixed tall fescue (Festuca arundinacea)/bermudagrass (Cynodon dactylon) pastures (n = 9 pastures, 7.2 ± 2.90 ha) from April 14 to September 17 (n = 155 d) using an enterprise budget analysis. Main plot supplemental treatments (n = 3 pastures/treatment) included 1) Fertilized Control (FC), no supplementation on fertilized pastures; 2) Fertilized Supplement (FS), 2.9 kg/steer DDGS supplemented 3-d/wk on fertilized pastures; and 3) Supplement (S), supplemental DDGS at 0.75% BW/d prorated for 5-d/wk feeding on unfertilized pastures. The assumptions used in this analysis were based on actual costs of inputs for pasture management and the DDGS offered, as well as the 5-year average Oklahoma auction market prices for 227 kg steers in April and 386 kg steers in October. Total cost per hectare was greater for S (P &amp;lt; 0.01), was least (P &amp;lt; 0.01) for FC, and FS was intermediate (P &amp;lt; 0.01). Cost per kg gain for FS and S was greater (P &amp;lt; 0.01) than for FC. Gross return per hectare tended to be greatest for S (P = 0.06), but net return per hectare was less for FS and S (P &amp;lt; 0.01) than FC. Although FS and S allowed for improvement of animal performance, our results imply that FC was the most profitable due to the cost of supplementation and low supplemental efficiency of S and FS.

Consumers’ and Farmers’ Perceptions in Europe Regarding the Use of Composted Bedding Material from Cattle

By-products like sawdust and straw are applied in compost bedded-pack barns (CBP) for cattle. These materials, which are gradually mixed with excreta and undergo a composting process, serve as a lying bed for the cattle. This study aims to assess the perception of consumers and farmers regarding the use of CBP during the grazing season of cattle for raising other animals or for growing food crops. This was examined by combining surveys with consumers from eight European countries and cattle farmers, focus groups with consumers, and in-depth interviews with individual farmers who implemented alternative uses of compost. The results showed that farmers preferred the compost bedded-pack system to the cubicle system in terms of sustainability and market aspects, although the cost of the bedding material required for CBP was seen as a significant negative aspect. Around half of all consumers indicated that the compost can be used for non-edible products and 26% indicated the compost can be used for raising other animals. Furthermore, 5% of consumers felt that compost should not be used for any other purpose. There were statistically significant differences between countries; therefore, regional specificities should be taken into account when marketing products from compost in CBP barns.