Environmental characteristics within a region often form site‐specific agro‐ecological responses to management. Using 92 fall‐stockpiled tall fescue Schedonorus arundinaceus (Schreb.) Dumort. field ...trials in North Carolina and surrounding states, our objective was to test the influence of two management factors (forage utilization and pasture age) and two environmental factors (elevation and soil textural gradients) on soil properties at 0‐to‐10‐cm depth, surface residue carbon (C) and nitrogen (N) contents, and absolute forage mass and nutritive values and their responses to N fertilization. Soil organic C and N fractions (i.e., total, particulate, and mineralizable) were greater (a) with improved (rotational stocking) than conventional (haying and/or continuous grazing) forage utilization, (b) in older pastures, (c) at higher elevation, and (d) with finer texture. Soil chemical properties were variably affected by these factors, and soil‐test P was not affected. Surface residue N tended to be greater with improved than conventional forage utilization, but surface residue C was not affected by any of the factors. Crude protein was greater and dry matter yield response to N fertilizer was lower with improved than with conventional forage utilization. Forage mass was lower and nutritive values were greater at higher elevation. Soil organic C and total soil N sequestration rates during a 25‐yr period were 0.75 Mg C ha−1 yr−1 and 75 kg N ha−1 yr−1, respectively. Elevation and soil texture imparted strong environmental controls on a diversity of soil properties, but management factors mostly affected surface‐soil organic C and N fractions, which helped sustain forage productivity and nutritive value with lower N fertilizer input.
Abstract
Fescue toxicosis is a syndrome that impairs growth and reproduction in cattle grazing endophyte-infected tall fescue Lolium arundinaceum (Schreb..) Darbysh) in the United States, resulting ...in approximately $1 billion in annual economic loss in species that utilize this forage resource. Approximately 90% of tall fescue contains an endophytic fungus (Epichloë coenophiala) that produces ergot alkaloids. Ergot alkaloids cause vasoconstriction and reduced blood flow to the extremities; however, it remains unknown how blood flow to the reproductive organs is affected in cattle. Therefore, the objective of this study was to determine if ergot alkaloids from endophyte-infected tall fescue reduce blood flow to the reproductive organs, thus hindering reproductive function. Angus heifers (n = 36) naïve to ergot alkaloids were placed in Calan gates and randomly assigned to receive either endophyte-infected fescue seed (E+) or noninfected fescue seed (E−; control) in a total mixed ration for 63 d. Weekly measurements were taken to monitor heifer growth and response to ergot alkaloid exposure. Reproductive measurements, including ovarian structures, uterine and ovarian vessel diameter, and hormone concentrations were determined after heifers were synchronized using the standard CO-Synch + 7 d CIDR protocol to ensure all measurements were collected at the same stages of the estrous cycle (0, 4, 10, and 17 d). Data were analyzed using repeated measures in PROC MIXED of SAS. Average daily gain was decreased for the E+ group (0.8 kg/d) compared to control heifers (1.0 kg/d). Body condition scores tended to be greater in control heifers compared to the E+ group (P = 0.053). Additionally, hair coat and hair shedding scores were greater in E+ heifers compared to controls (P < 0.05). Heart rate, rectal temperature, respiration rate, and blood pressure did not differ between treatments (P > 0.05). Vasoconstriction was observed in the caudal artery, but not the caudal vein, in heifers consuming the E+ fescue seed (P < 0.05). No differences were observed in antral follicle counts, corpus luteum area or circulating progesterone concentrations in E+ heifers compared to controls (P > 0.05). There was a significant decrease in the diameter of arteries and veins servicing the ovary and uterus on day 10 and 17 of the estrous cycle. Reduction in blood flow to the reproductive organs during critical times in the estrous cycle may contribute to the reduced ovarian function and pregnancy rates associated with fescue toxicosis.
Abstract
Fescue toxicosis is a syndrome that results when cattle consume toxic endophyte-infected tall fescue. The objective of this study was to compare the response in physiological variables, ...sweat gland function, hair follicle cycling, and gene expression to feeding a total mixed ration that included tall fescue haylage and tall fescue seed containing a toxic endophyte (EI) or tall fescue haylage containing a nontoxic novel endophyte (EN) in beef heifers (Angus × Senepol heifers, n = 31) with 2 different hair genotypes. Numbers in each subgroup were as follows: novel endophyte, heterozygous slick (EN-S; n = 8), novel endophyte, homozygous hairy (wild type, EN-W; n = 7), endophyte-infected, heterozygous slick (EI-S; n = 10), and endophyte-infected, homozygous hairy (wild type, EI-W; n = 6). Physiological measurements were taken weekly for 7 wk. Data were analyzed using the MIXED procedure of SAS including dietary fescue treatment (EN vs. EI) and hair genotype (S vs. W) as main effects, day as a repeated measure, and temperature–humidity index (THI) as a covariate. Skin biopsies were taken before treatment initiation and on day 37 of treatment. Average surface temperature (ST) increased as the THI increased (P < 0.0001). Average ST was greater (P < 0.01) for animals fed EI than for animals fed the EN fescue diet, and greater (P < 0.01) for animals with the W genotype compared with animals with the S genotype. The difference between heifers with the S and W genotype was greater at greater THI (genotype × day interaction, P < 0.01). Transepidermal water loss (TEWL) was greater (P < 0.05) for animals with the S genotype compared with the W genotype and greater (P < 0.05) for heifers with the S genotype than for heifers with the W genotype when fed EI (36.7, 38.5, 30.0, and 38.7 g/m2 per hour for EN-W, EN-S, EI-W, and EI-S, respectively). The fraction of follicles in telogen in plucked hair samples for heifers fed EI was greater for animals with the S genotype than the W genotype (fraction in telogen: 0.456, 0.565, 0.297, 0.702 for EN-W, EN-S, EI-W, and EI-S, respectively; diet × genotype interaction, P < 0.05). Fraction of follicles in anagen was the opposite. EI fescue resulted in increased ST, changes in hair follicle cycling that support greater hair growth, and decreased TEWL for heifers with the W genotype compared with S genotype, suggesting greater heat stress in response to EI.
This study evaluated the effects of gradual reduction in frequency of energy supplementation following vaccination on growth and measurements of innate and humoral immunity of beef steers. At 14-d ...postweaning (d 0), Angus steers (n = 42; 200 ± 5 kg of BW; 175 ± 4 d of age) were stratified by BW and age, and randomly assigned into 1 of 14 drylot pens (three steers/pen). From d 0 to 42, steers were provided ad libitum ground tall fescue hay (57% TDN, 13% CP of DM basis) and supplemented with concentrate at 1% of BW (50:50 soybean hulls and corn gluten feed; 71% TDN, 15% CP of DM basis). Treatments were randomly assigned to pens, and consisted of similar weekly concentrate DM supplementation (1% of BW multiplied by 7 d) that was divided and offered daily from d 0 to 42 (7X; 4 pens), 3 times weekly from d 0 to 42 (3X; Monday, Wednesday, and Friday; 5 pens), or daily from d 0 to 15 and then 3 times weekly from d 16 to 42 (7-3X; 5 pens). Steers were vaccinated against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3), Mannheimia haemolytica, and Clostridium on d 0 and 15. Individual shrunk BW was collected on d 0 and 42, following 12 h of feed and water withdrawal. Blood samples were collected via jugular venipuncture 4 h after concentrate supplementation on d 0, 1, 2, 3, 7, 15, 16, 17, 18, 22, and 42. Mean BW, ADG, G:F, hay DMI, and total DMI over the 42-d period did not differ among treatments (P ≥ 0.26). Plasma concentrations of cortisol and mean serum BVDV-1a titers also did not differ among treatments (P ≥ 0.35), but overall plasma haptoglobin concentrations were greater for 3X vs. 7-3X and 7X steers (P ≤ 0.05; 0.44, 0.37, and 0.33 ± 0.026 mg/mL, respectively). Also, 3X steers had less mean serum IBR titers (P ≤ 0.05; 0.29 vs. 0.88 and 0.79 ± 0.179 log2, respectively) and less seroconversion to PI-3 virus on d 15 than 7-3X and 7X steers (P ≤ 0.05; 36.0 vs. 76.6 and 57.8 ± 8.24%, respectively). In summary, a gradual reduction in frequency of energy supplementation during a 42-d preconditioning period did not negatively impact growth, but alleviated indices of inflammation and prevented reductions in vaccine response against BVDV-1a and PI-3 viruses compared to steers offered concentrate 3 times weekly during the entire study.
Agriculture faces a dilemma with nitrogen (N)—it is often the most necessary external input to optimize production, several generations of farmers became accustomed to its relatively inexpensive ...cost, and it contributes to widespread pollution due to numerous loss pathways to the environment. However, standard N fertilizer recommendations have not accounted well enough for a key source via mineralizable soil N. Soil‐test biological activity (STBA) is strongly associated with mineralizable soil N, both of which become surface‐enriched with conservation agricultural management using soil health principles. A series of field experiments assessed the contribution of mineralizable soil N to the N supply needed to optimize corn (Zea mays L.) grain and fall‐stockpiled tall fescue Schedonorus arundinaceus (Schreb.) Dumort. production. This essay synthesizes how STBA along with cost‐to‐value threshold can be used to modify the N fertilizer factor to optimize economic return and avoid environmental degradation.
Core Ideas
Standard N fertilizer recommendations do not account for management‐induced variation in mineralizable soil N.
Soil‐test biological activity is strongly associated with mineralizable soil.
Nitrogen fertilizer recommendations can be adjusted for field‐specific level of soil‐test biological activity.
Abstract
Three workshops were held to increase producer awareness of new production practices and opportunities for sheep production. These events were coordinated by Amazing Grazing with the ...assistance of county livestock agents. All workshops included classroom and breakout sessions featuring hands-on activities. In September 2016, the first sheep-focused workshop was held at the E. Carroll Joyner Beef Education Unit in Raleigh. Topics included opportunities for sheep production, ram selection, marketing, using temporary electric fence, grazing management to improve soil health, grazing sheep in solar farms and health management. The 2017 event was held in May at the Western NC Regional Livestock Center near Canton. Producers learned about opportunities for sheep production, improved grazing management, sheep marketing and fencing options. The Piedmont Research Station near Salisbury served as the location for the 2018 workshop. The agenda featured hoof health management and pre-breeding nutrition management, improving forage systems, breeding stock selection, pasture improvement cost-share programs and hoof trimming. Total registration was 132 with 83 evaluations completed. Participants were 60% male and 40% female with 57% being over age 50. Total pasture hectares grazed by participants was 886 with 97 ha as hay. Livestock inventories totaled 2,183 sheep, 733 goats, 720 beef cattle and 99 horses. A few participants had no livestock but were gathering information for future ventures. Post-workshop evaluation indicated 100% of attendees increased understanding of each major agenda topic. On a scale of 1 to 4 (1 = not satisfied to 4 = very satisfied), participants indicated they were very satisfied with the instructors’ knowledge (3.80±0.45), workshop environment/format (3.68±0.58), and overall quality (3.78±0.44). Ninety-seven percent of the attendees indicated that this workshop met their expectations, and one hundred percent would recommend it to others. Producer responses indicate a growing interest in sheep/goat production and a need for practical education programs.
Nitrogen fertilizer is an expensive input, and its necessity in grazed tall fescue (Schedonorus arundinaceus) pastures can be questioned when sufficient soil N mineralization occurs. A soil‐testing ...tool that could predict the need for N fertilizer inputs would be beneficial to producers to optimize profit and avoid environmental contamination. Thirty‐seven on‐farm trials were conducted in the Piedmont and Blue Ridge regions of Georgia, South Carolina, North Carolina, and Virginia in 2018 to evaluate fall‐stockpiled tall fescue yield response to N and P fertilizer inputs. Carbon and N characteristics of the soil surface (0‐ to 10‐cm depth) and surface residue varied among sites. Forage mass responses to P fertilizer input were below the economic threshold, regardless of Mehlich‐III extractable P. Forage mass responses to N fertilizer input did not exceed a low cost/value threshold of 5 kg forage kg−1 N in 24 of the trials. Economically optimum N rate was greatest when soil N mineralization and soil‐test biological activity (STBA) were at low levels. Results validated those of an earlier study on 55 fields, and taken together, suggest that N fertilizer for fall‐stockpiled tall fescue could be as high as 80 kg N ha−1 on fields with very low STBA (<100 mg CO2–C kg−1 soil 3 d−1) and declining to nil with medium STBA (>250 mg CO2–C kg−1 soil 3 d−1), depending on cost/value threshold. Healthy soils with high STBA can be managed effectively without N fertilizer inputs to recycle nutrients and promote more sustainable agricultural systems.
Spatial variation in soil properties is often considered significant across broad geographical regions due to soil formation factors. However, fine‐scale variations might also be significant. This ...study was conducted with the original intent of assessing how simple and complex mixtures of annual forages might be used to renovate perennial pastures. Private farmers in the Flatwoods, Piedmont, and Blue Ridge Major Land Resource Areas of North Carolina tested annual forages to renovate tall fescue pastures. Soil was sampled in multiple random locations in each field at depths of 0–6, 6–12, and 12–20 cm at the beginning and ending of a 3‐yr annual forage evaluation. Relative variation among five components (year of sampling n = 2, physiographic region n = 3, annual forage treatment n = 2, soil depth n = 3, and random variation from pseudoreplicates n = 3 in 2015 and n = 5 in 2018) was assessed for four soil physical, 10 soil biological, and 16 soil chemical properties. Soil chemical properties were mostly affected by physiographic region (47 ± 26% of total variation) and soil depth (33 ± 18%), soil biological properties were mostly affected by soil depth (63 ± 25%) and random pseudoreplication (14 ± 6%), and soil physical properties were equally affected by pseudoreplication (35 ± 21%), physiographic region (32 ± 18%), and soil depth (29 ± 22%). The type of annual forage had no discernible effect on soil properties, even the most biologically active. A diversity of spatial variations was important, suggesting that regional‐level ecological investigations require careful attention to an appropriate sampling design considering multiple factors.
Core Ideas
Soil properties were unaffected by annual forage species diversity during pasture renovation.
Chemical properties varied mostly due to physiographic region (separation of ∼300 km).
Biological properties varied mostly due to soil depth (separation of ∼10 cm).
Physical properties varied equally among region, pseudoreplication, and depth.
Net N mineralization was best predicted by a simple, rapid, and robust test of biological activity.
Most tall fescue
(Schreb.) Darbysh in the Southeastern United States contains an endophyte that causes fescue toxicosis (FT) in grazing animals, a serious disease that causes approximately $1 ...billion in economic losses to the animal industries in the United States. Recently, a genetic test called T-Snip (AgBotanica, LCC, Columbia, MO), was developed with the objective of identifying animals with genetic variation for FT tolerance. The aim of this study was to validate the use of this genetic test in mature, pregnant cows. Over 13 wk, weekly phenotypic data, including body weight, rectal temperatures, hair coat scores, hair shedding scores, and body condition scores, were collected on 148 pregnant purebred Angus cows at 2 locations in NC where infected fescue was the primary source of feed. Birth weights (cBW) and 205-d adjusted weaning weights (adjWW) from these cow's calves were recorded. All cows were genotyped for T-Snip. At the end of the trial, each phenotypic trait was calculated as the slope of the linear regression of performance on weeks. The effect of T-Snip rating genotypes (4 levels) on slope traits was tested using a linear model also including the fixed-effects of location, parity, and the initial measurement for each trait (covariate). For cBW and adjWW, the model also included the sex of the calf and the month of birth as categorical effects. Associations of T-Snip genotypes were observed for body weight gain (aBWd) of pregnant cows (
= 0.15; interaction with location), change in body condition score (aBCSd;
= 0.13), and adjWW (
= 0.06; interaction with location). For aBWd and adjWW, associations were found just within one location (
= 0.017 and 0.047, respectively), which was the location with higher endophyte infection rate. For all associations, the direction of the T-Snip genotypes was the same and as expected: the greater the genotype score, the better performance. No associations were found for the other traits (
> 0.10). These results indicate that the T-Snip test may be predictive of cow performance (aBWd, aBCSd, and adjWW) in an endophyte-infected tall fescue environment.
Abstract Pastureland Ecology 1 is a 2-wk continuing education course taught by cooperating faculty at NC State University for USDA-NRCS Staff. The course was founded in the early 1990s and has been ...taught 23 times to over 500 participants from all 50 states. Participants primarily include grazing specialists, soil conservationists, and district conservationists. Instruction is split between classroom lectures and hands-on experience with grazing management. Lecture topics include; introduction to pasture ecology, principles of plant growth, determining animal forage needs, pasture design, principles of soil health, principles of grazing management, and grazing management systems for small ruminants, horses and cattle. Small groups of students work with groups of goats, sheep, horses, and beef cattle throughout the course, learning concepts of forage allocation, temporary electric fence, and adaptive management. Popular demonstrations developed over the years include; the reel race, dung beetle buckets, burying underwear to demonstrate soil health, exploring root diversity, and troubleshooting electric fence. Farm tours are conducted to show how concepts being taught are applied on commercial farms. In 2023 there were 29 students from 13 states including VA (4), MD (4), PA (3), OK (4), MI (1), UT (2), TN (3), WV (1), MA (1), OH (1), NM (1), WA (3), and RI (1). Participants had 8.4 ± 1.39 (AVG ± SEM) years of experience with NRCS with a range of 1 to 27 yr. Students self-assessed their understanding of major concepts before and after the course. On a 1 to 5 scale students increased their understanding by an average of 1.05 ± 0.129, averaged over all topics. Topics more familiar to participants had less increase including; Soil Health (0.38), Pasture Condition Evaluation (0.51), and Grazing Management for Beef Cattle (0.79). Less familiar topics had greater increases including Grazing Management for Horses (1.27) and Small Ruminants (1.27), and Temporary Electric Fence (1.43). Pastureland Ecology 1 remains a critical part of the Amazing Grazing Program at NC State University, impacting pasture-based livestock producers across the country. This educational model has proven to be an effective way of teaching the principles of pastureland ecology.
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