Evaluation of a ruminally dosed tall fescue seed extract as a model for fescue toxicosis in steers1

2012 ◽  
Vol 90 (3) ◽  
pp. 914-921 ◽  
Author(s):  
A. F. Koontz ◽  
L. P. Bush ◽  
J. L. Klotz ◽  
K. R. McLeod ◽  
F. N. Schrick ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Seed Extract ◽  
Fescue Toxicosis

Ruminal tryptophan-utilizing bacteria degrade ergovaline from tall fescue seed extract

2017 ◽  
Vol 95 (2) ◽  
pp. 980 ◽  
Author(s):  
B. E. Harlow ◽  
J. P. Goodman ◽  
B. C. Lynn ◽  
M. D. Flythe ◽  
H. Ji ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Seed Extract

scholarly journals Development of a genetic evaluation for hair shedding in American Angus cattle to improve thermotolerance

2020 ◽  
Vol 52 (1) ◽  
Author(s):  
Harly J. Durbin ◽  
Duc Lu ◽  
Helen Yampara-Iquise ◽  
Stephen P. Miller ◽  
Jared E. Decker
Keyword(s):  
Heat Stress ◽  
Beef Cattle ◽  
Tall Fescue ◽  
The United States ◽  
Genetic Evaluation ◽  
Functional Enrichment ◽  
Fescue Toxicosis ◽  
Weaning Weight ◽  
Angus Cattle ◽  
Genetic Evaluations

Abstract Background Heat stress and fescue toxicosis caused by ingesting tall fescue infected with the endophytic fungus Epichloë coenophiala represent two of the most prevalent stressors to beef cattle in the United States and cost the beef industry millions of dollars each year. The rate at which a beef cow sheds her winter coat early in the summer is an indicator of adaptation to heat and an economically relevant trait in temperate or subtropical parts of the world. Furthermore, research suggests that early-summer hair shedding may reflect tolerance to fescue toxicosis, since vasoconstriction induced by fescue toxicosis limits the ability of an animal to shed its winter coat. Both heat stress and fescue toxicosis reduce profitability partly via indirect maternal effects on calf weaning weight. Here, we developed parameters for routine genetic evaluation of hair shedding score in American Angus cattle, and identified genomic loci associated with variation in hair shedding score via genome-wide association analysis (GWAA). Results Hair shedding score was moderately heritable (h2 = 0.34 to 0.40), with different repeatability estimates between cattle grazing versus not grazing endophyte-infected tall fescue. Our results suggest modestly negative genetic and phenotypic correlations between a dam’s hair shedding score (lower score is earlier shedding) and the weaning weight of her calf, which is one metric of performance. Together, these results indicate that economic gains can be made by using hair shedding score breeding values to select for heat-tolerant cattle. GWAA identified 176 variants significant at FDR < 0.05. Functional enrichment analyses using genes that were located within 50 kb of these variants identified pathways involved in keratin formation, prolactin signalling, host-virus interaction, and other biological processes. Conclusions This work contributes to a continuing trend in the development of genetic evaluations for environmental adaptation. Our results will aid beef cattle producers in selecting more sustainable and climate-adapted cattle, as well as enable the development of similar routine genetic evaluations in other breeds.

scholarly journals Effects of endophyte-infected tall fescue seed and protein supplementation on stocker steers: I. Growth performance and hemodynamic responses

2019 ◽  
Vol 97 (9) ◽  
pp. 3776-3785 ◽  
Author(s):  
Rebecca K Poole ◽  
Carrisa M Womble ◽  
Matthew H Poore ◽  
Daniel H Poole ◽  
Carrie L Pickworth
Keyword(s):  
Body Temperature ◽  
Growth Performance ◽  
Treatment Period ◽  
Tall Fescue ◽  
Repeated Measures ◽  
Negative Impact ◽  
Protein Supplementation ◽  
Fescue Toxicosis ◽  
Hemodynamic Responses ◽  
Minimal Impact

Abstract Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue and is detrimental to growth and performance. Recent research has shown that supplementing protein has the potential to enhance growth performance in weaned steers. Therefore, the objective of this study was to evaluate the effect of supplemental CP on physiological parameters in stocker steers experiencing fescue toxicosis. Thirty-six weaned Angus steers (6 mo of age) stratified by weight (196.1 ± 3.6 kg) were assigned to a 2 × 2 factorial arrangement for 56 d: endophyte-free (EF) seed and 14% CP (EF-14; n = 9), EF seed and 18% CP (EF-18; n = 9), endophyte-infected (EI) seed and 14% CP (EI-14; n = 9), and EI seed and 18% CP (EI-18; n = 9). Steer growth and hemodynamic responses were collected weekly during ergot alkaloid exposure. On day 14 of the trial, iButton temperature data loggers were subcutaneously inserted in the lateral neck region to record hourly body temperature for 42 d. Data were analyzed using PROC MIXED of SAS with repeated measures. No differences were observed in DMI, BW, ADG, F:G, or BCS during the treatment period (P > 0.05). Hair shedding scores, rectal temperatures, surface temperatures, and respiration rates were greater in EI steers compared to EF steers regardless of supplemental CP (P < 0.05). However, subcutaneous body temperature was greater in EI-14 steers (37.94 °C) compared to other steer groups (37.60, 37.68, 37.72 ± 0.04 °C for EF-14, EF-18, and EI-18, respectively; P < 0.05). Prolactin concentrations tended to be greater in EF steers when compared to EI steers (P = 0.07). Heart rate and hematocrit were reduced for EI-18 steers compared to other steer groups (P < 0.05). Caudal artery diameter was reduced in EI-18 steers compared to EI-14 steers (2.60 vs. 2.75 ± 0.05 mm, respectively; P < 0.05) and caudal vein diameter was reduced in EI-18 steers (3.20 mm) compared to all other steer groups (3.36, 3.39, 3.50 mm for EF-14, EF-18, and EI-14, respectively; P < 0.05). However, there was no difference observed in systolic or diastolic blood pressure during the treatment period (P > 0.05). Based on the data, exposure to low to moderate levels of ergot alkaloids during the stocker phase had a negative impact on hemodynamic responses and supplemental CP had minimal impact to alleviate symptoms. Therefore, feeding additional protein above established requirements is not expected to help alleviate fescue toxicosis.

scholarly journals Ruminal motility, reticuloruminal fill, and eating patterns in steers exposed to ergovaline

2019 ◽  
Vol 98 (1) ◽  
Author(s):  
Gyuchul Ahn ◽  
Kara Ricconi ◽  
Suelen Avila ◽  
James L Klotz ◽  
David L Harmon
Keyword(s):  
Tall Fescue ◽  
Rumen Content ◽  
Serum Prolactin ◽  
Fescue Toxicosis ◽  
Eating Patterns ◽  
Complete Understanding ◽  
Wireless System ◽  
Eating Pattern ◽  
Underlying Mechanisms ◽  
Pressure Changes

Abstract Fescue toxicosis is problematic for growing steers, causing lower DMI and productivity when fed endophyte-infected (E+) tall fescue. A complete understanding of underlying mechanisms of how fescue toxicosis affects growing steers is lacking. Therefore, the overall objective of this multiexperiment study was to determine whether ruminally dosed ergovaline (ERV) affects rumen motility, rumen contents, and eating patterns. In Exp. 1, an 8-h period to assess ruminal motility began 4 h after feeding by monitoring pressure changes using a wireless system for 21 d. Eight ruminally cannulated steers (283 kg BW) were pair fed with alfalfa cubes (1.5 × NEm) and assigned to endophyte free (E−; 0 μg ERV/kg BW/d) or E+ treatment (20 μg ERV/kg BW/d). Overall, E+ steers had more frequent rumen contractions (Seed P = 0.05 and day of feeding P = 0.02). On days 7 to 9, both treatments showed lower frequencies and E− steers had greater amplitude of contractions (P &lt; 0.001) that corresponded with decreased DMI. In Exp. 2, steers remained in pairs assigned in Exp. 1 (322 kg BW), but reversed seed treatments while increasing ERV levels (titrated 0, 5, 10, 15, and 20 μg ERV/kg BW/d over 57 d). There were no differences between E− and E+ for frequency (P = 0.137) or amplitude of contractions (P = 0.951), but increasing ERV dosage, decreased frequency (P = 0.018) and amplitude (P = 0.005), coinciding with lower DMI. In Exp. 3, 8 steers (589 kg) were pair fed and ruminally dosed 15 μg ERV/kg BW/d, and rumen motility data were collected for 21 d. E− steers showed higher amplitude and lower frequency of contractions than E+ steers with seed (P &lt; 0.001), day (P &lt; 0.001), and seed × day (P &lt; 0.04) effects, but rumen fill was not different between E− and E+ (P &gt; 0.29). Serum prolactin concentrations were lower in E+ steers in Exp. 1 to 3. Eating patterns of pair-fed E− and E+ steers were relatively slower in E+ than E− (Exp. 4) by measuring every 2 h across 24 h. Number of meals were higher in E+ than E− steers, but meal duration and meal size were not different between treatments. Rumen content (DM%) tended to be higher in E+ than in E− when steers were fed once a day (P = 0.07), but there was no difference for rumen content (DM%) when E− and E+ steers were fed 12 times a day (P = 0.13). These results suggest the changes in rumen fill associated with fescue toxicosis may be driven more by changes in feeding behavior and eating pattern rather than by changes in motility.

scholarly journals Tall Fescue Toxicosis Mitigation Strategies: Comparisons of Cow-Calf Returns in Spring- and Fall-Calving Herds

2012 ◽  
Vol 44 (4) ◽  
pp. 577-592 ◽  
Author(s):  
Stephen A. Smith ◽  
James D. Caldwell ◽  
Michael P. Popp ◽  
Kenneth P. Coffey ◽  
John A. Jennings ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Mitigation Strategies ◽  
Fescue Toxicosis ◽  
South Central ◽  
Central United States ◽  
Calving Rate ◽  
Cow Calf ◽  
Calving Season ◽  
Fall Calving ◽  
Tall Fescue Toxicosis

Tall fescue toxicosis adversely affects calving rate and weight gains reducing returns to cow-calf producers in the south–central United States. This grazing study estimated animal and economic performance implications of endophyte-infected fescue and calving season. Establishing novel endophyte-infected tall fescue on 25% of pasture acres resulted in improved calving rates (87% vs. 70%), weaning weights (532 lbs vs. 513 lbs), and partial returns per acre ($257 vs. $217). Additionally, fall-calving cows had higher calving rates (91% vs. 67%), weaning weights (550 lbs vs. 496 lbs), and partial returns per acre ($269 vs. $199) than spring calving cows.

Constriction of bovine vasculature caused by endophyte-infected tall fescue seed extract is similar to pure ergovaline1,2

2012 ◽  
Vol 90 (5) ◽  
pp. 1603-1609 ◽  
Author(s):  
A. P. Foote ◽  
D. L. Harmon ◽  
K. R. Brown ◽  
J. R. Strickland ◽  
K. R. McLeod ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Seed Extract

scholarly journals 141 The Alliance for Grassland Renewal presents workshops to enhance the understanding and adoption of Novel Endophyte Tall Fescue

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 8-9
Author(s):  
Matthew H Poore ◽  
Tony Stratton ◽  
Craig A Roberts ◽  
S Ray Smith ◽  
John G Andrae ◽  
...  
Keyword(s):  
Tall Fescue ◽  
New Technologies ◽  
Cost Benefit ◽  
Fescue Toxicosis ◽  
First Year ◽  
Academic Institutions ◽  
Governmental Agencies ◽  
The Past ◽  
Stocker Cattle ◽  
Second Year

Abstract The Alliance for Grassland Renewal (the Alliance) is a collaborative multi-state effort to enhance the understanding of fescue toxicosis and the adoption of Novel Endophyte Tall Fescue (NETF). The Alliance includes academic institutions, companies marketing NETF, allied companies, governmental agencies, and non-profits. The Alliance initially focused on the state of Missouri. After 2014, it expanded efforts with one-day workshops in MO, KY, OK, KS and UKY joined the board in 2017. In 2018, Clemson and NCSU joined the board, and workshops were expanded to the east coast, with five workshops in MO, KY, SC, NC and VA. In 2019, workshops will repeated in those states in addition GA. Key presentations included managing fescue toxicosis, establishment and first year management, second year management, and economics of conversion. Additionally the agenda included microscope viewing of the endophyte, quality control and endophyte testing, industry update, drill calibration, producer panel, and a tour of NETF plots. There were 214 paid attendees in 2018 (locations ranged 26 to 59; 75% farmers), and 146 evaluations were submitted. Attendees owned 9592 beef or dairy cows, 1997 stocker cattle, 121 horses, 545 sheep and goats, and 151 alpacas. Thirty percent of the audience had planted NETF in the past, while 55% intended to plant NETF in the future. Reasons given for not planting included: unclear cost/benefit (9%), limited financial resources (4%), lack of knowledge (5%), rented or unsuitable land (15%) and forage reserves lacking (5%). Registration fee was $60, and 45% of the audience said they would have paid $95, suggesting the registration fee was appropriate. The Alliance is a growing and successful partnership between academic institutions and industry. This approach is a model that could be applied to adoption of other new technologies.

Changes in Cytochrome P450 in Katahdin Ewes Fed Endophyte-infected Tall Fescue Seed Diets in Spring and Fall

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 40-41
Author(s):  
Mohan Acharya ◽  
Joan M Burke ◽  
Erin Wood ◽  
Yan Huang ◽  
Palika Dias Morse ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Serum Concentration ◽  
Rectal Temperature ◽  
Tall Fescue ◽  
Repeated Measures ◽  
Ergot Alkaloids ◽  
Serum Prolactin ◽  
Fescue Toxicosis ◽  
Pregnancy Status ◽  
Soy Hulls

Abstract Objective was to examine the activity of cytochrome P450 (CYP), a liver enzyme that metabolizes ergot alkaloids which is hindered by this fescue toxin, as an indicator of fescue toxicosis in sheep. In spring and fall, ewes were blocked by age and BW, and randomly assigned to 1 kg/ewe/d of endophyte-infected (E+; 61% of diet in fall, 13% of diet in spring; 0.8 µg/g of ergovaline; and soy hulls, alfalfa pellets, cottonseed hulls, molasses) or non-infected (E-; same proportion of E+/season and same feeds) tall fescue seed supplement (n = 10/diet in each season) for 28 d, plus hay, mineral and water. Ewes were exposed to teaser, d -21 to 0, and intact rams, d 0 (first day of diet) to 30. Rectal temperature (RT), serum concentration of prolactin (using RIA), and CYP were determined every 7–14 d between d 0–28, and pregnancy status on d 56. PromegaTM P450-Glo assay was used to determine CYP from serum. Data were analyzed by using PROC MIXED with repeated measures (SAS). Rectal temperature of E+ compared with E- ewes was elevated on at least one day in fall and spring (diet × season × d, P &lt; 0.001). Serum prolactin was lower in E+ compared with E- ewes (diet × d, P &lt; 0.001) and lower in fall (P &lt; 0.001). CYP was higher in E- ewes on d 28 in fall (diet × season × d, P = 0.008), but otherwise similar between diets, and higher in fall than spring (P &lt; 0.001). There was an unexpected negative correlation between CYP and prolactin (R = -0.24; P &lt; 0.009), but there appears to be a subpopulation of ewes with low prolactin and lower CYP. CYP activity in sera may not be a marker for fescue toxicosis in ewes.

scholarly journals Loline Alkaloids in Tall Fescue Hay and Seed and Their Relationship to Summer Fescue Toxicosis in Cattle

1984 ◽  
Vol 67 (1) ◽  
pp. 104-109 ◽  
Author(s):  
James A. Jackson ◽  
R.W. Hemken ◽  
J.A. Boling ◽  
R.J. Harmon ◽  
R.C. Buckner ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Fescue Toxicosis ◽  
Loline Alkaloids
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