scholarly journals 155 Evaluation of cytokine response as an indicator of genetic resistance to fescue toxicosis in purebred Angus cattle

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 45-46
Author(s):  
Kyle Mayberry ◽  
Rebecca K Poole ◽  
McKayla A Newsome ◽  
Piush Khanal ◽  
Matthew H Poore ◽  
...  
Keyword(s):  
G Protein ◽  
Tall Fescue ◽  
Repeated Measures ◽  
Genetic Resistance ◽  
Cytokine Response ◽  
Serum Prolactin ◽  
Fescue Toxicosis ◽  
Animal Performance ◽  
Negative Effects ◽  
G Protein Coupled

Abstract Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue. However, varying responses among cattle potentially implies genetic tolerance to the syndrome. Therefore, the objective was to evaluate the cytokine response of cows deemed either tolerant or susceptible to endophyte-infected fescue. Angus cows, 2–4 yrs old, grazed endophyte-infected tall fescue at two locations for 13 weeks starting mid-April 2016. A post-hoc analysis of animal performance was utilized to designate cattle into either tolerant (n = 20) or susceptible (n = 20) groups, based on physiological responses (changes in ADG) to chronic exposure to endophyte-infected fescue. Blood samples collected on weeks 1, 7, and 13 were used to evaluate serum prolactin (PRL) concentration. Cytokine concentrations were evaluated via Quantibody Bovine Cytokine Arrays. Data were analyzed using PROC MIXED of SAS with repeated measures. There were no differences by location or week. Tolerant cows tended to have decreased overall PRL concentrations compared to susceptible cows (98.3 and 138.4 ng/mL, respectively; P = 0.08). G protein-coupled receptor associated sorting protein (GASP)-1, a down-regulator of G protein-coupled receptors including D2-dopamine receptor a regulator of PRL secretion, was greater in tolerant cows when compared to susceptible cows (4.7 and 4.2 ng/mL; P = 0.03). Vascular endothelial growth factor (VEGF)-A was greater in tolerant cows when compared to susceptible cows (0.5 and 0.2 ng/mL; P = 0.02). Finally, interleukin (IL)-4, an anti-inflammatory cytokine, tended to be greater in tolerant cows when compared to susceptible cows (2.2 and 0.8 ng/mL, respectively; P = 0.07). Based on these data, greater concentrations of GASP-1, VEGF-A, and IL-4 in tolerant compared to susceptible cattle may mitigate the detrimental effects of fescue toxicosis, including suppressed PRL and vasoconstriction, leading to improved animal performance in a fescue environment. Additionally, these cytokines may serve as potential biomarkers for determining an animal’s tolerance or susceptibility to negative effects associated with endophyte-infected tall fescue

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 < 0.001). Serum prolactin was lower in E+ compared with E- ewes (diet × d, P < 0.001) and lower in fall (P < 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 < 0.001). There was an unexpected negative correlation between CYP and prolactin (R = -0.24; P < 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.

177 Ad Libitum Consumption of a 1:1 Blend of inorganic:organic Se by Steers Grazing Endophyte-infected Tall Fescue Increases Serum Prolactin and Alkaline Phosphatase Activity, but Not Average Daily Gain

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 94-95
Author(s):  
Kelsie Webb ◽  
Ronald J Trotta ◽  
Phillip Bridges ◽  
James Matthews
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Tall Fescue ◽  
Average Daily Gain ◽  
Serum Prolactin ◽  
Negative Effects ◽  
Ad Libitum ◽  
Ad Libitum Intake ◽  
Daily Gain

Abstract To test the hypothesis that average daily gain (ADG) and clinical parameters of steers grazing novel non-toxic (NTE) or toxic KY-31 (TE) endophyte-infected tall fescue would be improved by ad libitum intake of vitamin-mineral mixes (V-M) that contain 27 ppm Se as a 1:1 blend of SELPLEX:sodium selenite (MIX) vs sodium selenite (ISe), 32 TE-naïve beef steers depleted of Se were randomly assigned to ad libitum consumption ISe vs MIX for 35 d and fed enough of a NTE/alfalfa/grain diet to achieve 0.57 kg BW gain/d. Within Se-form treatments, 2 steers were randomly assigned to each of 4, 2-acre NTE (ISe = 316 ± 31 kg, MIX = 315 ± 22 kg) or TE (ISe = 316 ± 37 kg, MIX = 314 ± 39 kg) paddocks for 84 d and had ad libitum access to their respective V-M. The MIXED procedure of SAS was used to assess effects of day, Se-form (ISe, MIX) and endophyte (NTE, TE) treatments, and their interactions. Whole blood Se decreased (P < 0.01) 31% from d 0 to 84 and was 6.2% greater (P < 0.01) for MIX steers. Serum prolactin decreased (P < 0.01) 18% for NTE and 48% for TE steers from d 0 to 84 and was 17% greater (P = 0.01) for MIX vs. ISe TE steers. Alkaline phosphatase activity (AP) decreased (P < 0.02) 27% from d 0 to 84 and was 15% greater (P < 0.02) for MIX steers. Serum urea nitrogen increased (P < 0.02) 8.2% from d 0 to 84 for TE but not NTE steers. Average daily gain (kg/d) was less (P < 0.01) in TE (-0.18) vs NTE (0.09) steers. We conclude that the ad libitum intake of MIX ameliorated the negative effects of consuming TE on serum prolactin and AP but not ADG.

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 Functional and Physical Interactions among Saccharomyces cerevisiae α-Factor Receptors

2012 ◽  
Vol 11 (10) ◽  
pp. 1276-1288 ◽  
Author(s):  
Austin U. Gehret ◽  
Sara M. Connelly ◽  
Mark E. Dumont
Keyword(s):  
Saccharomyces Cerevisiae ◽  
G Protein ◽  
Dominant Negative ◽  
Negative Effects ◽  
Content Type ◽  
Functional Interactions ◽  
Wide Range ◽  
Physical Interactions ◽  
Mutant Receptors ◽  
G Protein Coupled

ABSTRACT The α-factor receptor Ste2p is a G protein-coupled receptor (GPCR) expressed on the surface of MAT a haploid cells of the yeast Saccharomyces cerevisiae . Binding of α-factor to Ste2p results in activation of a heterotrimeric G protein and of the pheromone response pathway. Functional interactions between α-factor receptors, such as dominant-negative effects and recessive behavior of constitutive and hypersensitive mutant receptors, have been reported previously. We show here that dominant-negative effects of mutant receptors persist over a wide range of ratios of the abundances of G protein to receptor and that such effects are not blocked by covalent fusion of G protein α subunits to normal receptors. In addition, we detected dominant effects of mutant C-terminally truncated receptors, which had not been previously reported to act in a dominant manner. Furthermore, coexpression of C-terminally truncated receptors with constitutively active mutant receptors results in enhancement of constitutive signaling. Together with previous evidence for oligomerization of Ste2p receptors, these results are consistent with the idea that functional interactions between coexpressed receptors arise from physical interactions between them rather than from competition for limiting downstream components, such as G proteins.

scholarly journals Effects of endophyte-infected tall fescue seed and protein supplementation on stocker steers: II. Adaptive and innate immune function

2019 ◽  
Vol 97 (10) ◽  
pp. 4160-4170 ◽  
Author(s):  
Rebecca K Poole ◽  
Alecia R Brown ◽  
Matthew H Poore ◽  
Carrie L Pickworth ◽  
Daniel H Poole
Keyword(s):  
Immune Response ◽  
Inflammatory Cytokines ◽  
Tall Fescue ◽  
Repeated Measures ◽  
Crude Protein ◽  
Protein Supplementation ◽  
Innate Immune ◽  
Fescue Toxicosis ◽  
Diarrhea Virus ◽  
Anti Inflammatory

Abstract Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue that affects performance; however, little information is available pertaining to its effects on immunity. Recently, it has been shown that supplemental CP can improve performance in weaned steers postvaccination. Thus, the objective of this study was to evaluate the effect of supplemental CP on innate and adaptive immune responses in stocker steers chronically exposed to ergovaline. Angus steers (n = 12 pens; 3 steers/pen) were stratified by weight and assigned to a 2 × 2 factorial arrangement to examine crude protein levels of supplement (14% or 18%) and ergovaline exposure (0 or 185 μg ergovaline/kg BW/d via ground endophyte-free (EF) or endophyte-infected (EI) tall fescue seed, respectively) on immune response. Consumption of low to moderate concentration of ergovaline from EI tall fescue seed was sufficient to induce mild symptoms associated with fescue toxicosis. Blood samples were collected at day 0, 42, and 56 to evaluate infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea virus (BVDV) type 1b titers following vaccine challenge. Additionally, serum cytokine concentrations were evaluated using Quantibody Bovine Cytokine Arrays on day 0, 28, and 42. Data were analyzed using PROC MIXED of SAS with repeated measures. Regardless of treatment, no differences were observed in IBR and BVDV-1b seroconversion following vaccine challenge (P > 0.05). Regardless of crude protein concentration, EI steers had greater concentrations of proinflammatory cytokines (TNF-α, IFN-γ, IL-1α), chemokines (CCL2, CCL4, MIG), anti-inflammatory cytokines (IL-2, -13, -15, -21), and various growth factors (FGF-1, IGF-1, VEGF-A) when compared to EF steers (P < 0.05). Furthermore, VEGF-A and IGF-1 concentrations were greater in EI-14 steers on day 28 compared to EI-18, EF-14, and EF-18 steers (P < 0.05), however, this difference was not observed on day 0 or 42 (P > 0.05). Based on these data, steers exposed to ergovaline have an increase in pro- and anti-inflammatory cytokines and supplemental CP had minimal impact to mitigate this response. However, in the current study, exposure to ergovaline had little to no effect on adaptive immunity and response to vaccination. Together, chronic exposure to ergovaline results in a hyperactive innate immune response, which may lead to an immuno-compromised animal.

scholarly journals Effects of extended-release eprinomectin on fescue toxicosis, performance, and reproduction on fall-calving beef cows

2019 ◽  
Vol 3 (4) ◽  
pp. 1423-1434
Author(s):  
Mareah J Volk ◽  
Taylor R Krause ◽  
Rebecca S Stokes ◽  
Frank A Ireland ◽  
Daniel W Shike
Keyword(s):  
Milk Production ◽  
Tall Fescue ◽  
Extended Release ◽  
Treatment Time ◽  
Beef Cows ◽  
Serum Prolactin ◽  
Fescue Toxicosis ◽  
Time Interaction ◽  
Tick Count ◽  
Fall Calving

Abstract The objective of this experiment was to evaluate effects of extended-release eprinomectin on fescue toxicosis and impacts on performance and reproduction in fall-calving beef cows. Fall-calving Angus × Simmental multiparous cows [n = 335; age = 5.8 ± 2.1 yr; 586.5 ± 6.0 kg body weight (BW); 5.48 ± 0.05 body condition score (BCS)] were stratified by BW, age, and BCS and randomly assigned to one of three treatments. Treatments included a spring injection of extended-release eprinomectin (SERE) on day 0, a fall injection of extended-release eprinomectin injection (FERE) on day 84, and a saline control (CON). All treatments were administered at a rate of 1 mL/50 kg BW. Prior to the experiment, all cows were treated with oral fenbendazole to minimize parasite load. Cows grazed endophyte-infected tall fescue. Hair coat score (HCS), BW, and BCS were recorded on all cattle. Fecal egg count (FEC), respiration rate (RR), horn fly and tick count, hematocrit (% packed cell volume, PCV), and serum prolactin were analyzed on a subset of cows (35/treatment). On day 194, cows were artificially inseminated (AI) and 11 d following AI were exposed to bulls for 51 d. Milk production was estimated on day 210 on a subset of 85 cow–calf pairs (28–29/treatment). There was a tendency for a treatment × time interaction (P = 0.07) for FEC likely driven by an increase in FEC of the CON cattle at day 126 compared to SERE and FERE. There was a tendency for a treatment × time interaction (P = 0.06) for cow BW, largely driven by time differences; however, there was no effect of treatment (P = 0.84) on BW. There was no difference (P ≥ 0.13) in cow PCV, fly and tick count, BCS, HCS, RR, and serum prolactin throughout the experiment. Additionally, there was no difference (P ≥ 0.46) in Julian calving date, calf birth BW, or milk production between treatments. Interestingly, heifer calves born to FERE dams tended to have greater (P = 0.06) weaning BW compared to heifer calves born to CON dams. In addition, there was no difference (P ≥ 0.17) in heat patch scores, AI conception rates, or overall pregnancy rates between treatments. Extended-release eprinomectin did not impact cow growth performance, reproductive performance or fescue toxicity symptoms when grazing endophyte-infected tall fescue; however, calf weaning BW tended to be improved.

scholarly journals PSI-22 Rumen fluid metabolites influenced by endophyte-infected tall fescue seed and red clover isoflavones in beef steers

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 269-270
Author(s):  
Juan F Cordero-Llarena ◽  
Brooke A Clemmons ◽  
Emily A Melchior ◽  
Taylor B Seay ◽  
Joshua B Powers ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Rumen Fluid ◽  
Red Clover ◽  
Basal Diet ◽  
Fescue Toxicosis ◽  
Beef Steers ◽  
Seed Type ◽  
Negative Effects ◽  
Beef Industry ◽  
Total Alkaloids

Abstract Fescue toxicosis causes substantial financial losses to the beef industry due to its negative effects on reproduction, growth and feed efficiency. Recent research has demonstrated that the negative effects of fescue toxicosis may be mitigated by supplementation of red clover isoflavones. To determine impacts on the ruminal environment, the objective of this study was to evaluate the effect of red clover isoflavones and endophyte-infected tall fescue on ruminal metabolites. Thirty-six Angus steers weighing 250±20 kg were randomly assigned to treatments in a 2×2 factorial arrangement, consisting of endophyte-free or endophyte-infected tall fescue seed with or without red clover isoflavones. For the 21d trial, steers were provided a basal diet supplemented with fescue seed targeting a minimum of 0.011 mg × kg of BW−1 × d−1 of total alkaloids. A total of 943 mg isoflavones were administered daily via bolus. Following the trial, 50mL of rumen fluid was collected via orogastric tubing. Untargeted metabolomic analysis was performed using an Exactive Plus Orbitrap MS, and 10µL sample was introduced using electrospray ionization into the Dionex UltiMate 3000 UPLC system. Peaks were identified in MAVEN, then normalized and analyzed in MetaboAnalyst 4.0, and 106 known metabolites were identified. Differences in seed type × isoflavone were analyzed by one-way ANOVA and main effects were analyzed by t-test. A total of 11 metabolites differed based on seed type × isoflavone treatment group (P ≤ 0.05), 11 differed by seed type (P ≤ 0.5), and seven differed by isoflavone treatment (P ≤ 0.05), namely amino acids or intermediates of amino acid metabolism. Methane (P = 0.03) and sulfur (P = 0.03) metabolism pathways were both impacted by isoflavone treatment, whereas 20 metabolic pathways were impacted as a result of differences in seed type (P ≤ 0.05). The rumen metabolome appears to be more affected by seed type, but a longer trial will likely result in more profound impacts.

scholarly journals Evaluation of Resistance to Fescue Toxicosis in Purebred Angus Cattle Utilizing Animal Performance and Cytokine Response

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 796
Author(s):  
Daniel H. Poole ◽  
Kyle J. Mayberry ◽  
McKayla Newsome ◽  
Rebecca K. Poole ◽  
Justine M Galliou ◽  
...  
Keyword(s):  
Tall Fescue ◽  
Ergot Alkaloid ◽  
Ergot Alkaloids ◽  
Fescue Toxicosis ◽  
Animal Performance ◽  
Angus Cattle ◽  
Study Support ◽  
Genetic Tolerance ◽  
Post Hoc ◽  
The Impact

Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue; however, varying symptomatic responses potentially imply genetic tolerance to the syndrome. It was hypothesized that a subpopulation of animals within a herd would develop tolerance to ergot alkaloid toxicity. Therefore, the goals of this study were to develop selection criteria to identify tolerant and susceptible animals within a herd based on animal performance, and then examine responsive phenotypic and cytokine profiles to fescue toxicosis. Angus cows grazed endophyte-infected tall fescue at two locations for 13 weeks starting in mid-April 2016. Forage measurements were collected to evaluate ergot alkaloid exposure during the study. A post hoc analysis of animal performance was utilized to designate cattle into either tolerant or susceptible groups, and weekly physiological measurements and blood samples were collected to evaluate responses to chronic exposure to endophyte-infected tall fescue. Findings from this study support the proposed fescue toxicosis selection method formulated herein, could accurately distinguish between tolerant and susceptible animals based on the performance parameters in cattle chronically exposed to ergot alkaloids, and provides evidence to warrant additional analysis to examine the impact of ergot alkaloids on immune responsiveness in cattle experiencing fescue toxicosis.

Sign in / Sign up

Export Citation Format

Share Document