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The objective was to determine the influence of melatonin supplementation on uterine and coccygeal artery hemodynamics of pregnant beef cattle grazing toxic, endophyte-infected (E+) tall fescue during mid-late gestation. Multiparous crossbred cows were artificially inseminated with sex-sorted semen (Y chromosome-bearing sperm) from a single Red Angus sire and maintained on pastures free from E+ fescue prior to the start of the treatment period. Pregnant cows (n = 50) were assigned to one of three treatment groups with two replications per treatment: non-toxic, novel endophyte-infected (NE+) fescue without melatonin supplementation (NE+/NM; n = 16), E+ fescue with melatonin supplementation (E+/M; n = 16), and E+ fescue without melatonin supplementation (E+/ NM; n = 18). Treatments were administered over a 70-d period between May and July (d 147 ± 1 to 217 ± 1 of gestation). A commercially available feed was mixed with or without melatonin [100 μg/kg body weight (BW)] and hand-fed daily. Cows were weighed at d 0, 14, 28, 42, 56, and 70 relative to the start of the treatment period. Measures of uterine and coccygeal artery hemodynamics included artery diameter, pulsatility index (PI), resistance index (RI), blood flow (BF), and blood flow as a proportion of BW (BF/BW) and were determined by color Doppler ultrasonography at the conclusion of the 70-d treatment period. Plasma prolactin was determined at the end of the 70-d treatment by radioimmunoassay. After the treatment period, cattle were maintained together as a single group on pastures that were free from E+ fescue. Body weights were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and replicate as random. Prolactin and arterial hemodynamics were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random. There was an effect of time and a treatment by time interaction on cow BW (P < 0.01). Prolactin was decreased (P = 0.02) in E+/NM (71.8 ± 14.0 ng/mL) and E+/M (86.9 ± 14.9 ng/mL) relative to NE+/NM (128.9 ± 14.9 ng/mL) cows. Coccygeal artery PI was decreased (P < 0.02) in E+/M (0.86 ± 0.1) relative to NE+/NM (1.06 ± 0.1) cows. Coccygeal artery RI was decreased (P < 0.01) in E+/M (0.53 ± 0.02) relative to NE+/NM (0.62 ± 0.02) cows. There were no other effects of treatment (P > 0.05). Preliminary results suggest limited effects of melatonin on uterine and coccygeal artery hemodynamics in pregnant multiparous crossbred beef cows grazing endophyte-infected tall fescue. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the influence of melatonin supplementation in pregnant beef cattle grazing toxic, endophyte-infected tall fescue (E+) on post-calving dam body weight (BW), milk production, and preweaning growth of steer calves. Multiparous cows were artificially inseminated with sex-sorted semen (Y chromosome-bearing sperm) from a single Red Angus sire and maintained on pastures free from E+ fescue prior to the start of the treatment period. Pregnant cows were assigned to one of three treatment groups with two replications per treatment: non-toxic, novel endophyte-infected (NE+) tall fescue without melatonin supplementation (NE+/NM; n = 15), E+ fescue with melatonin supplementation (E+/M; n = 16), and E+ fescue without melatonin supplementation (E+/NM; n = 18). The treatment period was over 70 d between May and July (d 147 ± 1 to 217 ± 1 of gestation). A commercially available feed was mixed with melatonin (100 µg/kg BW) or without melatonin and hand-fed to each cow daily. At the conclusion of the treatment period (56 ± 18 d before parturition), cattle were moved to a single group and maintained on pastures free from E+ fescue for the remainder of the study. Dams and steer calves were weighed at d 0, 28, 56, 84, 112, 140, and 168 relative to calving (d 0 = calving). Four-hour milk yields on d 28 ± 3 and d 56 ± 3 were used to estimate daily milk volume and weight. Dam and calf BW were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and replicate as random. Calf birth weight, dam milk volume, and dam milk weight were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random. On d 28, estimated daily milk volume and weight were decreased (P < 0.05) in E+/NM dams relative to NE+/NM dams. On d 56, estimated daily milk volume and weight were decreased (P < 0.03) in E+/NM and E+/M dams relative to NE+/ NM dams. There was an effect of time for dam and calf weights (P < 0.01). There was a treatment by time interaction for calf body weight, with calves born to E+/NM dams having decreased body weight relative to calves born to NE+/NM and E+/M dams from d 112 to d 168 (P = 0.02). There were no other effects of treatment, time, or the interaction (P > 0.05). These data suggest melatonin supplemented to pregnant crossbred multiparous beef cows grazing endophyteinfected tall fescue during mid-late gestation may increase preweaning growth of steer calves. [ABSTRACT FROM AUTHOR]

Cellular respiration is the metabolic process that breaks down glucose by use of oxygen to produce ATP. It consists of three main steps: glycolysis, the TCA cycle and oxidative phosphorylation. Oxidative phosphorylation provides most of the ATP for body functions. If oxidative phosphorylation is downregulated, then cellular metabolism will be disrupted. The objective of this study was to identify the cellular pathways impacted by maternal nutrient restriction in beef cattle. A total of 36 fetuses were examined: 18 fetuses from dams that were given either a restricted (RES) or an adequate (ADQ) diet from d 160 to 240 of gestation. At d 240 of gestation, dams underwent Cesarean section for fetal removal, morphometrics, blood and tissue collection. Liver tissue samples were sequenced via Illumina platforms and analyzed by DESeq2, while the screening threshold was set at |log2(FoldChange)| >= 1 and padj <= 0.05. Enrichment analysis of the differential expressed genes (DEGs) was performed by annotating genes to biological processes (Gene Ontology terms) and metabolic pathways (KEGG pathways). Genes with an adjusted P-value ≤ 0.05 were assigned as differentially expressed. Morphometrics data was evaluated by mixed procedures of SAS and significant was declared at P < 0.10. There was a significant group effect of the fetal necropsy weights (25.5 ± 0.55 vs 23.0 ± 0.60, kg, for ADQ and RES respectively, P < 0.02). Further, there was a significant group effect on the fetal liver weights (485.20 ± 29.19 vs 394.90 ± 29.19 g, for ADQ and RES, respectively, P < 0.07). RES fetuses exhibited 704 uniquely expressed genes compared with ADQ fetuses that showed 304 uniquely expressed genes. However, 13,145 genes were co-expressed by RES and ADQ Fetuses. A total of 2,327 genes were identified as differentially regulated between the groups. Of these 1,106 genes were up-regulated and 1,221 are down-regulated in RES vs. ADQ fetuses. KEGG pathway enrichment analysis showed downregulation of key enzymes involved in oxidative phosphorylation specifically in complexes I, II, III and IV. Thus, downregulation of oxidative phosphorylation is a potential mechanism by which maternal restriction retards fetal growth and development as seen in this project. Funded by NIFA CBG # 2021-38821-34599. [ABSTRACT FROM AUTHOR]

Agriculturally rich communities in Mississippi, particularly those with high minority populations, suffer from significant educational disparities, resulting in a median poverty rate 7.8% higher than the national average. Persistent unequal opportunities within the public school system, and a limitation of youth having access to advanced coursework and technology create challenges in improving the welfare of Mississippi communities. Despite being grossly underpaid, teachers in Mississippi remain passionate about agriculture education, often utilizing their personal finances to provide students with opportunities to succeed. Thus, an immersive learning agriculture science professional development program was created for 5th-12th grade classroom teachers. The objective was to improve the quality of education for students by advancing the ability of teachers to foster understanding and practices in agriculture literacy. Teachers (n = 20; cohort 1, n = 12; cohort 2, n = 8) participated in a 2-wk summer institute. Teachers received continuing education credits for their teaching license, a stipend to alleviate associated costs, and supplies for their classroom. The teachers learned agriculture content (e.g., animal, plant, and soil sciences), engaged in hands-on learning labs (e.g., anatomy and immunology), participated in field excursions (e.g., animal handling), received literary instruction, and discussed teacher leadership. To determine if program outcomes were achieved, participants completed surveys (n = 3), interviews (n = 3), and submitted lesson plans (n = 2). Post-institute survey results of participating teachers indicated they were eager to implement their new knowledge in their classrooms, including but not limited to fetal pig dissections, reproductive tract anatomy, blue's the clue, DNA extraction, carousel activity, mind mapping, and glow germ activity. Statistical analysis using one-way ANOVA was performed on pre- and post-survey knowledge assessment across both cohorts. Regarding agriculture content, self-assessment knowledge scores of both cohorts increased significantly (P ≤ 0.0001) during the post-survey. Both cohort 1 and 2 teachers responded with a score of 80% or higher to: "On an assessment where I had to, "Explain general livestock reproduction and reproductive management practices"; "Explain how a cow's immune system is similar to humans" and, "Explain why farmers work diligently to prevent disease". In addition, cohort 2 teachers responded with a score of 80% or higher to: "On an assessment where I had to, "Accurately label the anatomical organs of a fetal pig"; "Correctly explain the basic function of fetal pig organs" and, "Explain pregnancy detection in animal science." This professional development program successfully reached Mississippi teachers, equipping them with tools to increase agriculture literacy. The potential impact of this program extends to encourage more youth to pursue careers in agriculture, foster a more informed consumer base, and mitigate poverty rates within the state. Funding provided by USDA-NIFA-AFRI Education and Workforce Development proposal number 2021-67037-34210/1025666. [ABSTRACT FROM AUTHOR]