Key Considerations for the Use of Seaweed to Reduce Enteric Methane Emissions From Cattle.

Enteric methane emissions are the single largest source of direct greenhouse gas emissions (GHG) in beef and dairy value chains and a substantial contributor to anthropogenic methane emissions globally. In late 2019, the World Wildlife Fund (WWF), the Advanced Research Projects Agency-Energy (ARPA-E) and the Foundation for Food and Agriculture Research (FFAR) convened approximately 50 stakeholders representing research and production of seaweeds, animal feeds, dairy cattle, and beef and dairy foods to discuss challenges and opportunities associated with the use of seaweed-based ingredients to reduce enteric methane emissions. This Perspective article describes the considerations identified by the workshop participants and suggests next steps for the further development and evaluation of seaweed-based feed ingredients as enteric methane mitigants. Although numerous compounds derived from sources other than seaweed have been identified as having enteric methane mitigation potential, these mitigants are outside the scope of this article.

Exploration of veterinary shortages in the wake of the Veterinary Feed Directive.

OBJECTIVE To identify geographic areas in the United States where food animal veterinary services may be insufficient to meet increased needs associated with the US FDA's Veterinary Feed Directive. DESIGN Cross-sectional study. SAMPLE Data collected between 2010 and 2016 from the US Veterinary Medicine Loan Repayment Program, the National Animal Health Monitoring System Small-Scale US Livestock Operations Study, and the USDA's National Veterinary Accreditation Program. PROCEDURES Each dataset was analyzed separately to identify geographic areas with greatest potential for veterinary shortages. Geographic information systems methods were used to identify co-occurrence among the datasets of counties with veterinary shortages. RESULTS Analysis of the loan repayment program, Small-Scale Livestock Operations Study, and veterinary accreditation datasets revealed veterinary shortages in 314, 346, and 117 counties, respectively. Of the 3,140 counties in the United States during the study period, 728 (23.2%) counties were identified as veterinary shortage areas in at least 1 dataset. Specifically, 680 counties were identified as shortage areas in 1 dataset, 47 as shortage areas in 2 datasets, and 1 Arizona county as a shortage area in all 3 datasets. Arizona, Kentucky, Missouri, South Dakota, and Virginia had ≥ 3 counties identified as shortage areas in ≥ 2 datasets. CONCLUSIONS AND CLINICAL RELEVANCE Many geographic areas were identified across the United States where food animal veterinary services may be inadequate to implement the Veterinary Feed Directive and meet other producer needs. This information can be used to assess the impact of federal regulations and programs and help understand the factors that influence access to food animal veterinary services in specific geographic areas.

Regulation of nuclear factor-kappaB (NF-kappaB) activity and apoptosis by estradiol in bovine granulosa cells.

Although atresia of bovine follicles is associated with apoptosis of granulosa cells, the signals initiating this cell death have not been resolved. NF-kappaB has been implicated as an important regulator of genes controlling apoptosis, and previous studies indicate that estradiol may modulate NF-kappaB activation. We hypothesized that estradiol activates NF-kappaB, and thus, inhibits apoptosis in granulosa cells of dominant follicles. Dominant follicles were collected on Days 4, 6, and 8 of the first follicular wave following ovulation and assayed for NF-kappaB activity. Concentrations of estradiol in follicular fluid decreased on Day 6 compared to Day 4 of the wave. NF-kappaB activity in granulosa cells was lower on Day 8 compared to Days 4 and 6. In vitro, NF-kappaB activity and minimal incidence of apoptosis (<4%), as measured by Annexin V and TUNEL assays, were associated with production of estradiol. However, inhibition of NF-kappaB in vitro led to a suppression of apoptosis. These results indicate that follicular NF-kappaB activation is associated with estradiol production. However, whether NF-kappaB is playing a pro- or anti-apoptotic role in granulosa cells of the dominant bovine follicle remains to be elucidated.

Regulation of apoptosis in the atresia of dominant bovine follicles of the first follicular wave following ovulation.

During atresia of bovine follicles, granulosa cells are lost through the controlled form of cell death, apoptosis. The purpose of this study was to characterize the regulation of apoptotic death of granulosa cells in dominant bovine follicles during the first wave of follicular development. Dominant follicles were collected from Holstein heifers on days 4, 6 or 8 of the first follicular wave (n = 5/day). Regulation of apoptosis in granulosa cells was examined by annexin V and propidium iodide staining; measurement of relative levels of mRNA encoding Bcl-2, Bcl-xL and Bax; and activity of caspase-3, -8 and -9. Steady-state levels of mRNA encoding four oxidative stress-response proteins were determined. Compared with day 4, the incidence of apoptotic and nonviable granulosa cells tended to increase on day 6, and numbers of nonviable cells were higher on day 8. The ratios of relative levels of mRNA encoding Bcl-2 to Bax and Bcl-xL to Bax were higher on day 6 than days 4 and 8. Activity of caspases-3 and -9 in granulosa cells did not change among the 3 days, while caspase-8 activity decreased on day 8 compared with days 4 and 6. Amounts of GSHPx, MnSOD and Cu/ZnSOD mRNA in granulosa cells were higher on day 8 than day 6. In theca interna, amounts of Cu/ZnSOD mRNA decreased between days 4 and 6. From the decreased production of estradiol and increased numbers of apoptotic and nonviable granulosa cells, we conclude that atresia of the dominant follicle is initiated between days 4 and 6 of the first follicular wave. However, apoptosis of granulosa cells does not appear to be initiated by changes in expression of oxidative stress-response proteins.

Effects of nicotine and cotinine on bovine theca interna and granulosa cells.

The purpose of this study was to determine if nicotine or cotinine inhibits steroidogenesis in the ovarian follicle. Theca interna and granulosa cells were isolated from bovine follicles, cultured with nicotine or cotinine for 24h, and culture media were assayed for androstenedione or estradiol. Treatment of theca interna with 6, 60, and 600 micro M nicotine decreased (P