I nvited R eview : Matching forage systems with cow size and environment for sustainable cow-calf production in the southern region of the United States 1 1This review article is based on a presentation by the authors in the symposium “Management Strategies for Intensive, Sustainable Cow-Calf Production Systems in the Southeastern United States” at the meeting of the American Society of Animal Science Southern Section, February 9, 2016, San Antonio, Texas.

2017 ◽  
Vol 33 (3) ◽  
pp. 289-296 ◽  
Author(s):  
P.A. Beck ◽  
M.S. Gadberry ◽  
S.A. Gunter ◽  
E.B. Kegley ◽  
J.A. Jennings
2020 ◽  
Author(s):  
Hossein Noorazar ◽  
Lee Kalcsits ◽  
Vincent P. Jones ◽  
Matthew S. Jones ◽  
Kirti Rajagopalan

AbstractWinter chill accumulation is critical for the productivity and profitability of perennial tree fruit production systems. Several studies have quantified the impacts of global warming on risks of insufficient chill accumulation in the warmer tree fruit and nut production regions of the United States (US), such as the Southeast and California, where these risks are currently prevalent. In this work, we focus on the Pacific Northwest US – the largest production area in the US for apples, pears and cherries – and quantify the potential risk of insufficient chill accumulation. Our results highlight large spatial variations in response within the PNW, with northern areas projected to have reduced risks and southern areas projected to have increased risks. In the southern areas, rather than chill accumulation in and of itself, it is the combination of reduced and delayed chill accumulation with likely advancement in spring phenology that lead to production risks. In spite of future reductions to chill accumulation, risks of insufficient chill accumulation seem limited for apple even with advancement of spring phenology. Under the extreme “no climate policy” RCP 8.5 climate projections, the production risks are significant for early blooming crops (e.g. cherries) and varieties with relatively high chill portions requirements (e.g. Sam cherries), necessitating planning for management strategies such as frost protection and chemical management of budbreak to address potential risks which have not historically been a concern in the region. Under less extreme warming outcomes, the PNW tree fruit production systems are likely to remain resilient. Given that the convergence of the fulfillment of chilling requirements and environmental conditions promoting budbreak is where potential risk to perennial tree fruit production exists, future work should focus on understanding, modelling and projecting responses within this convergence space. Additionally, given significant spatial differences across a relatively small geographic range, it is also critical to understand and model these dynamics at a local landscape resolution for regions such as the PNW that faced limited risk historically, but could be exposed to new risks under a warming climate.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 124-124
Author(s):  
Vitor R G Mercadante ◽  
Nicholas W Dias ◽  
Claire L Timlin ◽  
Stefania Pancini

Abstract Over the last four decades, several advances in reproductive biotechnologies have helped beef producers improve genetic traits of their cattle, tighten the breeding season and shorten the calving season, leading to an increase in overall profitability of cow-calf production systems. However, even with these advancements, reproductive failure and embryo mortality are still a major cause for economic loss in beef production. Recently, we projected a loss of $6.25 per exposed cow for every 1% decrease in pregnancy rate, with an estimated gross loss of $2.8 billion annually in the United States due to pregnancy failure in beef females. It is estimated that 75 to 80% of embryonic loss occurs by d 20 of gestation; a large portion of these losses occur during the first week of gestation and likely are caused by issues relating to fertilization failure, incompetence of embryos originated from poor quality oocytes and suboptimal uterine conditions. Furthermore, within the first month of gestation, nearly half of all cows submitted to breeding will not be pregnant 30 d later, and another 5% will lose their pregnancy by d 100 of gestation. In addition, breeding related costs, including bull purchase, breeding soundness exam, estrous synchronization, semen purchase, labor associated with artificial insemination and pregnancy diagnosis, are estimate at $65 per cow exposed. Assuming a 90% pregnancy rate at the end of the breeding season, and a scenario where all 30 million beef females in the U.S. are exposed to fixed-time artificial insemination and undergo one pregnancy diagnosis, the added lost revenue of not producing a live calf to sell at weaning and the cost of breeding, would represent a loss of over $21 billion annually in the United States. Strategies that reduce pregnancy loss in beef cattle are essential to improve productivity and profitability of cow-calf production systems.


2006 ◽  
Vol 20 (3) ◽  
pp. 815-823 ◽  
Author(s):  
Anthony D. White ◽  
Drew J. Lyon ◽  
Carol Mallory-Smith ◽  
Case R. Medlin ◽  
Joseph P. Yenish

Feral rye, commonly referred to as cereal, winter, common, or volunteer rye, is an important weed in winter wheat production in many parts of the United States and the world. Feral rye reduces net profits in the United States by more than $27 million due to lower grain yields, increased dockage, and reduced land values. To date, limited research has been conducted on components that make feral rye a problem in various cropping systems. Herbicide-tolerant wheat technology can be used to manage feral rye, but current efficacy levels are not adequate for high feral rye densities. In addition, the long-term effects that individual management strategies may have on feral rye populations are unknown. This review addresses the physical, environmental, and genetic characteristics ofSecale cereale. Current economic impact, management, and research data gaps are also discussed.


Author(s):  
Andrew Valls

The persistence of racial inequality in the United States raises deep and complex questions of racial justice. Some observers argue that public policy must be “color-blind,” while others argue that policies that take race into account should be defended on grounds of diversity or integration. This chapter begins to sketch an alternative to both of these, one that supports strong efforts to address racial inequality but that focuses on the conditions necessary for the liberty and equality of all. It argues that while race is a social construction, it remains deeply embedded in American society. A conception of racial justice is needed, one that is grounded on the premises provided by liberal political theory.


Science ◽  
2021 ◽  
Vol 371 (6536) ◽  
pp. eaax9050
Author(s):  
Steffen Breinlinger ◽  
Tabitha J. Phillips ◽  
Brigette N. Haram ◽  
Jan Mareš ◽  
José A. Martínez Yerena ◽  
...  

Vacuolar myelinopathy is a fatal neurological disease that was initially discovered during a mysterious mass mortality of bald eagles in Arkansas in the United States. The cause of this wildlife disease has eluded scientists for decades while its occurrence has continued to spread throughout freshwater reservoirs in the southeastern United States. Recent studies have demonstrated that vacuolar myelinopathy is induced by consumption of the epiphytic cyanobacterial species Aetokthonos hydrillicola growing on aquatic vegetation, primarily the invasive Hydrilla verticillata. Here, we describe the identification, biosynthetic gene cluster, and biological activity of aetokthonotoxin, a pentabrominated biindole alkaloid that is produced by the cyanobacterium A. hydrillicola. We identify this cyanobacterial neurotoxin as the causal agent of vacuolar myelinopathy and discuss environmental factors—especially bromide availability—that promote toxin production.


2008 ◽  
Vol 48 (7) ◽  
pp. 930 ◽  
Author(s):  
L. J. Cummins ◽  
C. A. Morris ◽  
B. W. Kirkpatrick

Long-term selection programs in the United States and New Zealand have developed twinning herds. In Nebraska, the United States Meat Animal Research Centre population had a calving rate of 1.56 per parturition in 2004. They have shown that the location of ovulation has an important effect on the success of pregnancy and that ovulations ≥3 are probably undesirable. These cattle have issues associated with calving difficulty and calf survival, which present challenges for commercial application. Intensive management using existing technology and/or future genetic improvement to address these traits are required to realise the potential benefits to beef production systems.


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