11 Ergebnisse.

Since 1944, the National Research Council (NRC) has published seven editions of the Nutrient Requirements of Beef Cattle. This reference has guided nutritionists and other professionals in academia and the cattle and feed industries in developing and implementing nutritional and feeding programs for beef cattle. The cattle industry has undergone considerable changes since the seventh revised edition was published in 2000 and some of the requir...

Keine Beschreibung.

During the last century and today, the Tennessee walking horse has been used primarily for pleasure and show competition. Unique and natural to the breed is a smooth four-beat "running walk" gait. In the 1950s the accentuated or exaggerated running walk, known as the "big lick" became popular at high-level competitions. The combination of exaggerated high-action step in front and long stride behind is still considered desirable in today's hors...

A Research Strategy to Examine the Taxonomy of the Red Wolf provides independent guidance about taxonomic research on the red wolf, Canis rufus. Building from the 2019 report Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf, this report reviews and ranks research applications to determine the taxonomy of wild canid populations in southern Louisiana and other relevant locations. The report then develops a research strat...

Scientists strive to develop clear rules for naming and grouping living organisms. But taxonomy, the scientific study of biological classification and evolution, is often highly debated. Members of a species, the fundamental unit of taxonomy and evolution, share a common evolutionary history and a common evolutionary path to the future. Yet, it can be difficult to determine whether the evolutionary history or future of a population is sufficie...

Nearly one-third of the United States is covered by forests, accounting for more than one million square miles, an area exceeded only in Canada, Brazil, and Russia. These forest ecosystems play vital roles in carbon storage, nutrient cycling, and air and water purification, as well as in supplying habitat for wildlife. Forests hold historical, cultural, and social significance for Americans and are sources of both food and fiber. Today, these ...

Huanglongbing (HLB) or citrus greening, first observed more than a hundred years ago in Asia, is the most serious disease threat to the citrus-growing industry worldwide due to its complexity, destructiveness, and incalcitrance to management. First detected in Florida in 2005, HLB is now widespread in the state and threatens the survival of the Florida citrus industry despite substantial allocation of research funds by Florida citrus growers a...

Although ecosystems, humans, and fire have coexisted for millennia, changes in geology, ecology, hydrology, and climate as well as sociocultural, regulatory, and economic factors have converged to make wildland fire management exceptionally challenging for U.S. federal, state, and local authorities. Given the mounting, unsustainable costs and difficulty translating existing wildland fire science into policy, the National Academies of Sciences,...

Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade. In cattle, the primary cause of brucellosis is Brucella abortus, a zoonotic bacterial pathogen that also affects wildlife, including bison and elk. As a result of the Brucellosis Eradication Program that began in 1934, most of the country is now free of bovine brucellosis. The G...

The United States' tradition of conserving fish, wildlife, habitats, and cultural resources dates to the mid-19th century. States have long sought to manage fish and wildlife species within their borders, whereas many early federal conservation efforts focused on setting aside specific places as parks, sanctuaries, or reserves. With advances in landscape ecology over the past quarter-century, conservation planners, scientists, and practitioner...

Genetically engineered (GE) crops were first introduced commercially in the 1990s. After two decades of production, some groups and individuals remain critical of the technology based on their concerns about possible adverse effects on human health, the environment, and ethical considerations. At the same time, others are concerned that the technology is not reaching its potential to improve human health and the environment because of stringen...