Recent anrrec_sfrec items

Annotated Bibliography

Wed, 28 Jul 2004 00:00:00 +0000

All publications resulting from research conducted at Sierra Foothill Research & Extension Center from 1969 to 2003.

Residual Feed Intake

Fri, 2 Jul 2004 00:00:00 +0000

Introduction

Low rates of return on investment for livestock operations are a fact of life. Producers have little impact on the market price for their cattle; therefore management must be focused on the things producers can actually do something about. For many years, genetic selection programs have focused on production (output) traits, with little attention given to production costs (inputs). Recently, this view has begun to change, and the efficiency of conversion of feed (i.e., the amount of product per unit of feed input) has been recognized as more important. Numerous studies have shown what cattlemen have always known: profitability in this business depends on keeping the costs of production to a minimum. Within any beef cattle operation, feed costs are undoubtedly the main concern, since they typically account for 60 – 65 % of the total costs of production. That’s why greater feed efficiency has been targeted as a means of improving the profitability of the beef...

High Sierra Beef Progress Update

Fri, 2 Jul 2004 00:00:00 +0000

Research similar efforts in other regions

Research was completed on similar efforts in other regions. There are over 300 grass-fed beef marketing operations across the United States. Here in California, there are approximately 10. Most are selling approximately 50-60 head per year. This appears to be a marketing limit for those who produce, process, market and distribute on their own. Additional labor and space requirements for marketing, storage for dry-aging, and distribution appear to be the biggest barriers to increasing market share for producers working individually.

The largest grass-fed beef company in California is marketing around 1,000 head annually primarily to Bay Area restaurants. Branded beef consultant Allen Williams has noted the grass-fed beef market still has plenty of room to expand and that price is not a limiting factor. Ervin’s Beef in Arizona has noted that you can market all you can produce. One Bay Area restaurant is wanting grass-fed beef...

Oak Woodland Conservation Act of 2001

Fri, 2 Jul 2004 00:00:00 +0000

Background

In 2001, the California Legislature passed the California Oak Woodland Conservation Act. This Act grew out of concern that California’s oak woodland habitats were threatened and that the State was continuing to lose oaks to development, firewood harvesting, and agricultural conversions. Such losses could critically impact a wide range of wildlife species that are so dependent on this habitat type since oak woodlands are home to more than 300 species of terrestrial vertebrates, as well thousands of invertebrates. In addition, woodlands moderate temperatures, reduce soil erosion, facilitate nutrient cycling, and sustain water quality. The Act recognized the importance of California’s oak woodlands -- how they enhance the natural and scenic beauty of this great State, the critical role of the private landowner, and the importance of private land stewardship. The Act further acknowledged how oak woodlands increase the monetary and ecological value of real property...

BSE Prevention Update: Comparing France and California

Fri, 2 Jul 2004 00:00:00 +0000

Over the past four months we have read and heard more about BSE (Bovine Spongiform Encephalopathy; Mad Cow Disease) than we may have ever wanted to know. The California Cattlemen’s Association and other allied groups, particularly the NCBA have done a wonderful job in terms of getting out the facts about BSE and the message that beef is safe for consumers. The BSE issue is extremely complicated and I will compare some of what has been done in France with our situation in California.

What are the critical control points for preventing BSE in U.S. cattle?

The first step is to prevent the introduction of cattle into the U.S. that might be “incubating” the disease. This is the basis of our ban on the importation of any cattle from countries that are known or suspected of having BSE. For example, we banned the importation of cattle from Britain after 1986 and banned live cattle importation from Canada in May of 2003. Secondly, because this disease is transmitted...

Bovine Virus Diarrhea (BVD)

Fri, 2 Jul 2004 00:00:00 +0000

Bovine virus diarrhea (BVD) is a complicated disease to discuss as it can result in a wide variety of disease problems from very mild to very severe. BVD can be one of the most devastating diseases cattle encounter and one of the hardest to get rid of when it attacks a herd. The viruses that cause BVD have been grouped into two genotypes, Type I and Type II. The disease syndrome caused by the two genotypes is basically the same, however disease caused by Type II infection is often more severe. The various disease syndromes noted in cattle infected with BVD virus are mainly attributed to the age of the animal when it became infected and to certain characteristics of the virus involved.

Diseases caused by BVD infection

Fetal BVD infections (infection of the unborn calf): The result of a fetal infection with the BVD virus is usually determined by the age of the fetus at the time of infection. The virus is capable of passing from an infected cow to the unborn fetus...

Heparin-Binding Proteins as an Indicator of Bull Potency

Fri, 2 Jul 2004 00:00:00 +0000

INTRODUCTION

Over 20 years ago, research was underway to develop methods for in vitro fertilization utilizing bovine sperm and eggs. Freshly ejaculated sperm cannot fertilize an egg. Those sperm must reside in the female reproductive tract for 6-8 h and become diluted from seminal fluid. That process is called capacitation because it allows sperm to acquire the “capacity” to fertilize an egg. The final change sperm cells undergo after capacitation involves a morphological remodeling with release of enzymes packaged in the tip of the sperm head’s acrosome. This irreversible remodeling is known as the acrosome reaction. All of these events had to be controlled in the lab to successfully fertilize eggs from cows.

Proteins produced in the seminal vesicles, prostate, and Cowper’s glands convey the capacitating effects of heparin, a carbohydrate, to bull sperm. Those proteins are collectively referred to a heparin-binding proteins because they function as “docking’ molecules...

Marker-Assisted Selection Backgrounder

Thu, 1 Jul 2004 00:00:00 +0000

DNA (deoxyribonucleic acid) is a molecule that is shaped like a double helix and made up of pairs of nucleotides. DNA transmits genetic information. DNA is packaged into chromosomes which are located within the nucleus of all cells. Every cell in the body contains all of the chromosomes that collectively make up the genome of that organism. DNA codes for amino acids which are linked together to make proteins. A gene is a stretch of DNA that specifies all of the amino acids that make up a single protein. Proteins are the building blocks of life. There are thousands of proteins in the body (encoded by thousands of genes). The interaction and structure of proteins determines the visible characteristics or phenotype of an organism, while the genotype refers to the genetic makeup.

The sequence of nucleotides that encode a gene can differ between individuals. These differences are called genetic variants. As a result of these nucleotide differences, genetic variants or alleles...

Cows in Space

Wed, 11 Feb 2004 00:00:00 +0000

A great deal has been learned about foraging behavior and livestock distribution in the last several decades. We hope to apply and fine tune this knowledge to reduce the impacts of beef cattle on riparian areas, surface water and wildlife habitat. Likewise, to use cattle as a tool to manage weeds we need to be able to attract cattle into patches of undesirable species.

Beef cattle and other grazers focus on water sites and sites that provide thermal comfort, foraging away from these focal points to meet their nutritional needs. Most ungulates first harvest food, then move either to loafing and bedding sites to ruminate and digest the food ingested in a previous grazing bout (meal), and/or to areas for predator avoidance. The distance covered by the animal during foraging depends on digestive capacity, rate of passage, forage harvest rate, grazing velocity and level of hunger. Once satisfied the animal returns to a thermal, water or bedding site depending on their...

Estimating Environmental Loading Rates of the Waterborne Pathogenic Protozoa, Cryptosporidium Parvum, in Certain Domestic and Wildlife Species in California

Wed, 11 Feb 2004 00:00:00 +0000

Cryptosporidium parvum (C. parvum) is a protozoal parasite that can cause gastrointestinal illness in a wide variety of mammals, including humans, livestock, companion animals, and wildlife. New species of Cryptosporidium are constantly being discovered, such as C. canis and C. felis, but their significance relative to the large role that C. parvum plays in livestock and human cryptosporidiosis is still unclear. In the majority of livestock species, clinical disease and shedding of C. parvum typically occurs in youngstock under a few months of age, but fecal shedding of oocysts can also occur in healthy older animals which can then serve as a source of infection for these younger animals. In humans, clinical disease and shedding can appear at all ages, but is typically more common among children. The predominant clinical sign is profuse, watery diarrhea lasting from a few days to several weeks in normal (immunocompetent) individuals, but can be prolonged and life threatening...