May 15, 2004
Test Detects Brucella Bacteria in Goat's Milk
Goat milk sold in the United States may soon be better protected against brucellosis-causing bacteria, thanks to recent research conducted by two U.S. Department of Agriculture agencies in Ames, Iowa.
A test for detecting the bacteria Brucella melitensis in bulk goat milk has been developed by research chemist Louisa Tabatabai of the Agricultural Research Service's National Animal Disease Center, Barbara Martin of the Animal and Plant Health Inspection Service's National Veterinary Services Laboratories and graduate student Nathan Funk of Iowa State University. The test relies on an adaptation of an enzyme-linked immunoassay (ELISA) that Tabatabai helped develop in 1984 for testing cattle for B. abortus.
B. melitensis, one of six known species of Brucella bacteria that induce abortions in animals, mainly infects sheep and goats. In humans, B. melitensis infection causes Malta fever, which is characterized by headaches and fever.
Few cases of this infection in goats have occurred in the United States since 1972. However, it is essential that vigilance be maintained to prevent introductions of the bacteria into the country. B. melitensis is particularly common in Latin America, central and southwest Asia and the Mediterranean region.
Dairy goat milk is slowly gaining in popularity due to its high protein and low cholesterol levels, as well as its compatibility for people with intolerance to cow's milk. About 1 million goats are raised for milk and cheese production in the United States.
In the studies, the assay - which detects B. melitensis antibodies - identified one goat with a high concentration of infection in a herd of more than 1,600 animals, and one goat with a low concentration in a herd of 50 animals. It also correctly identified all 13 positive and 134 negative bulk milk samples tested. The researchers recommend that herds be sampled in groups of 50 animals or less for bulk milk testing.
Machine Vision Automating Cotton Gins
An Agricultural Research Service scientist has developed a patented machine vision system for automating cotton gins that is now being manufactured commercially. The system uses color video camera for a hands-off monitoring of the "on-the-fly" flow of cotton and attendant debris through the many machines that comprise a cotton gin. It can advise ginners or automatically turn cleaners on and off, depending on trash content. By knowing the trash content at each stage of ginning, gin operators will know exactly which stages they can or cannot skip to reach particular quality goals without under- or over-cleaning cotton. (Under-cleaning lowers cotton's value and makes the cotton more difficult to use at textile mills, while over-cleaning wastes cotton. Added weight from the saved cotton provides an additional $3 to $5 per 500-pound bale, which could lead to more than $100,000 in increased revenue for a typical cotton gin.) The system films 50 square feet of cotton per minute.
Telemetry System Helps Scientists Study Heat Stress in Cattle
A temperature sensor and transmitter, placed inside a small capsule inserted into a cow, will help researchers more effectively measure the animal's core body temperature, say ARS scientists. Gaining accurate information on an animal's internal temperature is important for researchers who are conducting long-term heat stress experiments on livestock. The system consists of a capsule containing a temperature sensor, battery, transmitter and a data recorder. For short-term measurements in pigs and poultry, the animal can swallow the capsule. For longer-term studies, the capsule is surgically inserted into the animal, where it can last for up to a year - an important advantage for long-term heat stress experiments. (Past telemetry systems had poor resolution.) Other systems designed for medical purposes were precise, but too expensive. The new system is less expensive, but still gives good results.
USDA's Gentle, but Tough, Termiticide Now Patented
The latest weapon in the war on termites - a toxic, tasty bait - has been patented by USDA scientists. This means that the low-dose termiticide is a step closer to reaching homeowners and others trying to put a stop to the wood-eating pest. Formosan subterranean termites alone cost Americans about $1 billion every year in control and repair costs. The new termiticide contains low concentrations of naphthalenic compounds similar to those used in mothballs. The scientists have found that, even at low doses, the termiticide helps control native Eastern subterranean termites, in addition to the more notorius Formosan subterranean termite. The researchers incorporated the naphlthalenic compounds into a cellulose-based matrix - a slow-acting toxic bait that appeals to termites' tastebuds, which encourages wider distribution throughout the colony. Because they're effective at low doses, the termite-killing compounds are both cost-effective and environmentally friendly.