Sheep and Goat Guide newsletter
Posted: May 31, 2011
Impacts of Livestock Chewing on Treated Wood
Livestock chew on treated lumber because of mineral imbalance or boredom. This raises concern over animal health and meat safety.
Treated wood is found in many places on a farm because over time it holds up to weather elements and prevents damage from insects remarkably well. It is treated with a combination of chromium, copper, and arsenic. Thus, wolmanized or treated wood may also be referred to as CCA treated wood. Inadequate mineral balance or consumption, particularly of phosphorus and selenium, or just plain boredom experienced by livestock may cause them to chew on the wood. This can affect the health of the animals, depending on the amount consumed.
The inclusion of arsenic in CCA treated wood is of concern to animal health if ingested. Arsenic in its inorganic form is a carcinogenic in humans. Arsenic is a natural element which is everywhere in the environ-ment. In addition to soil and plants, arsenic can also be found in some water sources, thus potentially adding to the amount ingested by an animal. Tolerance levels of inorganic arsenic (As2O3) in animal products ranges from 0.5 to 2.0 ppm. If an animal does ingest large quantities of As2O3 then acute arsenic toxicity could occur. Death could occur in animals with levels higher than 2 ppm in the liver. The concentration of chromium, copper, or arsenic would likely be found in the internal organs, including the liver, kidneys, lungs, and intestines, of animals experiencing toxicity from eating CCA treated wood. The concentration of arsenic in muscle is usually several folds lower than that in the internal organs. Other signs of toxicity that are less severe than death include diarrhea, depression, lack of coordination, and weakness.
The subsequent safety of the meat from an animal that ingests CCA treated wood depends on how much the animal ate and if there are other sources of arsenic in the animal’s diet. Arsenic has a short half-life in animals. Stopping exposure is an effective way to decrease its concentration in the tissues. Again, the highest concentration of arsenic would be found in internal organs like the liver and kidney. Without testing, one could not be certain of the level of inorganic arsenic found in the meat, and whether or not the meat would be safe for consumption.
Additionally, organic producers are not allowed to use treated lumber in new construction or with replace-ment projects in places where the lumber could come in contact with crops, livestock or soil.
Another important reminder when working with wolmanized or CCA-treated wood is to never burn it. Ashes and smoke created from burning CCA-treated lumber have greater health hazards because they are often associated with much higher exposure in human and animals than the wood itself.
Jeannine Schweihofer, Michigan State University Extension, and Karen Chou, MSU Department of Animal Science
Observe Young Goats for Possible Coccidiosis Symptoms
Understanding the life cycle of coccidia is an important step in learning what damage they do to the host and why they are so difficult to control. Coccidia are intercellular parasites and are everywhere in the environment. They live and grow within the cells lining the gastrointestinal tracts of the host. The oocyst is excreted in the feces of infected hosts. Oocysts must undergo a period of development (sporulation) after being excreted in order to become capable of infecting another host. This usually takes two to three days. Oxygen, moisture and warm temperatures are required for development. After sporulation occurs, the oocysts are very resistant to environmental conditions and ordinary disinfectants. After a susceptible goat ingests sporulated oocyst, "spores" are released and enter the cells lining the intestine. In the intestine they go through several stages of development. The intestinal cells are destroyed and thousands of smaller forms of coccidia are released. Eventually sexual stages are reached and new oocysts are passed into the environment. The complete cycle usually takes about two to three weeks.
The symptoms of coccidiosis range from loss of appetite and slight, short-lived diarrhea to severe cases involving great amounts of dark and bloody diarrhea and, in some cases, death. The severity of symptoms depends upon the number of parasites invading the intestines. Feces of sick goats contain many infective stages of coccidia. When an outbreak occurs, isolation and sanitation are key to preventing its spread throughout the herd. Additionally, coccidiosis is more of a problem in crowded conditions.
If a goat is exhibiting clinical signs of coccidiosis (diarrhea being the most common sign) there are some treatment options. These include sulfa drugs, such as sulfamethazine, sulfadimethoxine (Albon) and sulfaguanidine, tetracycline and amprolium (Corid R). Not all of these products are labeled for use in goats and require permission from a veterinarian for extra label use. Usually the treatment is given for five days. These drugs are called coccidiostats. Coccidiostats do not kill coccidia. However, they slow it down. With a heavily infected goat, treatment may not be successful, but it will help reduce the number of oocysts that are being excreted into the environment.
Coccidiosis can be prevented by adding coccidiostats, such as decoquinate (Decox) and lasalocid (Bovatec) to the goat’s diet. Goat rations that contain coccidiostats are available to producers who request them. This will aid in preventing an outbreak of coccidiosis. Another approach is to treat kids at three weeks of age with Albon, and treat them again in three weeks. Afterwards, use a feed with a coccidiostat. Caution: If you have horses, do not allow them to eat feed containing coccidiostats, as these products can be deadly to horses.
Coccidiosis is a very serious disease for goat producers. Remember to isolate and treat any animal that has coccidiosis. The best preventive measure a goat producer can take is to use a feed with a coccidiostat added. With careful management and sound preventive measures, the losses associated with this disease can be reduced to minimal levels.
Mike Metzger, Michigan State University Extension
Fast Bleat Predicts Lamb Survival
The time a lamb takes to bleat after being handled has emerged as a novel genetic avenue to boost lamb survival to weaning. As part of a Sheep CRC study exploring the genetics of lambing, SARDI scientists and colleagues across the country have been delving into the myriad ways to breed for sheep that are more likely to survive well after birth. Bleating is the cry sound that a lamb or goat does to whine or complain.
During the lambing season, managers at the CRC’s Information Nucleus sites, including at Struan and Turretfield in South Australia, do two paddock inspection rounds daily, taking crucial measurements of newborn lambs within 18 hours of birth, identifying them and their mother. One of their final measures involves popping the lambs on the ground and setting the stop watch to time how long it takes them to bleat and it has revealed some interesting insights.
SARDI livestock researcher Forbes Brien presented the results at the National Sheep CRC Conference in Adelaide. “We’ve found that if a lamb bleats within five seconds after release, it comes from a blood line linked to better lamb survival. If the lamb takes much longer, it’s less likely to be of such hardy stock,” Dr. Brien said.
Sheep CRC scientists got the idea to record the time to bleat from preliminary studies on small flocks carried out in Western Australia over 20 years ago.
The new study involved collecting records from more than 15,000 lambs, more than 6,000 merino and Border Leicester-Merino dams and 284 sires from the Sheep CRC’s eight Information Nucleus sites across Australia, representing many of the sheep breeds and crosses used in Australia.
The studies confirmed that of 14 traits investigated soon after birth, ease of lambing, hairier birth coat, shorter time taken for the lamb to bleat, warmer rectal temperature and a shorter crown-rump length (head to butt) showed links to genes for lamb survival.
“While it’s tough to achieve genetic gain in this field with only 1% of differences in lamb survival attributed to genes, the studies show that if we actively breed for these traits, we may be able to achieve a genetic increase of up to 5% in lamb survival over 10 years, which is very worthwhile.”
By contrast, Dr. Brien said the study had found some measures were not producing the gains people expected. “People have put faith in judging maternal behavior at lambing time, which involves scoring how close the ewe remains to the shepherd while her lambs are being tagged, but we’ve found that’s not consistently reliable in telling us about the genetic potential for lamb survival.”
In the long run the sheep industry is looking to improve the survival of lambs from birth to weaning, from 80% to 90% in Merino flocks. This will be possible through targeting ewe nutrition, shelter and genetics.
“We suggest one of the ways to make more rapid progress is for studs to select animals with these favorable traits, combining progeny records and half-sibling records to assist their efforts.”
Sheep CRC and Science Alert