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Lead Toxicity in Cattle

posted by Horse Owner Today    |   June 1, 2012 09:00



Dr. LeeAnn Forsythe DVM, MVetSc, Disease Surveillance Veterinarian

Lead poisoning continues to be the most predominant toxicity encountered in cattle and a cause of significant economic loss for beef and dairy producers. Currently, the primary source of lead on the prairies is discarded vehicle batteries.

 
Symptoms of lead poisoning in cattle include neurological signs such as depression, stumbling or difficulty walking, blindness, and seizures. The most severely affected animals die within 24 hours of initial onset of clinical signs, but some animals may die up to 2 weeks after exposure.  Not all animals exposed to the lead will develop clinical signs; some may appear to be perfectly normal even though the level of lead in their blood is high. The only way to be certain of which animals were exposed to lead is to test blood for lead.

Because lead is heavy, pieces of lead can become stuck in the cow’s stomach. These pieces slowly release lead into the cow’s body over a long period of time.  Lead is deposited in the kidneys, liver, and bone and excreted in the milk, urine and feces. The time to elimination from the body is highly variable. In some cases animals have found to have lead levels above the acceptable limit for years after the exposure.

Livestock producers need to ensure that cattle do not have access to lead by removing discarded batteries, old oil, paint, shingles and other sources of lead. Meat and milk from lead-poisoned cattle is a food safety concern; therefore, these animals should never be used for food production

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General

Common Grazing Management Mistakes

posted by Horse Owner Today    |   March 23, 2012 10:35


Nadia Mori, MSc, PAg, Regional Forage Specialist
Watrous Regional Services Office
Saskatchewan Ministry of Agriculture


Managing pastures for maximum productivity sounds easy in theory but once weather fluctuations, insect or wildlife damage, and other unforeseen circumstances enter the equation, pasture management quickly turns into a complex balancing act. Grazing management mistakes are bound to happen when dealing with the complexity of a pasture ecosystem. Learning from these mistakes is a good preparation for future unforeseen circumstances and better risk management in your grazing system.

1.    Looking only to the past to determine stocking rates.
Using the same stocking rates year after year often results in pasture degradation. What may have worked in the past may not be appropriate in the present. Most grazing animals have increased in frame size, thereby increasing forage demand for a single animal. Each year will also present a different moisture situation and therefore different amounts of available forage. Properly balancing your forage supply and animal demand based on weather patterns and herd requirements is recommended.
2.    Thinking that more animals grazed means higher profits.
As stocking rates go above what a pasture can carry sustainably, animal performance and animal health will start to decline. As forage supply becomes inadequate, animals are also more likely to graze harmful and toxic plants. In addition to compromised animal performance, the grazing pressure on your desirable forage plants can lead to reduced pasture health. Long periods of rest may be necessary to restore pasture productivity. Reduced pasture productivity can be costly if additional feed needs to be purchased to meet animal nutritional requirements. All these factors reduce your profit.
3.    Thinking that leaving forage behind is a waste of feed.
Drought is always a matter of when, not if it occurs in Saskatchewan. Keeping stocking rates conservative is the best drought insurance policy. Well rested, vigorous forage plants with a well developed root system will stand a much better chance of survival than an overgrazed, stressed plant with a compromised root system. Forage not used in above-average rainfall years can provide carry-over feed for periods of moisture shortfalls. Left-over forage material also turns into litter which helps protect the soil surface from soil erosion and keeps soils cooler and moister during the heat of the summer.
4.    Following the same pasture rotation year after year.
Grazing during rapid spring growth can be stressful to forage plants. Using the same pasture for spring turnout or during rapid spring growth, is taxing on forage plants. Desired plants are often selectively and repeatedly grazed during this rapid growth stage, which may give weedy or undesirable plants an opportunity to take over. Deferring grazing during critical plant growth periods, using pastures at different seasons of the year, and rotating through pastures in different sequences from year to year will help in maintaining good pasture health.
For more information, please contact:
 Watrous Regional Services Office (306-946-3220);

 Agriculture Knowledge Centre (1-866-457-2377); or
Visit our website at www.agriculture.gov.sk.ca.

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