This is the VOA SpecialEnglish AGRICULTURE REPORT.
People often experience stress as a result of events in theirlives. Stress is a physical condition that results from real orexpected problems. People may experience stress when they lose a jobor feel threatened. Common signs include increased heart rate,higher blood pressure and muscle tension.
American agriculture experts say farm animals also may experiencestress. Animals may experience stress after giving birth or forother reasons. They say stress may affect meat quality, milkproduction and the health of farm animals.
Experts say stress in animals ismore difficult to identify. Farmers can look for signs such as lowerthan expected body weight and increased risk of disease.
Ted Elsasser is a scientist at the United States AgriculturalResearch Service. He is studying a possible sign of stress inanimals. He says changed proteins called nitrated proteins may serveas an early warning system for the problem.
Currently, farmers use antibiotics to treat stress in animals.However, repeated use of use antibiotics can lead to bacteria thatresist the drugs.
Mister Elsasser is studying another method. He found that VitaminE may protect farm animals against the harmful effects of stress. Inan experiment, he gave Vitamin E to six young cows. Then he injectedthe animals with a harmful substance taken from the cell walls ofbacteria. This toxin causes the defense system of the animals toreact as if an infection were present. The scientist injected sixother calves with only the toxin. Four other cows did not receivethe toxin or the Vitamin E.
Then Mister Elsasser studied the animals. All of the animals thatreceived the toxin had lower levels of a natural growth substance intheir liver and blood, compared with the untreated calves. However,the calves that were given Vitamin E and the toxin had higher levelsof the growth factor than those that received only the toxin. Thecalves given vitamin E also recovered more quickly from the effectsof the harmful substance.
Mister Elsasser says using Vitamin E helps support growth ratesand may prevent some infections. He says being able to preventinfections linked to stress could lead to lower medical costs andhealthier farm animals.
This VOA Special English AGRICULTURE REPORT was written by GeorgeGrow.