Effect of feeding sheep on naturally spoiled rice straw, clover hay and concentrate feed mixtures

The effects of feeding naturally contaminated feedstuffs to sheep were investigated through feeding of contaminated and uncontaminated clover hay, rice straw, and concentrate feed mixture were compared. The highest level of contamination with fungi was observed in the concentrate feed mixture followed by clover hay and rice straw. The most dominant mycotoxin in the contaminated feedstuffs was zearalenone. Contamination resulted in increases of crude protein, ash and silica in feedstuffs while both ether extract and crude fibre decreased. In vivo digestibility of different diet constituents in both contaminated and uncontaminated feedstuffs were determined using four mature Rahmani rams. Contamination resulted in significant increase in the digestibility of dry matter, crude fibre and energy. Contamination affected feed intake of the different feedstuffs particularly the concentrate feed mixture. A metabolism trial was also conducted to study the nitrogen and mineral balance. Retention of nitrogen and calcium was reduced when mouldy feeds were given. On the other hand, magnesium was relatively increased. Blood analysis for sheep at the end of the trials resulted in elevated values of inorganic phosphorus and phospholipid phosphorus and declined total nitrogen, calcium, cholesterol, calcium/phosphorus ratio and cholesterol/calcium ratio due to feeding on mouldy ration. Results of the urine analysis during the metabolism trials proved that mouldy ration increased the estimated values of the concentration of calcium, magnesium and vitamin C; whereas pH values, total nitrogen, ammonia nitrogen and inorganic phosphorus were declined during the feeding on the mouldy ration. Mouldy feeds tested, seemed to have toxic, nephritic and hepatic effect.