Low light intensity. The frequent use of nitrogen fertilizers in recent years has resulted in an increased incidence of nitrate poisoning. The belief that nitrate poisoning occurs only when annual forages are fed is quite untrue. Perennial forages are just as likely to accumulate nitrates where high fertilizer dressings are used. Understanding Nitrate Toxicity Nitrates normally occur in plants and are a necessary soil nutrient for crop growth.
Ammonia is a protein-building chemical.
If excess nitrates are ingested, excess nitries accumulate in the rumen because the bacteria are unable to convert all the nitrite into ammonia. Nitrite is absorbed into the oxygen transporting chemical hemoglobin. Many publications report that consumption of nitrates at levels above normal, but below toxic stage, can cause lower milk production, reduced weight gains, and vitamin a deficiency. Abortions started 48 hours after the exposure and continued for 3 weeks. Nine abortions occurred from 96 hours to 7 days after esposure.