ARS | Publication request: DIET EFFECTS ON DAIRY MANURE NITROGEN EXCRETION AND CYCLING

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 15, 2004
Publication Date: N/A

Technical Abstract: The amount and forms of nitrogen (N) excreted by ruminant livestock and post excretion manure N cycling are highly influenced by what is fed. We evaluated dairy diet effects on amount and forms of manure N excreted and post excretion cycling of manure N from different diets after application to soil. Most observed diets had no impact on milk production but affected the amount, and the relative N partitioning in, and composition of urine and feces. Fresh and stored slurry from a low CP diet (13.6%) had less than one-half the ammonia loss than slurries from a high CP (19.4%) diet. Fresh slurry derived from a birdsfoot trefoil, high tannin (BF-T-High) forage diet had less ammonia loss than slurry from alfalfa or a birdsfoot trefoil, low tannin (BF-T-Low) forage diet. Stored slurry from BF-T-High and -Low diets had less ammonia loss than slurry derived from alfalfa. As fecal C:N ratio increased, net N mineralisation and N uptake by oats and sudangrass decreased. Results from these studies and the lactation trials from which these manures were derived indicate that diets could be formulated to meet nutritional requirements of high producing dairy cows and produce excreta less susceptible to environmental loss.