Abstract
A method for treating maize straw with urea was developed and used to produce enough treated material for a feeding trial with native Bunaji (Zebu) cattle in the dry season. Chopped maize straw was treated with graded levels of urea of 0, 20, 40, 60 and 80 g, each dissolved in 500 ml water and applied to 1 kg of the chopped straw. The treated forages were ensiled in laboratory silos for 1, 3, 5 or 7 weeks duration. The extent of dry matter disappearance of treated material was determined by nylon bag incubation in vivo. The lowest urea concentration and shortest ensilage period which gave a maximal dry matter disappearance was 40 g urea kg
−1 straw (4% urea concentration) ensiled for 1 week.
Chopped corn straw treated with 4% urea and ensiled for 1 week was given in a 2 × 2 factorial feeding trial with native Zebu cattle. The factors were straw type (treated vs. untreated) and supplement type (groundnut haulms vs. no groundnut haulms). The crude protein content of chopped maize straw was 8.4% compared with 4.8% for the untreated material. Organic matter digestibility was 65.3% for treated straw and 51.0% for untreated straw. Both urea treatment and supplementation with groundnut haulms significantly increased straw intake, but did not prevent cattle weight loss. There was no significant treatment effect on cattle weight changes, although there were trends favouring such treatments.
Treatment of maize straw with 4% urea ensiled for 1 week for cattle feed, coupled with the feeding of groundnut haulms for cattle in the dry season, is likely to minimise weight losses in the season.