Effects of silage sealing films on fermentation dynamics of ensiled maize and nutrient utilization by Damara rams

Abstract

An experiment was conducted to evaluate the effects of two silage sealing films on whole crop maize (WCM) fermentation, aerobic stability and nutrient digestion by rams. Prior to ensiling (day 0), triplicate samples of the WCM were collected to determine dry matter, pH, water-soluble carbohydrates (WSC), lactic acid (LA) bacterial counts and nutrient concentration. A single bunker silo was divided into eight sections that were ensiled using either a standard polyethylene film (PE) or an orange oxygen barrier (OB) Silostop film for 180 days. After 180 days of ensiling, six silage samples were collected from each replicate. Three samples were used for nutrient analysis and the other three to determine aerobic stability. Sixteen four-year-old Damara rams with an average live weight of ± 54 kg were housed individually in wooden pens (2.2 m²) to determine digestibility of nutrient in the silage. The digestibility study was conducted as a switchover design with four feeding phases. The silage was supplemented daily with 1% urea and fed to the rams ad libitum. Nutritional value of the silage was not (P >0.05) affected by the ensiling films. The OB-ensiled maize had higher (P <0.05) LA, lower pH, CO₂ production and yeast and mould populations, and lower WSC compared with the PE-ensiled maize. Dry matter intake, nutrient digestion and nitrogen balance of rams fed the silage were not affected (P >0.05) by treatments. The OB film improved the fermentation and aerobic stability of WCM silage but did not influence its nutrient utilization by rams.

Keywords: cereals, digestibility, forage, rams, nitrogen, supplementation