The Effect of Sodium Hydroxide Treatment of Fescue-Corn Stillage Diets on Intake, Digestibility and Performance with Lambs

Abstract

One laboratory silo trial, two lamb digestion trials and one lamb growth trial were conducted to determine the feeding value of diets containing NaOH-treated tall fescue hay and corn whole stillage. Lamb trials were conducted at ad libitum intakes. Untreated or 4% NaOH-treated fescue was ensiled with 0, 15, 30 or 60% stillage in a fermentation study. After 20 d of fermentation, silages treated with NaOH had higher (P<.05) pH, butyrate and acetate, and lower (P<.05) lactate and crude protein than untreated silages. Average pH was 7.4 for NaOH-treated silages compared with 5.0 for untreated silages. Lactate and crude protein increased linearly (P<.05) with level of stillage. Butyric acid was highest for silage containing 60% stillage and NaOH-treated fescue. When the same silages were evaluated in a digestion trial, NaOH-treatment increased (P<,05) dry matter intake (916 vs 747 g/d) and dry matter digestibility (63 vs 56.2%) compared with untreated silages. Both intake and digestibility increased linearly (P<.05) with level of stillage. Level of NaOH (0, 2, 4 or 6%) and direct ensiling or mixing of ingredients at time of feeding were evaluated in a digestion study with diets containing 30% stillage. Dry matter intake and digestibility were not affected (P>.05) by method of feeding. Two or four percent NaOH addition increased intake more than 0 or 6% NaOH (P<.05, quadratic). Neutral detergent fiber digestibility was greater for 2% NaOH-treated fescue mixed with stillage at feeding (60.4%) compared with the corresponding ensiled diet (46.7%) suggesting a neutralization of NaOH during ensiling. In a lamb growth trial, lambs fed an ensiled 4% NaOH-treated fescue plus 30% stillage diet consumed more dry matter, but had similar gains and feed efficiency compared with lambs fed untreated fescue plus stillage or corn silage diets.