Abdelhadi LO, Mattioli GA, Owens FN, DiLorenzo N. · Translational animal science · 2026

Growth performance and nutrient digestibility of beef heifers fed sorghum silage processed at harvest and stored for less than five months or over one year.

Resumo original em inglês

This study evaluated the effects of feeding sorghum silage ( SS ), either processed ( PRO ) or not ( NPR ) at harvest, on animal performance, apparent total tract digestibility ( ATTD ), and in situ nutrient degradability ( ISND ). The sorghum plant was harvested when the kernels were at the hard dough stage and kernel processing was applied or not prior to ensiling. Kernel processing was done with 110-tooth rolls, at 1.1 mm gap, and 50% speed differential, yielding a theoretical length of cut of 15 mm. On a dry matter (DM) basis, diets contained 90.5% SS, 6.5% soybean expeller, and 3% vitamin-mineral supplement. Performance and ATTD trials were conducted over two consecutive years using SS stored for Y1 ) or > 375 days ( Y2 ). In situ nutrient digestibility was assessed on samples ensiled from 0 to 455 d. Animal performance studies were conducted using 96 Angus heifers each year in a completely randomized design with 6 pens (8 heifers/pen in both years), followed by an experiment to determine ATTD using one randomly selected heifer/pen at the end of each performance study. Data were analyzed as a completely randomized design using the Mixed procedure of SAS, with treatment as a fixed effect and initial body weight as covariate in the performance trials, and repeated measures in the ISND trial. In Y1, no differences in dry matter intake (DMI) were detected between treatments, but PRO improved final body weight and average daily gain (ADG; P P = .03). Apparent total tract digestibility of starch in Y1 was greater in PRO ( P P = .01), but ADG and feed efficiency were not different between treatments ( P > .10). Nutrient intake and digestibility in Y2 were unaffected by treatments. For ISND, a treatment × day interaction was detected ( P P 375 days. Processing appears to enhance in situ DM degradability up to ∼300 days of storage, while starch degradability increased with storage time regardless of processing.