The trial was conducted at the Centro de Producción Agrícola of ICfA in Cuyuta, Escuintla-Guatemala in order to generate information on the yield and quality of edible mulberry (Morus sp.) roughage treatments consisted of three harvest frequencies (6; 9 and 12 weeks and three fertilization levels of nitrogen (0.40 and 80 kg/ha). A complete randomized block experimental design, with a factorial arrangement (3x3) was used. The cutting height was 0.3 m above the ground level with two sequencies: from August 2nd to September 13 th and from September 13th to December 6th, 1990. In both cases, the 12 week frequency cutting and 80 kg of N were superior to the others (P<=0.01), yielding 6.87 and 6.15 t/ha of dry matter respectively. The yields at 9 weeks were statistically higher than those at 6 weeks. The highest protein percentage of the whole plant, leaves and stalks were produced at 6 weeks. The dry matter digestibility values in vitro showed little variability among treatments, with averages for whole plants, leaves and stalks of 65, 91 and 41 %, respectively. The preceeding data suggests that the mulberry has an excellent potential as a balanced supplement (protein and energy) for dual purpose cattle on the Southern coast of Guatemala.

Two experiments were conducted to evaluate the effects of feeding corn modified wet distillers grain plus solubles (MWDGS) co-ensiled with direct-cut forage (DC) to beef steers, on feedlot performance and total tract digestibility. In Exp. 1, sixty-four crossbred Angus steers (n = 64; 329 ± 43 kg) were blocked by BW and randomly assigned to 1 of 4 dietary treatments: 1) corn-silage and soybean meal (CON), 2) DC co-ensiled with MWDGS (CO-EN), 3) haylage mixed with MWDGS at feeding (H+WDG), and 4) haylage mixed with dry distillers grains plus solubles at feeding (H+DDG). Steers were harvested when they reached an endpoint of 1.1 cm of 12th-rib back fat. In Exp. 2, four ruminally cannulated beef steers (initial BW = 556 ± 31 kg) were used in a 4 × 4 Latin square to evaluate digestibility of diets used in Exp. 1. Experimental periods were 14 d in length with 10 d for diet adaptation and 4 d for sample collection. Three linear orthogonal contrasts were used to compare effects of 1) CON vs. diets containing distillers grains (DGD), 2) CO-EN vs. diets where distillers grains were mixed at feeding (MIX), and 3) H+WDG vs. H+DDG. In Exp. 1, DMI was less (P < 0.001) for steers fed CON compared with those fed DGD and greatest (P < 0.001) for steers fed CO-EN compared with MIX. Corn-silage- and soybean-meal-fed steers had more days on feed than those fed DGD (P = 0.001). Body weight gain (P = 0.02) was greater for CO-EN compared with MIX. Fat thickness at the 12th and 13th ribs was greater (P = 0.03) for DGD steers compared with CON steers. Hot carcass weight was greater (P = 0.03) for steers fed CO-EN compared with those fed MIX. Steers fed CON resulted in greater marbling scores (P = 0.01) compared DGD-fed steers. Longissimus muscle area was greater (P = 0.01) for CON-fed steers compared with all other treatments. In Exp. 2, no differences (P > 0.10) in DM, OM, or N intakes were observed. Apparent total tract DM (P = 0.01) and N (P = 0.02) digestibility were greatest in steers fed CON compared with all others. Steers fed DGD had less (P = 0.02) rumen NH(3) concentrations compared with CON. The CON diet resulted in greater molar concentrations of VFA (P = 0.03) and decreased acetate to propionate ratio (P = 0.03) compared with all DGD. These data suggest that feeding MWDGS co-ensiled with direct-cut forage results in reduced diet digestibility but equal or greater feedlot performance and similar carcass and characteristics when compared with a corn diet supplemented with soybean meal and diets where MWDGS and DDGS were added at the mixer.

Two experiments were conducted to evaluate the effect of feeding corn modified wet distillers grain plus solubles (MWDGS; 48% DM) co-ensiled with chopped whole plant corn (WC) on growth performance, dietary intake, and nutrient digestibility of beef cattle. In Exp. 1, 96 Angus-crossed heifers (2 yr old; 522 ± 49.1 kg BW; 5.3 ± 0.1 BCS) were stratified and blocked according to BW and stratified by BCS in each block in a randomized complete block design (24 pens; 4 heifers/pen; 6 treatment replications). Groups were assigned to 1 of 4 dietary treatments for a 62 d trial. Treatments were 1) corn silage (CS) and soybean meal (CON), 2) MWDGS co-ensiled with chopped whole plant corn (WC; CO-EN), 3) CS mixed with MWDGS at feeding (CS+WDG), and 4) CS mixed with dry distillers grain plus solubles (DDGS) at feeding (CS+DDG). In Exp. 2, 4 crossbred beef steers (initial BW = 278 ± 18 kg) fitted with permanent ruminal cannulas were used in a balanced 4 × 4 Latin square to test the effects of feeding MWDGS co-ensiled with WC on DM intake, ruminal fermentation characteristics, and total tract digestibility. There were four 14-d periods, with 10 d for diet adaptation and 4 d for samples collection. Orthogonal contrasts were used and compared CON vs. diets containing distillers grains (DGD), CO-EN vs. diets where distillers grains were mixed at feeding (MIX), and CS+WDG vs. CS+DDG. In Exp. 1, the CON fed heifers resulted in greater G:F (P = 0.04) compared with those fed DGD. However, ADG (P = 0.03), final BW (P = 0.04), and BW gain (P = 0.03) were greatest for DGD diets compared with CON and greatest (P = 0.04) for CO-EN when compared with MIX. Apart from a slightly greater acetate concentration (P = 0.05), which resulted in a greater acetate to propionate ratio (P = 0.03) for the CON diet compared with DGD, no important differences were observed on intake, diet digestibility, or fermentation characteristics when comparing the CON treatment with DGD or when comparing CS+WDG with CS+DDG. However, the CO-EN diet resulted in decreased DMI (P = 0.05) and consequently decreased OM (P = 0.05), N (P = 0.04), and NDF (P = 0.02) intakes compared with MIX. Data from these studies suggest that MWDGS co-ensiled with WC can successfully replace traditional corn-based diets supplemented with soybean meal and corn silage diets supplemented with distillers grains without compromising digestibility and growth performance in pregnant heifers.