RESUMEN
A feedlot study was conducted comparing a natural feed additive at varying corn silage (CS) inclusions on receiving and finishing cattle performance. The study utilized 480 crossbred steers (initial shrunk body weight [BW] = 296 kg; SD = 24.1 kg) in 48 pens with 10 steers/pen and 8 pens per treatment. Treatments were designed as a 2 × 3 factorial with 3 inclusions of CS (14%, 47%, 80%; dry matter [DM] basis) with or without (+, -) the inclusion of a feed additive containing fumaric acid and palm oil (FAPO). All treatment diets contained 16% modified distillers grains plus solubles and 4% supplement with dry-rolled corn replacing CS on a DM basis. All steers were fed the 80 CS diet and adapted to 47% and 14% CS over a 10- and 24-d period, respectively. Cattle fed 80 CS were fed for 238 days, 47 CS for 195 days, and 14% CS were fed for 168 days to a common backfat of 1.28 cm (P ≥ 0.59). There were no interactions for CS inclusion and the inclusion of FAPO on final body weight (FBW), DMI, ADG, G:F, hot carcass weight (HCW), LM area, marbling, or calculated yield grade (CYG; P ≥ 0.15). There was no significant difference for FBW, DMI, ADG, G:F, HCW, marbling, or CYG for cattle fed with or without FAPO (P ≥ 0.13). However, there was a quadratic response for FBW, ADG, G:F, HCW, marbling, and CYG with increased inclusion of CS (P ≤ 0.04). Inclusion of FAPO had no effect on performance. Feeding CS at greater inclusions decreased daily gain and feed efficiency but increased FBW when fed to an equal fat endpoint. CS gave greater returns ($/animal) when fed at 80% of diet DM. Feeding greater amounts of CS can be an economical way to finish cattle. In this study, FAPO did not affect animal performance, carcass characteristics, or economic return.
RESUMEN
To determine the effects of harvest method and ammoniation (3.7% of dry matter) on consumption and waste of baled corn residue, a 6 × 6 Latin square with a 3 × 2 factorial treatment structure was conducted. Six treatments consisted of either nonammoniated or ammoniated residue, harvested one of three ways: conventional rake and bale (CONV), New Holland Cornrower with two rows of stem chopped into the windrow with tailings (2ROW), or EZBale system (EZB) with a disengaged combine spreader and tailings dropped in a windrow. Open cows were grouped by body weight to produce a light block of two pens (448 kg ± 49.6) and a heavy block of four pens (649 kg ± 65.9). One bale was fed to each pen during each of six 7-d periods using round bale ring feeders with closed bottom panels. Residue falling around (waste) and remaining in (refusals) the feeder was collected. The daily nutrient intake was estimated as the difference between what was offered and what remained (waste plus refusals). Crude protein (CP) of residue offered did not differ (P = 0.58) among harvest methods. The digestible organic matter (DOM) content of residue offered in 2ROW and EZB bales did not differ (P = 0.86) and was greater (P < 0.01) than CONV. Ammoniation increased (P < 0.01) CP and DOM content of the residue offered. Total wasted and refused residue did not differ (P = 0.12) between 2ROW (29%) and EZB (37%), while CONV (42%) was greater (P = 0.02) than 2ROW but did not differ (P = 0.34) from EZB. Ammoniation reduced (P = 0.03) total waste and refusals from 41% to 32%. The nutrient content of both waste and refusals did not differ (P ≥ 0.34) among harvest methods and, with the exception of CP, was not affected (P ≥ 0.15) by ammoniation. The CP content of the waste was greater (P = 0.02) and refusals tended to be greater (P = 0.08) from ammoniated bales. The CP intake of 2ROW was greater (P ≤ 0.02) than both EZB and CONV, while EZB tended (P = 0.06) to be greater than CONV. The CP intake of all ammoniated residues was greater (P < 0.01) than the nonammoniated residue. The DOM intake of nonammoniated 2ROW and EZB did not differ (P = 0.61) but was greater than nonammoniated CONV (P < 0.01). Ammoniation increased (P < 0.01) DOM intake. Overall, ammoniation had much larger effects than harvest method, resulting in reduced waste and refusals and greater intake of DOM and CP. However, the combination of both ammoniation and selective harvest (2ROW or EZB) was needed to result in energy and protein intakes that would meet the needs of a mature cow in mid-gestation.