Effects of feeding a live yeast on rumen fermentation and fiber degradability of tropical and subtropical forages.

BACKGROUND: The effect of live yeast Saccharomyces cerevisiae strain CNCM I-1077 (SC) on the ruminal degradability of different forages commonly found in dairy diets in South America was evaluated. We also assessed if SC supplementation interacts with forage group to affect ruminal fiber degradability. Four non-lactating rumen-cannulated Holstein cows were randomly assigned to two treatment sequences: Control-SC-Control or SC-Control-SC, in a switchback design, with three 30-day periods. Cows in the SC treatment were supplied with 1 × 1010 colony-forming units of yeast daily via rumen cannula. In situ degradability of dry matter (DM) and neutral detergent fiber (aNDF) was measured in 15 forages collected in South America. Forages were assigned to one of three groups: corn silages; tropical grasses (sugarcane silages and tropical grass silages); and temperate grasses and alfalfa (oat silages, ryegrass silages, alfalfa silage, and alfalfa hay). RESULTS: Cows supplemented with SC had higher (P = 0.05) counts of yeasts and lower (P = 0.03) concentration of lactate in rumen fluid. There was no interaction between forage group and yeast supplementation (P > 0.10) on in situ degradability. The SC increased DM (by 4.6%) and aNDF degradation (by 10.3%) at 24 h of incubation (P < 0.05). Metabolomics revealed that a chemical entity (C17 H29 N6 O3 , m/z 365.2284 [M + H]+ ) from the family of lipids and related molecules was suppressed in the rumen fluid of cows supplemented with SC. CONCLUSION: The SC supplementation improved DM and aNDF degradability regardless of the forage group. © 2021 Society of Chemical Industry.

Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls.

Exogenous fibrolytic enzymes (EFE) improve the energy availability of grains for nonruminant animals by reducing encapsulation of the endosperm nutrients within grain cell walls; however, these benefits are unknown in the treatment of corn-based silage for cattle. The objective of the present study was to evaluate the effects of adding EFE at ensiling on the nutritive value of high-moisture corn (HMC) and snaplage (SNAP) for finishing Nellore bulls. The EFE dose was 100 g/Mg fresh matter in both HMC and SNAP. Diets were 1) a SNAP + HMC control (without enzyme addition); 2) SNAP + HMC EFE (with enzymes); 3) a whole-plant corn silage (WPCS) + HMC control (without enzyme addition); and 4) WPCS + HMC EFE (with enzymes). In addition to the silages, the diets were also composed of soybean hulls, soybean meal, and mineral-vitamin supplement. The statistical design was a randomized complete block with a factorial arrangement of treatments, and the experiment lasted 122 d. For in situ and in vitro analyses, 2 cannulated dry cows were used. There was no interaction between the diets and EFE application (ADG, P = 0.92; DMI, P = 0.77; G:F, P = 0.70), and there was no difference between the SNAP and WPCS diets regarding the DMI (P = 0.53), ADG (P = 0.35), and feed efficiency (ADG:DMI, P = 0.83). Adding EFE to the HMC and SNAP at ensiling did not affect ADG but decreased DMI (P = 0.01), resulting in greater feed efficiency by 5.91% (P = 0.04) than that observed in animals fed diets without the addition of EFE. Addition of EFE to HMC resulted in reduced NDF content and increased in vitro and in situ DM digestibility compared with untreated HMC. No effects were found for the addition of EFE to SNAP. Fecal starch decreased with EFE application (P = 0.05). Therefore, the diet energy content (TDN, NEm, and NEg) calculated from animal performance increased (P = 0.01) with the addition of EFE to HMC. In conclusion, exchanging the NDF from WPCS with that from SNAP did not affect the performance of finishing cattle, whereas the addition of EFE to HMC at ensiling improved animal performance by increasing the energy availability of the grain.

Energy balance in grazing Jersey cows in early lactation supplemented with peanut and sunflower oils.

In this study, we evaluated the effects of supplementation with peanut and sunflower oils on intake and digestibility, milk yield and composition, energy balance (EB), changes in weight and body condition score (BW and BCS), and blood metabolites of Jersey cows on pasture in early lactation. Twenty-four cows were distributed in a randomized block design where they received the following treatments: concentrate without oil (CON), concentrate plus 59.6 g/kg DM peanut oil (PEA), concentrate plus 59.6 g/kg DM sunflower oil (SUN), and concentrate plus 59.6 g/kg DM of a 1:1 mixture of peanut oil and sunflower oil (MIX). The data were analyzed at 30 and 60 days in milk (DIM). Oil supplementation did not affect total dry matter intake or forage intake. The treatment SUN reduced daily milk yield, 4% fat-corrected milk yield, and milk fat, while the other treatments generated similar results. The treatment SUN reduced the milk net energy and the use efficiency of the NEL for milk production and BW and BCS changes, and improved EB up to 60 DIM. On tropical pastures, supplementation with unsaturated oils for cows in early lactation does not result in better milk performance. The supplementation with sunflower oil improves the energy balance in early lactation.