Evaluation of yeast-based additives on rumen fermentation in high- and low-concentrate diets using a dual-flow continuous culture system.

The objective of this study was to evaluate the efficacy of using 3 yeast-based additives as an alternative to sodium monensin on rumen fermentation parameters using a dual-flow continuous fermentation system. Ten fermenters (1,223 ± 21 mL) were used in 2 simultaneous 5 × 5 Latin squares arrangement with 3 periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. Each Latin square assigning either a low or high level of concentrate to beef cattle diets, with 5 specified treatments: Control: no additives; Blend 1: yeast culture (), beta-glucans, fructooligosaccharides, galactooligosaccharides, and mannanoligosaccharides [1,600 mg/kg dry matter (DM)]; Blend 2: Beta-glucan and mannanoligosaccharide fractions from (1,600 mg/kg DM); Yeast Cells: hydrolyzed, inactivated, and spray-dried yeast cells (; 2,133 mg/kg DM); monensin (25 mg/kg DM).

Phenotypic association among performance, feed efficiency and methane emission traits in Nellore cattle.

Enteric methane (CH4) emissions are a natural process in ruminants and can result in up to 12% of energy losses. Hence, decreasing enteric CH4 production constitutes an important step towards improving the feed efficiency of Brazilian cattle herds. The aim of this study was to evaluate the relationship between performance, residual feed intake (RFI), and enteric CH4 emission in growing Nellore cattle (Bos indicus).

Animals selected for postweaning weight gain rate have similar maintenance energy requirements regardless of their residual feed intake classification.

Data of comparative slaughter were used to determine Nellore bulls' net energy requirements classified as efficient or inefficient according to residual feed intake (RFI) and selection lines (SL). Sixty-seven Nellore bulls from the selected (SE) and control (CO) lines of the selection program for postweaning weight gain were used. The animals underwent digestibility trials before being submitted to the finishing trial.

Genetic association among feeding behavior, feed efficiency, and growth traits in growing indicine cattle.

This study aimed to estimate genetic parameters, including genomic data, for feeding behavior, feed efficiency, and growth traits in Nellore cattle. The following feeding behavior traits were studied (861 animals with records): time spent at the feed bunk (TF), duration of one feeding event (FD), frequency of visits to the bunk (FF), feeding rate (FR), and dry matter intake (DMI) per visit (DMIv). The feed efficiency traits (1,543 animals with records) included residual feed intake (RFI), residual weight gain (RWG), and feed conversion (FC).

Association between residual feed intake, digestion, ingestive behavior, enteric methane emission and nitrogen metabolism in Nellore beef cattle.

This study aimed to evaluate nutrient intake and digestibility, enteric methane emission and nitrogen utilization efficiency in Nellore cattle ranked by residual feed intake (RFI). Twenty-four Nellore bulls at 466 ± 24 days of age and with 352 ± 14.6 kg of body weight, classified as low and high RFI, were evaluated.

The phenotypic relationship between residual intake and gain and other feed efficiency traits in Nellore cattle.

This study aimed to compare feed efficiency measures of Nellore beef cattle on different residual intake and gain (RIG) classes. We used data from 610 animals weighing on average 236.33 kg and average of 283 days of age from feedlot performance tests carried out between 2005 and 2012.

Correction: Genomic Regions Associated with Feed Efficiency Indicator Traits in an Experimental Nellore Cattle Population.

[This corrects the article DOI: 10.1371/journal.pone.

Digestion and metabolism of low and high residual feed intake Nellore bulls.

Understanding the reasons why animals of similar performances have different feed requirements is important to increase profits for cattle producers and to decrease the environmental footprint of beef cattle production. This study was carried out aiming to identify the associations between residual feed intake (RFI) and animal performance, nutrient digestibility, and blood metabolites related to energy balance of young Nellore bulls during the finishing period. Animals previously classified as low (n = 13) and high RFI (n = 12), with average initial body weight of 398 kg and age of 503 days were used.

Genomic Regions Associated with Feed Efficiency Indicator Traits in an Experimental Nellore Cattle Population.

The objective of this study was to identify genomic regions and metabolic pathways associated with dry matter intake, average daily gain, feed efficiency and residual feed intake in an experimental Nellore cattle population. The high-density SNP chip (Illumina High-Density Bovine BeadChip, 777k) was used to genotype the animals. The SNP markers effects and their variances were estimated using the single-step genome wide association method.

Feed efficiency, blood parameters, and ingestive behavior of young Nellore males and females.

This study aimed to evaluate differences in efficiency of feed utilization between young Nellore males and females by comparing growth traits, feed intake, blood parameters, and ingestive behavior of the animals. Data from 768 Nellore males and females that participated in eight performance tests for individual feed intake evaluation were used. Performance and feed efficiency measures, efficiency-related hematological, metabolic and hormonal variables, and data regarding ingestive behavior were collected.

Methane emission by Nellore cattle subjected to different nutritional plans.

The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to different nutritional plans, as well as the intake and digestibility of nutrients from the diets supplied. Forty-seven animals in a confinement system (feedlot) were fed a corn silage-based diet for 35 days. Afterwards, these animals were evaluated in a grazing system during the rainy periods, in Urochloa brizantha cv Marandu paddocks, for 44 days.