Sebastiao Valadares Filho

• Federal University of Viçosa

This study evaluated two roughage types (sugarcane and corn silage) and two concentrate feed levels (0 and 25% of the total dry matter) in the cattle diet, in a 2x2 factorial design, and compared passage rate measurements (indicator and rumen evacuation). Four Holstein-Zebu heifers cannulated in the rumen and ileum were evaluated, in a 4x4 Latin sq...

Simple Summary This study examined the effects of different prepartum supplementation plans for Nellore cows, testing a control group receiving only minerals and three groups receiving 2 g, 4 g, or 6 g of protein-energy supplement per kilogram of body weight daily. Cows receiving 4 g and 6 g supplements showed improved body weight, condition scores...

Simple Summary Several studies with Bos taurus cows report a decrease in voluntary intake close to parturition. However, there are few studies on the evaluation of these parameters in grazing Nellore cows receiving protein supplementation, which could mitigate the decrease in forage intake and improve animal performance. Hence, this study sought to...

The aims of this study were to predict carcass and meat traits, as well as the chemical composition of the 9th to 11th rib sections of beef cattle from portable NIR spectra. The 9th to 11th rib section was obtained from 60 Nellore bulls and cull cows. NIR spectra were acquired at: P1 –center of Longissimus muscle; and P2 –subcutaneous fat cap. The...

The objective of this meta-analysis was to develop and evaluate models for predicting nitrogen (N) excretion in feces, urine, and manure in beef cattle in South America. The study incorporated a total of 1,116 individual observations for N excretion in feces and 939 individual observations for N excretion in feces and in urine (g/d), representing a...

The aim of this study was to develop and validate regression models to predict the chemical composition and ruminal degradation parameters of corn silage by near-infrared spectroscopy (NIR). Ninety-four samples were used to develop and validate the models to predict corn silage composition. A subset of 23 samples was used to develop and validate mo...

The objective of this research was to evaluate how pregnancy and feeding regimens affect the feed intake, digestibility, and efficiency of microbial nitrogen (N) synthesis in beef cows. Forty-four multiparous Nellore cows, comprising 32 gestating and 12 non-gestating cows, with an average weight of 451 ± 10 kg, were assigned to either a HIGH (ad li...

We evaluated the effects of various wild strains of Lentilactobacillus buchneri on the fermentation and aerobic stability of sorghum silages as well as on their intake, digestibility, nitrogen balance, and ruminal fermentation in lambs. Four Santa Inês × Dorper crossbred lambs with rumen fistulations were distributed using a 4 × 4 Latin square desi...

This study evaluated the fermentation characteristics, microbial diversity, chemical composition, and in vitro digestibility of forage peanut silage harvested at two regrowth ages and treated with microbial inoculants at different fermentation periods. A randomized block design was used, with two regrowth ages (R; 40 and 80 days), three microbial i...

We aimed to estimate the protein requirements of pregnant Holstein × Gyr cows. Sixty-one Holstein × Gyr (HG) cows were used, with an average initial BW of 480 ± 10.1 kg and 5 ± 0.5 yrs of age. Cows were divided into 3 groups: pregnant (n = 43), non-pregnant (n = 12), and baseline (n = 6). Baseline animals were slaughtered before starting the experi...

Objective: This study was realized to evaluate the effects of supplementation with blends of water and fat-soluble vitamins on animal performance and carcass traits of young Nellore bulls. Methods: Forty-three Nellore bulls, with an initial weight of 261 ± 27.3 kg and a mean age of 8 ± 1.0 months, were used. Five animals were slaughtered at the...

Objetivou-se desenvolver e avaliar modelos de regressão para a predição da composição química da cana-de-açúcar, farelo de soja e fubá de milho por NIR portátil aliado a técnicas quimiométricas. Foram utilizadas 95 amostras de cana-de-açúcar, 92 amostras de farelo de soja e 120 amostras de fubá de milho. Após a moagem das amostras, foi realizada aq...

Simple Summary Although weaning is a necessary and indispensable practice for the beef cattle production system, it is known to cause multiple stressors in the cow–calf pair. However, few studies have explored the effects of stress on weaning in the dams, and little is known about the effect of parity on stress responses. The objective of this stud...

Creatinine is a urinary marker used widely in ruminant’s experimental trials. However, despite its great importance no data were found in the literature about the best way to store bovine urine samples. In the sheep urine, was observed an increase in the urinary concentration of creatinine when it was stored acidified (pH 2.5 to 3.5) at a temperatu...

On-farm methane (CH4) emissions need to be estimated accurately so that the mitigation effect of recommended practices can be accounted for. In the present study prediction equations for enteric CH4 have been developed in lieu of expensive animal measurement approaches. Our objectives were to: (1) compile a dataset from individual beef cattle data...

The accurate prediction of milk yield is necessary to estimate the nutrient requirements of cows and calves. It still necessary the development of reliable equations that include data from beef cows experiencing different conditions in different years. The objective of this study was to evaluate the milk yield of grazing Nellore cows under tropical...

We objective was to understand the changes in nutritional characteristics and performance of grazing Nellore cows during the peripartum receiving or not supplementation. Forty multiparous cows were used, divided into two treatments: CON - mineral mixture and SUP – protein supplementation. Digestibility trial was performed (-45,-30,-15, + 20, +40; d...

Context Supplementation during the pre- and post-weaning periods is essential to improve the development of beef heifers in tropical pastures. Especially during the dry period, performance of heifers is limited due to low forage yield and poor nutritional value. Aim Evaluate the effect of supplementation during pre- and post-weaning periods on per...

Rumen cannulated Nellore bulls (n = 4) were used in a 4 × 4 Latin square design, with a 2 × 2 factorial scheme to evaluate the effects of vitamin supplementation on: 1) ingestive, digestive, and ruminal parameters; 2) serum concentrations of 25-hydroxyvitamin D (25(OH)D); and 3) in situ degradability of complete diets. The factors consisted of two...

Manure N from cattle contributes to nitrate leaching, nitrous oxide and ammonia emissions. Measurement of manure N outputs on commercial beef cattle operations is laborious, expensive, and impractical; therefore, models are needed to predict N excreted in urine and feces. Building robust prediction models requires extensive data from animals under...

The objective of this study was to evaluate the effects of silage and concentrate on nutrients digestibility, ruminal fermentation, efficiency of nitrogen use and animal performance of feedlot beef cattle. Two experiments were conducted simultaneously evaluating the same diets. The forage: concentrate ratio was 50:50 and diets consisted of Stylosan...

This study aimed to create an equation to predict the dry matter intake (DMI) of Nellore cattle using intake data from Azevedo et al. (2016) and intake data from animals raised in commercial feedlots in Brazil. This equation will then be compared with other equations already published. A correlation analysis between performance variables and DMI wa...

This study aims to determine the effects of dietary crude protein (CP) content of early-weaned calves; and the influence of flint maize processing methods on intake, total tract nutrient digestibilities and performance of Nellore heifer calves. Fifteen early-weaned Nellore female calves (4 ± 0.5 months; 108 ± 13.1 kg) were used. In phase 1, animals...

The objective was to evaluate the effect of including low-fat dried distillers grains (DDG) in finishing diets on protein and energy intake and retention and to estimate the protein and energy requirement of young Nellore bulls. Thirty-five animals were used: baseline (n = 4), maintenance (n = 4), and ad libitum intake (n = 27). Ad libitum animals...

This study aimed to evaluate the effect of parity order on milk yield (MY) and composition over time of grazing beef cows and to evaluate non-linear models to describe the lactation curve. Thirty-six pregnant Nellore cows (12 nulliparous, 2 years; 12 primiparous, 3 years; and 12 multiparous, 4–6 years) were included in the study. With calving day a...

An experiment was conducted to evaluate the feed intake, nutrient digestibility and selected rumen parameters in feedlot bulls fed diets containing different feed additives. Six rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 225 ± 13.2 kg) were distributed in a 6 × 6 Latin square design. Six experimental diets based on 30% corn...

The objective of this study was to evaluate the total and partial digestibility, ruminal pH and ammonia nitrogen (NH3-N) concentration, nitrogen balance (Experiment 1) and performance (Experiment 2) of beef cattle fed diets containing corn silage (CS) and Stylosanthes (silage or hay) as forage source. Treatments were: 1) CS; 2) Stylosanthes silage...

Background Metabolic profile evaluation is a tool widely used in ruminant nutrition as metabolic cues that relate nutrition to physiology. Metabolic and hormonal traits change during pre-partum and lactation according to parity in dairy cows, but studies of beef cows under grazing are scarce. The present study aimed to evaluate how metabolic and ho...

This study aimed to evaluate ruminal in situ degradation of diets containing different levels of dried distillers grains (DDG) replacing soybean meal, urea and corn and the effect of these diets on in situ ruminal degradation of DDG, and to propose alternative methods to estimate in vivo digestibility of diets. Four rumen-cannulated Nellore bulls w...

Latin America and Caribbean (LAC) is a developing region characterized for its importance for global food security, producing 23 and 11% of the global beef and milk production, respectively. The region's ruminant livestock sector however, is under scrutiny on environmental grounds due to its large contribution to enteric methane (CH4) emissions and...

This study evaluated the effect of including low-fat dried distillers grains (DDG) on young Nellore bulls performance, nutritional parameters, and nitrogen metabolism. Thirty-five Nellore cattle were randomly divided into four diets: without dried distillers grains (D0) or with the inclusion of DDG at 150 g/kg (D150), 300 g/kg (D300), or 450 g/kg (...

The objective of this study was to evaluate nutrient intake, in vivo digestibility, and in situ degradability of different cultivars of hay (i.e., [Jiggs] and [Tifton-85] bermuda grass (Cynodon spp.) and [alfalfa] (Medicago sativa) and [stylo] Campo Grande (Stylosanthes sp.)) and nitrogen balance in sheep. We used eight rumen-cannulated F1 Santa In...

Microbial crude protein (MCP) produced in rumen could be estimated by a variety of protocols of experimental sampling and analysis. However, a model to estimate this value is necessary when protein requirements are calculated for small ruminants. This model could be useful to calculate rumen degradable protein (RDP) requirements from metabolizable...

Background: Metabolic profile evaluation is a tool widely used in ruminant nutrition as metabolic cues that relate nutrition to physiology. Metabolic and hormonal traits change during pre-partum and lactation according to parity in dairy cows, but studies of beef cows under grazing are scarce. The present study aimed to evaluate how metabolic and h...

Equations to estimate energetic content of small ruminants’ diets from chemical composition, in tropical conditions, are still not available. The main objective of this study was to develop equations to predict the digestible content (ether extract (EE), non-fiber carbohydrate (NFC), crude protein (CP) and neutral detergent fiber (NDF)), for differ...

The objective of this study was to evaluate the inclusion of physically effective fiber (peNDF) from sugarcane in feedlot diets containing whole corn grain on ingestive, digestive, and ruminal parameters. Five rumen-cannulated Nellore bulls (BW = 393 ± 9 kg) distributed in an incomplete 5 × 5 Latin square received diets containing 5% (D5), 15% (D15...

The study aimed to evaluate the excretion of purine derivatives (PDs) and nitrogen compounds (NCs) and their ratios with creatinine in supplemented Zebu heifers kept on pastures by comparing total urine collection and spot sampling. Five Nelore heifers (400 ± 15 kg) were used in a 5 × 5 Latin square design. The treatments were the amount of concent...

This study aimed to (1) evaluate the effects of flint maize processing methods on the estimation of the readily soluble fraction ( a ), the potentially degradable fraction ( b ) and the rate of degradation of b ( c ) for dry matter (DM), organic matter (OM) and starch in the rumen; and (2) verify whether two different applications of in situ techni...

Effects of protein supplementation, with and without starch supplementation, on nutritional performance and metabolic characteristics of cattle fed low- and medium-quality tropical forages were evaluated using 4 cannulated steers distributed according to a 4 × 4 Latin square. Experimental periods were divided into two subperiods. In the first subpe...

The accurate supply of energy is essential to optimize livestock productivity and profitability. Furthermore, replacing empty BW gain (EBG) with carcass gain (CG) might be a suitable alternative to estimate the retained energy (RE) of beef cattle. Thus, this multi-analysis study was conducted aiming to estimate and validate new equations to predict...

Growth rate of cattle depends on their genetic makeup and nutrient intake. Moreover, increased growth rate may lead to increased amino acid (AA) requirements. Therefore, we evaluated the AA content of the empty body and estimated the net AA and energy requirements of purebred and crossbred beef bulls fed rations of different dietary CP concentratio...

This study aims to (1) verify the influence of flint corn processing methods on intake; rumen digestion kinetics; microbial efficiency; rumen pH; and ruminal, intestinal, and total tract digestibilities in Nellore bulls; and (2) determine whether snaplage (SNAP) plus a mineral–protein supplement could be used successfully to supply energy, fiber, a...

Our objective was to estimate the nutrient intake, ruminal flow, total apparent and ruminal digestibility, rates of passage and digestion, ruminal and omasal pH, blood metabolite concentrations, and body measurements during the gestation of Holstein heifers. Eleven pregnant heifers, 8 of which were fitted with a rumen cannula (450 ± 27.6 kg of body...

This study evaluates the intake and digestion of nutrients, parameters of rumen fermentation and degradation, omasal digesta and milk fatty acid composition, productive performance, and the concentration of serum metabolites in cows fed 600 g kg-1 sugarcane-based diets containing 0 (control), 15, 30, and 45 g kg-1 sunflower oil (SO) on a dry matter...

The objectives were to determine the effects of restricted-feeding strategies on blood concentrations of hormones, metabolites, and minerals in Holstein × Zebu finishing steers. Twenty steers (body weight = 319 ± 16.2 kg; age = 19 ± 1 months) were randomly allotted in 4 groups of 5 steers, which were restricted to 85% ad libitum feed intake for eit...

Tropical grass has some advantages for ensilage, such as high annual production of dry matter per unit area, perennity, low loss risk, and higher harvest flexibility. We aimed with this study to assess the chemical composition, microbial population, fermentation characteristics, and effluent production of stylo (Stylosanthes capitata × S. macroceph...

This study aimed to determine feeding behavior, water intake, and energy requirements of high and low residual feed intake (RFI) Nellore bulls. Data were collected from forty-two weaned Nellore bulls (initial BW 260 ± 8.1 kg; age 7 ± 1.0 mo) housed in a feedlot in group pens that contained electronic feeders, waterers, and a scale connected to the...

Accurate estimates of methane (CH 4) production by cattle in different contexts are essential to developing mitigation strategies in different regions. We aimed to: (i) compile a database of CH 4 emissions from Brazilian cattle studies, (ii) evaluate prediction precision and accuracy of extant proposed equations for cattle and (iii) develop special...

Two experiments were conducted: (1) to evaluate the effect of ensiling time and grain source on dietary nitrogen fractions; and (2) to verify the influence of concentrate level, processing method and grain source on intake, microbial efficiency, and digestibility by young Nellore bulls. In Experiment 1, corn and sorghum grains were milled, reconsti...

This study aimed to estimate energy requirements of pregnant Holstein × Gyr cows. Different planes of nutrition were established by two feeding regimens: ad libitum or maintenance. Sixty-two nonlactating cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. Cows were divided into three groups: pregnant (n = 44), non-...

Objective: Objectives were to estimate energy and protein requirements of dairy crossbred steers, as well as to evaluate equations previously described in the literature (HH46 and CS16) to predict the carcass and empty body chemical composition of crossbred dairy cattle. Methods: Thirty-three Holstein × Zebu steers, aged 19 ± 1 months old, with...

An experiment was conducted to evaluate: (1) the effects of ensiling maize or sorghum grains after reconstitution on readily soluble fraction (a), potentially degradable fraction in the rumen (b) and rate constant for degradation of b (c) of dry matter (DM), organic matter (OM) and starch (STA); and (2) an appropriate incubation time for in situ or...

Our objective was to estimate nutrient intake, ruminal flow, total apparent and ruminal digestibility, rates of passage and digestion, ruminal and omasal pH, blood metabolite concentrations, and body measurements during gestation of Holstein heifers. Eleven pregnant Holstein heifers, 8 of which fitted with a rumen cannula (450 ± 27.6 kg of body wei...

Background: Supplementation programs for prepartum beef cows are usually adopted because the nutritional status of the cows upon calving is a main factor impacting reproductive performance of the next production cycle. This study evaluated the effects of 60-d pre-partum energy-protein supplementation on performance, metabolic and hormonal response...

The objective of this meta-analysis study was to develop and validate equations estimated from in situ and in vitro methods to predict in vivo ruminal digestibility of organic matter (OM) of beef cattle diets. The database was composed of individual data of 23 diets from six experiments. Information collected from these studies was: in vivo digesti...

Context Previously feed-restricted cattle may exhibit compensatory growth during the finishing phase. However, the efficiency in converting feed into carcass should be evaluated since cattle undergoing compensatory growth usually have high non-carcass weight gain. Aims The objective of this study was to evaluate the effect of growth rate throughou...

Restricted-feeding may be a useful management tool available to reduce environmental impact in feedlots. Therefore, the objectives of the present study were to determine the effects of the duration of restricted-feeding on nitrogen (N) and phosphorus (P) excretion, growth performance and carcass characteristics of finishing steers. Twenty-five Hols...

This study aimed to evaluate the effects of plane of nutrition and advancing days of pregnancy (DP) on maternal body composition and fetal development. Differing planes of nutrition were established by 2 feeding regimens (FR): ad libitum (AL) or maintenance (MA). Sixty-two nonlactating multiparous Holstein × Gyr cows with average body weight of 480...

Chemical composition was assessed in soybean silages without any additive (control), with a microbial inoculant (I), with I + molasses (I+M), and with molasses only (M). Soybean plants were harvested at the reproductive 6 (R6) stage and ensiled in 2 kg-capacity PVC laboratory silos. The SIL ALL C4 inoculant produced by Alltech Brazil was used in co...

This study determined feed intake behavior, performance, feed efficiency, and maintenance requirements of bulls with high and low residual feed intake and body weight gain. Data were collected from 42 weaned Nellore bulls (initial BW 260 ± 8.1 kg; age 7 ± 1.0 mo) housed in a feedlot in a group pen that contained electronic feeders. Individual dry m...

We measured nutrient intake and digestibility, performance and mineral status of young Nellore bulls fed three diets with and without supplementation comprising calcium (Ca), phosphorus (P) and micro-minerals during the growing and finishing phases. Five bulls were slaughtered at the beginning of the experiment to measure initial mineral status. Fo...

This study evaluated the effects of the amount and frequency of N supplementation on intake, digestion, and urinary and blood characteristics in cattle fed low-quality tropical grass hay. Five ruminally and abomasally fistulated crossbred bulls averaging 262±20 kg of body weight were used in a 5 × 5 Latin square design. The basal diet was composed...

Background: Rehydration of grains, such as corn and sorghum, is used to increase nutrient absorption. However, the effect of this practice on meat quality is poorly understood. Objective: To evaluate the effects of type of grain and processing on the meat quality of Nellore steers in a feedlot. Methods: Twenty-four non-castrated Nellore steers (2...

This study was undertaken to examine production performance, pasture and milk intakes and nutrient digestibility in heifers supplemented with different levels of energy in a creep-feeding system on Urochloa decumbens Stapf pastures during the rainy-dry transition season. Fifty-one heifers with predominant Nellore genetic composition (average initia...

Starch can represent 70 to 80% of the cereals grains (on a dry matter basis) used for livestock feeding. Several methods have been developed to estimate the feed starch contents of energy feed sources. However, the efficiency of these methods to evaluate the starch content in other feed sources, as well as other types of samples used to evaluate st...

Objectives were to evaluate equations proposed by NASEM to predict net energy (NEg) and net protein (NPg) for gain of crossbred dairy cattle. Twenty-nine Holstein × Zebu steers (average initial body weight [iSBW]=320 kg, initial age=19 mo, and average final body weight [fSBW]=446 kg) were used. Five steers were slaughtered to provide baseline empty...

A meta-analysis study was conducted aiming to estimate and validate a new equation to predict net protein requirements for growth (NPg) of Zebu cattle. A database composed of 552 observations encompassing bulls, steers, and heifers of different genetic groups (Zebu, beef crossbred, and dairy crossbred) was used for generating the new equation. The...

The present study aimed to evaluate the use of dual-energy x-ray absorptiometry (DXA) to predict the physical and chemical composition of beef carcass. Fifteen Nellore heifers with weight of 263.66±62 kg and a mean age of 11 months were fasted for 16 hours and slaughtered. The carcass was divided lengthwise and cooled at 4 °C for 24 hours. The left...

The objective of this study was to evaluate the physical and chemical composition of the 9th to 11th rib section with other rib sections in Nellore cattle. Fourteen Nellore bulls (average age = 13 mo and carcass weight = 259 kg) were used. The six ribs sections were: 9th to 11th rib section (HH); prime rib section (PR; 6th to 12th rib section); tip...

The objective of this study was to determine the net amino acid (AA) requirements for Nellore and Nellore-Angus crossbred bulls fed different crude protein (CP) contents (100, 120 and 140 g CP/kg dry matter intake). Forty-four bulls (22 Nellore and 22 crossbred) were used in this experiment. Four bulls from each genetic group were slaughtered at th...

A multi-study analysis was conducted aiming to estimate and validate new equations to predict carcass weight (CW), empty body weight gain (EBG), and retained energy (RE) of Zebu cattle. A database composed of 1,748 observations of bulls, steers, and heifers of different breeds (Zebu, beef crossbred, and dairy crossbred) was used for generating the...

Effects of dietary crude protein (CP) supply on intake, digestibility, performance, and N balance were evaluated in young Nellore bulls consuming static or oscillating CP concentrations. Forty-two young bulls (initial BW of 260 ± 8.1 kg; age of 7 ± 1.0 mo) were fed ad libitum and were randomly assigned to receive one of six diets with different CP...

The objective of this study was to evaluate the effects of creep-feeding supplementation on growth performance and efficiency, feed intake and digestibility for Nellore calves grazing on tropical pastures, using a meta-analytical approach. The dataset was collected from 18 studies, which were carried out between 2007 and 2017, totalling 75 treatmen...

The objective of this study was to evaluate whole body chemical composition and energy and protein nutrient requirements for maintenance and gain of Nellore bulls. Fifty young bulls, with an average age of 7 ± 1 mo and initial body weight (BW) of 260.0 ± 8.1 kg, were used in this experiment. Four bulls were used as baseline reference animals and we...

Enteric methane (CH4) production attributable to beef cattle contributes to global greenhouse gas emissions. Reliably estimating this contribution requires extensive CH4 emission data from beef cattle under different management conditions worldwide. The objectives were to: 1) predict CH4 production (g d−1 animal−1), yield [g (kg dry matter intake;...

Sugarcane is a strategic roughage source for milk production in the tropics, and its supplementation with plant oils offers great potential for obtaining milk enriched with beneficial fatty acids, such as oleic (cis-9 C18:1), vaccenic (trans-11 C18:1), and rumenic (cis-9, trans-11 CLA) acids. The aim of this study was to evaluate the milk fatty aci...

The California net energy system (CNES) was the reference for the development of most energy requirement systems worldwide, such as Nutrient Requirements of Beef Cattle (NASEM, Nutrient requirements of beef cattle, 8th Revised ed, 2016) and Brazilian Nutrient Requirements of Zebu and Crossbred Cattle (Valadares Filho, S. C., L. F. C. Silva, M. P. G...

O objetivo do presente estudo foi predizer a composição corporal e da carcaça de novilhas Nelore e suas cruzas com Angus e Simental. Foram utilizadas 60 novilhas de três grupos genéticos, sendo 20 Nelore, 20 Nelore × Angus e 20 Nelore × Simental, destas 12 (quatro de cada grupo genético) foram abatidas no início do experimento (grupo referência). A...

Water is the most important nutrient in animal nutrition; however, water intake is rarely measured. The objective of this study was to determine whether previously published water intake (WI) equations for beef cattle would accurately predict WI from four experiments conducted under tropical conditions. The experiments were conducted from 2013 to 2...

Sugarcane is an important forage source for dairy cows in tropical countries. However, it provides limited digestible fiber and energy intake, and fat supplementation can be a way to increase energy density and decrease dietary, non-fiber carbohydrates concentrations. We aimed to evaluate the performance, digestion and metabolism of dairy cows in e...