ABSTRACT This study evaluated how nutritional insults applied at different stages of intrauterine development affect the growth and development of total tract organs and the mRNA expression of genes that encode growth factors, tight junction proteins, digestive enzymes, and glucose transporters in the small intestine of newborn goats. Fourteen nulliparous dairy goats were assigned to one of two nutritional plans over gestation: maintenance-restriction (M-R, n = 8) – 100% of maintenance requirement from d 8-84 of gestation followed by feeding at 50% maintenance requirement from d 85 of gestation to parturition; or restriction-maintenance (R-M, n = 6) – 50% of maintenance requirement from d 8-84 of gestation followed by feeding at 100% maintenance requirement from d 85 of gestation to parturition. Fisher's least significant difference test was performed using SAS 9.4, considering a full fixed-effect model. When expressed per kg of body weight, the weights of the small intestine and total intestine were 18.7 and 18.1% lower, respectively, for R-M offspring. The lengths of the small intestine and the total intestine of the R-M newborns were 19.1 and 9.5% shorter, respectively. This group also had a lower villus height:intestinal crypt depth ratio. The R-M offspring tended to have lower Solute carrier family 5 member 1 (SLC5A1), Solute carrier family 2 member 2 (SLC2A2), and Occludin (OCLN) mRNA expressions. Therefore, feed restriction in the first half of gestation is detrimental to the second half of gestation, reducing the offspring's intestinal absorptive area but enhancing their intestinal permeability.

ABSTRACT The objective of the present study was to evaluate the stability of candidate reference genes and select the genes that can be used for normalizing real-time polymerase chain reaction (PCR) in the liver, skeletal muscle, and jejunum tissues of Nellore or Nellore × Angus steers fed different diets. Fourteen purebred and 14 crossbred steers were used, in which half of the animals of each genetic group received a diet containing whole shelled corn (WSC) and the other half whole shelled corn and sugarcane bagasse (WSCB). Stability was analyzed by the RefFinder program. To validate the selection of candidate reference genes, the expression of target genes was evaluated using the different groups of reference genes. The most stable genes were 18S, ACTB, and CASC3 for skeletal muscle; HMBS, ACTB, and 18S for the liver; and GAPDH, ACTB, and CASC3 for the jejunum, regardless of breed and diet provided. Possible errors caused in data analyses were clarified comparing the more and less stable genes as reference for normalization of the target genes FASN, ACOX, SCD1, MGAM, and SLC2A1. The use of the more stable and less stable sets of reference genes may lead to different conclusions in respect to the expression profile of the target studied gene. The selection of more suitable reference genes for each experiment is of utmost importance to ensure the reliability of gene expression studies so that they can be applied in practice.

ABSTRACT This research was conducted to investigate the effect of live and inactive sugarcane yeast on beef cattle voluntary intake, apparent digestibility of nutrients, ruminal pH, volatile fatty acids (VFA) concentrations, and ruminal ammonia. Five rumen-cannulated Nellore heifers were distributed in a 5×5 Latin square design, with five experimental periods of 15 days, with seven days for adaptation to the additives and the remaining days for data records and sampling. Total mixed ration (TMR) was composed by corn silage (20%) and concentrate (80%) based on corn and soybean meal. Five treatments were evaluated: without additive use (negative control; NC); chemical buffer addition – 0.71% in concentrate DM of sodium bicarbonate and 0.18% of magnesium oxide (positive control, PC); 10 g/day live yeast (LY); 15 g/day of inactive yeast (IY15); and 30 g/day of inactive yeast (IY30). Sugarcane yeasts were directly infused in rumen immediately after morning and afternoon feed supply. Feed additives did not affect voluntary intake, nutrient digestibility, and sorting behavior of animals. However, heifers from all treatments presented preferential intake of fibrous fraction of diet, especially those from NC and IY15. Nitrogen balance, VFA concentrations, and blood parameters were not influenced as well. Sodium bicarbonate and magnesium oxide led to greater ruminal pH than yeast, and IY15 presented greater pH than IY30. Ruminal ammonia was increased by the use of additives. Active and inactive yeasts are not recommended as feed additives for bovines fed diets with 80% of concentrate since it allows animals to select fibrous particles from TMR, and no representative gain in ruminal parameters and digestibilities are guaranteed.

The objective of this study was to evaluate nutrients and dry matter intake, average daily gain, feed efficiency and digestibility of diets, microbial efficiency, cold carcass yield and basic cuts yields of young Nellore heifers receiving two concentrate levels. Nineteen heifers with initial average weight of 165.6±29.8 kg were used. Three animals were used in a trial to determine the digestibility and microbial efficiency of the two levels of concentrate (225 and 450 g/kgDM) and a treatment with a restricted intake maintenance level. The remaining 16 heifers were confined for 168 days for evaluation of performance and intake, divided into two levels of concentrate. Every 42 days, four animals, two from each concentrate level, were slaughtered to determine carcass characteristics, making a 2 × 4 factorial arrangement. Digestibility and microbial efficiency were not affected by concentrate level or intake level, both for ad libitum and restricted feeding. Heifers fed 450 g/kgDM concentrate diet had greater average daily gain than those fed 225 g/kgDM concentrate. Dry matter intake and feed efficiency did not differ between levels of concentrate. Average daily gain (kg/day), dry matter intake (% body weight/day) and feed efficiency were higher in the first period of feedlot (0-42 days) compared with the other (42 to 168 days). Heifers fed 450 g/kgDM concentrate had greater average daily gain than those fed 225 g/kgDM concentrate.

The objective of this study was to determine the energy nutritional requirements for females of Nellore, Nellore × Angus and Nellore × Simmental fed on two levels of concentrate. Sixty heifers from three genetic groups were used: 20 Nellore, 20 Nellore × Angus and 20 Nellore × Simmental. Twelve belonged to the reference group (four of each genetic group) and were slaughtered at the beginning of the experiment. Another 12 heifers (four of each genetic group) were fed on the maintenance level and 36 heifers (12 animals of each genetic group) were kept in feeding system ad libitum with 30 (six in each group) or 50% (six of each group) dry matter concentrate. Animals were randomly assigned to six treatments in a 3 × 2 factorial arrangement (three genetic groups and two diets) with six replicates per treatment. Nine more heifers were used in a parallel experiment to estimate the apparent digestibility coefficients (three from each genetic group). Net energy requirements were estimated by the equation of retained energy as a function of metabolic empty body weight (EBW0.75) and empty body weight gain (EBWg). Requirements of metabolizable and net energy were estimated for maintenance by the equation of heat production as a function of metabolizable energy intake. Using the combined equation RE (retained energy; Mcal/day) = 0.0703 × EBW.75 × EBWg1.128 to predict net energy requirements for weight gain is recommended. The requirement of metabolizable and net energy for maintenance of all groups is 70.55 and 106.53 kcal/kgEBW0.75/day, respectively. Use efficiencies of metabolizable energy for gain and maintenance are 36.41 and 66.23%, for the three genetic groups respectively.

Objetivou-se avaliar as equações de Hankins & Howe para estimação da composição física da carcaça e as de Paulino para estimação da composição de macrominerais no corpo vazio de bovinos Nelore. Foram utilizados nove machos castrados, nove machos não-castrados e nove fêmeas. Três animais de cada classe foram abatidos ao início do experimento como referência. Os 18 animais remanescentes foram alimentados durante 112 dias com uma ração com 12,5% de proteína bruta, e concentrado, fornecido na proporção de 1,00 ou 1,25% do PV, e abatidos ao final para determinação da composição corporal. As composições física e química foram determinadas em uma amostra entre a 9ª e 11ª costelas (seção HH) da meia-carcaça esquerda e na meia-carcaça direita inteira, a qual foi totalmente dissecada. A seção HH não possibilitou estimar corretamente a composição física de nenhum dos componentes da carcaça, e apenas a equação proposta para cálcio foi eficiente para estimar a porcentagem de cálcio no corpo vazio. Propõe-se o uso de novas equações para estimar o conteúdo corporal dos macrominerais a partir de sua concentração na seção HH. As equações de Hankins & Howe não estimam corretamente a composição física da carcaça de bovinos Nelore, no entanto, é possível estimar a composição de macrominerais no corpo vazio de Nelore a partir da seção HH.

The objective of this study was to evaluate the Hankins and Howe equations, to estimate the carcass physical composition, and the Paulino equations, to estimate the empty body weight macromineral composition of Nellore cattle. Twenty seven Nellore animls (9 bulls, 9 steers and 9 heifers) were used, and nine animals (three of each gender) were slaughtered at the beginning and formed the reference group. The 18 remaining animals (6 of each gender) were allotted in two levels of concentrate offer (1.0% and 1.25% live weight) and were fed over 112 days. At the end of the trial all the animals were slaughtered to determine the empty body weight and physical and chemical body composition using the right carcass half. From left carcass half one sample from 9th to 11th ribs (HH section) was obtained. The HH section did not estimate well the physical carcass composition. The Paulino equation was efficient in estimating the Ca concentration in the empty body weight. New equations were proposed for all the macrominerals to estimate their contents in empty body weight using the HH section. It was concluded that the Hankins and Howe equations did not correctly estimate the carcass physical composition in Nellore cattle, and that the macromineral composition can be estimated using the HH section in Nellore cattle.

Esta pesquisa foi realizada com os objetivos de estimar os consumos individuais de matéria seca, concentrado e volumoso de bovinos alimentados em grupo, avaliar o consumo de matéria seca (CMS), o ganho médio diário (GMD) e a conversão alimentar (CA) de bovinos de três classes sexuais (machos não-castrados, machos castrados e fêmeas) alimentados individualmente ou em grupo, com dois níveis de oferta de concentrado (OC) (1,00 ou 1,25% do peso vivo), e analisar as características de carcaça de animais Nelore terminados em confinamento. Utilizaram-se 45 bovinos Nelore - 15 machos castrados (MC), 15 machos não-castrados (MNC) e 15 fêmeas (FE). Desses animais, nove (três de cada classe) foram abatidos no início do experimento e serviram como referência nas avaliações. Os animais restantes (36) foram distribuídos em dois esquemas de alimentação (EA) e alimentados, individualmente ou em grupo, com dois níveis de concentrado, perfazendo um esquema fatorial 2 × 2 × 3. Nas avaliações, utilizaram-se a LIPE® para estimativa da produção fecal; o óxido crômico e o dióxido de titânio para determinação do consumo de concentrado; e a FDNi e FDAi para estimativa do consumo de volumoso. Ao final do experimento, todos os animais alimentados individualmente foram abatidos para avaliação das carcaças e dos rendimentos de cortes. O esquema de alimentação não influenciou o consumo de matéria seca nem o ganho médio diário dos animais. Ofertas de 1,00 ou 1,25% do PV em concentrado não influenciaram o rendimento e as principais características de carcaça. Machos Nelore não-castrados ganham 24% a mais de peso que machos castrados, que, por sua vez, ganham 22% a mais que as fêmeas. Entre as classes sexuais, machos não-castrados são mais eficientes que os castrados e as fêmeas na deposição de carne e apresentam maiores rendimentos de alguns cortes básicos.

The present work aimed to estimate the individual intake of dry matter, concentrated and forage for animals feed in group. Evaluate also, dry matter intake, average daily gain and feed conversion ratio by animals from one of three genders (bulls, steers or heifers) fed individually or in groups, with two levels of concentrate offer (1.00 or 1.25% of BW), and carcass traits of confined Nellore cattle. Forty five Nellore cattle - 15 bulls, 15 steers and 15 heifers were used. Nine animals (three from each gender) were slaughtered at beginning of the trial performing reference group. The remaining 36 animals were fed either 1.0 or 1.25% of concentrate under two feeding schemes (individually or in groups), in a 2 × 2 × 3 factorial arrangement. In order to estimate the individual DMI of animals fed in group, LIPE® was used to estimate the fecal dry matter production, Cr2O3 and TiO2 were used to estimate the individual concentrate intake and NDFi and ADFi were used to estimate the individual forage intake. At the end of the experiment all animals individually fed were slaughtered to evaluate carcass traits and yield of commercial cuts. The feed scheme had no influence upon DMI and DWG of Nellore cattle from different gender. There were no effect of 1.00 or 1.25% of concentrate on carcass traits and carcass yield. Bulls grow 24% more than steers and steers grow 22% more than females and bulls tend to be more efficient in meat deposition and had higher yield in some commercial cuts.