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In beef cattle farming, there are numerous challenges to reduce costs. As a solution to transaction costs in marketing, there is a search for models that signal the behavior of cattle and fat cow prices, guiding strategies and investments. In this context, the objective of this study was to analyze the behavior of prices paid to the producer of beef cattle from different mesoregions of Rio Grande do Sul between 2015 and 2020, evaluating the trend and seasonality to verify the cost-benefit benefit of arbitrage. This study used descriptive exploratory analysis of the data provided weekly by NESPro/UFRGS. The data for July 2020 was deflated, and after reorganizing, the monthly average for the period was extracted at the state level and evaluated mesoregions. The Tukey mean comparison test and econometric tests for Dickey-Fuller and Durbin-Watson time series were used. The series are non-stationary, whose average state prices paid to the producer for Boi Gordo and Vaca Gorda vary by 87% and 89% between the minimum and maximum average, respectively. It is observed that, on average, the northeastern mesoregion, for Boi Gordo, presented prices 4.49% higher than the other regions. For Vaca Gorda there was no statistical difference. It is concluded that prices vary across regions, and arbitrage, even with its transaction costs, can result in better remuneration. [ABSTRACT FROM AUTHOR]

This study evaluated the structure of vegetation and the performance of rearing heifers and cull cows in Campos grasslands managed in the rotational stocking method with first-last stocking in the spring-summer period. The treatments were different rest intervals of 402 and 252 degrees-day, which favor the growth of different functional groups of grasses. A completely randomized block design with two treatments and three repetitions was used. The test animals were 24 heifers in the "first" group and 24 cows in the "last" group. In the stratum between tussock grasses, sward heights greater than 0.16 m were predominant in both treatments, it was 1.3 times more frequent in the 402 DD treatment compared to the 252 DD treatment. Average stocking rate was 22% higher in the 252 DD treatment. Although, no differences were observed for the average daily gain of heifers (0.227 kg.day-1) and cows (0.336 kg.day-1) between treatments, the weight gain per area in the experimental period was greater in the 252 DD treatment. Despite the management system with first and last stoking does not provide significant changes in the structure of the pasture, it allowed to achieve satisfactory performance goals in areas of Campos grassland. [ABSTRACT FROM AUTHOR]

Hypomagnesaemia (grass tetany) is a metabolic disorder of ruminants due to a reduced dietary intake of magnesium (primary deficiency), incorrect digestibility or associated metabolic factors reducing Mg intake (secondary deficiency). Grass tetany is a production disease responsible for important economic losses in beef herds from Argentina. Several factors influence the development of grass tetany in cattle, including physiological status, weather, soil and forage. This research described a retrospective analysis over the past 20 years, revising the cases of beef cattle clinical hypomagnesaemia registered at the Veterinary Diagnostic Service in INTA Balcarce, Argentina. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of the physically effective fiber (peNDF) content on nutrient composition of the total mixed ration (TMR), orts and fecal parameters in 15 commercial beef feedlots. The particle size distribution of TMR was measured adopting Penn State Particle Size Separator (PSPS). Samples were evaluated for dry matter (DM), ash, ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch content. Fecal samples were also evaluated for pH and score. The feedlots were categorized into peNDF<20% and peNDF ≥ 20%. Data were analyzed by a model that included fixed effects of treatment and covariates (sex and genetic groups). Levels of DM, CP, EE and starch were lower in TMR with peNDF ≥ 20% (P<0.05). Fecal dry matter was higher and morning fecal pH was lower for TMR with peNDF<20% (P<0.05). Physically effective fiber changed nutrient levels in TMR, orts, fecal pH and DM. So, using PSPS and fecal parameters are practical and indirect tools for measuring fecal starch and assessing the effectiveness of the diet supplied to ruminants. [ABSTRACT FROM AUTHOR]

This review was carried out with the objective of describing metabolic changes, clinical signs, methods of prevention, control and detoxification of the main mycotoxins consumed by beef cattle. After the discovery of aflatoxin and the problems that this can cause for animals and also in humans, especially cancer, scientific research has increased year after year, and today more than 18000 secondary metabolites produced by fungi are described, but the most studied are: aflatoxins, ochratoxin A, trichothecenes, zearalenone, patulin, fumonisin and Ergot alkaloids. Ruminants generally require higher concentrations of mycotoxins in the diet when compared to monogastrics for clinical symptoms of intoxication. This happens because some mycotoxins can be partially or fully degraded by rumen microorganisms. However, ruminal fermentation does not necessarily result in inactivation of the toxin, and the extent of metabolism depends the type of mycotoxin consumed, animal species, age, sex, breed, type of diet and consequently the types of microorganisms that inhabit the rumen. In addition, some mycotoxins have antimicrobial action and can negatively alter rumen metabolism. The presence of mycotoxins in the diet can affect productive and reproductive performance, which can lead to high economic losses. Thus, cattle production systems must adopt agricultural practices that minimize the production of these metabolites. [ABSTRACT FROM AUTHOR]

The presence of anti-Neospora caninum antibodies in beef cattle slaughtered in the northern region of the state of Paraná, Brazil, was evaluated. A total of 401 blood samples were collected; 281 samples from the municipality of Rolândia and 120 from the municipality of Borrazópolis, between April 2015 and November 2016. Of the total samples, 289 were from females and 112 from males, aged one and a half to eight years. Indirect fluorescent antibody test (IFAT) was performed, using a cut-off of 1:100. Variables were tabulated for statistical analyses (Fisher's exact test and chi-square tests, p=0.05). The analysis showed that of the 401 samples, 37 were positive for N. caninum, indicating a prevalence of 9.2 %, and observed titers were 1:100 (16), 1:200 (14), and 1:400 (7). The variables sex, age, and location did not differ statistically (p>0.05). Our results showed a sero-occurrence of N. caninum in cattle slaughtered in the northern region of the state of Paraná. [ABSTRACT FROM AUTHOR]

In order to develop a simulation model that reconciles the different biological-based mathematical algorithms used to calculate mineral requirements in beef cattle, bibliographic theoretical information has been compiled to lay the foundations for it. The model was developed in an Excel environment with the help of Excel macros. Two mineral samples were evaluated, simple mineral salt and protein salt for beef cattle. For validation were employed beef cattle with +/-290 kg body weight maintained on native pasture. Both, the mineral salt as the protein salt showed deficiencies to cover the mineral requirement of macro minerals, mainly phosphorus with a shortfall of 56 % in average. In the case of the trace minerals they were all covered sufficiently and expressed excesses principally in Fe and Mn, both for the mineral salt and for the protein salt. As for the simulations of daily weight gain, the software yielded results in both cases with lower daily weight gains than those obtained in practice, with a difference of 12%. [ABSTRACT FROM AUTHOR]

The expansion of the biodiesel industry has created opportunities for crude glycerol use in beef cattle diets. The objective of this study was to determine the effects of substituting sorghum grain with crude glycerol on dry matter intake (DMI), weight gain and feed intake pattern of 28 non-castrated Nelore males with initial body weight (BW) of 441 ± 40.2 kg and 21.5 ± 0.5 months of age housed in individual or collective pens. The experiment lasted 98 days (June 29 through October 5, 2015), with a 14 day-period of adaptation and 84 days for data collection. Crude glycerol was included at 15% of the ration dry matter as a replacement for sorghum grain. Orts were collected and weighed daily, and DMI was calculated by difference between feed offered and feed refused. Feed intake pattern was determined every two weeks after the beginning of the study in three intervals relative to feed delivery (0-4, 4-10, and 10-24 hours post-feeding). Animals' BW was obtained on days 1, 13, 27, 41, 55, 69, and 83 days of the trial after a 12-hour solid fasting. Crude glycerol did not alter (P>0.05) DMI, weight gain, hot carcass weight and dressing percentage compared with the control diet. A treatment × days of experiment response (P<0.05) occurred due to a decreased DMI in animals fed crude glycerol during the first 14 days of the trial. Crude glycerol-fed animals decreased (P<0.05) the neutral detergent fiber (NDF) intake pattern in individual and collective pens. Crude glycerol can be recommended at 15% of the total DM ration as a sorghum grain replacement in diets fed to Nelore animals finished in feedlot. [ABSTRACT FROM AUTHOR]

The manipulation of rumen fermentation provides the best profits by alterations in the composition of rumen microbiota. Rumen processes are accelerated by fiber degradation, decrease in methane production and excess of lactate, coupled to stable pH and rumen health. Current study comprises theory with a review of the literature on the use of modifying additives of rumen fermentation with regard to metabolic functions and to the productive performance of beef cattle. Nutritional planning through additives and antibiotics in controlled doses is increasingly employed in beef production systems to reduce costs, improve food conversion and weight gain, favoring the animals' health and metabolism. The above contributes towards a better performance, especially in the growth and finishing phases. The insertion of functional oils and vegetal extracts as additives included in the diet of ruminants has been adopted. The use of additives in animal feed enhances gains in productive performance through the manipulation of rumen fermentation standards, producing alterations in the composition of microorganisms, making the synthesis of products from rumen digestion more efficient, decreasing energy losses and reducing harmful gases. Ionophores, such as monensin, antibiotics, such as virginiamycin, and functional oils, have already demonstrated their antimicrobial and antioxidant potential in beef cattle. [ABSTRACT FROM AUTHOR]

The expansion of the biodiesel industry has created opportunities for crude glycerol use in beef cattle diets. The objective of this study was to determine the effects of substituting sorghum grain with crude glycerol on dry matter intake (DMI), weight gain and feed intake pattern of 28 non-castrated Nelore males with initial body weight (BW) of 441 ± 40.2 kg and 21.5 ± 0.5 months of age housed in individual or collective pens. The experiment lasted 98 days (June 29 through October 5, 2015), with a 14 day-period of adaptation and 84 days for data collection. Crude glycerol was included at 15% of the ration dry matter as a replacement for sorghum grain. Orts were collected and weighed daily, and DMI was calculated by difference between feed offered and feed refused. Feed intake pattern was determined every two weeks after the beginning of the study in three intervals relative to feed delivery (0-4, 4-10, and 10-24 hours post-feeding). Animals' BW was obtained on days 1, 13, 27, 41, 55, 69, and 83 days of the trial after a 12-hour solid fasting. Crude glycerol did not alter (P>0.05) DMI, weight gain, hot carcass weight and dressing percentage compared with the control diet. A treatment × days of experiment response (P<0.05) occurred due to a decreased DMI in animals fed crude glycerol during the first 14 days of the trial. Crude glycerol-fed animals decreased (P<0.05) the neutral detergent fiber (NDF) intake pattern in individual and collective pens. Crude glycerol can be recommended at 15% of the total DM ration as a sorghum grain replacement in diets fed to Nelore animals finished in feedlot. [ABSTRACT FROM AUTHOR]

forages play a key role on the performance of beef cattle in feedlot systems. Twenty-four non-castrated F1 Red Norte × Nelore males with an average initial body weight (BW) of 439.8 ± 59.6 kg and 21.7± 2.7 months of age were distributed in three experimental groups, and housed either in individual or collective pens (twelve animals in individual pens and twelve in three collective pens) at the Dairy and Beef Research and Education Center of the School-Farm of IF Goiano (Iporá Campus). The experiment lasted 84 days (14 days for adaptation and 70 days for data collection). Animals were fed once daily with diets containing sugar cane in natura (Ci), sugar cane silage (SC) or corn silage (CS) as sources of forage in amounts that ensured 10 to 15% of orts. Feed refusals were measured daily and dry matter intake (DMI) was determined by difference, BW was recorded every two weeks after a twelve-hour fasting period. There was no effect (P>0.05) of source of forage on DMI in animals housed in individual pens, as well as there was no response (P>0.05) of source of forage on growth performance. There was a tendency (P = 0.09) of BW increase in animals housed in individual pens (561.4 ± 21.2 kg) compared with collective pen-housing (509 ± 21.2 kg). Sources of forage did not alter (P>0.05) carcass traits. Animals housed in individual pens increased (P<0.05) empty gastrointestinal tract weight (11.9 kg) compared with animals housed in collective pens (10.2 kg). There was a tendency (0.05≤P≤0.10) of increase in pre-slaughter BW, full gastrointestinal tract weight and liver weight in animals housed in individual pens in comparison with collective pens. Ci, SC and CS can be recommended for beef cattle feeding in feedlot systems. [ABSTRACT FROM AUTHOR]

Correct determination of beef cattle production costs remains a relatively confusing subject and is therefore difficult for producers to apply. In the present study, a bioeconomic simulation model, which describes various livestock production systems, was used to determine profitability, and to emphasize the impact of maintenance activities and pasture recovery. Eight productive systems were evaluated in the Cerrado region; a standard system, named as Modal, and seven Improved systems, named 1 to 7, using different techniques and activities such as pasture management, nutritional management, reproduction, and health. In all simulated scenarios, the size of the property was uniform (1500 hectares), whereby 20% of the area was set aside for environmental reserves. The profitability of the simulated scenarios was R$ 41 997 for Modal, R$ 389,924 for Improved 1, R$ 395 427 for Improved 2, R$ 341,509 for Improved 3, R$ 454,198 for Improved 4, R$ 433 390 for Improved 5, R$ 47 221 Improved 6 and R$ 348 587 Improved 7. The results indicate that with an increase in the level of adoption of technologies in the property, productions costs also increased; however, it also led to a considerable increase in revenues, leading to an improvement in the use of technological resources. The use of activities linked to pastures had a positive impact, enabling greater profitability and increasing the production costs, as seen in Improved scenarios 4 and 5, with an expenditure of R$ 0.21 and R$ 0.27 on pasture for head/day paid. Expenditure on pastures is suggested to be viable for producers as it improves productivity and profitability. [ABSTRACT FROM AUTHOR]

This simulation was develop aiming to estimate the emission of greenhouse gas (GHG) in different production systems, as well as the uptake by the pasture areas. Four hypothetical scenarios for beef cattle breeding systems were developed. The first system occurred in areas of degraded pastures, with production rates similar to Brazilian average (SMB), the second occurred in areas of well-managed pastures (SMP), the third occurred in a life-cycle raising systems, in which the first part of the raising took place in areas of well-managed pastures and the termination part was in feedlot (SMC), and the forth occurred in areas of well-managed pastures with protein and energy supplementation (SIP). The GHG sources considered were enteric and fecal methane, nitrous oxide from the wastes and carbon dioxide from agricultural and the animals' supplementation activities. The equations used to estimate the GHG production were based on the diet quality, animal performance and the duration of each cycle, using the Intergovernmental Panel on Climate Change (IPCC) method, level 2. The SMP showed higher emission with 199.748.72, followed by SMB, SMC and SIP with 151.012.17; 125.356.63 and 102.418.01 t CO2eq per production cycle, and their duration of 42, 30, 24 and 18 months, respectively. However, the individual CO2eq emission was higher in SMB, with 259.23 t CO2eq / animal. The relationship between CO2 emissions and carcass production was also lower for the more intensified systems. The adoption of more intensive production systems, the adoption of feedlot systems or supplementation through the entire cycle, proved to be more efficient both productive and environmentally, by reducing GHG emissions and increasing production per area. [ABSTRACT FROM AUTHOR]

The multiple mineral mixture is an animal supplementation technique that allows to accelerate the weight gain of ruminants, potentiate the use of forages and to meet the ruminal microbial demands of the animal. Therefore, the aim of this research was to investigate aspects of the use of multiple mineral mixture in beef cattle feed by farmers. To this end, it was applied structured forms to 32 rural producers in the states of Minas Gerais, Goiás and Tocantins, it was carried by means of field research, thus obtaining aspects regarding the use of the product. The results of the research indicate that the majority, 71.88%, use grazing as a form of management, 50% of respondents adopt their use, 84.22% use it in the dry season and 68.75% use it as ingredient maize and soybean meal. Therefore, it is concluded that it is necessary to disseminate the usage information, as well as to encourage the implementation of techniques that improve the use of the mineral multiple mixture. [ABSTRACT FROM AUTHOR]

Ingestion of toxic plants causes considerable economic losses in extensive cattle raising. The survey of the presence of toxic plants in Brazilian regions is necessary, brings knowledge to the decision makers, increasing the yield of the animals and reducing economic losses. The objective of this study was to determine the presence of toxic plants of animal interest present in grassland and cerrado areas of the municipality of Rio Verde-GO. We analyzed properties that corresponded to 13,630 hectares of pastures. These areas were inspected and collected for plant identification. In the dry season, the species Crotalaria spectabilis, Senna obtusifolia, Lantana camara, Pteridium aquilinum, Dimorphandra mollis, Enterolobium contortisiliquum were found. In the rainy season, the most frequent were Crotalaria spectabilis, Lantana camara, Pteridium aquilinum, Senna obtusifolia.. There should be control or eradication of the same in the pastures, especially in the dry season where there is a shortage of fodder and where some of these plants, which are typical trees of the savannah, provide besides its desirable shade, its toxic pods. [ABSTRACT FROM AUTHOR]

Grounded by the German physician Christian Frederich Samuel Hahnemann (1775-1843), in the middle of the eighteenth century, the doctrine of homeopathy consists basically in stimulating the organic reaction through minimal and diluted administrations of medicines and is constituted of four fundamental principles: A (Similia similibus curantur), experimentation on healthy man, the use of single individualized medicine and the use of diluted and dynamized drugs. The objective of this work was to document, through a brief literature review, the history, fundamentals and its main uses in beef cattle, since the energetic character of this therapeutic principle has become a viable and beneficial alternative for allowing selfmedication of animals through mineral supplementation, thus avoiding stress and ensuring greater animal welfare when compared to invasive treatments through individual medication, in addition to providing healthy food (meat) for humans. [ABSTRACT FROM AUTHOR]

The aim of the present study was to describe an outbreak of atypical interstitial pneumonia affecting 15 Angus cattle aged 7-30 months in the south of Rio Grande do Sul. The clinical course of the disease was approximately 1-3 days. The cattle were kept in the native field and had received feed containing the remains of wafers from a food factory before the outbreak. Clinical signs included dyspnea and abdominal breathing, with a clinical evolution period of up to 3 days. Nine animals presented apathy and respiratory difficulty and died within 24h, while three animals exhibited a clinical evolution period of 36-48h. Three other animals died without any clinical signs. The main macroscopic lesions were observed in the lungs, which did not collapse at the opening of the thoracic cavity and showed a rubbery consistency. On the cut surface, the organs were firm and dark red, with marked distension of the interlobular septa due to edema. Histopathological analysis revealed thickening of the interlobular pulmonary septa; interstitial edema and emphysema; mild mononuclear cell, eosinophil, and neutrophil infiltration; areas of type II pneumocyte proliferation, and thickening of the alveolar walls. Fibrin was observed in the alveolar lumen with the formation of hyaline membranes. On the basis of macroscopic and histological examinations and epidemiological data, a final diagnosis of atypical interstitial pneumonia was made. Although, the cause of the disease has not been identified, it is believed that the bran wafer meal contained ingredients that were not suitable for animals, consequently triggering the disease. [ABSTRACT FROM AUTHOR]

The adoption of the cattle feedlot system allows greater control of costs, however, the survey of spending must be well planned. This study aimed to analyze and evaluate the economic feasibility of producing a feedlot beef cattle in Auriflama/SP. Input costs have integrated 85.14%, however obtained profitability index 68.55% and positive net present value from the 4th year. Considering the analysis studied the livestock had to be a profitable and viable activity. [ABSTRACT FROM AUTHOR]

Background: Bovine viral diarrhea virus (BVDV) is a pathogen that causes great economic losses in dairy and beef herds. The main disturbances caused by this virus are related to abortion, fetal malformation and mummification, and the birth of weak calves. In addition, this disease may result in persistently infected animals, as well as individual immune tolerance to the virus. However, the symptoms are nonspecific and variable, and dependent on the age of affected animal. The objective of the present study was to report three cases with clinical signs of BVDV infection, with subsequent confirmation of the diagnosis by reverse transcription - polymerase chain reaction technique (RT-PCR). Cases: In a beef production farm located at the state of Para, Brazil, three animals presented severe diarrhea; the feces were liquefied and greenish-yellow in color; crusted lesions were visible and scattered over various parts of the animals' bodies, including the muzzle, nostrils, periauricular region, and hooves; the tongue mucosa was undergoing an intense desquamation process. One of the affected animals, a 6-month-old calf, was euthanized following the recommendations of the "Brazilian guide to good practices for animal euthanasia" of the Ethics, Bioethics and Animal Welfare Committee / Federal Council of Veterinary Medicine. After euthanasia, this calf was necropsied and some of its organs, including the tongue and skin, were sent to the Biological Institute of Sao Paulo State for histopathology examination (HE) and identification and isolation of the virus. Positive samples for the presence of BVDV were diagnosed by RT-PCR, confirming the suspicion and explaining the signs observed in that animal and reported in other dead animals of the farm. Because RT-PCR was performed in ulcerative lesions present in the tongue, negative reactions were detected for bovine herpesvirus (BoHV) and positive reactions for BVDV. The cutaneous tissue was marked with lymphocytic infiltration, observed in both epidermis and dermis, which refers to crusted lesions distributed in several regions of the animal's body. In the lungs, we observed rare areas of emphysema and marked lymphocytic interstitial pneumonia with hemorrhagic spots, correlated with symptoms of respiratory disease. Also, marked renal damage and spleen lesions were identified, indicating glomerulonephritis and lymphocytic splenitis. Discussion: This study evidenced the occurrence of BVDV in two calves and one adult animal, which is in agreement with the described higher incidence of symptomatic infection in young animals. Clinical signs of severe greenish-yellow diarrhea and crusted lesions distributed throughout several regions of the animals' bodies, including the muzzle, nostrils, periauricular region, and hooves were described, with intense tongue epithelium desquamation, which is a particular and characteristic symptom of Mucosal Disease - the classical form of the physiopathogeny caused by bovine viral diarrhea virus. The clinical findings of severe diarrhea are possibly related to the histopathological results, which showed hyalinization of the intestinal mucosa and rare mononuclear cells in the liver nodules. Pulmonary histopathological findings of rare areas of lymphocytic interstitial pneumonia, severe emphysema, and hemorrhagic foci refer to respiratory diseases. Based on the clinical signs and laboratory findings, we conclude that the affected animals showed classic symptoms of bovine viral diarrhea. This diagnosis highlights the presence of the disease in cattle raised in the state of Para, Brazil. [ABSTRACT FROM AUTHOR]

Currently, the increase in livestock productive capacity in previously explored areas is essential while looking for economical sustainability. Strategies such as crop-livestock system have been developed aiming at optimizing the land use and yield. The success of this technological solution depends on several factors concerning animal and vegetal production. In animal production, the main factors are the suitable genetic resource, handling, and nutritional plan. With the increase in meat products demand to attend more demanding customers, the production chain is willing to offer ascertained quality products with sustainable production, in order to increase the reliability and, consequently, to increase the trade of this products. This paper aims to review the literature involving the research in crop-livestock system, searching for its specific focus on the animal component inside these productive systems. In animal factor, the objective was to review studies involving cattle, encompassing the nutritional aspects and the genetic resources used. A bibliographic review was conducted including scientific journals and public and private entities with relevant data on the subject. [ABSTRACT FROM AUTHOR]

The tegument of cattle may harbor a great diversity of filamentous fungi that can potentially cause skin diseases, including fungi belonging to the dermatophyte group. This study aimed to characterize the population of filamentous fungi from a healthy coat of cattle, checking for dermatophytes as part of the microbiota, as well as evaluating the presence of dermatophytes in the soil occupied by the animals. During the period of one year, 56 healthy cattle in four properties in the western boundary of the state of Rio Grande do Sul, Southern Brazil, were subjected to monthly samples of hair and skin scrapings. In the same period soil samples were obtained for the detection of dermatophytes. The results indicated a fungal biota classified into 30 different genera, among which the most frequent were (in order of frequency): Nigrospora, Fusarium, Curvularia, Alternaria, Epicoccum, Paecilomyces and Trichoderma. Isolates of Trichophyton mentagrophytes (0.4%), Microsporun gypseum (0.3%), and T. verrucosum (0.1%) were obtained in the samples of skin scrapings. M. gypseum was the dermatophyte most frequently isolated from soil. The results showed that the fungal biota of the external tegument of healthy cattle is transient. Moreover, it was shown that healthy cattle do not act as asymptomatic carriers of T. verrucosum, suggesting that this species of dermatophytes is not resident in the tegument of animals. [ABSTRACT FROM AUTHOR]

With the aim to determine the occurrence of antibodies against Toxoplasma gondii in beef cattle of the region of Guarapuava, Paraná State, Brazil and to correlate this with the age, the sex and the breed of the animals, samples of blood of 250 bovine were obtained and sent to the Zoonoses and Public Health Laboratory of the Preventive Veterinary Medicine Department of the State University of Londrina. After getting the serums, these were stored to -20°C, up to the realization of the examinations. The detection of antibodies anti-T. gondii was carried out by IFAT (cut off ≥1:64). The statistical analysis was carried out through Fisher's exact and of qui-square tests (p≤0,05) to correlate the results of the serology with the analyzed variables. Of 250 evaluated samples of serum, 77 (30.8 %) were positive for T. gondii. The titles obtained were 1:64 (70) and 1:256 (seven). The results demonstrate large distribution of the protozoa among beef cattle in the region of Guarapuava, PR. Animals seropositives were present in 56% (14/25) evaluated properties. Animals mix breed presented higher rates of seropositives for T. gondii (P=0.001). The age presented positive correlation with the occurrence of antibodies against T. gondii (P=0.01), indicating horizontal transmission of the agent. The high incidence of beef cattle positives to T. gondii observed in this work indicates the potential risk of the consumption of meat cattle for the human toxoplasmic infection. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the influence of body condition score (BCS) on the probability of pregnancy in Nellore cattle on programs of timed artificial insemination (TAI). The TAI protocol and visual evaluation of the BCS (being 1, too lean to 5, too fat) were developed on 5,082 females with different calve orders raised in three farms located in Northern Minas Gerais. The result of pregnancy diagnosis -positive, 1 and negative, 0 was used to study the probability of pregnancy, from the model of logistic regression, from the regression variable as calve orders, farm and body conditions. The mean of probability of pregnancy was 52.03 %. The farm and calve orders effect did not influence the pregnancy probability in Nellore cattle. An increase of 0.5 unit of BC showed an increase of 39.0 % in the pregnancy probability. The body condition affects the probability of pregnancy in Nellore cows in timed artificial insemination programs. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the performance through weight gain, carcass yield and yield forecasting of cuts of meat from Nellore steers and F1 Brangus × Nellore, supplemented with mineral mixture with addition of chromium chelate, submitted to a grazing system in Pantanal Matogrssense . 160 animals (80 Nellore steers and 80 F1 Brangus × Nellore steers) were used, they were 210 day-old and they were divided into four treatments: T1 (40 Nellore steers with chromium chelate), T2 (40 Nellore steers without chromium chelate), T3 (40 F1 Brangus × Nellore steers with chromium chelate) and T4 (40 F1 Brangus x Nellore steers without chromium chelate). The experimental design was completely randomized, in factorial design. The following variables were measured: hot carcass weight (HCW); carcass yield (CY), calculated in relation to fasting weight; rib eye area (REA) and subcutaneous fat thickness at the back (SFTB) by ultrasound. These data along with the hot carcass weight (HCW) were used to calculate the equations of carcass yield, Brazilian commercial cuts (CCB) and total usable meat (CAT). The results have shown that Nellore supplied with chromium chelate had significantly higher hot carcass weight (p <0.05)if compared to control animals, 241.42 kg and 228.73 kg respectively. There has been no significant difference (p> 0.05) among Nelore animals, the Brangus × Nelore group, and the animals with mineral supplementation associated with chromium chelate when compared to control animals. As for the retailers index, the values obtained by Nellore cattle with chromium chelate and control group are 55.34% and 52.56%, respectively, and as for F1 Brangus × Nellore animals with chromium chelate and control group, the results are56.83%, and 49.51%, respectively. A significant difference (p <0.05)was observed only for the animals supplemented with chromium chelate in both genetic groups. Concerning CAT and CCB, no significant differences (p> 0.05) between breeds and treatments were observed. [ABSTRACT FROM AUTHOR]

This paper proposes a mixed linear integer programming model of master production planning on beef cattle farms environment with complete cycle (breeding and finishing). In spite of operations research approach be restricted to blending problems to formulate diets, it's an useful and viable approach, mainly because of the special feature of this production system (comparing to factories) of having high variations of capacity ("capacity sazonality") during the year, due to dry stations. So, the model presented aims to support decisions of animal lots dimensions and, also, in the adoption of technologies for forages (intensification decisions) and nutrition (supplementation and feedlots use). The model was run with actual date of a company of western of São Paulo and Mato Grosso do Sul, through interviews with managers and workers. Interesting results were obtained, maing possible the optimized use of forage resources and budget dimension in advance. Preliminary results motivated to a new revision of parameters and open new fields to extend the research with new elements to empower the decision support tool. [ABSTRACT FROM AUTHOR]

This study aimed to assess the influence of transport on the occurrence of carcass bruising of cattle slaughtered in the Pantanal, by quantifying the number and size of bruises, locating the frequency of occurrence of bruises in the main commercial cuts standardized for interne market. From a total of 121 carcasses assessed, 102 (84.3%) had one or more bruises, totaling 270 bruises, which resulted in the removal of 56.1kg meat. The frequency of carcass bruises of cattle showed significant difference, according to the conditions of transport. The highest proportions of bruises found in animals submitted to road transport for more than one hour in distances longer than 70km, a great part of which on dirty toads. The conclusion is that the animals submitted to the successive series of handling and transported on dirty roads for long distances caused the highest proportion of bruises, whereas the animals submitted to lot IV presented the highest number of bruises. [ABSTRACT FROM AUTHOR]

Hemoncose is a parasitic disease that affects ruminants and is present in most regions, especially the tropical climate. The occurrence of severe usually is associated with inadequate management fact that favors massive infestations. The disease cause profound anemia, lethargy and weight loss. This paper aims to report an outbreak of hemoncose in a farm producing beef cattle in Santa Isabel do Oeste, southwest region of Paraná. Four animals in the farm of a batch of 50, showed weight loss, listlessness, and submandibular edema, and one developed a more severe, which was euthanized to perform the autopsy. The animal was severely anemic, with pale mucous membranes and viscera and marked edema widespread . The abomasal mucosa was reddened and swollen, dark red contents and countless copies the parasite. The diagnosis was determined by observation of the lesions presented. [ABSTRACT FROM AUTHOR]

O objetivo desta pesquisa foi avaliar três grupos genéticos de bovinos (Nelore puro, ½ Nelore + ½ Charolês e Charolês puro) sobre o ganho de peso diário. Foram utilizados 45 animais, sendo: 15 da raça Nelore (NE), 15 ½ Nelore + ½ Charolês (NC) e 15 Charolês puro (CH), com idade média de 20 meses e peso vivo médio de 350 kg. Os animais foram distribuídos aleatoriamente em três piquetes, contendo área total de um hectare cada, com capim Brachiaria brizantha cv. Marandu (Proteína bruta: 6,4%; Matéria Mineral: 9,6%; Fibra em detergente neutro: 64,5%; Fibra em detergente ácido: 34,3%, ambos na matéria seca) numa lotação de 15 animais/ha, totalizando cinco animais de cada grupo genético em cada piquete. Os animais foram pesados individualmente antes de entrarem nos piquetes e logo após o término do experimento. O ganho de peso diário foi calculado através da diferença entre o peso inicial e o peso final divido por 60 dias. O delineamento experimental adotado foi o inteiramente casualisado, com três repetições. Os dados experimentais foram analisados utilizando-se o programa SAEG (Sistema para Análises estatísticas e Genéticas 8.1, 2001), submetidas à análise de variância, considerando como fonte de variação os grupos genéticos, adotando-se um nível de significância de 5% de probabilidade. A comparação entre os efeitos dos grupos genéticos sobre o ganho de peso diário foi realizada por meio do teste de Tukey. Os tratamentos diferiram entre si estatisticamente (P<0,05). Animais da raça Nelore puro (NE) apresentou (GPD) de 0,74 kg, significativamente inferior aos animais do grupo NC e CH com GPD de 0,97 e 1,24 kg, respectivamente. Resultado semelhante foi encontrado por Menezes e Restle (2005), que trabalhando com bovinos de diferentes composições genéticas, zebuíno (Nelore) e taurino (Charolês), observaram maiores ganhos de peso para os animais taurinos, em relação aos zebuínos. Segundo estes autores, o menor ganho de peso apresentado por animais zebuínos pode estar relacionado a menor capacidade de ingestão de alimentos. De acordo com Kippert et al. (2008), o desempenho de bovinos oriundos de cruzamentos se deve aos efeitos da heterose individual e materna, fatos estes que provavelmente explicam o melhor desempenho dos animais Charolês puro e ½ Nelore + ½ Charolês, quando comparados aos Nelores puros neste estudo. Pode se concluir que animais Charolês, puro e mestiço, podem ser recomendados para terminação a pasto, com capim Brachiaria brizantha cv. Marandu, pois, apresentaram desempenho positivo. [ABSTRACT FROM AUTHOR]

Background: Heat stress derived from global warming is causing major economic losses in the livestock industry. Objective: To develop a novel methodological approach for determining the influence of climatic factors on the estimation of genetic parameters for growth traits in Retinta cattle breed by using reaction-norm models. Methods: Live weight records (n=7,753) from 3,162 Retinta calves born from 1,249 dams and 85 sires and raised in the Andalusian region (Spain) were analyzed. The effect of heat stress was measured using the temperature-humidity index, calculated with climatological data obtained from four weather stations. A bivariate-random-regression reaction-norm model was used to estimate the (co)variance components of weight until weaning in two different climatic seasons corresponding to warm and cold months. Results: The heritability pattern of individuals reared under diverse environments during the first 90 days of age was different. However, differences were not significant at the end of the growing period. Weaned calves reared during the cold season showed greater growth from 70 to 160 days in comparison with those reared during the warm season. Conclusions: Highly significant evidence of genotype-climatic condition interaction was found during the calf's first three months of growth. [ABSTRACT FROM AUTHOR]

The use of markers minimizes interference with animal behavior patterns. However, finding compounds that make more accurate estimates is critical for nutrition. In Exp. 1, we sought to replace titanium dioxide with kaolin as fecal markers and used chromic oxide as a marker of feed intake. Three sequential trials were performed, in each trial four Nelore heifers were used, which individually received 20 g TiO2 and 80 g kaolin/animal orally, and 2.0 kg of supplement containing 1% chromic oxide. In order to verify the difference in nutritional evaluations between different times of collecting feces, feces were collected at two times (08:00 am and 16:00 pm). There were no significant differences (P=0.7976) in the determination of fecal excretion when determined by the external markers TiO2 and kaolin. When stool collections at different times were compared, there was no significant effect. Kaolin was able to estimate the fecal excretion of grazing beef cattle, and the management of collecting the feces once a day is sufficient to estimate the nutritional evaluations. In Exp. 2, we evaluated the possibility of replacing titanium dioxide with kaolin, supplied via supplement, as markers of fecal excretion in pasture-raised beef cattle (4 heifers/study). It was observed that kaolin showed higher fecal excretion values (P ≤ 0.0002) when estimated by TiO2 (5.25 and 2.70 kg/day, respectively). Supplemental feeding of the external marker kaolin overestimated fecal excretion in cattle. [ABSTRACT FROM AUTHOR]

In beef cattle breeding programs, various selection criteria have been proposed and employed with the aim of improving traits related to carcass composition and the quality of the final product, meat. However, the importance of genotype by environment interaction (G×E) for such traits is still not well understood. Our objectives were: 1) to investigate the importance of G×E on ultrasound carcass traits, growth and visual scores and 2) to estimate the genetic correlation of ultrasound carcass traits with growth and visual scores taking into account the G×E in Hereford and Braford cattle. A multiple-trait reaction norm model was fitted to the field records of 37,948 animals. With the exception of postweaning average daily weight gain (ADG), the G×E can lead to important changes in the ranking of estimated breeding values of sires across environments for all traits. Thus, models that consider heterogeneity of genetic variances along an environmental gradient may be considered more appropriate for genetic evaluations of animals reared under conditions similar to the present study. Based on estimates of genetic correlation, the quality of visual scores or ADG as indicators of carcass quality assessed by ultrasonography is dependent on the production environment. [ABSTRACT FROM AUTHOR]

The beef cattle is among the most important activities of Brazilian agribusiness in socio-economic terms, since it is developed in almost all Brazilian municipalities, with a wide variety of breeds and crosses between breeds, production systems and marketing strategies, according to the peculiarities and requirements of each region and market the intended production. Therefore, to minimize the impact of extensive livestock an alternative that is being discussed is the creation of super early cattle, which still represents a little explored activity in Brazil. This review will aim to address some primordial characteristics for creating this system that is increasingly being of interest from farmers and Refrigeration industries. [ABSTRACT FROM AUTHOR]

Background: Generally, the forages used in cow-calf and backgrounding cattle operations have low crude protein and high fiber concentration, limiting animal performance and increasing greenhouse gas emissions. Chlorella spp., a green microalga, shows promising potential to provide nutrients, especially nitrogen, to low-protein diets. However, information is limited regarding the effects of Chlorella spp. on the in vitro fermentation and methane (CH4) production of diets. Objective: To evaluate the effects of increasing inclusion levels of algae (Chlorella spp.) on ruminal in vitro fermentation profile and CH4 production of a corn silage-based diet. Methods: Incubations were conducted on three separate days using corn silage and gin trash as substrate (70:30 ratio, respectively). Treatments were control (without algae) and 1, 5, and 10% of algae inclusion in the substrate replacing the basal diet. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum a corn silage and gin trash diet. Final pH, concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), total gas, and CH4 production were determined after 24 h of incubation. Variables were evaluated using the MIXED procedure of SAS software, and means were compared using orthogonal polynomial contrasts. Results: Algae inclusion linearly increased (p<0.01) the IVOMD. However, the final pH and concentration of VFA and NH3-N did not differ (p>0.05) among algae levels. Molar proportion of VFA and the acetate:propionate ratio was not affected (p>0.05) by increasing algae inclusion. Finally, total gas and CH4 production were not different (p>0.05) among treatments. Conclusion: The inclusion of Chlorella spp. does not modify the ruminal in vitro fermentation profile nor the CH4 production of a corn silage-based diet. [ABSTRACT FROM AUTHOR]

The andrological examination is a periodic evaluation that corresponds to the set of methods that aim to obtain information, such as changes in the reproductive system, pathologies and semen evaluation, with the aim of estimating the reproductive potential of males. The main objective of the examination is to select sires and estimate the reproductive potential of bulls, in addition, to identify animals with fertility problems. Therefore, the andrological examination must be seen as an integral part of the reproductive season, being a foundation to guarantee good results for beef and dairy cattle herds. Despite the increase in technology on properties in Brazil, the vast majority of producers have little information about the importance of carrying out andrological examinations before the reproductive season. Thus, the literature review aims to address the andrological examination and its benefits and encouragement in carrying out the examination on properties belonging to the local dairy production arrangement (APL) in western Goiás. [ABSTRACT FROM AUTHOR]

Production performance and methane production in two breeding and finishing systems in the state of Rondônia, Brazil, are evaluated. Study comprised totally randomized design, with two treatments, with 128 non-castrated heifers, mean initial weight 281.906 ± 1.69 kg. Production systems were classified by technology level employed, with supplementary pasture and finishing in confinement (SPC) as the highest technology-based production system, and breeding and finishing with supplementary pasture (SP), as average technology level. SP system had the greatest pasturing pressure on breeding, lowest availability of DM (t/ha) and highest stocking rate. Breeding period within the most technical system was reduced to 61 days, with a 41.42% decrease in CH4 per kg of body weight. Finishing cycle was concluded in 94 days prior to the SPC system, with a decrease of 57.20% CH4 emission per kg of body weight gain. Results show that the technology level applied to animal production affects performance. In CH4 evaluation of weight gain, it has the lowest impact on the environment by gas emission, decrease in the animal production cycle and faster financial returns. [ABSTRACT FROM AUTHOR]

Beef cattle is responsible for a large portion of food production in the world. One of the main strategies to improve cattle breeding is feeding, with minerals playing an important role for diet supplementation. Sulfur is characterized as a macromineral, due to its requirement in cattle, and has several vital functions, therefore, it must often be supplemented in the diet. The present study aimed to compare the inorganic source of sulfur (sulfur flower) with an organic source (sulfur chelate) and their different levels of supplementation performance of ½ Nellore x ½ Aberdeen Angus heifers submitted to a feed lot system. Thus, 24 heifers aged between 13 and 16 months, with an average initial weight of 230 kg, were randomly distributed into four treatments: recommended daily dose (6.72 g) of sulfur from the sulfur flower; recommended daily dose (6.72 g) from sulfur chelate; 50% of the recommended dose of sulfur (3.36 g) from sulfur chelate and 75% of the recommended daily allowance (5.04 g) from sulfur chelate. During the 90-day experimental period, a diet consisting of 81% concentrate and 19% forage was provided in an amount equivalent to 2% of the live weight in the dry matter of each heifer. There were no significant differences between treatments for animal performance, feed conversion and feed efficiency. Treatment with an organic source of sulfur at half the recommended daily dose showed a reduction of 29.7% in fecal sulfur excretion. In conclusion, the use of half the dose of sulfur in the organic form (sulfur chelate) can be an option to reduce the inclusion of the mineral element in the diet of beef cattle, since the animals submitted to half the dose of sulfur chelate reached the same animal performance of the group submitted to the recommended daily dose of the inorganic source of sulfur. [ABSTRACT FROM AUTHOR]

This study examined the effects of annual nitrogen (N) rates of 100 and 200 kg ha-1 on the morphogenetic and structural traits of Ipyporã grass (Brachiaria brizantha × Brachiaria ruziziensis) under intermittent grazing during the seasons of the year. The experiment was laid out in a randomized-block design with two treatments and three area replicates. Ipyporã grass pastures were grazed by beef cattle. Morphogenetic and structural traits of the forage canopy were evaluated using the marked-tiller technique. Forage accumulation and tiller density (TD) were also evaluated. Significant interaction effects (P < 0.05) between N rates and seasons were observed for the rest period, leaf lifespan (LLS), phyllochron, stem elongation rate (SER) and final leaf length (FLL). During winter, the rest period was shorter (40 vs. 50 days) in the pastures fertilized with 200 kg ha-1 N. Conversely, in winter, the pastures fertilized with 100 kg ha-1 N showed higher LLS, SER and phyllochron values, but lower FLL values. There was no isolated effect of N rates (P > 0.05) on forage accumulation rate; leaf appearance, elongation or senescence rates; leaf:stem ratio; or TD. However, the effect of seasons was significant for these variables, with the highest values occurring during spring and summer. The use of 200 kg ha-1 N in Ipyporã grass pastures reduces the seasonality of forage production. [ABSTRACT FROM AUTHOR]

Background: The genetic test for Expected Progeny Differences (EPDs) is one of the newest technologies to reduce uncertainty in calf production. It provides information about the genetic composition of a bull, which relates to its propensity to produce offspring with specific growth and quality characteristics. Objective: To evaluate the influence of EPDs reports on the variation of Nellore bull semen prices for artificial insemination in the Brazilian beef cattle industry. Methods: Ordinary Least Squares (OLS) regressions were estimated. The study utilized genetic data provided by GENEPLUS as well as market prices of semen and physical measurements of the bulls collected from the Alta Genetics Insemination Agency. Results: Genetic results, except for age at first calving, weaning weight, and weight at 120 days EPDs, have little influence on semen prices. For each additional day expected for the first calving of the progeny average price of semen decreases by 0.66%. For each additional kg expected in weaning weight, the semen price was 1.73% higher. Furthermore, for each additional kg expected in the progeny at 120 days, semen price increased by 2.46%. Conclusion: Joint analyses of genetic reports and physical characteristics of bulls may provide a better explanatory power. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate heritability and repeatability for different measures of cows' productive efficiency and determine the best way to calculate the weight ratios, in order to use as selection criteria in Ne/ore herds. Data of Ne/ore animals from Centro APTA Bovinos de Corte-Sertãozinho, Instituto de Zootecnia were analyzed. The animals are selected for higher yearling weight (NeS and NeT herds, considered as a single herd in this paper) and, for mean yearling weight (NeC) within contemporary group, since 1980. The traits used in this study were: 1) RPN = ratio of birth weight ofthe calf! cow weight at calving; 2) RPN2 = ratio of birth weight of the calf/metabolic cow weight at calving; 3) RPD = ratio of weaning weight of the calf! cow weight at weaning and, 4) RPD2 = ratio of weaning weight of calf / metabolic cow weaning weight. For estimate genetic and phenotypic parameters, were considered two files: cows with calves (CB) or with and without calves (SB). The RPN and RPN2 were calculated only on GB file, and RPD and RPD2 were calculated in both files (GB and SB). Genetic parameters were estimated by restricted maximum likelihood. Estimates of herita bilityfor traits RPN; RPN2; RPD_GB; RPD2òGB: RPD_SB and RPD2 SB were: 0.17±0.02, 0.16±0.02, 0.22±0.04, 0.19±0.03, 0.20±0.01 and 0.1 6±0.01, respectively The repeatability estimates ranged from 0.22 to 0.68. The use of weight ratios as selection criteria should promote, at long-term, improvements in production efficiency In some breeding programs, weight ratios have been considered only as information for disposal of cows, but could be included in selection indices, especially if if is calculated considering the metabolic weight of cow at weaning from both cows, that weaned a calf as those thatfailed to wean. [ABSTRACT FROM AUTHOR]

The Pampa-Corte model was developed to simulate the growth of beef cattle in grazing systems in a dynamic and mechanistic way. It was validated under Brazilian conditions. This paper aims to verify the performance of the model in conventional and alternative beef cattle finishing systems in Spain. An experimental dataset of 21 Parda de Montaña calves of similar age and weight at weaning was used to evaluate the model. They were slaughtered individually on reaching 450kg liveweight. The model considered genetic group maturity rather than breed, in order to adjust growth parameters, once Parda de Montaña breed is not contemplated by AFRC (1993). Parameters from late maturing group were initially used considering adult animal size of Parda de Montaña animals; however, the best fit was with values from the early maturing group. The model predicted accurately animal growth in grazing and conventional finishing systems in Spain, although estimates were less precise when changes in animal management involved physiologic modifications. [ABSTRACT FROM AUTHOR]

Nutrition has a fundamental role in the production of beef cattle, directly interfering in the costs, productivity and profitability of the activity. In this sense, the objective of the present study was to evaluate the challenges, opportunities and advantages of the production of the entire cattle fattening diet on the Angico farm, in the municipality of Corumbá - Mato Grosso do Sul. Applied research was carried out as a way of studying case. In the 2017/2018 harvest, the farm's own production yielded 116 bags/hectare of corn, 40 bags / hectare of soybeans, 42 tons / hectare of silage sorghum and 72.5 bags/hectare of grain sorghum. All these ingredients were used in the feed of the feedlot animals. It was concluded that at the Angico farm, with the use of proper planting and management techniques, it was possible to overcome production barriers (adverse weather, attack by pests, diseases and wild animals), thus improving the efficiency of the enterprise. In addition, it was possible to recover degraded pasture areas and increase the farm's food independence by reducing the purchase of food from third parties and reducing costs per arroba produced with the animals' own food production. [ABSTRACT FROM AUTHOR]

Food production and water scarcity, both in constant growth and intrinsically linked, are subjects of great relevance in current studies in several areas of knowledge. The impacts generated by the production of beef are at the center of major environmental debates, especially the consumption of water for the production and development of the livestock production chain. This research analyzed the use of water resources in the production of beef in the Amazon biome. The water footprint for beef cattle was of 13,074 L.kg-1 compared to a world average of 21,829 L.kg-1. Based on the data obtained it was possible to demonstrate that the presence and operationalization of this production chain in the Amazon is more efficient from the water point of view than in the other locations reported in the literature. [ABSTRACT FROM AUTHOR]

Thepurpose of thisreview isto show the increase in number of researches on covariance components and genetic evaluation using random regression models (RRM) for growth traits of Nellore cattle. Random regression models (RRM), also known as infinite-dimension models have been used to estimate variance components and genetic parameters for weight of beef cattle. In addition, those models are a standard alternative for genetic analyses of longitudinal data, however, the availibility of computational resources for performing genetic evaluations widely is an obstacle. Traits related to animal growth are adopted as selection criteria in beef cattle breeding programs, because the remuneration of cattle breeders is made based on the weight of carcasses. In recent years, RRM have been adopted as standard procedure in relation to the analysis of longitudinal data in animal breeding. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare structural, morphological and bromatological characteristics of forage as well as performance of Caracu beef cattle (200 ± 9 kg of initial body weight) supplemented with a multi-mineral mixture (0.25% of body weight) on deferred pastures of Brachiaria brizantha 'Marandu' and Brachiaria decumbens 'Basilisk' under continuous grazing. After the pasture was grazed to 10 cm of height, in March 2014, both grasses were left to rest and subjected to a 126-day deferment period. The experimental period lasted from July to October 2014; the sward characteristics and the animal's weight were evaluated every 28 days. The highest forage mass was recorded in 'Marandu' grass, whereas the highest leaves percentage and lowest dead material percentage were observed in 'Basilisk' pastures. Similarly, the highest crude protein content (8.1 vs. 7.0 ± 0.2%), in vitro organic matter digestibility (57.7 vs. 53.9 ± 0.4%), lowest neutral detergent fiber content (69.2 vs. 72.7 ± 0.4%), and; consequently, the highest average daily gain (680 vs. 530 ± 0.04g animal-1) were recorded for 'Basilisk' pastures. 'Marandu' and 'Basilisk' deferment was associated with a multi-mineral mixture supplementation as a management alternative for rearing beef cattle during the drought periods. Because of the duration of the pasture recovery period in this study, B. decumbens pastures were more likely to achieve the highest animal performance. [ABSTRACT FROM AUTHOR]

Feedlot cattle performance was evaluated upon diets offering different levels and frequencies of sweet corn residue as source of roughage. The animals were divided into five groups, in a total of 30 animals per treatment. 1) roughage:grain ratio (R:G) of 50:50 from the start to the end of experiment, 2) 30 days with 100% roughage, followed by 30 days with R:G ratio of 50:50, and then R:G ratio of 30:70 until the end of the experimental period; 3) first 45 days at feedlot condition with 100% of roughage and then R:G ratio of 50:50 until the end of experimental period; 4) 30 days at start of feedlot with 100% of roughage, and then a ratio of 50:50 until the end of experimental period; 5) 100% of roughage. The lowest body weight, average daily gain and dry matter intake were achieved by animals receiving only roughage during the total period of feedlot; however, these animals presented the best feed conversion between evaluated treatments and lowest cost per pound produced. The concentrate inclusion offered, in general, highest animal performance, but with high-cost production. [ABSTRACT FROM AUTHOR]

The objective of the review was to describe the physical and chemical characteristics of kaolin in order to know the substance and to propose as an option for external marker of dry matter consumption and output fecal of beef cattle grazing. A marker considered ideal when it presents characteristics such as being inert, not being toxic, not having a physiological function, not metabolized, and others. Currently all markers have limitations, so research has been conducted in order to find a marker that presents all these characteristics. Thus, kaolin becomes an interesting alternative because it is part of animal nutrition and it is a mineral whose characteristics show the use, such as being inert (pH 3 to 9), easy dispersion, low thermal and electrical conductivity, low cost and good resistance to chemical by acids or alkalis. For the measurement of the substance via feces, it is necessary to determine the concentration of some of its elements, i.e., the fact that Al is present in forages in very small concentration, and practical analytical methodology, leads to believe that this element is the most coherent choice. It is concluded that kaolin characteristics of a potential external marker and can be accurately quantified in stool by means of the aluminum element. [ABSTRACT FROM AUTHOR]

Beef cattle kept in extensive systems are constantly exposed to the effects of the climate. In tropical and intertropical regions, the reproductive management of Bos taurus animals with B. indicus animals is an alternative for zootechnical improvement. The objective was to evaluate morphophysiological characteristics of heat adaptation of beef heifers on pasture. For this, fifty-four animals from four distinct genetic groups: (1) Nellore, (2) Senepol, (3) Angus x Nellore and (4) ¼ Brahman x ¼ Nellore x ½ Senepol (Tri-cross), with six months-old, were evaluated during the summer and autumn seasons of 2016. The morphological characteristics of the coat (length, diameter, thickness, density and number of hairs and coat color) and physiological (skin, hair and rectal temperature; sweat rate; respiratory and heart rate) were evaluated. The environment was evaluated using the temperature and humidity index, black globe temperature, humidity index and radiation thermal load. We observed that the production environment presented thermal discomfort for the animals. Thus, the animals' rectal temperature differed between seasons. All groups studied showed some adaptive characteristic to the tropical environment. Angus x Nellore heifers had the highest values for the morphological measures in the months evaluated, coinciding with thermal comfort indexes above those considered comfortable for cattle and the lowest value of respiratory rate when compared between the crossing. In conclusion, all genetic groups have at least three adaptive characteristics to the tropical environment when analyzing the physiological responses. [ABSTRACT FROM AUTHOR]

O objetivo do trabalho foi avaliar a eficácia da salinomicina (Saligran®G120) como melhorador de desempenho em bovinos de corte. Foram avaliados 32 novilhos distribuídos em dois tratamentos: T1-Controle; T2-com inclusão de salinomicina (1 g/animal/dia do produto Saligran®G120, quantidade suficiente para disponibilizar 120 mg de salinomicina) na dieta. Os animais permaneceram em confinamento com dois animais por baia. Foi avaliado o consumo da baia diariamente e foram realizadas pesagens com intervalos de 28 dias, totalizando 4 avaliações. Os animais que receberam o produto apresentaram maior ganho de peso médio diário e melhor conversão alimentar (P=0,05). O ionóforo salinomicina (Saligran®G120) se mostrou eficiente como melhorador de desempenho, sendo assim recomendado para bovinos de corte. [ABSTRACT FROM AUTHOR]

This work brings to quantify and provide benefits to using this early weaning protocol, showing the benefits for the calf and for females, it is multiparous and / or mostly gilts. Several studies on weaning weight in cattle, which show great variation in the average of this feature. This variation may be the result of genetic variation between arrays, food, reproductive and health management that varies from region to region and from farm to farm, in addition to the different programs of selection and genetic improvement of beef cattle used in the country. [ABSTRACT FROM AUTHOR]

Context: Most Brazilian beef breeding programs perform selection for young bodyweight, which will inevitably increase mature weight due to the genetic correlation among weights at different ages. Aims: The objective of the present study was to estimate genetic parameters for bodyweight from birth to maturity in Gir, Guzerat, Nelore and Caracu cows born between 1981 and 2014 at Centro APTA Bovinos de Corte, Instituto de Zootecnia, Sertãozinho, São Paulo, Brazil. Methods: The model included the fixed effects of contemporary group (herd and year of birth), month of birth and previous reproductive status (calved = 1, or not calved = 0), the linear and quadratic effects of animal and cow age as covariates, and direct additive genetic, maternal genetic and maternal permanent environmental effects as random effects. The genetic parameters were estimated by univariate analysis of weights adjusted at birth, and at 120, 210, 378, 450 and 550 days of age, and annually from 2 to 10 years. In addition, multivariate analysis was performed considering weights at birth, and at 210 and 550 days, and at 5 years of age for all breeds. Key results: For the different breeds, the heritability estimates ranged from 0.28 to 0.49 for birthweight, from 0.11 to 0.31 for weaning weight, from 0.25 to 0.43 for yearling weight, and from 0.25 to 0.69 for weights from 2 to 10 years of age. The genetic correlations were high and positive, indicating that selection at any age will affect weights at the other ages. Conclusions: The results suggest the possibility of genetic progress for weights at different ages and the use of the young weights to monitor the mature weight of the animals. Implications: As the trait most strongly correlated with mature weight was yearling weight, already used as the selection criteria for females in the breeding program of the Instituto de Zootecnia, selection indexes should be derived to keep the mature cow weight constant, since heavier cows could be undesirable for pasture-based Brazilian production systems. Selecting cattle for bodyweight at young ages alters mature weight, which may not be desirable due to the rearing of cows in extensive pasture systems and the increased nutritional requirements of larger animals. High and positive genetic correlations indicated a strong association among measurements at different ages, and selection for the desired mature weight should be performed through selection indices to simultaneously select the desired weight at young age and at maturity. [ABSTRACT FROM AUTHOR]