Determinação da melhor dose de virginiamicina em suplementos para bovinos Nelore em pastejo

Pós-graduação em Zootecnia - FCAV

Comportamento ingestivo de bovinos mantidos em pastos de Brachiaria brizantha cv. Xaraés manejado em diferentes alturas de pastejo

This experiment was conducted to evaluate the effect of grazing heights on daytime behavioral activities of Nellore beef cattle in the rainy season. The experimental area was 12 hectares divided into paddocks of one hectare each. The treatments consisted of four defoliation heights (15, 30, 45 and 60 cm) in pastures of Brachiaria brizantha cv. Xaraes with three replicates each. It was used the continuos grazing method, with variable stocking rate. Forage samples collected on the plots were sent to the laboratory for separation of the botanical components, weighing and determination of dry matter, with the material collected by simulated grazing. The variables: grazing time, idle time and ruminating time were evaluated for 12 consecutive hours on days 15 and 16 February 2011, considering the morning and afternoon periods. It was used a completely randomized design. The height of the canopy significantly influenced the daily grazing time and ruminating time, with a quadratic response as a function of time of defoliation. The bite rate decreased as a function of heights studied. However the chemical composition of the material collected by simulated grazing did not differ between treatments. Xaraes grass swards grazed at around 45 cm height provide greater ease of apprehension by grazing cattle.

Influência da imunocastração (Bopriva®) no ganho de peso, características de carcaça e qualidade da carne de bovinos Nelore

The objective of this study was evaluate the effects of immunocastration on body weight gain, carcass characteristics and meat quality of Nellore beef cattle. Eighty Nellore beef cattle, with initial body weight of 357 +/- 8.63 kg, were placed in feedlots and distributed in two treatments (40 animals per treatments) as follow: one - non-vaccinated bulls and two - immunocastrated bulls (Bopriva (R), Pfizer Animal Health). The animals placed on treatment two were vaccinated in two doses, first application 30 days before they arrive on the feedlots and second on the day they arrive on feedlots. After 67 days of experimental period, was calculated the daily gain of live weight in kg/day of the 80 animals and selected 20 animals from each treatment for the slaughter and carcass evaluations, and ten from each group for the meat analyzes. The data were submitted to analysis of variance. Immunocastrated animals showed lower daily weight gain, hot carcass weight, carcass yield, pH, leg thickness, muscle depth, loin muscle area, carcass muscle percentage, shear force and moisture. However, this animals had higher concentration of lactate and cortisol blood, chest depth, fat thickness, finishing degree, a *, b * and c*, liquid loss in thawing process, myofibrillar fragmentation index and ether extract of meat when compared to non-vaccinated bulss. The immunocastration (Bopriva (R)) is an alternative for improving the quality of meat by the higher fat deposition and by the reduction of the shear force of the meat when compared to non-vaccinated bulls.

Desempenho de bovinos de corte em pastos de Brachiaria brizantha cv. Xaraés manejados em diferentes alturas de pastejo

The production of grazing cattle has been very interesting, due to the low cost to produce fodder, compared to other sources of forage used to feed these animals, but the adequate management pasture has high influence on the success and profitability of cattle production systems. Thus, the objective of this study was to determine the optimum grazing height of Brachiaria brizantha cv. Xaraes, which provides the highest individual weight gain and gain per area. The stocking rate was continuous, with variable stocking rate. The experimental period was from January to December 2010. Three Nellore males were used in each experimental plot, and, when needed, additional animals were used for adjusting the desired heights. Monthly sampling was obtained to estimate forage mass (kg.ha(-1) of DM) and the structural characteristics of the pastures, such as, leaf: stem ratio. The animals were weighed at the beginning of the experiment and every 28 days, after 12 hours of fasting, to measure the average daily gain (ADG) After weighings were performed adjustments stocking rate to desired heights. Throughout the experimental period the animals received mineral supplementation. The desired sward heights were 15, 30, 45 and 60 cm, with three replicates each. The experimental design was completely randomized with four treatments and three replications. To body weight gain (BWG) and average daily gain (ADG), each animal was considered an experimental unit. To gain per area and stocking rate, the paddock was considered the experimental unit. The leaf: stem ratio showed a linear increasing behavior in the spring and summer seasons. The smaller grazing heights provided higher gain per unit area (812.15 kg ha(-1)), while the highest grazing heights promoted high individual weight gain (0.790 kg.dia(-1)). The results suggest that Xaraes grass pastures should be grazed between 30 and 45 cm to allow reasonable performances by area and individual performances.

Ácidos graxos da gordura de cobertura do contrafilé de bovinos Nelore e Canchim terminados em confinamento e alimentados com diferentes níveis de concentrado nas dietas

The objective was to evaluate fatty acids composition of the back fat in loin meat (Longissimus muscle) from Nellore and Canchim young bulls. The animals were finished at feedlot and received sugar cane diets with two concentrate levels (40 and 60% of dry matter). The concentrates were formulated with sunflower grains, corn, soybean meal, dry sugar cane yeast, urea and mineral mixture. The experimental design was a completely randomized design with a 2x2 factorial arrangement (genetic group x concentrate level), and the results were submitted to the variance analysis and means compared by Tukey test at 5% probability, when the interaction was significant. The loin backfat of Nellore bulls had higher concentration of conjugated linoleic acids than Canchim bulls (0.86 and 0.59%, respectively). On the other hand, the loin back fat of Canchim bulls had higher concentrations of estearic (17.07%) and linoleic acids (2.40%) and polyunsaturated fatty acids than Nellore bulls, that showed values of 13.47 and 1.44%, respectively. The Nellore and Canchim loin back fat presents significant amounts of beneficial fatty acids to human health. Levels of 40 and 60% of concentrate in the diet did not alter the fatty acids composition of loin backfat.

Análise de componentes principais para características de crescimento em bovinos de corte

The objetive of this research was to study the relation among body weight and average daily gain in different ages, using principal components analysis. Data on 1663 birth weight (BW), weaning weight adjusted to 230 days (WW), yearling weight adjusted to 365 days (YW), long yearling weight adjusted to 550 days (LYW), average daily gain from birth to weaning (AGW), average daily gain from weaning to 365 days (AGY) and average daily gain from 365 days weight to 550 day weight (AGL) from crossbred animals, and data on 320 observations of the same traits from straightbreed Nellore animals were analysed. The model included the fixed effects of breed (only crossbred data), contemporary group, and linear and quadratic effects of age at calving. For body weight in different ages, the first principal component contrasted heavier and light animals after birth and explained about 79,0% and 78,0% of the variation for data on crossbred and Nellore animals, respectively. The second principal component compared heavier animals at weaning and yearling weight those at long yearling weight. It explained around 13,5% and 15,5% of the total variation, respectively, for data on F1 and Nellore breed. The major source of variation among animals on the two data set for body weight was due to differences in weight followed by differences in the ages they got those weight. For the traits expressed as average daily gain, the variation among animals was due to differences in birth season, the first principal component explaining about 52,0% of the variation on crossbred animals. This component compared animal with higher AGY with those with higher AGW and AGL. For data on Nellore breed, the first component explain about 56,0% of the total variation and also compared animals with higher AGY with those with higher AGW and AGL.

Doenças metabólicas do periparto em bovinos leiteiros

Peripartum or Transition Period is, generally, defined as the period between three weeks pre-calving and three weeks after calving. It is a critical and crucial stage to the cow’s health and to economic profitability during the lactation. During this phase the cows experience several changes that prepare them to calve and milk yield. These changes contribute to metabolic disorders’ incidence, and can lead to reproductive function and milk yield reduction, and increase the herd’s disposal. This paper aimed to review the peripartum metabolic diseases, which includes Ketosis, Hypocalcemia, Hepatic Steatosis, Ruminal Acidosis and Lameness

Influência da adição de fator de crescimento fibroblástico 10 (FGF10), durante a maturação oocitária, na produção in vitro de embriões bovinos

The Brazilian livestock stands out for having the world largest commercial herd of cattle and leads meat exportation and production of bovine embryos. The in vitro production (IVP) of embryos is considered an effective option to overcome problems such as infertility in cows with high economic value and also for genetic improvement of cattle. The in vitro oocyte maturation is an essential step to the success of IVP, but is still considered poor when compared to in vivo maturation. Recent studies have suggeested an important role of Fibroblast Growth Factor 10 (FGF10) on the in vitro maturation of oocytes, which favored the expression of genes related to oocyte maturation and cumulus cell expansion. Aware that maturity stage influences the final production of blastocysts, we aimed study to verify if the addition of FGF10 into the maturation medium is able to affect positively the IVP of bovine embryos. Hence, FGF10 was added to maturation in five different concentrations: 0.5 ng/mL (group 0.5), 2.5 ng/mL (group 2.5), 5 ng/mL (group 5), 10 ng/mL (group 10) and 50 ng/mL (group 50). Additionally, two other maturation groups were used, group BSA (Bovine Serum Albumin, 4 mg/mL) and group FCS (Fetal Calf Serum, 10%). The rates of cleavage, morula and blastocyst were analyzed by Analysis of Variance (ANOVA), differences of P<0.05 were considered significant. Cleavage rates did not differ between the seven groups. On the other hand, morula rate on FCS group was higher than groups BSA, 0.5, 10 and 50 (P<0.05), but did not differ among groups treated with intermediate doses of FGF10 (2.5 and 5). FCS group presented higher blastocyst rate compared to all other groups that were well below the FCS group (P<0.0001). Therefore, the use of FGF10 during oocyte maturation did not affect positively embryo development on the IVP of bovine embryos

Anormalidades fetais e placentárias decorrentes da produção in vitro de embriões bovinos

In vitro production of bovine embryo (IVP) has become a remarkable assisted reproduction biotechnology in Brazil, once it is considered an important tool for the genetic improvement of the herd. However, many abnormalities are associated with IVP technologies, such as higher incidences of embryo loss, abortions, hydrallantois and dystocia, prolonged gestation, increased birth weight and high perinatal mortality. Collectively, these abnormalities are known as “Large Offspring Syndrome”, which has limited the large-scale use of IVP technologies in cattle industry

Etiopatogenia e tratamento do deslocamento de abomaso em bovinos leiteiros de alta produção

The dairy business is in constant development, in order to achieve better results and higher profits to the producer, and this search for improvement has led to the selection of a herd more productive. But this has caused some problems heightened, among them the displacement of the abomasum, a disease that affects much of the high producing dairy herd. The main reasons are apparently related to the feeding management, with the abrupt changes that the animal suffers in the post partum period, with diseases that would cause abomasal atony favoring its displacement, among others. When affected, the animals lose their appetite and in milk production, and may even, in severe cases, death to come. Treatments described in literature are varied and there are conservative and chirurgical methods. The choice of a particular technique depends on the financial condition of the producer, the economic value of the cow and from personal experience and technique of the veterinarian. Understanding the clinical implications of displaced abomasum is necessary not only for its animal identification in the field and its appropriate treatment but also for finding the errors and inadequacies in the management system of production that trigger this disease

Remoção de matéria orgânica e nitrogênio de efluentes provenientes de abatedouros de bovinos por meio de reator aeróbio operando em bateladas sequenciais com adição de coagulante químico

The volume of liquid effluent generated in cattle slaughterhouses is quite high and cannot be released untreated in water bodies due to its high pollution load of predominantly organic origin. To minimize the environmental impacts of its industrial wastewater and meet the local environmental legislation, abattoirs shall make the treatment of these effluents. The present work aims to develop the study of a reactor by sequential batch pilot scale, in order to optimize their performance in treating wastewater from a cattle slaughterhouse. The treatment system used was developed and installed in the Laboratory of Wastewater Treatment, in Faculty of Science and Technology UNESP, Presidente Prudente campus. The procedure used followed the operation of sequential batch reactors, in which all processes and treatment operations occurring sequentially in a single unit, by establishing specific operating cycles, which comprise the following separated phases: aerobic reaction, anoxic reaction, sedimentation and emptying. Aiming to improve the quality of treatment was planned the addition of coagulant Poly Aluminum Chloride (PAC) in the reactor, by determining their optimal dosage by Jar-test trials. Were prepared four steps with specific operating cycles: step one or acclimatization (10 hour of aeration, one hour and 30 minutes of sedimentation and 30 minutes for exchanging the effluent); step 2 (6 hours of aeration or aerobic phase, 4 hours and 45 minutes of stirring or anoxic phase and 1 hour and 15 minutes for sedimentation and exchange effluent); step 3 (2 hours and 30 minutes of aeration, 8 hours and 15 minutes of stirring and 1 hour and 15 minutes for sedimentation and exchange) and step 4 (2 hours of aeration, 8 hours and 45 minutes of stirring and 1 hour and 15 minutes for sedimentation and exchange)... (Complete abstract click electronic access below)

Enfermidades genéticas com mutações caracterizadas em bovinos

The genetic inheritance, beyond determining the regular features of all the live beings, can also be the cause of diseases, called as hereditary or genetic diseases. In the case of livestock, especially cattle, little genetic variation, by the use of the same sires for a long time, can facilitate the emergence of problems. In this study, we reviewed eight of the most important genetic diseases in cattle herds around the world, whose mutation has already been characterized. Some of these diseases are reported in Brazil, but there are few studies and articles on this subject, due to the difficulty of a definitive diagnosis, which often is only possible with the use of molecular biology techniques. The knowledge of the disorders and the correct diagnosis are essential to initiate an action plan aimed at eradicating them

Utilização de gonadotropina coriônica equina em protocolos de inseminação artificial em tempo fixo em bovinos de corte

Current cattlemen must seek methods to maximum reproductive efficiency of their beef herds, making the business competitive and enhancing greater profitability. For the cow-calf producers, efficiency translates into more cows producing one calf every year. Fixed-time artificial insemination (TAI) is one of several technologies that producers utilize to reach this goal. Postpartum anestrus is one of the biggest obstacles to overcome in order to obtain suitable results at the end of the breeding season. The TAI protocols are efficient in re-establishing cyclicity in noncycling cows during the postpartum period, streamlining the use of labor on farms, allowing the use of artificial insemination (AI) on a large scale, and introducing superior genetics to the herd. The protocols that are most commonly used in Brazil are based on progesterone (P4) releasing devices that prevent premature estrus and ovulation; and estradiol (E2) to synchronize the initiation of a new follicular wave. In such protocols, administration of equine chorionic gonadotropin (eCG) helps the development of the follicle, increases ovulation rate, improves the endocrine and uterine environment during proestrus and diestrus, and improves fertility. The use of eCG in TAI protocols for suckled cows, non-lactating cows and heifers increases the pregnancy rate allowing more calves at the end of the breeding season and higher profitability to the cattlemen

Manejo pré-abate de bovinos

The pre-slaughter moment begins with the animal´s loading on the farm and ends up in its drain. It is a period in which the animal is under physical stress caused by hunger, thirst, fatigue, injuries, and extremes of temperature and psychological stress, due to restraint, handling, innovation and fear. Stress and inappropriate handling bring bad consequences for the final product´s quality, requiring better handling conditions, facilities and equipment. Examples of consequences of mishandling: meat with abnormal color, DFD meat (dark, firm and dry), reduced product´s shelf life, bruises and broken bones in carcasses. The operators should be trained and oriented on the basic principles of biology, behavior and management of cattle. At every step of the pre-slaughter moment, the animals should be handled calmly and quietly to avoid excitement and stress. Operators should avoid shouting, whistling or any noise since cattle have very sensitive ears and can become stressed. If the animals refuse to move, the cause of the problem should be determined

Brucelose e tuberculose como doenças ocupacionais em matadouros-frigoríficos de bovinos no Brasil

Tuberculosis and brucellosis are important diseases in national scenario, as they affect national cattle and can be transmitted to human, as they are zoonosis. The transmission risk increases mostly for those who have strict contact with animals, as is this case of slaughterhouse workers. This paper presents a bibliographic review of data referent to both diseases occurring in bovine slaughterhouse workers in Brazil, characterizing as occupational zoonosis diseases. We still have few data available of this subject, what raise difficulties to know the real incidence of both diseases in national cattle and in people who work in contact with animals, and most of the time are not instructed to the risk that they are exposed and how to prevent it. It’s important to know which is the situation of both diseases so that prevention and even eradication measures can be taken, as we know the Veterinary has an essential function in this matter, protecting animal health as much as protecting national public health