Perfil gênico no oviduto bovino de fêmeas Nelore e Aberdeen angus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Glicerina associada à ureia na alimentação de bovinos Nelore

Pós-graduação em Zootecnia - FCAV

Taxa de deposição de tecidos corporais de novilhas Nelore e suas cruzas com Angus e Simental

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Plasma anti-mullerian hormone: an endocrine marker for in vitro embryo production from Bos taurus and Bos indicus donors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro and in vivo acaricide action of juvenoid analogs produced from the chemical modification of Cymbopogon spp. and Corymbia citriodora essential oil on the cattle tick Rhipicephalus (Boophilus) microplus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

BILL E. KUNKLE INTERDISCIPLINARY BEEF SYMPOSIUM: Temperament and acclimation to human handling influence growth, health, and reproductive responses in Bos taurus and Bos indicus cattle

Temperament in cattle is defined as the fear-related behavioral responses when exposed to human handling. Our group evaluates cattle temperament using 1) chute score on a 1 to 5 scale that increases according to excitable behavior during restraint in a squeeze chute, 2) exit velocity (speed of an animal exiting the squeeze chute), 3) exit score (dividing cattle according to exit velocity into quintiles using a 1 to 5 scale where 1 = cattle in the slowest quintile and 5 = cattle in the fastest quintile), and 4) temperament score (average of chute and exit scores). Subsequently, cattle are assigned a temperament type of adequate temperament (ADQ; temperament score <= 3) or excitable temperament (EXC; temperament score > 3). To assess the impacts of temperament on various beef production systems, our group associated these evaluation criteria with productive, reproductive, and health characteristics of Bos taurus and Bos indicus-influenced cattle. As expected, EXC cattle had greater plasma cortisol vs. ADQ cattle during handling, independent of breed type (B. indicus x B. taurus, P < 0.01; B. taurus, P < 0.01; B. indicus, P = 0.04) or age (cows, P < 0.01; heifers or steers, P < 0.01). In regards to reproduction, EXC females had reduced annual pregnancy rates vs. ADQ cohorts across breed types (B. taurus, P = 0.03; B. indicus, P = 0.05). Moreover, B. taurus EXC cows also had decreased calving rate (P = 0.04), weaning rate (P = 0.09), and kilograms of calf weaned/cow exposed to breeding (P = 0.08) vs. ADQ cohorts. In regards to feedlot cattle, B. indicus EXC steers had reduced ADG (P = 0.02) and G:F (P = 0.03) during a 109-d finishing period compared with ADQ cohorts. Bos taurus EXC cattle had reduced weaning BW (P = 0.04), greater acute-phase protein response on feedlot entry (P <= 0.05), impaired feedlot receiving ADG (P = 0.05), and reduced carcass weight (P = 0.07) vs. ADQ cohorts. Acclimating B. indicus x B. taurus or B. taurus heifers to human handling improved temperament (P <= 0.02), reduced plasma cortisol (P < 0.01), and hastened puberty attainment (P <= 0.02). However, no benefits were observed when mature cows or feeder cattle were acclimated to human handling. In conclusion, temperament impacts productive, reproductive, and health characteristics of beef cattle independent of breed type. Hence, strategies to improve herd temperament are imperative for optimal production efficiency of beef operations based on B. taurus and B. indicus-influenced cattle.

Ação da dopamina na secreção do hormônio do crescimento em novilhas pré-púberes da raça Nelore

The aim of this study was to evaluate the response of dopamine in the growth hormone secretion (GH) during Nellore heifer's sexual maturation. The animals were randomly assigned into two experimental groups: Sulpiride group (dopamine D-2 antagonist, 0.59 mg/kg, S. C.) and control group (saline solution S. C.) at 8, 12 and 16 months of age. Blood samples were collected every 15 min for 10h after drug injection. Growth hormone was quantified by RIA, sensitivity (0.25 ng/mL) and intra and inter-assay variation coefficients were 15% and 17%, respectively. GH concentration was higher in sulpiride group than control group at 8 mo (10.1 +/- 0.38 ng/mL vs 4.3 +/- 0.34 ng/mL; P < 0.05) and 12 mo of age (9.46 +/- 0.35 vs 3.74 +/- 0.19 ng/mL; P < 0.05). In sulpiride group GH average concentration was greater at 8 and 12 mo compared to 16 mo of age (10.10 +/- 0.38 ng/mL and 9.46 +/- 0.35 ng/mL vs 4.87 +/- 0.35 ng/mL; P < 0.05) respectively. There was no difference between groups (P > 0.05) in total GH secretion area, total peak area and maximum peak amplitude. These results suggested an inhibitory dopamine effect on GH secretion in pre-pubertal Nellore heifers that decreases according to age.

Comportamento ingestivo de novilhas Nelore em pastejo recebendo suplemento a base de própolis ou monensina sódica

We evaluated the effect of additives the basis of propolis and monensin on ingestive behavior (grazing -GRA, rumination lying -RLY, rumination in foot -RFO, rumination -RUM; idleness lying -ILY, idleness in standing -IDS, idleness -IDL, walking -WAL, posture standing -POS, posture lying -PLY, intake of supplement and water -ISW) of heifers in Tifton 85 grazing. The treatments were: no additive (NAD); propolis - PRO (33.24 mg animal-1 of total flavonoid in apigenin), and monensin -MON (100 mg animal(-1)). Were used five heifers treatment(-1) for evaluation of ingestive behavior during 12 hours of total valuation, which was divided into three periods. Used a factorial design into 3 x 3 for evaluation of ingestive behavior as a function of the evaluation periods. Were utilized three paddocks of 2.9 acres of grass Tifton 85. The additives and mineral supplement (50 g animal(-1)) were provided with 200 g of corn meal to 17 hours. For all activities of the ingestive behaviors observed the effect of period on the time spent on of different activities. The activities of GRA and ISW were higher in the third period (15hours to 19hours) compared to the first period (7hours at 11hours). For IDL and PLY, there was a higher time in minutes for heifers treatment with PRO in the period of 7hours at 11hours, compared to other treatments (NAD and MON). Thus, it is concluded that the use of the additive based on propolis enables sodium monensin replacement, to heifers maintained on pasture without changing eating behavior as well as providing greater idleness during the day the without affecting animal performance.

Puberdade em novilhas

The age which heifers reach puberty depend on factors like genetics, environment and nutrition. Puberty in heifers can be defined as the onset of reproductive competence, the ability to ovulate a fertile oocyte with an estrous behavior and development of a corpus luteum with normal lifespan. The metabolic signals that trigger puberty are not yet fully defined. In Brazil, where most beef cattle are zebu, the age at puberty is very advanced, mainly these animals are feed with a poor diet. Many researches are trying to discover the metabolic signals that trigger puberty and anticipate better economic return in breeding farms. It has been demonstrated that the cascade of endocrine events that culminate in puberty can be hastened by an alternative management scheme that involves increased nutrient intake between 3 and 7 months of life. Different diet concentrations, different products and by-products have been used in research to achieve puberty early (less than 300 days of age). The hormonal induction of puberty, especially with the use of progestagens, has been developed in heifers as an alternative tool to improve reproductive efficiency in herds, increasing the amount of pregnant heifers in breeding season

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

Avaliação da taxa de concepção de novilhas e vacas (Bos taurus x Bos indicus) com o uso de sêmen sexado na inseminação artificial ou embriões produzidos in vivo e in vitro

Pós-graduação em Medicina Veterinária - FCAV

Controle e estimulação de crescimento folicular em doadoras da raça holandesa para a produção in vitro de embriões

Pós-graduação em Medicina Veterinária - FCAV

Fast determination of beef quality parameters with time-domain nuclear magnetic resonance spectroscopy and chemometrics

The noteworthy of this study is to predict seven quality parameters for beef samples using time-domain nuclear magnetic resonance (TD-NMR) relaxometry data and multivariate models. Samples from 61 Bonsmara heifers were separated into five groups based on genetic (breeding composition) and feed system (grain and grass feed). Seven sample parameters were analyzed by reference methods; among them, three sensorial parameters, flavor, juiciness and tenderness and four physicochemical parameters, cooking loss, fat and moisture content and instrumental tenderness using Warner Bratzler shear force (WBSF). The raw beef samples of the same animals were analyzed by TD-NMR relaxometry using Carr-Purcell-Meiboom-Gill (CPMG) and Continuous Wave-Free Precession (CWFP) sequences. Regression models computed by partial least squares (PLS) chemometric technique using CPMG and CWFP data and the results of the classical analysis were constructed. The results allowed for the prediction of aforementioned seven properties. The predictive ability of the method was evaluated using the root mean square error (RMSE) for the calibration (RMSEC) and validation (RMSEP) data sets. The reference and predicted values showed no significant differences at a 95% confidence level.

Desempenho de bovinos cruzados e parâmetros qualitativos de músculos maturados

Pós-graduação em Zootecnia - FCAV

Análise genética da espessura do couro, do crescimento pós desmama e das resistências ao carrapato e à babesiose em bovinos de corte

Pós-graduação em Genética e Melhoramento Animal - FCAV