935 resultados para animal performance


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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The elevated T-maze has been developed as an animal model of anxiety to generate both conditioned and unconditioned fears in the same rat. This study explores a version of the elevated T-maze fit for mice. Inhibitory (passive) avoidance-conditioned fear-is measured by recording the latency to leave the enclosed arm during three consecutive trials. One-way escape-unconditioned fear-is measured by recording the time to withdraw from open arms. The results showed that mice do not appear to acquire inhibitory avoidance in the standard T-maze, since their latencies to leave enclosed arm did not increase along trials. Nevertheless, the open arms seemed to be aversive for mice, because the latency to leave the enclosed arm after the first trial was lower in a T-maze with the three enclosed arms than in the standard elevated T-maze, In agreement, the exposure of mice to an elevated T-maze without shield, that reduces the perception of openness, increased significantly the latencies to leave the enclosed arm, However, the absence of the shield also increased the time taken to leave the open arms when compared to that recorded in standard T-maze. Systematic observation of behavioral items in the enclosed arm has shown that risk assessment behavior decreases along trials while freezing increases. In the open arms, freezing did not appear to influence the high latency to leave this compartment, since mice spend only about 8% of their time exhibiting this behavior, These results suggest that mice acquire inhibitory avoidance of the open arms by decreasing and increasing time in risk assessment and freezing, respectively, along three consecutive trials, However, one-way escape could not be characterized. Therefore, there are important differences between mice (present results) and rats (previously reported results) in the performance of behavioral tasks in the elevated T-maze. (C) 1999 Elsevier B.V.

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The data used in the present study were recorded at the Jockey Club of Sorocaba for 5094 racing performance of 1350 Quarter Horses at the Paulista Race Track of Sorocaba, state of São Paulo, Brazil, from 1991 to 1997. The considered traits were time and final rank. The model used in analysis included random animal and permanent environmental effects, and race, sex, age and origin as fixed effects. The variance and covariance components were estimated by the restricted maximum likelihood for an animal model, using the derivative-free process method and the MTDFREML software. For the time, heritability was 0.17 (0.05), while estimate of repeatability 0.55 (0.05). The lower heritability for the final rank, 0.13 (0.04), indicate that this trait is not the most appropriate one for inclusion in programs of Quarter horse selection in Sorocaba racetrack. The repeatability estimate for rank was 0.44 (0.04) and the genetic correlation between this trait and time was 0.99.

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This study aimed at evaluating the effect of nucleotides on the performance and carcass yield of broilers fed diets with no antibiotic growth promoters (AGP), anticoccidials, or animal feedstuffs. In the trial, 600 Ross 308 male broilers were distributed in a completely randomized experimental design into six treatments with four replicates of 25 birds each. Treatments consisted of a control diet (CD), CD + AGP, CD + 0.04%, CD + 0.05%, CD + 0.06%, and CD + 0.07% nucleotides. The experimental diets did not contain anticoccidials, and birds were vaccinated against coccidiosis at three days of age. No significant differences were detected among broilers submitted to the different treatments in none of the studied parameters. Under the conditions of this experiment, diets supplemented with nucleotides did not influence broiler performance or carcass yield at 42 days of age, and were not different from the feeds not containing any additive or with AGP.

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O presente estudo teve por objetivo avaliar o efeito da utilização de níveis crescentes do gluconato de sódio sobre o desempenho, o rendimento de carcaça e de partes e a morfometria da mucosa intestinal de frangos de corte de 22 a 42 dias de idade. Foram utilizados 1200 frangos de corte da linhagem Cobb, distribuídos em um delineamento inteiramente casualizado, envolvendo cinco tratamentos (0,00; 0,10; 0,20; 0,30 e 0,40% de gluconato de sódio) com oito repetições de 30 aves cada parcela. As variáveis foram submetidas à análise de variância e em caso de significância estatística foram realizadas análises de regressão pelos modelos polinomial e quadrático. A inclusão do gluconato de sódio não afetou o desempenho e o rendimento de carcaça e de partes. Entretanto, exerceu efeito benéfico sobre a morfometria da mucosa intestinal do duodeno e do jejuno.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This study aimed to investigate the influence of calf genetic group on the performance of Nellore lactating cows. The variables studied included milk ingestion, pasture intake, calf weight gain and cow body weight. A total of 13 Nellore calves and 8 crossbred Simental x Nellore calves were used, all born from Nellore mothers. During the experimental period of 210 days, calves were weighted at birth and at 30-day intervals, whereas cows were weighed every 14 days. Milk intake was estimated using the weigh-suckle-weigh method. Pasture intake was determined 6, 12, and 24 weeks after birth by using chromic oxide as an external marker and indigestible acid detergent fiber as an internal marker. Average weight of crossbred calves was 10.1 kg and their milk intake was 0.42 kg higher than in purebred calves. There was no difference, however, in pasture intake between genetic groups. In Nellore cows, body weight and pasture consumption (9.2 kg of DM/cow/day) were not influenced by calf heterosis.

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The objective of this study was to compare the effects of 24-h road transport or 24-h feed and water deprivation on acute-phase and performance responses of feeder cattle. Angus x Hereford steers (n = 30) and heifers (n = 15) were ranked by gender and BW (217 +/- 3 kg initial BW; 185 +/- 2 d initial age) and randomly assigned to 15 pens on d -12 of the experiment (3 animals/pen; 2 steers and 1 heifer). Cattle were fed alfalfa-grass hay ad libitum and 2.3 kg/animal daily (DM basis) of a corn-based concentrate throughout the experiment (d -12 to 28). on d 0, pens were randomly assigned to 1 of 3 treatments: 1) transport for 24 h in a livestock trailer for 1,200 km (TRANS), 2) no transport but feed and water deprivation for 24 h (REST), or 3) no transport and full access to feed and water (CON). Treatments were concurrently applied from d 0 to d 1. Total DMI was evaluated daily from d -12 to d 28. Full BW was recorded before treatment application (d -1 and 0) and at the end of experiment (d 28 and 29). Blood samples were collected on d 0, 1, 4, 7, 10, 14, 21, and 28. Mean ADG was greater (P < 0.01) in CON vs. TRANS and REST cattle but similar (P = 0.46) between TRANS and REST cattle (1.27, 0.91, and 0.97 kg/d, respectively; SEM = 0.05). No treatment effects were detected for DMI (P >= 0.25), but CON had greater G: F vs. TRANS (P < 0.01) and REST cattle (P = 0.08) whereas G: F was similar (P = 0.21) between TRANS and REST cattle. Plasma cortisol concentrations were greater (P <= 0.05) in REST vs. CON and TRANS cattle on d 1, 7, 14, and 28 and also greater (P = 0.02) in TRANS vs. CON cattle on d 1. Serum NEFA concentrations were greater (P < 0.01) in REST and TRANS vs. CON cattle on d 1 and greater (P < 0.01) in REST vs. TRANS cattle on d 1. Plasma ceruloplasmin concentrations were greater (P = 0.04) in TRANS vs. CON cattle on d 1, greater (P = 0.05) in REST vs. CON on d 4, and greater (P <= 0.05) in REST vs. TRANS and CON on d 14. Plasma haptoglobin concentrations were greater (P < 0.01) in TRANS vs. CON and REST cattle on d 1 and greater (P <= 0.05) for REST vs. TRANS and CON cattle on d 7. In conclusion, 24-h transport and 24-h nutrient deprivation elicited acute-phase protein reactions and similarly reduced feedlot receiving performance of feeder cattle. These results suggest that feed and water deprivation are major contributors to the acute-phase response and reduced feedlot receiving performance detected in feeder cattle transported for long distances.

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Five experiments evaluated the effects of supplemental Ca salts of PUFA on reproductive function of Bos indicus beef cows. In Exp. 1, nonlactating and multiparous grazing cows (n = 51) were assigned to receive (as-fed basis) 0.1 kg of a protein-mineral mix + 0.1 kg of ground corn per cow/d, in addition to 0.1 kg per cow/d of 1) Ca salts of PUFA (PF), 2) Ca salts of SFA (SF), or 3) kaolin (control). Treatments were offered from d 0 to 20 of the estrous cycle. No treatment effects were detected on serum progesterone concentrations (P = 0.83), day of luteolysis (P = 0.86), or incidence of short cycles (P = 0.84). In Exp. 2, nonlactating and multiparous grazing cows (n = 43) were assigned to receive PF, SF, or control from d 0 to 8 of the estrous cycle. on d 6, all cows received (intramuscularly) 25 mg of PGF(2 alpha). No treatment effects were detected on serum progesterone concentrations on d 6 (P = 0.37), and incidence (P = 0.67) or estimated time of luteolysis (P = 0.44). In Exp. 3, twenty-seven lactating and multiparous grazing cows, approximately 30 to 40 d postpartum, were assigned to receive PF or control for 10 d beginning at the first postpartum ovulation. No treatment effects were detected (P = 0.85) on incidence of short cycles. In Exp. 4, lactating and multiparous grazing cows (n = 1,454), approximately 40 to 60 d postpartum, were assigned to receive 1 of the 7 treatments for 28 d after timed AI (TAI; d 0): 1) control from d 0 to 28, 2) SF from d 0 to 14 and then control, 3) PF from d 0 to 14 and then control, 4) SF from d 0 to 21 and then control, 5) PF from d 0 to 21 and then control, 6) SF from d 0 to 28, and 7) PF from d 0 to 28. Cows receiving PF for more than 21 d after TAI had greater (P < 0.01) pregnancy to TAI compared with all other treatments combined (50.4 vs. 42.4%, respectively). In Exp. 5, lactating and multiparous grazing cows (n = 501), approximately 40 to 60 d postpartum, were assigned to receive 1 of the 4 treatments for 21 d after TAI (d 0): 1) PF from d 0 to 14 and then control, 2) control from d 0 to 6 and then PF, 3) control from d 0 to 13 and then PF, and 4) PF from d 0 to 21. Cows receiving PF after d 14 of the experiment had greater (P = 0.02) pregnancy to TAI compared with cows not receiving PF during the same period (46.8 vs. 33.1%, respectively). In summary, supplemental Ca salts of PUFA during the expected time of luteolysis increased pregnancy to TAI in beef cows.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)