Shading effects on canopy and tillering characteristics of continuously stocked palisadegrass in a silvopastoral system in the Amazon biome     

Fagner Junior Gomes  Bruno Carneiro Pedreira  Patrícia Menezes Santos  Cristiam Bosi  Carlos Guilherme Silveira Pedreira 《Grass and Forage Science》2020,75(3):279-290

In silvopastoral (SP) systems, forage responses depend on the microenvironment in which the plants develop. Our objective was to evaluate canopy and tillering characteristics of shaded 'Marandu' palisadegrass [Brachiaria brizantha (Hochst A Rich) Stapf, syn. Urochloa brizantha] under continuous stocking in a SP system. Treatments were one full sun (FS) and three shaded systems (silvopasture, SP) corresponding to distances from tree groves: 7.5 m north (SP1), and 15 m (SP2) and 7.5 m south (SP3) studied during two rainy seasons (Year 1 and Year 2). The tree in the SP system was Eucalyptus urograndis (hybrid of Eucalyptus grandis W. Hill ex Maiden × Eucalyptus urophylla S. T. Blake). The photosynthetic active radiation was greater in FS (923 μmol m^-2 s^-1), followed by SP2 (811 μmol m^-2 s^-1), SP1 (727 μmol m^-2 s^-1) and SP3 (673 μmol m^-2 s^-1). Forage accumulation in FS was 15% greater than the mean of SP1, SP2 and SP3 (10,663 kg DM/ha). There was no difference in net accumulation of leaf, stem and dead material, averaging 3,302, 3,420 and 4,063 kg DM/ha respectively. Leaf accumulation and accumulation rate were greater in Year 2, and leaf accumulation rate was similar among treatments (19 kg DM ha⁻¹ day⁻¹). Leaf proportion increased 14% from Year 1 to Year 2. Specific leaf area was greater for treatments SP1 and SP3 (193 cm²/g). Tiller population density was similar across treatments in Year 1. Shaded palisadegrass maintains leaf productivity similar to FS under continuous stocking in an SP system.  相似文献   

The effect of life history events on carcass merit and price of cull dairy cows     

Ligia C Moreira  Tiago L Passafaro  Daniel M Schaefer  Guilherme J M Rosa 《Journal of animal science》2021,99(1)

Cull dairy cows contribute almost 10% of national beef production in the United States. However, different factors throughout the life of dairy cows affect their weight and overall body condition as well as carcass traits, and consequently affect their market price. Therefore, the objectives of this study were: (1) to assess relationships between price ratio and carcass merit of cull dairy cows sold through several sites of an auction market and (2) to investigate the effect of animal life history events and live weight on sale barn price (BP) and price ratio (as a measure of relative price), as an indicator of carcass merit. Data from 4 dairy operations included 3,602 cull dairy cow records during the period of 2015 to 2019. Life history events data were collected from each dairy operation through Dairy Comp software; live weight and price were obtained periodically from the auction market, and the carcass data were provided by a local packing plant. Cow price in dollars per unit of live weight ($/cwt) and price ratio were the 2 outcome variables used in the analyses. Price ratio was created aiming to remove seasonality effects from BP (BP divided by the national average price for its respective month and year of sale). The association between price ratio and carcass merit traits was investigated using canonical correlation analysis, and the effect of life history events on both BP and price ratio was inferred using a multiple linear regression technique. More than 70% of the cows were culled in the first 3 lactations, with an average live weight of 701.5 kg, carcass weight of 325 kg, and dressing percentage of 46.3%. On average, cull cows were sold at $57.0/cwt during the period considered. The canonical correlation between price ratio and carcass merit traits was 0.76, indicating that price ratio reflected carcass merit of cull cows. Later lactations led to lower BP compared with cows culled during the first 2 lactations. Injury, and leg and feet problems negatively affected BP. Productive variables demonstrated that the greater milk production might lead to lower cow prices. A large variation between farms was also noted. In conclusion, price ratio was a good indicator of carcass merit of cull cows, and life history events significantly affected sale BP and carcass merit of cull cows sold through auction markets.  相似文献   

Continuous infusion of propofol in calves: bispectral index and hemodynamic effects          下载免费PDF全文

Mauricio Deschk  Juliana T Wagatsuma  Marcelo A Araújo  Guilherme GF Santos  Sergio SR Júnior  Caio JX Abimussi  Carlos E Siqueira  Jéssica CL Motta  Silvia HV Perri  Paulo SP Santos 《Veterinary anaesthesia and analgesia》2016,43(3):309-315

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Genomic prediction for meat and carcass traits in Nellore cattle using a Markov blanket algorithm     

Fernando Brito Lopes  Fernando Baldi  Ludmilla Costa Brunes  Marcos Fernando Oliveira e Costa  Eduardo da Costa Eifert  Guilherme Jordão Magalhães Rosa  Raysildo Barbosa Lobo  Cláudio Ulhoa Magnabosco 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2023,140(1):1-12

This study was carried out to evaluate the advantage of preselecting SNP markers using Markov blanket algorithm regarding the accuracy of genomic prediction for carcass and meat quality traits in Nellore cattle. This study considered 3675, 3680, 3660 and 524 records of rib eye area (REA), back fat thickness (BF), rump fat (RF), and Warner–Bratzler shear force (WBSF), respectively, from the Nellore Brazil Breeding Program. The animals have been genotyped using low-density SNP panel (30 k), and subsequently imputed for arrays with 777 k SNPs. Four Bayesian specifications of genomic regression models, namely Bayes A, Bayes B, Bayes Cπ and Bayesian Ridge Regression methods were compared in terms of prediction accuracy using a five folds cross-validation. Prediction accuracy for REA, BF and RF was all similar using the Bayesian Alphabet models, ranging from 0.75 to 0.95. For WBSF, the predictive ability was higher using Bayes B (0.47) than other methods (0.39 to 0.42). Although the prediction accuracies using Markov blanket of SNP markers were lower than those using all SNPs, for WBSF the relative gain was lower than 13%. With a subset of informative SNPs markers, identified using Markov blanket, probably, is possible to capture a large proportion of the genetic variance for WBSF. The development of low-density and customized arrays using Markov blanket might be cost-effective to perform a genomic selection for this trait, increasing the number of evaluated animals, improving the management decisions based on genomic information and applying genomic selection on a large scale.  相似文献   

Chemical restraint of peccaries with tiletamine/zolazepam and xylazine or tiletamine/zolazepam and butorphanol   总被引：3，自引：0，他引：3  

Selmi AL  Mendes GM  Figueiredo JP  Guimarães FB  Selmi GR  Bernal FE  McMannus C  Paludo GR 《Veterinary anaesthesia and analgesia》2003,30(1):24-29

Objective To evaluate the use of a combination of tiletamine/zolazepam and xylazine (TZX) in collared and white‐lipped peccaries and to compare its efficacy as an anesthetic technique with that of tiletamine/zolazepam and butorphanol (TZB). Study design Prospective experimental trial. Animals Seven white‐lipped peccaries (Tayassu pecari) (four females and three males) and four collared peccaries (Tayasu tajacu) (two males and two females). Methods Animal immobilization was attempted with TZX and TZB (IM) on two different occasions. Heart and respiratory rates (HR, RR), rectal temperature (RT), sedation, muscle relaxation, posture, auditory response and analgesia were evaluated every 15 minutes during immobilization. Induction, anesthesia, standing and walking time were determined after drug administration. Results Doses for white‐lipped peccaries were 1.23 ± 0.26 mg kg^?1 (mean ± SD) of TZ and 1.23 ± 0.26 mg kg^?1 of X, and 1.46 ± 0.09 mg kg^?1 of TZ and 0.14 ± 0.008 mg kg^?1 of B; doses for collared peccaries were 1.51 ± 0.29 mg kg^?1 of TZ and 1.51 ± 0.29 mg kg^?1 of X and 1.68 ± 0.02 mg kg^?1 of TZ and 0.17 ± 0.002 mg kg^?1 of B. In white‐lipped peccaries, both drug combinations provided a smooth induction and good immobilization for more than an hour. Anesthesia and standing times were significantly longer in animals given TZB, whereas walking time was significantly longer in animals given TZX. A significant decrease in HR was observed with both treatments. Respiratory rate decreased significantly with TZX, but the rate remained higher than with TZB. Induction and recovery quality in white‐lipped peccaries was better with TZB than with TZX. Neither protocol provided adequate immobilization in collared peccaries. Conclusion and clinical relevance At the doses described, TZB is effective in providing a long period of immobilization, whereas TZX is adequate for short to medium immobilization in white‐lipped peccaries. Neither drug combination was effective in collared peccaries at the doses given.  相似文献   

Ineffectiveness of pruning to control citrus huanglongbing caused by <Emphasis Type="Italic">Candidatus</Emphasis> Liberibacter americanus     

Silvio Aparecido Lopes  Guilherme Fernando Frare  Pedro Takao Yamamoto  Antonio Juliano Ayres  José Carlos Barbosa 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(4):463-468

The huanglongbing (HLB) disease of citrus trees, caused by Candidatus Liberibacter asiaticus and Ca. Liberibacter americanus, was first reported in Brazil in March, 2004. The presence of the disease has caused serious concerns among growers. Pruning experiments were conducted to determine if removal of symptomatic branches or the entire canopy (decapitation) would eliminate infected tissues and save HLB-affected trees. Pruning was done in five blocks on a total of 592 3- to 16 year-old ‘Valência’, ‘Hamlin’ or ‘Pêra’ sweet orange trees showing no symptoms or with two levels of symptom severity. Ten decapitated trees per block were caged and all trees were treated with insecticides to control the psyllid vector, Diaphorina citri. Mottled leaves reappeared on most symptomatic (69.2%) as well on some asymptomatic (7.6%) pruned trees, regardless of age, variety, and pruning procedure. Presence of the pathogen (Ca. Liberibacter americanus) in all symptomatic trees was confirmed by PCR. In general, the greater the symptom severity before pruning the lower the percentage of trees that remained asymptomatic after pruning.  相似文献   

Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate     

Felipe Nogueira Soares  Maria Emilia Franco Oliveira  Luciana Cristina Padilha-Nakaghi  Luís Guilherme de Oliveira  Marcus Antônio Rossi Feliciano  Felipe Brener Bezerra de Oliveira  Pedro Paulo Maia Teixeira  Wilter Ricardo Russiano Vicente  Cristian Faturi  Luiz Fernando de Souza Rodrigues 《Tropical animal health and production》2015,47(8):1465-1471

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The influence of the obstetrical condition on canine neonatal pulmonary functional competence          下载免费PDF全文

Liege Garcia Silva DVM  PhD  Guilherme Vannucchi Portari PhD  Cristina Fátima Lúcio DVM  PhD  Jaqueline Aguiar Rodrigues DVM  MSc  Gisele Lima Veiga DVM  PhD  Camila Infantosi Vannucchi DVM  PhD 《Journal of Veterinary Emergency and Critical Care》2015,25(6):725-730

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Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats     

Correa Mdo A  Aguiar AJ  Neto FJ  Mendes Gda M  Steagall PV  Lima AF 《American journal of veterinary research》2007,68(9):932-940

OBJECTIVE: To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats. ANIMALS: 8 adult cats. PROCEDURES: On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, i.v.) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 microg/kg/ min, i.v.) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (> or = 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II). RESULTS: In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 microg of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 microg of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 microg/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 microg/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique.  相似文献   

Genetic variability in plants regenerated from in vitro culture of sunflower (Helianthus annum L.)     

S. Barotti    M. Fambrini    C. Pugliesi  A. Lenzi 《Plant Breeding》1995,114(3):275-276

In vitro regenerated sunflower (Helianthus annuus L.) plants (R₁) were self-fertilized and the R₂ generation was evaluated for qualitative traits. A broad range of phenotypic variation was observed and mutation frequencies were calculated. Some in vitro induced variant phenotypes were similar to known spontaneous or induced mutations in sunflower, while others were new. Chlorophyll and carotenoid deficiencies, chimaerical variegation, fasciated stem and capitulum, abnormal shoot development, and other morphological variations, were noted. Substitution of anthers with petaloid structures in a disk-floret mutant indicates a possible homeotic mutation induced by in vitro tissue culture.  相似文献