Increasing levels of supplementation for crossbred steers on pasture during the dry period of the year     

Daniele Soares Barroso Neves  Robério Rodrigues Silva  Fabiano Ferreira da Silva  Laize Vieira Santos  George Abreu Filho  Sinvaldo Oliveira de Souza  Marceliana da C. Santos  Weder Jansen Rocha  Ana Paula Gomes da Silva  Mateus de Melo Lisboa  Maria Magna Silva Pereira  Venício Macedo Carvalho 《Tropical animal health and production》2018,50(7):1411-1416

The aim of this study was to evaluate the effect of increasing concentrate supplementation levels on the intake, nutrient digestibility, and performance of crossbred steers during the dry period of the year. The experiment was developed on Princesa do Mateiro farm, in the municipality of Ribeirão do Largo, located in the southwest region of Bahia State, Brazil. Forty uncastrated male crossbred (½ Holstein-Zebu) steers with an average body weight (BW) of 232.55?±?24.97 kg were distributed into four treatments in a completely randomized design with ten replicates. The animals were managed in an experimental area formed by Brachiaria brizantha cv. Marandu, in an intermittent grazing system. Treatments consisted of the following supplementation levels: 0.2% BW, with 60% crude protein (CP); 0.3% BW, with 40% CP; 0.4% BW, with 30% CP; and 0.5% BW, with 24% CP. The intakes of forage dry matter in kg/day and %BW and neutral detergent fiber corrected for ash and protein (NDFap) in %BW decreased linearly, whereas the intake of non-fibrous carbohydrates corrected for ash and protein in kg/day and average daily gain increased linearly. Therefore, the use of supplementation at 0.5% BW (24% crude protein) to provide gains of up to 0.500 kg/day is recommended for grazing steers during the post-weaning period in the dry season of the year.  相似文献   

Bayesian analysis of complex traits in pedigreed plant populations     

M. C. A. M. Bink  M. P. Boer  C. J. F. ter Braak  J. Jansen  R. E. Voorrips  W. E. van de Weg 《Euphytica》2008,161(1-2):85-96

A Bayesian approach to analyze complex traits is presented that can help plant eneticists and breeders in exploiting the marker and phenotypic data on pedigreed populations as available from ongoing breeding programs. The statistical model for the quantitative trait may include non-genetic and genetic components. The latter component can be divided into QTL on known marker linkage groups, major genes and a polygenic component. The full probability model, prior assumptions on model variables are presented and criterion for model selection and posterior inferences are given. Simulated data on a known pedigreed population structure of the EU project HiDRAS was used to illustrate the use of the Bayesian approach to analyze complex traits. It was shown that estimates for QTL parameters were more accurate when non-genetic factors were included in the model and when a polygenic component was included when not all linkage groups were analyzed simultaneously. The Bayesian approach has been implemented into the software package FlexQTL and allows plant breeders explore their pedigreed populations for segregating QTL alleles that are relevant in their breeding program.  相似文献   

Survival of fast- and slow-growing Rhizobium spp under conditions of relatively mild desiccation     

H.Jansen van Rensburg  B.W. Strijdom 《Soil biology & biochemistry》1980,12(4):353-356

When subjected to desiccation with Ca(NO₃)₂ at 27°C, strains of the fast growing Rhizobium meliloti and R. trifolii, survived better than slow-growing strains of R. japonicum and of the “cowpea miscellany”. At lower vapour pressures in a forced-draught oven, the pattern of survival changed and strains of slow-glowing Rhizobium withstood desiccation better than those of fast-growing species. The results are considered to be consistent with the interpretation that a lower internal water-retaining ability at any relative vapour pressure, renders strains of slow-growing Rhizobium more resistant to severe desiccation than strains of fast-growing species. It is suggested that under conditions of milder desiccation, this property is disadvantageous to the slow-growing Rhizobium because insufficient moisture is available to allow for the functioning of vital enzymes.  相似文献   

New management PiR-DAP     

Jansen J 《Tijdschrift voor diergeneeskunde》2006,131(10):384

  相似文献   

Opening and closing of the bacterial RNA polymerase clamp     

A Chakraborty  D Wang  YW Ebright  Y Korlann  E Kortkhonjia  T Kim  S Chowdhury  S Wigneshweraraj  H Irschik  R Jansen  BT Nixon  J Knight  S Weiss  RH Ebright 《Science (New York, N.Y.)》2012,337(6094):591-595

  相似文献   

A survey of village poultry production in the Solomon Islands     

T. Jansen  P. C. Glatz  Z. H. Miao 《Tropical animal health and production》2009,41(7):1363-1370

A total of 84 farmers in 31 villages of Guadalcanal, Western, Malaita and Central Provinces of the Solomon Islands were surveyed to obtain baseline information on the current feeding practices and farmer attitudes to village poultry production. Farming of village chickens in the Solomon Islands is conducted on a small scale. Most surveyed farmers thought chickens were easy to care for, provide food for the family and was a good cash income enterprise. Some farmers were interested in keeping local chickens, but found it difficult to obtain the birds. The main feed sources are fresh coconut, copra meal, fish meal, mill run, food scraps and forage sources from the range. Some villagers believe that chickens only need to eat household scraps and did not provide drinking water. Many villagers lacked the knowledge of managing a village poultry enterprise. Some chicken houses were built by using bush materials or by purchasing construction materials. Farmers indicated they would like the government to provide funds for establishing a smallholder poultry enterprise and to provide information on feeding and management of birds.  相似文献   

Trypanosoma cruzi: adaptation to its vectors and its hosts     

Fran?ois Noireau  Patricio Diosque  Ana Maria Jansen 《Veterinary research》2009,40(2)

American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability.  相似文献   

Characterization of aflatoxigenic and non-aflatoxigenic strains of <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> isolated from corn grains of different geographic origins in Brazil     

Liliana de Oliveira Rocha  Gabriela Martins Reis  Raquel Braghini  Estela Kobashigawa  Jansen de Araújo  Benedito Corrêa 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(3):353-366

Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B₁, while 47.2% aflatoxins B₁ and B₂. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson’s correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB₁ and AFB₂, but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.  相似文献   

Life history trade-offs assemble ecological guilds     

Bonsall MB  Jansen VA  Hassell MP 《Science (New York, N.Y.)》2004,306(5693):111-114

  相似文献   

Dietary soyabean oil depresses the apparent digestibility of fibre in trotters when substituted for an iso-energetic amount of corn starch or glucose     

Jansen WL  Geelen SN  van der Kuilen J  Beynen AC 《Equine veterinary journal》2002,34(3):302-305

The aim of the present study was to establish whether the inhibitory effect of fat feeding on fibre digestion has been underestimated due to the substitution of fat for corn starch. A high fat intake has been shown to lower total intestinal tract apparent digestibility of crude fibre in horses but, since fat was substituted for nonstructural carbohydrates, including starch, the specific effect of fat could not be ascertained. The possibility could not be excluded that starch also inhibits fibre digestibility, so that the fat effect observed earlier would have been underestimated. In this study, the intakes of iso-energetic amounts of soyabean oil, corn starch or glucose were compared as to fibre digestibility. Unlike starch, glucose is fully absorbed by the small intestine and, therefore, is not expected to influence fibre fermentation in the caecum and colon. Six trotters were fed rations high in soyabean oil (158 g/kg dry matter), corn starch (337 g/kg dry matter) or glucose (263 g/kg dry matter) according to a 3 x 3 Latin square design. Apparent crude fibre digestibility was similar for the rations with corn starch (mean +/- s.d., 70.7 +/- 3.06% of intake, n = 6) or glucose (71.0 +/- 1.90%), but was significantly depressed by fat feeding (56.5 +/- 7.65%). Similar observations were made for apparent digestibilities of neutral and acid detergent fibre and of cellulose. It was concluded that the addition of fat to the feed ration of horses has a specific inhibitory effect on fibre utilisation and, therefore, reduces the amount of energy provided by dietary fibre.  相似文献