Fermentation Profile of Signal Grass Silages Intercropped With Calopo or Fertilized With Nitrogen and Treated With Microbial Inoculant

Tropical grasses have characteristics that allow the occurrence of undesirable fermentations resulting in low quality silage. Inoculants can improve silage quality. Fermentation profile and microbial population of signal grass silages under four management (M), with and without microbial inoculant, were evaluated. The experiment was carried out in a 4 × 2 factorial scheme, with silages of signal grass managed without N application (control, 0N), fertilized with 50 kg ha-1 of N (50N), fertilized with 100 kg ha-1 of N (100N), or signal grassintercropped with calopo (Calopogonium mucunoides D.) (LEG), with inoculant (I) andwithout inoculant (WI), in a randomized block design, with two replications of area and two replications of treatment per block. Analysis of pH, organic acids, ethanol, ammonia nitrogen, and microbial populations were performed in the silages. The use of inoculant reduced the acetic acid concentration in the 100N treatment silages (20.1 to 12.8 g kg-1 of DM). The lowest concentration of butyric acid (BA) (2.33 g kg-1 DM) was observed in signal grass silage fertilized with 100 kg of N, without inoculant. In inoculated silages, the treatments 50N and LEG provided lower concentrations of BA in relation to the control. Silage from the uninoculated 50N treatment had the lowest concentration of N-NH3 in relation to the other silages. The lactic acid bacteria (LAB) population was not affected by the factors studied. The inoculant provided a reduction in the population of enterobacteria. No mold and yeast populations were detected in the silages investigated. Signal grass silage fertilized with N or intercropped with calopo, with microbial inoculant, had better fermentative characteristics and could be an option for strategic management of pastures in tropical areas

Milk fatty acid profile of Holstein x Gyr cows on 'Marandu' grass pasture under different grazing strategies

O objetivo deste trabalho foi avaliar o perfil de ácidos graxos (AG) do leite de vacas Holandesas x Gir submetidos a dois tipos de manejo de pastejo (períodos de descanso fixo e variável) de pastagem de Urochloa brizantha 'Marandu'. Utilizou-se o delineamento de blocos ao acaso, com duas repetições de área de pastagem (blocos) por tratamento e quatro vacas por bloco. A produção e a composição do leite não foram influenciadas pelas estratégias de pastejo. Não houve efeito dos tratamentos sobre as proporções (g 100 g-1 de AG totais) dos principais AG (palmítico, linoleico e α-linolênico) do pasto, mas suas ingestões (gramas por dia) foram influenciadas pelas diferenças de ingestão de matéria seca da forragem. As concentrações dos AG no plasma e na gordura do leite não foram influenciadas pelos tratamentos. As concentrações dos ácidos rumênico, vacênico, oleico e α-linolênico na gordura do leite variaram de 0,71 a 0,93, 1,40 a 1,50, 19,40 a 19,70 e 0,39 a 0,43 g 100 g-1 de AG totais, respectivamente. As estratégias de pastejo de U. brizantha 'Marandu' não alteram o perfil de ácidos graxos do leite das vacas.The objective of this work was to evaluate the milk fatty acid (FA) profile of Holstein x Gyr cows subjected to two different grazing managements (fixed and variable rest periods) of Urochloa brizantha 'Marandu' pastures. A randomized complete block design was used, with two replicates of pasture areas (blocks) per treatment and four cows per block. Milk production and composition were not affected by grazing strategies. No treatment effects were observed on the proportions (g 100 g-1 of total FA) of the main FAs (palmitic, linoleic, and α-linolenic) of the pasture, but their intakes (grams per day) were affected by differences in forage dry matter intake. The concentrations of FAs in milk plasma and fat were not affected by the treatments. Milk fat contents of rumenic, vaccenic, oleic, and α-linolenic acids varied from 0.71 to 0.93, 1.40 to 1.50, 19.40 to 19.70, and 0.39 to 0.43 g 100 g-1 total FAs, respectively. Grazing strategies of U. brizantha 'Marandu' cause no changes on the milk fatty acid profile of cows

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements