A meta-analysis of 158 peer-reviewed articles was conducted to examine effects of inoculation with Lactobacillus buchneri (LB)-based inoculants (LBB) that did or did not include homolactic or obligate heterolactic bacteria on silage fermentation and aerobic stability. A complementary meta-analysis of 12 articles examined LBB inoculation effects on dairy cow performance. Raw mean differences between inoculant and control treatment means weighted by inverse variance were compared with a hierarchical effects model that included robust variance estimation. Meta-regression and subgrouping analysis were used to identify effects of covariates including forage type, application rate (≤10 4 , 10 5 , 10 6 , or ≥ 10 7 cfu/g as fed), bacteria type (LB vs. LB plus other bacteria), enzyme inclusion, ensiling duration, and silo type (laboratory or farm scale). Inoculation with LBB increased acetate (62%), 1, 2 propanediol (364%) and propionate (30%) concentration and aerobic stability (73.8%) and reduced lactate concentration (7.2%), yeast counts (7-fold) and mold counts (3-fold). Feeding inoculated silage did not affect milk yield, dry matter intake, and feed efficiency in lactating dairy cows. However, forage type, inoculant composition, and dose effects on silage quality measures were evident. Inoculation with LBB increased aerobic stability of all silages except tropical grasses. Adding obligate homolactic or facultative heterolactic bacteria to LB prevented the small increase in DM losses caused by LB alone. The 10 5 and 10 6 cfu/g rates were most effective at minimizing DM losses while aerobic stability was only increased with 10 5 ,10 6 , and ≥ 10 7 cfu/g rates. Inoculation with LBB increased acetate concentration, reduced yeast counts and improved aerobic stability but did not improve dairy cow performance.

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Objetivou-se identificar e quantificar os indicadores associados com o tamanho, com a taxa de giro do capital investido (TGC) e com a lucratividade que afetam a rentabilidade da pecuária de leite. Os dados originaram-se de vinte e sete produtores de leite (213,6 ± 193,9 litros de leite/fazenda/dia) no Estado de Mato Grosso, coletados durante doze meses. Dos fatores associados com a lucratividade, o custo com mão-de-obra relativa à renda com leite e a produtividade da mão-de-obra afetaram negativamente a rentabilidade. O preço do leite, os custos com alimentação concentrada ou volumosa relativos à renda bruta com leite não afetaram a rentabilidade da pecuária.  Os indicadores associados com a produtividade da terra (produção de leite por área e número de vacas em lactação por área usada pelo rebanho) apresentaram maior impacto na rentabilidade da pecuária de leite que os indicadores de produtividade do rebanho. A proporção de vacas em lactação em relação ao rebanho e a produção de leite por total de vacas (mas não por vaca em lactação) são os indicadores de produtividade do rebanho de maior impacto na rentabilidade.Palavras-chave: custo de produção; eficiência; lucratividade. FACTORS AFFECTING THE PROFITABILITY OF DAIRY FARMING  ABSTRACT: The objective was to identify and quantify the impact of indicators associated with size, return on invested capital (ROIC) and profitability on economic performance (rentability) of dairy farms. Data from twenty seven dairy farms (213.6 ± 193.9 liters milk/farm/day) were collected in Mato Grosso State, during twelve months. Of the factors associated with profitability, the labor cost and labor productivity negatively affected rentability. Milk price and concentrate feed cost (in relation with milk gross income) did not affect rentability of dairy farm. Land productivity index (milk yield/dairy farm area; lactating cows/dairy farm area used by dairy herd) had greater impact on economic performance than animal productivity index. Lactating cows/head ratio and milk yield per total cows (but not by lactating cow) are the animal productivity index that had the greatest impact on rentability of dairy farms.Keywords: cost of production; efficiency; profitability.

A mandioca (Manihot esculenta crantz) é uma planta originária da América do Sul, principalmente da região Amazônica, que vem sendo cultivada em diversos países devido à sua ampla adaptação. As indústrias voltadas ao processamento da mandioca para fabricação de farinha e fécula, localizadas principalmente na região sul e sudeste do Brasil, geram resíduos sólidos e líquidos de alta capacidade poluidora, o que tem resultado em grande impacto ao meio ambiente. Atualmente, a produção animal sofre com o alto custo na alimentação, principalmente, em função da oscilação dos preços dos grãos no mercado. Como forma de redução da poluição ambiental e dos custos de produção animal, tem-se o aproveitamento dos resíduos provenientes do processamento da mandioca na alimentação animal. A presente revisão bibliográfica tem como objetivo destacar a utilização dos principais subprodutos da indústria de processamento da mandioca, como substituto ao milho, na alimentação de frangos de corte.

Context Dry matter intake (DMI) is the variable that most affects beef cattle performance in feedlot conditions. Accurate prediction of DMI is essential because it is the basis for calculating nutritional requirements for maintenance and production. Aims A meta-analysis was conducted to develop DMI prediction models for feedlot beef cattle under tropical conditions, and to compare the models with those proposed by the National Research Council, USA, in 2000 and 2016, as well as those recommended by the Brazilian System of Nutritional Requirements (BR-Corte) and published by Azevêdo and colleagues in 2010 and 2016. Methods The dataset was created from 56 published studies conducted under tropical conditions. The dataset was randomly separated into two subsets for statistical analysis. The first subset was used to develop the models to predict DMI, and the second to evaluate the adequacy of the prediction models. The models were developed by using mixed linear and nonlinear analysis. Key results A nonlinear model and a linear model to predict DMI are proposed. These models were similar in terms of accuracy and were superior to the other evaluated models. The nonlinear and linear models explained, respectively, 59% and 62% of the DMI variation and had greater accuracy and precision than the other models. The 2016 model used by BR-Corte explained 55% of the DMI variation, and underestimated it at 0.20 kg/day. The remaining three models presented a systematic constant bias and were not adequate for predicting DMI. Conclusion The proposed nonlinear and linear prediction models of beef cattle in feedlot developed under tropical conditions are more precise and accurate than those recommended by the National Research Council and the 2010 model used by BR-Corte. They also present better prediction quality of DMI from beef cattle in feedlots under tropical conditions than the 2016 model used by BR-Corte. Implications The proposed models in the present study are the most suitable for use in predicting the DMI of beef cattle under tropical conditions.

Objetivou-se avaliar o método de espectroscopia por ultrassom (EU) e o efeito do congelamento do leite nas análises de gordura e proteína do leite de vaca. Cem amostras foram analisadas imediatamente após a coleta em tanque de expansão (in natura), congeladas a -20ºC por 30 dias e novamente analisadas por métodos oficiais (gordura por butirômetro de Gerber e proteína por micro-Kjeldahl) e por EU. Observou-se efeito de interação (P < 0,01) entre o método analítico e congelamento do leite. A EU superestimou (P < 0,01) o teor de gordura e subestimou (P < 0,01) o teor de proteína no leite in natura ou congelado. O congelamento não afetou (P = 0,15) o teor de gordura obtido pelo método oficial, mas reduziu o teor de gordura (P < 0,01) obtido com a EU. O congelamento aumentou (P < 0,01) o teor de proteína obtido pelo método oficial, mas reduziu (P < 0,01) quando obtido por EU. Os teores de gordura e proteína do leite obtidos pelo método de EU são divergentes daqueles obtidos por métodos oficiais, independente da amostra ser in natura ou congelada.Palavras-chave: método analítico; análise química; correlação. EFFICACY OF ULTRASONIC SPECTROSCOPY AND FREEZING IN EVALUATION OF MILK CHEMICAL COMPOSITION ABSTRACT: The objective was to evaluate the ultrasound spectroscopy (US) method and the effect of milk freezing on the cow's milk fat and protein analysis. One hundred samples were collected from one milk tank, immediately analyzed, and frozen at -20ºC for 30 days and analyzed again by official method (fat: Gerber butyrometer, protein: micro-Kjeldahl) and US. It was observed effect of interaction (P < 0.01) between analytical method and milk freezing. Ultrasound spectroscopy overestimated milk fat content and underestimated milk protein content on in natura or frozen. The milk freezing for 30 days did not affect the milk fat content obtained by official method (P = 0.15), but it reduced the milk fat content (P < 0.01) obtained by US. The milk freezing increased (P < 0.01) the milk protein content obtained by official method, but reduced (P <0.01) when obtained from US. The milk fat and protein content obtained by US are different from those obtained by official methods, regardless of the sample is in natura or frozen.Keywords: analytical method; chemical analysis; correlation.