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Enteric methane emission is the main source of greenhouse gas contribution from dairy cattle. Therefore, it is essential to evaluate drivers and develop more accurate predictive models for such emissions. In this study, we built a large and intercontinental experimental dataset to: (1) explain the effect of enteric methane emission yield (g methane/kg diet intake) and feed conversion (kg diet intake/kg milk yield) on enteric methane emission intensity (g methane/kg milk yield); (2) develop six models for predicting enteric methane emissions (g/cow/day) using animal, diet, and dry matter intake as inputs; and to (3) compare these 6 models with 43 models from the literature. Feed conversion contributed more to enteric methane emission (EME) intensity than EME yield. Increasing the milk yield reduced EME intensity, due more to feed conversion enhancement rather than EME yield. Our models predicted methane emissions better than most external models, with the exception of only two other models which had similar adequacy. Improved productivity of dairy cows reduces emission intensity by enhancing feed conversion. Improvement in feed conversion should be prioritized for reducing methane emissions in dairy cattle systems.

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.

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 (≤104, 105, 106, or ≥ 107 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 105 and 106 cfu/g rates were most effective at minimizing DM losses while aerobic stability was only increased with 105, 106, and ≥ 107 cfu/g rates. Inoculation with LBB increased acetate concentration, reduced yeast counts and improved aerobic stability but did not improve dairy cow performance.

Objetivou-se avaliar a qualidade da predição das exigências de energia para vacas leiteiras do sistema de Oliveira (2015) para condições tropicais, em comparação aos sistemas AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2004), INRA (2007), CSIRO (2007) e Moraes et al. (2015). Utilizou-se observações de quatro experimentos de alimentação de vacas leiteiras do tipo rotativo, totalizando 181 observações de consumo de nutrientes digestíveis totais (NDT) de 16 dietas experimentais. O conjunto de dados construídos apresentou uma ampla variação nas características dos animais (produção de leite entre 6,1 a 36,5 kg/dia), dieta e consumo de NDT (4,0 a 16,6 kg/dia). O sistema energético de Oliveira (2015) explicou 83% do consumo de NDT observado, superestimou o consumo de NDT em média 0,35 kg/dia e apresentou raiz quadrada do erro médio de predição (RQEMP) de 12,2% do valor observado. Os sistemas AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2014) e Moraes et al (2015) apresentaram RQEMP similares (P > 0,05) ao sistema de Oliveira (2015), indicando similaridade na acurácia para predizer as exigências de energia para vacas leiteiras em condições tropicais. Recomenda-se ainda investigar a adequação destes sistemas energéticos em experimentos de longa duração.Palavras-chave: acurácia; energia; sistemas nutricionais. EVALUATION OF ENERGETICS SYSTEMS FOR DAIRY COWS ABSTRACT: The objective was evaluate accuracy and precision of the estimated energy requirements for lactating dairy of the Oliveira (2015) system to tropical condition, compared to AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2004), INRA (2007), CSIRO (2007) and proposed by Moraes et al. (2015). Four rotative feeding trials were used as dataset, totalizing 181 observations of total digestible nutrient (TDN) intake from 16 diets. Dataset had wide variation in animal performance (milk yield between 6.1 to 36.5 kg/day), diet and TDN intake (4.0 to 16.6 kg/day). The Oliveira (2015) system explained 83% of the observed TDN intake, over-predicted TDN intake by 0.34 kg/day and presented root mean square error of prediction (RMSPE) of the 12.2% of the observed TDN intake. AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2014) e Moraes et al (2015) systems had similar RMSPE (P > 0.05) to Oliveira (2015) system, indicating similar accuracy to predict energy requirement for dairy cows under tropical conditions. We recommended to investigate the adequacy these systems in long term feeding trials.Keywords: accuracy; energy; nutritional systems.

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.

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

A meta-analysis of 52 peer-reviewed papers was conducted to investigate the effects of ionophores (IOP) supplementation on the performance and ruminal fermentation of lactating dairy cows. We used random-effects models to examine the raw mean difference (RMD) between the IOP group (diets with IOP) and the control group (diets with no additives), weighed by inverse of the variance. We also evaluated the effects of the covariates IPO supplementation level dose groups ( 25 mg/kg dry matter (DM) diet), IOP type (monensin or lasalocid), feeding system (total mixed ration or pasture) and days in milk (DIM) on RMD, by meta-regression and subgroup analysis. Overall, IOP supplementation (21.3 ± 8.3 mg/kg DM) reduced DM intake (DMI; RMD = - 0.39 ± 0.22 kg/d; P N (P = 0.63) and acetate concentrations (P = 0.08); however it enhanced the rumen concentration of propionate (P

Two experiments were conducted to evaluate the effect of alkaline treatments (20, 40 or 60 g CaO/kg) or water extraction on glucosinolate (GIs) concentration in crambe meal (CM), and to determine effects of replacing soybean meal with CM on intake, digestibility and nitrogen balance in sheep. Twenty-five samples of CM (300 g each) were randomly assigned to one of the following treatments: Control (446 mg GI/kg dry matter (DM)); alkaline treatment (20, 40 or 60 g CaO/kg CM); and water extraction. Alkaline treatment and water extraction of CM did not differ ( P > 0.05) in GI concentration. In addition, the level of CaO added (20, 40 or 60 g/kg CM as feed) did not affect ( P = 0.47) the GIs concentration. Eight Santa Ines male sheep (25.6 ± 2.6 kg body weight) were distributed to two 4 × 4 Latin squares with four periods of 15 days each (10 days of adaptation and 5 days of sample collection) and received one of the following four different isonitrogenous diets (160 g CP/kg dry matter), formulated by substituting soybean meal: Control (soybean meal); untreated CM; Alkaline-treated CM (40 g CaO/kg); and water extracted CM. Replacing soybean meal with CM did not affect ( P > 0.05) feed intake, apparent total-tract digestibility, nitrogen balance and urinary excretion of allantoin. Alkaline treatment or water extraction partially decreased GIs concentration in CM by 46 ± 12% ( P P > 0.05) feed intake, apparent total-tract digestibility, nitrogen balance and urinary excretion of allantoin. The processing method (alkaline treatment vs. water extraction) had no effect ( P > 0.05) on feed intake, apparent total-tract digestibility, nitrogen balance and urinary excretion of allantoin. Therefore, CM with GIs concentrations under 450 mg/kg DM can be used as substitute for soybean meal as an exclusive protein source in ruminant diets.

A meta-analysis was conducted to elucidate the factors affecting drinking water intake (DWI) in order to develop new DWI empricial predictive models for lactating dairy cows and to compare with existing models. A large dataset, containing 262 experimental diets from 75 experiments published in 65 peer-reviewed papers was built. Selected explanatory variables were grouped into animal (body weight (BW); BW0.75; milk yield), diet composition (dry matter; ash; sodium; potassium; crude protein (CP); neutral detergent fiber), dry matter intake (DMI) and environment (mean air temperature and relative humidity) inputs. To develop the predictive models, the dataset (peer-reviewed papers) was randomly divided into two subsets for statistical analyses. The first data subset was used to develop equations to predict DWI (41 peer-reviewed papers; 47 experiments; 157 experimental diets), and the second data subset was used to assess the adequacy of the predictive models (24 peer-reviewed papers; 28 experiments; 105 experimental diets). Ash was the main diet input affecting DWI in lactating dairy cows, while BW0.75 affected DWI more than milk yield. Use of dietary characteristics (DM, ash and CP) and DMI as inputs could be enough to predict DWI as accurately as more complete models. Dry matter intake as predictive variable does not improve DWI prediction in models with only animal (BW0.75 and milk yield) as input, but it substantially improves prediction of models without use of animal as input. Among the existing models evaluated, those developed from just one experiment (Castle and Thomas, 1975; Little and Shaw, 1978; Murphy et al., 1983; Stockdale and King, 1983; Dahlborn et al., 1998) had poor prediction quality. We proposed the use of two models (diet II and animal + diet models) that presented the lowest root mean square prediction error (RMSPE) to predict DWI in lactating dairy cows.

RESUMO Objetivou-se com este estudo avaliar os parâmetros da cinética de degradação ruminal dos concentrados protéicos, farelo de soja(FS) e torta de algodão(TA). Para estimativa dos parâmetros da cinética de degradação in situ da matéria seca (MS) e proteína bruta (PB) dos concentrados, foi realizado o ajuste de 5 diferentes modelos matemáticos não-lineares: Exponencial, Van Milgen, Logístico, Gompertz e Richards. Para avaliação in situ dos alimentos, foram utilizados dois bovinos adultoscanuladosno rúmen. As amostras foram incubadas nos tempos 0; 2; 4; 6; 12; 16; 24; 36; 48 e 72 horas, nos resíduos de incubação foram determinados os teores de MS e PB, e sua degradabilidade potencial e efetiva. Os valores de degradabilidade efetiva da MS do FS foram de 86,35; 74,23 e 65,50%,e da TA de 53,44; 41,70 e 35,21% nas taxas de passagem de 0,02; 0,05 e 0,08.h-1, respectivamente. O FS e a TA apresentaram valores para a fração A da PB de 18,15 e 34,77% e para a fração B, 79,76 e 55,10%, respectivamente. De acordo com a ponderação de Akaike (Wi) o modelo de Richards apresenta; 95,45 e 49,64% de chance de ser o modelo mais adequado, para caracterizar a cinética de degradação in situ da MS do, FS e da TA, respectivamente. Contudo, o modelo de Gompertz apresenta 63,86 e 66,49 % de chance de ser o modelo mais adequado para caracterizar a degradação da PB do FS e TA. SUMMARY This studied aimed to evaluate the parameters of ruminal degradation kinetics of protein concentrates, soybean meal (SM) and cotton cake (CC).To estimate the in situ degradation parameters of DM and CP from coproducts were fitted 5different non-linear mathematical models: Exponencial, Van Milgen, Logístico, Gompertz and Richards. For in situ evaluation were used two cattle cannulated in the rumen. The samples were incubate dat 0, 2, 4, 6, 12, 16, 24, 36, 48 and 72 hours and in the incubation residues were determined DM and CP and their degradability. The DM degradability of SM were 86.35, 74.23, 65.50% and to CC were 53.44, 41.70 and 35.21% in passage rates of 0.02; 0.05 and 0.08.h-1, respectively. The SM and CC showed values for the CP soluble fraction of the 18.15, 34.77% and 79.76, 55.10% to insoluble potentially degradable fraction, respectively. According to the Akaike weights (Wi) the model of Richards has 95.45 and 49.64% of chance to be the most suitable model to characterize the in situ DM degradation of SM and CC. However, the Gompertz model has 63.86 and 66.49% chance to be the most suitable model to characterize the CP in situ degradation of SM and CC.