O experimento foi conduzido em delineamento completamente casualizado com o objetivo de avaliar o efeito da densidade de compactação, 500 kg (médio) e 600 kg (alto) de matéria verde por metro cúbico de massa ensilada, na qualidade final da silagem em relação ao material original. A ensilagem de milho safrinha foi realizada no dia 18/05/2004 em minissilos, com quatro repetições por grau de compactação, quando os grãos de milho se encontravam no estádio ½ leitoso ½ farináceo. As densidades de compactação afetaram significativamente os teores de açúcares solúveis (1,60 <FONT FACE=Symbol>´</FONT> 2,15% da MS), matéria orgânica do resíduo insolúvel em etanol a 80% (76,02 <FONT FACE=Symbol>´</FONT> 71,53% da MS), carboidratos não-estruturais (39,21 <FONT FACE=Symbol>´</FONT> 41,70% dos carboidratos totais), fibra em detergente neutro corrigida para cinzas e proteína (52,57 <FONT FACE=Symbol>´</FONT> 50,37% da MS), lignina em detergente ácido (2,74 <FONT FACE=Symbol>´</FONT> 2,57% da MS) e nitrogênio amoniacal (4,35 <FONT FACE=Symbol>´</FONT> 3,84% do nitrogênio total). A maior densidade de compactação resultou em melhor conservação dos glicídios solúveis, em menor alteração dos carboidratos estruturais e em menor proteólise na silagem de milho.

The objective of the present study was to perform a meta-analysis that compared the chemical composition of corn silage produced for different experimental purposes, i.e., by research groups that studied corn silage (SCS) or by research groups that only used corn silage (UCS) as a form of roughage. We analyzed 203 papers that were published between January 1994 and December 2014 and contained a total of 647 treatments and the analysis of 1701 silos. We found a significant difference (P < 0.0001) in the dry matter (DM) content of SCS silage (33.00%) and that of UCS silage (30.64%). The DM contents of neutral detergent fiber for the SCS and UCS silage were high (54.72 and 55.14% DM, respectively) but were not significantly different from one another (P = 0.5936), and the acid detergent fiber content of the UCS silage (31.04% DM) was higher than that of the SCS silage (29.65%, P = 0.0214), which indicated that the UCS silage was less digestible than the SCS silage. This was also corroborated (P = 0.0064) by the mean content of total digestible nutrients (64.18% DM) in the UCS silage, which likely results from the lower level of care taken when using standard silage production methods, compared to that taken by SCS researchers. Therefore, we concluded that the corn silage produced by research groups in Brazil are not analyzed in full and that, as a result, there is a paucity of important information, such as the content of organic acids. In addition, we also found that corn silage produced in Brazil contains a high level of neutral detergent fiber. Key words: Starch. Carbohydrate. Fiber. Ruminant. Conserved roughage. Zea mays. ResumoObjetivou-se analisar metanaliticamente a composição bromatológica de silagens de milho, estudadas ou utilizadas em dietas para ruminantes, em condições experimentais brasileiras. Foram utilizados artigos publicados entre janeiro de 1994 e dezembro de 2014, totalizando 203 artigos científicos com 647 tratamentos, envolvendo a análise de 1.701 silos. Observou-se diferença (P < 0,0001) no teor de matéria seca (MS) encontrado nas silagens entre pesquisas que estudam especificamente silagem de milho (ESM, de 33,00% de MS), para as que utilizam silagem de milho como suporte em outras avaliações científicas USM, 30,64% de MS). Os teores de fibra em detergente neutro são elevados para ESM (54,72% da MS) e para USM (55,14% da MS), não havendo diferença (P=0,5936). As USM apresentam valores maiores (P = 0,0214) de fibra em detergente ácido (FDA) (31,04% da MS), ou seja, fornecem volumoso de menor digestibilidade que as ESM. Este fato é também corroborado (P = 0,0064) pelo nível médio de nutrientes digestíveis totais (NDT) (64,18% da MS) nos estudos USM, pois geralmente não há o mesmo cuidado com as premissas básicas de produção de silagem, comparado com o grupo ESM cujas silagens apresentaram em média 29,65% de FDA e 66,79% de NDT. As silagens de milho de planta inteira produzidas em condições experimentais no Brasil não são analisadas por completo, faltam informações imprescindíveis como...

The present study aimed to evaluate the chemical composition of carbohydrates and nitrogenous fractions of late-crop corn silages with different specific masses (SM; 90, 134, 172, and 214 kg dry matter m -3 ). The silage was held in 20-L mini-silos, and the experimental design was completely randomized, with four replications (mini-silos) per treatment. In the present study, differences in the compression (i.e., SM) of corn silages caused changes in the contents of soluble sugar and nitrogenous constituents; however, SM alone did not explain the entire preservation of the ensiled material. ResumoObjetivou-se avaliar alterações bromatológicas sobre as frações glicídicas e nitrogenadas de silagens de milho "safrinha" com diferentes massas específicas (ME) no momento da ensilagem (90, 134, 172 e 214 Kg de MS.m -3 ). A ensilagem foi realizada em minissilos com capacidade de 20 L. O delineamento experimental foi inteiramente casualizado com quatro repetições (minissilos) por tratamento. O fracionamento foi realizado segundo The Cornell Net Carbohydrate and Protein System (CNCPSv5.0). A ME afetou linearmente os teores de extrato etéreo Ŷ = 1,718 + 0,0041*ME (P = 0,009; R 2 = 39,2), açúcares solúveis Ŷ = 0,9502 -0,003445*ME (P < 0,001; R 2 = 59,9) e fibra solúvel Ŷ = -0,4731 + 0,01158*ME (P = 0,025; R 2 = 31,2). Nos carboidratos, a fração B1 apresentou comportamento linear ascendente Ŷ = 14,88 + 0,2566*ME (P = 0,043; R 2 = 38,4) com o aumento da ME, enquanto as demais frações não foram influenciadas. Nos constituintes nitrogenados houve variação no nitrogênio total Ŷ = 2,003 -0,01065*ME + 0,000036*ME 2 (P = 0,041; R 2 = 38,8), no nitrogênio não proteico Ŷ = 1,436 -0,01103*ME + 0,000036*ME 2 (P = 0,060; R 2 = 35,1), no nitrogênio solúvel Ŷ = 1,715 -0,01450*ME + 0,00005*ME 2 (P = 0,024; R 2 = 43,8) e no nitrogênio insolúvel em detergente neutro Ŷ = 0,4979 -0,001057*ME (P < 0,001; R 2 = 70,6), cujos resultados também contribuíram para as diferenças nas frações A Ŷ = 66,47 -0,5291*ME + 0,00174*ME 2 (P = 0,095; R 2 =30,4), B2 Ŷ = 6,78 + 0,05857*ME (P = 0,076; R 2 =20,8) e B3 Ŷ = 19,03 -0,05565*ME (P = 0,018; R 2 = 34,1) do modelo de Cornell. A ME de compactação, de forma isolada, não serve para explicar, na totalidade, a preservação do material ensilado. Diferentes ME causam alterações no teor de açúcares solúveis das silagens de milho e nos constituintes nitrogenados.

RESUMO Este trabalho teve como objetivo verificar se há alteração na composição dos carboidratos de silagens de milho safrinha quando colhidas nas alturas de corte (AC) de 20, 45, 70

RESUMO -Objetivou-se avaliar o efeito da maturidade dos grãos de milho e do tempo de exposição ao ar antes da ensilagem sobre os teores de carboidratos de silagens de milho "safrinha". O experimento foi conduzido em delineamento completamente casualizado com arranjo fatorial 2 x 4, no qual foram testados dois estádios de maturidade ao corte (grão completamente leitoso (GL) ou grão ½ leitoso e ½ farináceo (GF)) e quatro tempos de exposição ao ar, sem compactação (0, 12, 24 ou 36 horas) antes da ensilagem em minissilos. Os cortes das plantas ocorreram nos dias 26/04 e 18/05/2004. Houve efeito significativo dos estádios de maturidade (M) e dos tempos de exposição ao ar (TE), além de interação entre os efeitos, para a maioria das variáveis estudadas. O teor de MS diferiu entre os estádios de maturidade e os tempos de exposição ao ar. As silagens GL e GF, respectivamente, diferiram quanto ao teor de açúcares solúveis (1,51 a 1,31% da MS) e de amido (4,23 a 13,21% da MS). Quanto aos tempos de exposição ao ar, os açúcares solúveis diminuíram entre os tempos zero (1,64% da MS) e 36 horas (1,05% da MS). O maior impacto dos TE foi verificado nos teores de fibra em detergente neutro corrigidos para cinzas e proteína (FDNcp). O tempo de exposição ao ar do material verde picado, de 12 horas antes da ensilagem, afetou ABSTRACT -The objective of this experiment was to evaluate the effect of corn grain maturity and air exposure time prior to ensiling on the carbohydrate concentration of corn silage from corn crop planted late in the season. A complete randomized design was used with a 2 x 4 factorial arrangement, testing two stages of maturity at harvest (MK -milky kernel and MDK -½ milky and ½ dough kernel) of maize crops and four air exposure time prior to ensiling: 0, 12, 24 and 36 hours. Harvests occurred in 2004 on April 26 th and May 18 th . Stage of maturity (M) and periods of air exposure (TE) showed significant effects as well as interactions in most of tested variables. DM content was different according to M and TE. The MK and MDK silages showed different residual sugar and starch concentrations, respectively, 1.51 and 1.31% and 4.23 and 13.21% of DM. Soluble sugars decreased with TE with values of 1.64% (DM basis) with zero h air exposure to 1.05% after 36 hours exposure. The greatest impact of TE was observed on NDFap values (NDF corrected for ash and protein). Even a short 12-hour period of air exposure before ensiling affects negatively the nutritional value of corn silages.

A number of studies have addressed the relations between climatic variables and milk composition, but these works used univariate statistical approaches. In our study, we used a multivariate approach (canonical correlation) to study the impact of climatic variables on milk composition, price, and monthly milk production at a dairy farm using bulk tank milk data. Data on milk composition, price, and monthly milk production were obtained from a dairy company that purchased the milk from the farm, while climatic variable data were obtained from the National Institute of Meteorology (INMET). The data are from January 2014 to December 2016. Univariate correlation analysis and canonical correlation analysis were performed. Few correlations between the climatic variables and milk composition were found using a univariate approach. However, using canonical correlation analysis, we found a strong and significant correlation (r = 0.95, p value = 0.0029). Lactose, ambient temperature measures (mean, minimum, and maximum), and temperature-humidity index (THI) were found to be the most important variables for the canonical correlation. Our study indicated that 10.2% of the variation in milk composition, pricing, and monthly milk production can be explained by climatic variables. Ambient temperature variables, together with THI, seem to have the most influence on variation in milk composition.

-This study was carried out to evaluate the effect of the use of supplementation in pasture cultivated with Avena strigosa (black oats), Lolium multiflorum (ryegrass) and Vicia sativa L. (common vetch) on the composition and somatic cells count (SCC) of Jersey cow milk. Eight cows of the Jersey breed were separated by milk production, lactation period and live weight and were randomly blocked into two homogeneous groups (one with supplementation and other only on pasture), in a randomized complete design. Both groups were allowed to pasture for about 7 hours per day in a rotational grazing system in strips, with a one-day occupation period. The supplemented group was fed daily with 8 kg of supplement made of soy bean meal, soy shells, calcium limestone and mineral salt. The results showed significant differences between the two groups, because the percentage of total solids, protein and milk fat were higher in the supplemented cows. The lactose percentage was not influenced by the supplement intake. The somatic cell count, although there was a lower statistical difference for the group on pasture, showed small numerical oscillation between the groups and therefore should not be considered an effect of supplementation. The supplement supply to Jersey cows during lactation caused an increase in the total milk solid percentage, because it raised the fat and protein concentration.

Our objective was to quantify the relationship between seasons of the year, milk production, and milk composition of a dairy farm based on data for 48 consecutive months, using multivariate statistical analyses. The dataset contained information on productive indexes and milk composition from the bulk tank milk, which was measured from milk samples, collected monthly and used to determine the total dry extract and defatted dry extract, lactose, fat, protein, somatic cell count, and total bacterial count. Seasons of the year and milk production/hectare were also considered. Factor, cluster, and discriminant analysis were used to study the relationships between the above-mentioned variables. A positive relationship was noted between season and total dry extract, defatted dry extract, milk fat, and protein, with higher values being observed in winter and spring. Similarly, a positive relationship was noted between season and milk production/hectare, lactose content, with an increase in milk production and lactose content in winter and spring, which was negatively related to the somatic cell count and total bacterial count. Milk production and composition varied mainly with seasons. Multivariate analyses facilitated a better understanding of the relationship between milk production and composition on this dairy farm.