Production performance, nutrient digestibility, and milk fatty acid profile of lactating dairy cows fed corn silage- or sorghum silage-based diets with and without xylanase supplementation.

The objective of this study was to evaluate the effects of supplementing xylanase on production performance, nutrient digestibility, and milk fatty acid profile in high-producing dairy cows consuming corn silage- or sorghum silage-based diets. Conventional corn (80,000 seeds/ha) and brown midrib forage sorghum (250,000 seeds/ha) were planted, harvested [34 and 32% of dry matter (DM), respectively], and ensiled for more than 10 mo. Four primiparous and 20 multiparous Holstein cows were randomly assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and 19-d periods. Treatment diets consisted of (1) corn silage-based diet without xylanase, (2) corn silage-based diet with xylanase, (3) sorghum silage-based diet without xylanase, and (4) sorghum silage-based diet with xylanase. The xylanase product was supplemented at a rate of 1.5 g of product/kg of total DM. Corn silage had higher concentrations of starch (31.2 vs. 29.2%), slightly higher concentrations of crude protein (7.1 vs. 6.8%) and fat (3.7 vs. 3.2%), and lower concentrations of neutral detergent fiber (36.4 vs. 49.0%) and lignin (2.1 vs. 5.7%) than sorghum silage. Xylanase supplementation did not affect DM intake, milk yield, milk fat percentage and yield, milk protein percentage and yield, lactose percentage and yield, and 3.5% fat-corrected milk yield. Cows consuming corn silage-based diets consumed 13% more DM (28.8 vs. 25.5 kg/d) and produced 5% more milk (51.6 vs. 48.9 kg/d) than cows consuming sorghum silage-based diets. Milk from cows consuming sorghum silage-based diets had 16% greater fat concentrations (3.84 and 3.30%) than milk from cows consuming corn silage-based diets. This resulted in 8% greater fat yields (1.81 vs. 1.68 kg/d). Silage type did not affect milk protein and lactose concentrations. Xylanase supplementation did not affect nutrient digestibility. Cows consuming corn silage-based diets showed greater DM (77.3 vs. 73.5%), crude protein (78.0 vs. 72.4), and starch (99.2 vs. 96.5%) digestibilities than cows consuming sorghum silage-based diets. In conclusion, xylanase supplementation did not improve production performance when high-producing dairy cows were fed corn silage- or sorghum silage-based diets. In addition, production performance can be sustained by feeding sorghum silage in replacement of corn silage.

The occurrence of aflatoxigenic Aspergillus spp. in dairy cattle feed in Southern Brazil

ABSTRACT The presence of mycotoxins or related fungi in animal feed is a major problem for animal and human health. Silage and concentrated feed samples were collected from 21 dairy farms in the Western part of Paraná state in Southern Brazil. Water activity and pH of all samples were measured, and each sample was analyzed to check for the presence of aflatoxigenic Aspergillus. Water activity was observed to be lower in the concentrated feed samples. The pH was lower in the silage samples, indicating fermentation processes. Two silage samples and four concentrated feed samples were contaminated with Aspergillus spp. Seven isolates of Aspergillus spp. were obtained and their potential to produce aflatoxins was evaluated. Four of the isolates, two from the silage samples and two from the concentrated feed samples, produced the aflatoxins B1, B2, G1, and G2 in culture media. These isolates were identified as Aspergillus parasiticus and Aspergillus nomius. The presence of aflatoxigenic isolates of Aspergillus spp. in silage and concentrated feed samples is a matter of concern, because of the risk of aflatoxin production and contamination of the animal feed.

Características de silagens de capim-elefante (Pennisetum purpureum) e casca de maracujá in natura / Characteristics of Pennisetum purpureum and passion-fruit-peel silages

Objetivou-se avaliar as características sensoriais, as perdas totais, o padrão fermentativo e a composição bromatológica de silagens contendo combinações de capim-elefante (Pennisetum purpureum) com diferentes tempos de emurchecimento e casca de maracujá in natura (CM). Os tratamentos experimentais foram compostos por silagens confeccionadas com 100% de capim-elefante (CE); 100% de casca de maracujá; 75% CE/25% CM; 50%/CE 50% CM; 25% CE/75% CM, para cada tempo de emurchecimento do capim (zero; quatro; seis e oito horas), com três repetições. As silagens apresentaram coloração amarelada, odor levemente acre, exalando maracujá nos tratamentos contendo CM. Observou-se um aumento da perda total das silagens contendo casca de maracujá (0,09; 0,15; 1,01; 1,77 e 2,52kg de perdas para os tratamentos 100% CE; 75% CE/25% CM; 50% CE/50% CM; 25% CE/75% CM e 100% CM, respectivamente). O pH e o N-NH3 variaram de 3.58 a 4.63 e de 8.11 a 12.13, respectivamente. Tratamentos com CM reduziram os teores de MS, FDN e carboidratos totais e elevaram as concentrações de PB, NIDA, NIDN e carboidratos não fibrosos das silagens avaliadas. Mesmo com baixos níveis de MS, os tratamentos proporcionaram silagens de boa qualidade.(AU)

This study aimed at evaluating sensorial characteristics, total waste, fermentative profile, and chemical composition of Pennisetum purpureum (PP) and passion-fruit-peel (PFP) silages. Four PP dehydration times (0,4,6 and 8 hours) and five combinations of ingredients (100% PP; 100% PFP; 75% PP/25% PFP; 50% PP/50% PFP; 25% PP/75% PFP) were evaluated. The silages presented a yellowish color, a slightly acrid odor, and exhaled passion fruit scent in the treatments containing PFP. There was an increase in total waste of silages containing passion fruit peel (0.09, 0.15, 1.01, 1.77 and 2.52kg of waste for treatments 100% PP, 75% PP/25% PFP, 50% PP/50% PFP, 25% CE/75% CM and 100% CM, respectively). The pH and N-NH3 values ranged from 3.58 to 4.63 and 8.11 to 12.13, respectively. Mixtures containing PFP decreased the levels of DM and NDF and increased the levels of CP, NFC, ADIN and NDIN in the silages. Despite the reduced levels of DM, all treatments provided a good silage.(AU)

Ensiling characteristics, structural and nonstructural carbohydrate composition and enzymatic digestibility of Napier grass ensiled with additives.

Ensiling characteristics, structural and nonstructural carbohydrate composition and enzymatic digestibility (ED) of Napier grass silage was examined. Napier grass ensiled with no additive control, 0.2% formic acid, 0.4% molasses, and 0.3% fibrolytic enzyme for, 7, 30, 60 and 90days. Additives increased lactic acid, soluble carbohydrate and decreased all of lignocellulosic contents except acid detergent lignin and pH than control. The highest value of nonstructural carbohydrate and large reduction in lignocellulosic contents was observed in formic acid and fibrolytic enzyme silage respectively. The content of glucose and fructose showed rapid drop in the first 7days of ensilage. Ensilage decreased lignocellulosic contents and increased ED compared to fresh material. The ED of formic acid and molasses silage was significantly higher than control and fibrolytic enzyme silages in all tested days. In summery the ensiling quality structural and nonstructural carbohydrate and ED value of mature Napier grass silage improved through additives.

Use of principal component analysis to classify forages and predict their calculated energy content.

A set of 180 forages (47 alfalfa hays, 26 grass hays, 52 corn silages, 35 small grain silages and 20 sorghum silages) were randomly collected from different locations of the Po Valley (Northern Italy) from 2009 to 2010. The forages were characterised for chemical composition (11 parameters), NDF digestibility (five parameters) and net energy for lactation (NEL). The latter was calculated according to the two approaches adopted by the 2001 Nutrient Research Council and based on chemical parameters either alone (NEL3x-Lig) or in combination with 48 h NDF degradability in the rumen (NEL3x-48h). Thereafter, a principal component analysis (PCA) was used to define forage populations and limit the number of variables to those useful for obtaining a rapid forage quality evaluation on the basis of the calculated NEL content of forages. The PCA identified three forage populations: corn silage, alfalfa hay and a generic population of so-called 'grasses', consisting of grass hays, small grain and sorghum silages. This differentiation was also confirmed by a cluster analysis. The first three principal components (PC) together explained 79.9% of the total variation. PC1 was mainly associated with protein fractions, ether extract and lignin, PC2 with ash, starch, NDF and indigestible NDF (iNDF) and PC3 with NDF digestibility. Moreover, PC2 was highly correlated to both NEL3x-Lig (r = -0.84) and NEL3x-48h (r = -0.94). Subsequently, forage-based scores (FS) were calculated by multiplying the original standardised variables of ash, starch, NDF and iNDF with the scoring factors obtained from PCA (0.112, -0.141, 0.227 and 0.170, respectively). The FS showed a high determination coefficient for both NEL3x-Lig (R 2 = 0.86) and NEL3x-48h (R 2 = 0.73). These results indicate that PCA enables the distinction of different forage classes and appropriate prediction of the energy value on the basis of a reduced number of parameters. With respect to the rumen in situ parameters, iNDF was found to be more powerful at discriminating forage quality compared with NDF digestibility at different rumen incubation times or rates of NDF digestion.

Effects of feeding Mediterranean buffalo sorghum silage versus maize silage on the rumen microbiota and milk fatty acid content.

Sorghum presents a sustainable feedstock for Mediterranean buffaloes due to its reduced water and nitrogen requirements compared with maize, which is currently fed primarily. We investigated the effects of feeding sorghum as opposed to maize on Mediterranean buffalo rumen microbial diversity and milk fatty acid content. Four cannulated lactating Mediterranean buffalo cows were fed a basal diet for one month before switching either to maize or sorghum-silage based diets for a 3-month period. Buffaloes were then changed over to the contrasting diet for a further one month. Rumen and milk samples were collected at the end of each month. DGGE- and T-RFLP-based dendrograms generated from rumen samples did not show an effect of diet on rumen bacterial diversity. Milk samples also did not differ in terms of their fatty acid content post sorghum feeding as compared with maize feeding. Thus, sorghum provides an environmentally beneficial alternative to maize for feeding Mediterranean buffalo with little effect on rumen microbial diversity or milk fatty acid composition compared with maize feeding.

Verification of silage type using near-infrared spectroscopy combined with multivariate analysis.

The ability to authenticate the feed given to animals has become a major challenge in animal production, where the diet fed to the animal is one of the most important production factors affecting the composition of milk and meat from cattle, sheep, and goats. Hence, there is currently an increased consumer demand for information on herbivore production factors and particularly the animal diet. The aim of this study was to evaluate the reliability and accuracy of near-infrared (NIR) reflectance spectroscopy as a tool to verify and authenticate the type of silage used as fed for ruminants. Grain silage (GrS, n = 94), grass and legume silage (GLegS, n = 121), and sunflower silage (SunS, n = 50) samples were collected from commercial farms and analyzed in the visible and NIR regions (400-2500 nm) in a monochromator instrument in reflectance. Principal component analysis (PCA), partial least-squares discriminant analysis (PLS1-DA), and linear discriminant analysis (LDA) models were used as methods to verify the different silage types. The classification models based on the NIR data correctly classified more than 90% of the silage samples according to their type. The results from this study showed that NIR spectra combined with multivariate analysis could be used as a tool to objectively authenticate silage samples used as a feed for ruminants.