Feeding incremental amounts of ground flaxseed: effects on diversity and relative abundance of ruminal microbiota and enteric methane emissions in lactating dairy cows.

We evaluated the effects of incremental amounts of ground flaxseed (GFX) on diversity and relative abundance of ruminal microbiota taxa, enteric methane (CH4) emissions, and urinary excretion of purine derivatives (PD) in lactating dairy cows in a replicated 4 × 4 Latin square design. Twenty mid-lactation Jersey cows were used in the study. Of these 20 cows, 12 were used for ruminal sampling, 16 for enteric CH4 measurements, and all for spot urine collection. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. Diets were formulated by replacing corn meal and soybean meal with 0%, 5%, 10%, and 15% of GFX in the diet's dry matter. Ruminal fluid samples obtained via stomach tubing were used for DNA extraction. Enteric CH4 production was measured using the sulfur hexafluoride tracer technique. Diets had no effect on ruminal microbiota diversity. Similarly, the relative abundance of ruminal archaea genera was not affected by diets. In contrast, GFX decreased or increased linearly the relative abundance of Firmicutes (P < 0.01) and Bacteroidetes (P < 0.01), respectively. The relative abundance of the ruminal bacteria Ruminococcus (P < 0.01) and Clostridium (P < 0.01) decreased linearly, and that of Prevotella (P < 0.01) and Pseudobutyrivibrio (P < 0.01) increased linearly with feeding GFX. A tendency for a linear reduction (P = 0.055) in enteric CH4 production (from 304 to 256 g/d) was observed in cows fed increasing amounts of GFX. However, neither CH4 yield nor CH4 intensity was affected by treatments. Diets had no effect on the urinary excretion of uric acid, allantoin, and total PD. Overall, feeding GFX decreased linearly the relative abundance of the ruminal bacterial genera Ruminococcus and Clostridium and enteric CH4 production, but no change was seen for CH4 yield and CH4 intensity, or urinary excretion of total PD, suggesting no detrimental effect of GFX on microbial protein synthesis in the rumen.

Feeding Calcium-Ammonium Nitrate to Lactating Dairy Goats: Milk Quality and Ruminal Fermentation Responses.

We aimed to investigate the effects of calcium-ammonium nitrate (CAN) fed to lactating dairy goats on dry matter (DM) intake, digestibility of nutrients, milk properties (composition, antioxidant capacity, fatty acid profile, and nitrate residues), and ruminal fermentation parameters. Twelve lactating Saanen goats averaging 98.5 ± 13.1 days in milk, 53.5 ± 3.3 kg of body weight, and 2.53 ± 0.34 kg of milk/day were randomly assigned in four 3 × 3 Latin squares to receive the following diets: a control group (without CAN) with 7.3 g/kg DM of urea (URE), 10 g/kg DM of CAN (CAN10), and 20 g/kg DM of CAN (CAN20). Each period lasted 21 days, with 14 days for diet adaptation and seven days for data and sample collection. The DM intake, digestibility of nutrients, yields of milk, 3.5% fat-corrected milk, and energy-corrected milk were not affected by treatments. Similarly, there were no treatment effects on the yields and concentrations of milk fat, true protein, and lactose, along with minor effects on milk fatty acid profile. Total antioxidant capacity in milk was unaffected by treatments; however, concentration of conjugated dienes increased, while thiobarbituric acid reactive substances in milk decreased linearly. Nitrate and nitrite residues in milk were elevated by treatments, while the total of volatile fatty acids and ammonia-N concentration in the rumen were unaffected. Collectively, feeding CAN (up to 20 g/kg of DM) to lactating dairy goats did not affect feed intake, nutrient digestibility, and milk composition; however, it may increase milk lipid oxidation, as evidenced by increased conjugated diene concentration.

Production performance, nutrient use efficiency, and predicted enteric methane emissions in dairy cows under confinement or grazing management system.

There has been an intense debate regarding the economic, social, and environmental sustainability of confinement versus grazing dairy systems. Our goal was to conduct a meta-analysis to compare dry matter intake, milk yield and composition, nutrient use efficiency (i.e., feed efficiency, milk N efficiency), and predicted enteric CH4 emissions using studies that simultaneously evaluated confinement and grazing. We were able to include in the meta-analysis 8 peer-reviewed articles that met the following selection criteria: (1) publication between 1991 and 2021 in English language, (2) report either SEM or SD, (3) inclusion of at least 1 confinement [total mixed ration or fresh cut herbage fed indoors (i.e., zero-grazing)] and 1 grazing treatment in the same study, and (4) use of markers (internal or external) to estimate herbage dry matter intake. Two unpublished experiments were added to the data set resulting in a total of 10 studies for comparing confinement and grazing. The magnitude of the effect (i.e., effect size) was evaluated using weighted raw mean differences between grazing and confinement systems for a random effect model. Enteric CH4 production was predicted as follows: CH4 (g/d) = 33.2 (13.54) + 13.6 (0.33) × dry matter intake + 2.43 (0.245) × neutral detergent fiber. Dry matter intake (-9.5%), milk yield (-9.3%), milk fat yield (-5.8%), milk protein yield (-10%), and energy-corrected milk (-12%) all decreased in grazing versus confined dairy cows. In contrast, concentration of milk fat and feed efficiency (energy-corrected milk/dry matter intake) were not affected by management system. Whereas milk protein concentration increased, milk nitrogen (N) efficiency (milk N/N intake) tended to decrease in grazing compared with confinement. Predicted enteric CH4 production was 6.1% lower in grazing than confined dairy cows. However, CH4 yield (g/kg of dry matter intake) and CH4 intensity (g/kg of energy-corrected milk) did not change between confinement and grazing. In conclusion, while production performance decreased in grazing dairy cows, nutrient use efficiency and predicted enteric CH4 emissions were relatively similar in both management systems. Results of our meta-analysis should be interpreted with caution due to the small number of studies that met our inclusion criteria leading to a limited number of treatment mean comparisons.

Influence of the storage period on the nutritional and microbiological value of sun-dried brewer's grains / Influencia del período de almacenamiento sobre el valor nutricional y microbiológico de los granos de cervecería secados al sol / Influência do período de estocagem sobre o valor nutricional e microbiológico de grãos de cervejaria secos ao sol

Abstract Background: Brewer's grains, a by-product of the brewery industry, can be included in the diet of ruminants. However, its high humidity makes it difficult to store and preserve. Objective: To evaluate the efficiency of sun dehydration of wet brewer's grains (WBG) and the effect of storage period on its nutritional and microbiological quality. Methods: A completely randomized experimental design was used to evaluate WBG dehydration efficiency, with treatments corresponding to 0, 1, 2, 4, 6, 8, 10, 12, 14 and 16 hours of sun exposure. A second experiment was carried out using also a completely randomizeddesign to evaluated the effect of storage with the following treatments: 0, 10, 20, 30, 60, 90, 120, 150 and 180 days of storage of the dry by-product. Results: Dry matter (DM) content linearly increased with dehydration period. The chemical composition of the dried brewer's grains had no effect as a function of storage period. Indigestible protein (C fraction) increased linearly but did not compromise the cumulative gas production and the in vitro digestibility of DM and protein. Storage time had no effect on fungus population. The maximum aflatoxin value was 45.5 μg/kg, and remained within acceptable limits for bovine feed. Conclusion: Dehydration of WBG in the sun is efficient to guarantee conservation and makes it possible to store the by- product. The storage of the dry by-product for 180 days does not compromise its nutritional or microbiological quality.

Resumen Antecedentes: Los granos de cervecería son un subproducto de la industria cervecera que puede ser incluido en la dieta de rumiantes; sin embargo, su alta húmedad dificulta el almacenamiento y conservación de ese producto. Objetivo: Evaluar la eficiencia de la deshidratación al sol de los granos húmedos de cervecería (WBG) y el efecto del período de almacenamiento sobre su calidad nutricional y microbiológica. Métodos: Para evaluar la eficiencia de la deshidratación de los WBG se utilizó un diseño experimental completamente al azar, con tiempos de tratamiento de 0, 1, 2, 4, 6, 8, 10, 12, 14, y 16 horas de exposición al sol. En un segundo experimento, también con diseño experimental completamente al azar, se evaluó el efecto del almacenamiento comparando los siguientes tratamientos: 0, 10, 20, 30, 60, 90, 120, 150 y 180 días de almacenamiento del subproducto seco. Resultados: La materia seca (DM) del WBG presentó un efecto lineal creciente con el proceso de deshidratación. La composición química de los granos secos de cervecería no tuvo efecto en función de los tiempos de almacenamiento. La proteína no digestible (fracción C) aumentó linealmente; sin embargo, no comprometió la producción acumulativa de gas y la digestibilidad in vitro de la DM y de la proteína. El tiempo de almacenamiento no tuvo efecto sobre la población de hongos. El valor máximo de aflatoxina obtenido fue de 45,5 μg/kg y permaneció dentro de los limites aceptables para alimentación de bovinos. Conclusión: La deshidratación de WBG al sol es eficiente para garantizar la conservación del material y viabilizar su almacenamiento. El almacenamiento por 180 días de este subproducto seco no compromete su calidad nutricional y microbiológica.

Resumo Antecedentes: Os grãos de cervejaria são um subproduto que podem ser incluídos na dieta de ruminantes, no entanto sua forma úmida dificulta o armazenamento e a conservação desse produto. Objetivo: Avaliar a eficiência de desidratação ao sol dos grãos úmidos de cervejaria (WBG) e o efeito do período de armazenamento sobre a qualidade nutricional e microbiológica. Métodos: Para avaliar a desidratação do WBG, utilizou-se um delineamento experimental inteiramente casualizado, sendo os tratamentos os tempos de 0 e 1, 2, 4, 6, 8, 10, 12, 14 e 16 horas de exposição ao sol. Um segundo experimento foi realizado em delineamento inteiramente casualizado. Os tratamentos foram 0, 10, 20, 30, 60, 90, 120, 150 e 180 dias de armazenamento do subproduto seco. Resultados: A matéria seca (DM) do WBG apresentou efeito linear crescente com o processo de desidratação. A composição química dos grãos secos de cervejaria não apresentou efeito em função dos tempos de armazenagem. A proteína indigestível (Fração C) aumentou linearmente, no entanto não comprometeu a produção cumulativa de gás e a digestibilidade in vitro da DM e da proteína. A população de fungos não apresentou efeito com o tempo de armazenamento. O valor máximo de aflatoxina obtido foi de 45,5 μg/kg e permaneceu dentro dos limites aceitáveis para a alimentação de bovinos. Conclusão: A desidratação do WBG ao sol foi eficiente em garantir a conservação do material e viabilizar o seu armazenamento. A estocagem desse subproduto seco por 180 dias não comprometeu a sua qualidade nutricional e microbiológica.

Annatto seeds as Antioxidants Source with Linseed Oil for Dairy Cows.

This study aimed to evaluate the effects of annatto seeds, linseed oil and their combination on DMI, apparent total tract digestibility, antioxidant capacity and milk composition of dairy cows. Four lactating Holstein cows (120 ± 43 days in milk; 15.98 ± 2.02 kg of milk/day, mean ± SD) were allocated in a 4 × 4 Latin square with a 2 × 2 factorial arrangement (with or without annatto seeds at 15 g/kg of dry matter (DM); with or without linseed oil at 30 g/kg of DM) and provided four different diets: control (no annatto seeds or linseed oil); annatto seeds (15 g/kg of DM); linseed oil (30 g/kg of DM); and a combination of both annatto seeds and linseed oil. Annatto seeds reduced DM intake, and milk yield, protein and lactose, but increased content of fat, total solids and short chain fatty acid, with no effect on total antioxidant capacity of milk. Linseed oil supplementation decreased medium chain fatty acid proportion and n-6/n-3 ratio, conversely it increased long chain fatty acids and n-3 fatty acid content of milk, ether extract intake and total-tract digestibility. Thus, linseed oil supplementation in dairy cow diets improved the milk FA profile but decreased milk fat concentration, whereas annatto seeds did not influence antioxidant capacity and depressed feed intake and milk yield.