This study investigated the effects of ensiled mulberry leaves (EML) and sun-dried mulberry fruit pomace (SMFP) on the ruminal bacterial and archaeal community composition of finishing steers. Corn grain- and cotton meal-based concentrate was partially replaced with EML or SMFP. The diets had similar crude protein (CP), neutral detergent fiber (NDF), and metabolizable energy. Following the feeding trial, the steers were slaughtered and ruminal liquid samples were collected to study the ruminal microbiome. Extraction of DNA, amplification of the V4 region of the 16S rRNA gene, and Illumina MiSeq pyrosequencing were performed for each sample. Following sequence de-noising, chimera checking, and quality trimming, an average of 209,610 sequences were generated per sample. Quantitative real-time PCR was performed to examine the selected bacterial species in the rumen. Our results showed that the predominant phyla were Bacteroidetes (43.90%), Firmicutes (39.06%), Proteobacteria (4.31%), and Tenericutes (2.04%), and the predominant genera included Prevotella (13.82%), Ruminococcus (2.51%), Butyrivibrio (2.38%), and Succiniclasticum (2.26%). Compared to the control group, EML and SMFP groups had a higher abundance of total bacteria (p < 0.001); however, the bacterial community composition was similar among the three groups. At the phylum level, there were no significant differences in Firmicutes (p = 0.7932), Bacteroidetes (p = 0.2330), Tenericutes (p = 0.2811), or Proteobacteria (p = 0.0680) levels among the three groups; however, Fibrobacteres decreased in EML (p = 0.0431). At the genus level, there were no differences in Prevotella (p = 0.4280), Ruminococcus (p = 0.2639), Butyrivibrio (p = 0.4433), or Succiniclasticum (p = 0.0431) levels among the groups. Additionally, the dietary treatments had no significant effects on the archaeal community composition in the rumen. Therefore, EML and SMFP supplementation had no significant effects on the ruminal bacterial or archaeal community composition of finishing steers.

The aim of the present study was to measure the apparent absorption of magnesium (Mg) originating from Mg-butyrate. Six mid-lactation Holstein Friesian dairy cows were used with dietary treatments arranged in a cross-over design. Two different diets were fed during the experiment, consisting of a low Mg diet without Mg-butyrate (L-Mg, 3.1g Mg/kg dry matter) or a high Mg diet with Mg-butyrate (H-Mg, 3.9 g Mg/kg dry matter). Cows offered the L-Mg diet ingested 54.7 g Mg/day while the cows fed the H-Mg diets ingested 66.3 g Mg/day (P &lt; 0.001). The fecal excretion of Mg, however, was similar between the two experimental diets (P = 0.174). Consequently, apparent Mg absorption was found to be 7.9 percentage units greater (P = 0.038) when the cows were fed the diet supplemented with Mg-butyrate. The greater Mg absorption after feeding the H-Mg diet was, however, not reflected by a greater urinary Mg concentration (P = 0.228). These results indicate that the availability of Mg from the Mg-butyrate supplemented diet is high (34.1% of intake). The fractional Mg absorption from Mg-butyrate was calculated to be 71.6%. In conclusion, Mg-butyrate is an attractive alternative to supplement dairy rations with Mg.

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A daily Na intake of heat-stressed lactating cows to a ration intake of 1.6 g Na kg DM was insufficient to restore Na deficiency. One week was sufficient to deplete heat-stressed lactating cows of Na, allowing for rapid dose-response studies utilizing the salivary Na/K ratio as a parameter for Na status of cows under tropical conditions. © 2016 Society of Chemical Industry.

Objective Supplemental nitrate is known to be an effective tool to mitigate methane emission by ruminants. Based on theoretical considerations, supplemental nitrate can improve but also deteriorate the growth performance. The overall effect of supplemental nitrate on growth performance, however, is not yet known. The objective of the current study was therefore to evaluate the effect of a higher dose of NO 3 − on overall growth performance when feeding either Pangola grass hay or rice straw. Methods Thirty-two crossbred, 3-month-old Thai native×Anglo-Nubian crossbred male goats were used. The experiment had a 2×2 factorial design with an experimental period of 60 days. Eight goats were randomly allocated to each dietary treatment, i.e. a ration containing either Pangola hay ( Digitaria eriantha Steud ) or rice straw ( Oryza Sativa ) as a source of roughage, supplemented with a concentrate containing either 3.2% or 4.8% potassium nitrate. The rations were formulated to be isonitrogenous. The animals were weighed at the start of the experiment and at days 30 and 60. Feces were collected during the last five days of each 30-day period. Results High-nitrate increased overall DM intake by approximately 3%, irrespective the source of roughage, but only the goats fed a rice straw-based ration responded with an increase in body weight (BW). Thus, the overall feed conversion ratio (kg feed/kg BW gain) was influenced by roughage source ×nitrate and decreased by almost 60% when the goats were fed rice straw in combination with a high versus a low dietary nitrate content. The digestibility of macronutrients was only affected by the source of roughage and the digestibility of organic matter, crude protein, and neutral detergent fibre was greater when the goats were fed Pangola hay. Conclusion It was concluded that the replacement of soybean meal by nitrate improves the growth performance of meat goats fed rations based on rice straw, but not Pangola hay.