This experiment was conducted to investigate nutrient digestibility, rumen microbial protein synthesis, and lactation performance when a portion of alfalfa was replaced with combinations of dry corn gluten feed (DCGF) and Chinese wild rye grass in the diet of lactating cows. Six multiparous and 3 primiparous Chinese Holsteins were arranged in a replicated 3 × 3 Latin square experiment for 21-d periods. The animals were fed 1 of 3 treatment diets during each period: (1) 0% DCGF (0DCGF); (2) 6.5% DCGF (7DCGF); and (3) 11% DCGF (11DCGF). Diets were isonitrogenous, and a portion of alfalfa hay was replaced with DCGF and Chinese wild rye grass, with similar concentrate mixtures and corn silage contents. The dry matter intake was greater for 11DCGF (21.9 kg/d) than for 0DCGF (20.7 kg/d) or 7DCGF (21.2 kg/d). The treatment diets did not result in difference in milk production, fat and lactose concentration, or yield. Compared with 0DCGF, the ration containing 11% DCGF improved the milk protein concentration. Dry matter and neutral detergent fiber digestibility was greater for 7DCGF (62.7% and 45.6%) and 11DCGF (63.1% and 47.2%) than for 0DCGF (59.4% and 42.3%), and the nitrogen digestibility was similar for the 3 treatments. The concentration of rumen volatile fatty acids was higher in cows fed the 11DCGF diet than in those fed the 0DCGF diet, with no difference between the 7DCGF and 11DCGF diets. The estimated microbial crude protein yield was greater for the 11DCGF diet (1985.1 g/d) than for the 0DCGF diet (1745.0 g/d), with no difference between the 0DCGF and 7DCGF diets. Thus, it appears that feeding DCGF and Chinese wild rye grass in combination can effectively replace a portion of alfalfa hay in the rations of lactating dairy cows.

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The objective of this study was to evaluate the effects of feeding gallic acid on the growth, nutrient digestibility, plasma metabolites, rumen fermentation, and bacterial community in the rumen fluid and feces of preweaning calves. Thirty-six female Holstein calves with similar ages (means ± SD; 3.1 ± 1.39 d) and body weights (40.8 ± 2.87 kg) were randomly assigned to receive 3 treatments. Calves were fed 1 of 3 treatments as follows: basal diet with no gallic acid (control), 0.5 g/kg gallic acid in starter diet (low), and 1 g/kg gallic acid in starter diet (high). The results showed that feeding gallic acid increased growth by improving the starter intake and average daily gain of the calves. The fecal score tended to decrease in a linear manner with the addition of gallic acid. Total-tract apparent protein digestibility tended to increase linearly with feeding gallic acid. Feeding gallic acid led to a linear increase in the plasma total protein and β-hydroxybutyrate levels. In addition, feeding gallic acid linearly increased catalase and total antioxidant capacity levels and decreased malondialdehyde and tumor necrosis factor-α concentrations. The concentrations of total volatile fatty acids, propionate, butyrate, and valerate in the rumen fluid increased linearly with the addition of gallic acid, resulting in a linear pH reduction. Feeding gallic acid linearly increased the relative abundances of Prevotella_1, Saccharofermentans, and Prevotellaceae_ UCG-001 and linearly decreased the relative abundance of Prevotella_7 in the rumen fluid. The Shannon index of ruminal bacterial communities linearly increased by feeding gallic acid. Feeding gallic acid linearly increased the relative abundances of Ruminococcaceae_UCG-005, Bacteroides, and Christensenellaceae_R-7_group in the feces. In summary, feeding gallic acid improved growth, antioxidant function, and rumen fermentation and altered the bacterial community in the rumen fluid and feces of preweaning dairy calves.