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Publications (4)0 Total impact

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    ABSTRACT: Twelve dual-flow continuous culture fermenters (culture 8 d with 5 d for adjustment and 3 d for sample collection) were used to evaluate the effects of rumen-degradable protein balance (RDPB) on rumen fermentation. The different RDPB levels in six diets were as follows: − 16.84, − 8.87, − 0.87, + 7.13, + 15.13, and + 23.12 g RDPB /kg DM. Results indicated that RDPB had a significant effect on fermenter NH3-N (P < 0.0001), but had less effect on the fermenter pH (P = 0.058), total VFA concentration (P = 0.57), or acetate molar proportion (P = 0.70). The decrease in rumen-available N in the diets with the RDPB levels at + 15.13, + 7.13, − 0.87, − 8.87, − 16.84 g RDPB/kg DM resulted in NH3-N concentration decreasing at 9%, 52%, 104% and 118% in rumen compared with the diet of + 23.12 g RDPB/kg DM. Total VFA concentration, acetic acid and valeric acid at different time points was altered (P < 0.05) by the treatment. With the increase of dietary RDPB, the total NH3-N flowing out of fermenters linearly increased, and the N losses also increased.
    Frontiers of Agriculture in China 5(4).
  • Yanxia Gao, Tao Sun, Jianguo Li
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    ABSTRACT: Nine multiparous cows averaging 93±13 days in milk production (DIM) were used in a triple 3×3 Latin square design to determine the effects of feeding them whole roasted flaxseed, cracked roasted soybean and fresh alfalfa in the diet on milk production, milk fatty acid profiles and the digestibility of nutrients. Each experimental period lasted 30 d and a sample collection was performed during the last 7 d. The cows were fed on the control basal diet (CON) or diets containing whole roasted flaxseed (FLA) or cracked roasted soybean (SOY). All diets were fed as a total mixed ration (TMR) and had similar concentrations of crude protein (CP), Net Energy Lactation (NEL), acid detergent fibre (ADF) and neutral detergent fibre (NDF). The dry matter intake (DMI) was not significantly different (P>0.05), but tended to increase in FLA and SOY diets compared with the control (P>0.05). Cows in all treatments had a similar milk yield, although 4% fat corrected milk (FCM) yield was higher on the FLA and SOY diets than on the CON diet. Milk fat percentage (3.45%) increased in the FLA diet compared with the control (3.31%) and SOY diets (3.39%). Milk protein percentages were similar among the diets (P>0.05). There were similar digestibilities of DM, CP and ADF among the treatments and lower digestibilities of NDF and ether extract in the SOY diet compared with the CON diet. Feeding various oilseeds significantly increased the concentrations of C18:1, C18:3 and conjugated linoleic acid (CLA). The FLA diet decreased the ratio of omega-6 to omega-3 fatty-acids in the milk, which would improve the nutritive value of the milk.
    Frontiers of Agriculture in China 3(3):311-318.
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    ABSTRACT: This paper aims at studying the effect of steam-flaked corn instead of corn in the diet for finishing steers on the growth performance and blood biochemical parameters. A single-factor design was used. There were 28 simmental crossbred steers with the similar bodyweight (414.4±29.3 kg, P > 0.05) selected and allotted to four groups with seven duplicates in each group. Steam-flaked corn replaced the proportion of normal cracked corn, which was of 0, 30%, 60%, or 90% in the concentrate of Groups I, II, III, or IV, respectively. The results showed that the steam-flaked corn replacing ordinary cracked corn could significantly improve the growth of steers. The daily growth rate (ADG) was increased by about 37.16% from 985.3 g/d to 1351.4 g/d. The feed efficiency was significantly improved by 27.46%. The feed to gain ratio was decreased from 5.68 to 4.12. Serum urea nitrogen was decreased from 4.59 mmol/L to 3.66 mmol/L. Under the experiment conditions, steam-flaked corn replacing ordinary cracked corn could increase the feed efficiency with an optimal replacing ratio of 90%.
    Frontiers of Agriculture in China 5(4).
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    ABSTRACT: Eight Chinese Holstein cows were used in a 4 × 4 Latin square design to determine the effects of rumen protected methionine (RPMet) and Niacin on milk yield and milk composition of lactating cows with 14 d adaptation and 6-d sampling periods. The cows were fed the control diet or the control diet plus RPMet (25 g·−1), niacin (6 g·−1), or RPMet (25 g·−1) + niacin (6 g·−1). The results showed that RPMet supplementation in the diet increased 4% fat corrected milk (FCM) yield (P < 0.05) and milk fat percentage (P < 0.05). However, supplemental RPMet had no effect on the solid non fat (SNF) (P > 0.05) and lactose percentage (P > 0.05). Dietary niacin supplementation increased milk yield (P < 0.05), milk protein percentage (P < 0.05) and lactose percentage (P < 0.05), but had no effect on milk fat percentage (P > 0.05) and SNF (P > 0.05). RPMet supplementation in the diet of lactating cows significantly decreased serum urea nitrogen (P < 0.01) and glucose contents (P < 0.05), but had no effects on nonesterified fatty acids (NEFA), total cholesterol and triglyceride (P > 0.05). Niacin supplementation influenced the contents of glucose and NEFA in serum, but had no effects on the urea nitrogen, total cholesterol and triglyceride (P > 0.05).
    Frontiers of Agriculture in China 2(1):121-124.