| China’s dairy industry is in the development of large-scale and intensive farming processes. However, dairy cattle breeding still undergoes continuous refinement and improvement. There are three problems as follow:(1) Highly intensive aquaculture environment caused greater stress to dairy cows, which decreases the ability of resistance, reduces production and reproduction performances, and enhances the incidence of culling.(2)Feed formulations are only limited to estimation of protein and energy contents, with minimum considerations on the trace elements.(3)Crude feed accounts a large proportion of ruminant diet and thus its digestibility inside rumen is crucial for rumunal activities.Experiment1:Determine the nutrition level of different dairy diets used in Huanggang and estimation of trace elements in the blood. The results showed that:(1)In some farms, CP, ADF levels were low, so should be increased.(2)Dietary manganese and cobalt can meet the needs of the cows. The contents of iodine and iron were2-3and13times higher than the recommended values respectively. The possible reason might be high iron contents in the feed itself or mixed with the soil roμghage during stroaging or feeding. On the other hand, selenium content was57.67%of the recommended value. In some farms, the content of copper, zinc was lower than the recommended value.(3)The serum concentrations of zinc, manganese, selenium were lower than normal values considering the fact that both have lower absorption rate, thus insufficient for these cows. Increase the required amount of iron can also compete with divalent ion binding protein, thereby reducing the biological absorption rate of zinc and manganese.(4)On the Large-scale farms, cows exhibited hoof problems, mastitis and high rumen acidity.Experiment2:Effects of DHP, AOX, VE on the fermentation and degradation of feed and their antioxidant capacity inside rumen. The results showed that:(1)the addition of VE significantly decreased rumen NH3-N concentration by33.67%than the control group, and appeared beneficial for microbial protein synthesis. The three antioxidants increased dry matter degradation rate by7.34%-9.42%, the degradation rate of CP increased by5.97%-9.02%, ADF increased by12.57%-19.18%and NDF increased by7.98%-18.91%. The effect of AOX is best among all three antioxidants.(3)Compared with control, activity of GSH-PX (52.70%) and SOD (45.89%) increased, however, the activity MDA decreased (23.43%) significantly in AOX group (P<0.05). Compared with the control group, the activity of GSH-PX and CAT was increased46.70%and38.29%respectively in DHP group (P<0.05). In vitamin E group, CAT activity was significantly higher (35.81%) than the control group (P<0.05). AOX performed the best among antioxidants. DHP, AOX, VE can improve rumen fermentation and degradation rate, furthermore, it can enhance antioxidant capacity of rumen.Experiment3:This experiment was conducted to investigate the effects of zinc, manganese, selenium and Agrado Plus on production performance of dairy cows. The results showed as follow:(1)The organic and organic+Agrado Plus group cows produced more milk and4.0%fat-corrected milk than control group(P<0.05). The treatment groups have higher fat, protein, lactose, solid and non-fat solid while lower somatic cell count(SCC) than control group(P>0.05).(2)The milk selenium (24%) and zinc (16.35%) of the organic+AOX was higher than the control group, with significant difference (P<0.05);(3)There are no significant differences of BCS among all four groups (P>0.05).The results showed that dairy diets imbalance of trace elements (zinc, manganese, selenium) in the feed contents resulted in their lower concentration in the serum. Furthermore, antioxidants are of prime importance as they can significantly improve the antioxidant capacity of dairy goat rumen, feed digestibility and fermentation ability of rumen. Addition of organic zinc, manganese and selenium in the diet can improve milk yield compare to that of inorganic form, furthermore, addition of AOX in the diet can improve the production performance of dairy cows. |
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