Abstract:

[Objective] The aim of this study was to clarify the effects of different forage diets on ruminal fluid pH value, ruminal volatile fatty acid （VFA） content and blood parameters of Simmental brood cows. [Method] A total of 18 Simmental brood cows were assigned into the following three groups according to the principle of homogeneity and the source of dietary forage: group 1 fed the forage of dried corn straw, group 2 fed the forage of whole plant corn silage, and group 3 fed the forage combination of whole plant corn silage and dried corn straw. The feeding experiment was composed of a 14-day pre-trial and a 42-day formal trial. At the end of the experiment, the ruminal fluid and blood samples were collected, and the ruminal fluid pH value, ruminal VFA content and blood parameters were determined. [Result] There was no significant （P>0.05） difference in the ruminal fluid pH value among the three groups. The group 2 had significantly （P<0.05） higher ruminal acetic acid content than group 1; the group 2 and group 3 had significantly （P<0.05） higher ruminal propionic acid content than group 1; the group 2 had significantly （P<0.05） higher n-butyric acid and isobutyric acid contents than the remaining groups. The serum activities of SOD and T-AOC of the group 1 were significantly （P<0.05） lower in comparison to those of the other groups, and the serum activity of GSH-Px of the group 1 was significantly （P<0.05） lower in comparison to that of the group 3. Significantly （P<0.05） decreased serum contents of Fe and Zn was observed in group 1 compared with group 2, and significantly （P<0.05） increased serum content of Se was observed in group 1 and group 2 compared with group 3. The group 1 had significantly （P<0.05） lower serum contents of VD and VE than the remaining groups. [Conclusion] The Simmental brood cows fed with whole plant corn silage or combination of whole plant corn silage and dried corn straw as forage performed better in ruminal fermentation and blood parameters than those fed with dried corn straw. Considering the feeding cost and forage supply status in agricultural area, the combination of whole plant corn silage and dried corn straw was recommended as an appropriate dietary forage source in Simmental brood cows production.

Key words: forage, Simmental brood cows, ruminal fermentation, blood parameters