Effects Of Different Concentration To Forage Ratio On The Metabolism Of Ca,P,Mg,Zn And The Milk Production Of Holestein Cow

Four Holstein cows(490±20kg body weight)fitted with permanent ruminal,duodenum and ileum cannulas were used in a 4×4 Latin square design experiment to study the effects of different concentrate to forage ratios in dietary on rumen fermentation, metabolism of mineral(Ca,P,Mg,Zn) and milk production for dairy cattle. The basal diets consisted of corn grain,soybean meal, wheat bran, alfalfa ,hay and corn silage with concentrate to forage ratio of 30:70,50:50 and 65:35.Diets with concentrate:forage ratio of 30:70 contained two diets, one forage was consisted with only hay grass, the other was hay grass, alfalfa and corn silage as forage. Treatments were expressed with LCG, LC, MC and HC. The results showed that:Apparent digestibility of Ca(5.27%,27.60%,28.14%,43.29%),P(57.55%,69.05%,69.01%,70.96%),Mg(–37.48%,9.23%,22.96%,37.03%),Zn(15.69%,19.56%,19.49%,37.42%) was increased by the ratios of concentrate and forage. There were no significant difference with concentration of Ca, P, Mg, Zn in the blood with different diets at before and after feed(P>0.05).There were significant difference on ruminal pH value(P<0.05), NH3-N(P<0.01), total volatile fatty acid(VFA)(P<0.05), propionate(P<0.01), butyrate(P<0.01) and acetate: propionate ratios(P<0.01) ;there were no significant effects on acetate(P>.05). VFA, propionate, NH3-N were increased by concentrate, however pH , acetate, acetate: propionate ratios and butyrate were increased.There were significant difference on milk yield(P<0.01),FCM(P<0.01), milk fat and milk protein(P<0.05). Milk yield(15.04,15.36,17.47and19.30kg/d),FCM, milk protein(3.37%,3.36%,3.56% and 3.66%) are increased by concentrate. milk fat(3.89%) of LCG is the most lowest. The other is 4.42%, 4.41% and 4.34%. There was no significant difference in the concentration of Ca ,P , Mg and Zn in milk.