| In this study, the levels of VA, VD, VE and Zn, Se, Cu in diets and in blood, status ofoxidative stress and liver function in lactating cows from two intensive dairy farms wereinvestigated to understand the relationship between vitamins and trace elements and metabolichealth, to provide a early warning risk indexes for deficiency of trace elements, and then to offera theoretical foundation for early prevention of vitamins deficiency and trace elementsdeficiency.To understand deficiency of the Main Vitamin and Trace Elements in Lactating Dairy Cows,in two intensive dairy farms(Ⅰ,Ⅱ),20cows in early lactation period (15-20d), lactation peakperiod (50-60d), mid-lactation period (120-150d), late lactation period (200-220d) were selectedrespectively to detect levels of VA, VD, VE and Zn, Se, Cu in diets and concentrations of VA,VD, VE, Zn, and Cu in serum. The results showed that1) The dietary levels of VA、VE、Se indifferent lactation periods in farm I were lower than those in farm II, and the VA levels in farmII was higher than that from NRC(2001). The dietary VD levels of farm I in late lactation periodand early lactation period was lower than those in farm II, but higher in middle lactation period,and the VD levels in farm II was higher than that from NRC(2001). The dietary VE levels offarm II was higher than that in farm I in lactation periods, and in both farm were higher thanthose from NRC(2001). The dietary Cu, Zn levels in farm I was lower than those in farm II inlactation periods, but in farm II was higher than those from NRC(2001), and in farm I was lowerthan those from NRC(2001).2) The lactating cows in farm I and farm II had no deficiencies ofVA, VD, and Zn, but was lack of VE and Cu. The incidence of Cu deficiency in differentlactation periods was0%,20%,10%,40%in turn in farm I, and30%,0%,30%, and25%in turnin farm II. It suggested that the levels of vitamin A, D, E and Zn, Se, Cu in diets and in plasma inwere different in lactation periods from two farms. In both farms there were deficiency ofvitamin E and Cu, but the incidence were different.To understand liver function and oxidative stress in Lactating Dairy Cows, the tested cowswere selected in two dairy farms, the levels of TP, ALB, GLB, A/G, SOD, T-AOC and GSH-PXin serum were measured. The results showed that levels of serum TP in early lactation periodwere significantly lower than that in mid-lactation period (P<0.05) and was no significant difference among other lactation periods (P>0.05)in farm I, while in early lactation period wassignificantly lower than other three lactation periods (P<0.05) and was no significant differenceamong other three lactation periods(P>0.05) in farm II. Levels of ALB in serum in early lactationperiod was significantly lower than other three lactation periods (P<0.05) and was no significantdifference among other lactation periods (P>0.05) in two farms. Levels of GLB in serum in earlylactation period was significantly lower than other three lactation periods (P<0.05).Levels ofGLB in serum were no significant difference among four lactation periods in farm II (P>0.05).A/G in serum in early lactation period were significantly lower than that in late lactation period(P<0.05) and were no significant difference among other lactation periods(P>0.05) in two farms.Serum SOD levels in early lactation period and peak lactation period were significantly lowerthan those in other lactation periods in two farms (P<0.05) and were no significant differenceamong other lactation periods(P>0.05) in two farms. Serum T-AOC levels were no significantdifference among four lactation periods in farm I (P>0.05), while in peak lactation period wassignificantly lower than that in late lactation periods in farm II (P<0.05) and were no significantdifferences among other lactation periods(P>0.05). Serum GSH-PX levels in early lactationperiod were significantly higher than those in other three lactation periods in two farms (P<0.05)and were no significant difference among other lactation periods(P>0.05). It suggested that liverfunction and oxidative stress vary to some extent during four lactation periods in two farms.To explore relationship between Cu deficiency and liver function and oxidative stress inLactating Dairy Cows, the tested cows were selected in two dairy farms, which were divided into28cows affected Cu deficiency and and129cows with normal Cu based on serum Cu. Levelsof CP, SOD, T-AOC, GSH-Px, TP, GLB, ALB, A/G and Cu in serum were detected and analyzedby pearson correlation analysis and regression analysis. The results showed that1) levels of GLB,CP and T-AOC in serum had very significantly positive correlation with Cu deficiency (in turnR=0.311, P=0.00; R=0.490, P=0.00; R=0.212, P=0.008). Level of ALB and A/G in serum hadvery significantly negative correlation with Cu deficiency (in turn R=-0.273, P=0.001; R=-0.237,P=0.003).Level of TP, SOD and GSH-PX in serum had no correlation with Cudeficiency(R=0.096, P=0.232;R=-0.076, P=0.347; R=-0.027, P=0.741).2) CP, ALB, and T-AOCin lactation cows may be used as the index to predict Cu deficiency in two farms.2) CP, ALB,and T-AOC in lactation cows may be used as the index to predict Cu deficiency in two farms. It suggested that Cu deficiency could aggravate oxidative stress and reduce immune function inlactation cows.Conclusion obtained that1) the levels of vitamin A, D and E&trace element Se, Cu,and Zn inlactation period are different in two dairy farms, which is lower or higher than those fromNRC(2001), should be adjusted in order to meet nutrient levels of lactating dairy cows.2) In twofarms, there is no deficiency of vitamin A, vitamin D and Zn, but there is deficiency of vitamin Eand Cu in lactating cows, which may be related to the oxidative stress or intestinal absorptiondysfunction.3) The lactating cows from two farms experience oxidative stress and presentabnormal liver function and poor immune function.4) CP, ALB, and T-AOC in lactation cowsmay be used as predicting parameters for Cu deficiency. |
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