Investigation And Clinical Changes Of Selenium Deficiency In Intensive Cattle Farms

Se deficiency is an important nutritional and metabolic disease of the lactating cows. It mayreduce milk yield and immune function, and secondary to other diseases such as mastitis,endometritis, etc. In recent years, as milk yield constantly increased in intensive dairy farms, thesubclinical metabolic diseases have sometimes occurred, and its hazard has also increasedgradually. Therefore, in this study Se deficiency in two intensive dairy farms was investigated todetermine incidence, antioxidant, immune, liver function and milk components&reproductiveperformance. It aimed at clarifying the influence of Se deficiency on cattle health and to providea scientific basis for the early prevention of Se deficiency for high-yielding dairy cows in thefuture.In this study, eighty cows were randomLy selected from two intensive dairy farms (A and B)respectively at early lactation (15-20d), peak lactation (50-70d), mid-lactation (120-150d) andlate lactation (200-220d),10cows per period, whose age, body condition and parity are similar.The incidence of Se deficiency from farm A and B was surveyed by detecting of plasma Se level.According to plasma Se level, Se deficiency group (30cows) and healthy control group (20cows)were assigned to analyze their lactation traits, reproductive performance and energy metabolism(NEFA, BHBA, and GLU), anti-oxidation ability (GSH-Px, SOD, T-AOC, MDA, T-NOS, LPO,NO, CAT), immune function (TNF-α, IL-6, IgG, IL-1β, IL-2), liver function (ALB, ALP, TP,GLB, A/G) and reproductive hormones (FSH, LH, E2, P4). Further, Pearson correlation analysisand regression analysis were performed to warn Se deficiency in dairy farms.Results shown that1) Incidence of Se deficiency was72.5%in farm A, and77.5%in farm B;2) Compared with the healthy control group, there were significant reduction in milk fat, milkprotein and lactose (P <0.05), and the significant extension of insemination and breeding days (P<0.05) in Se deficiency group;3) Compared with the healthy control group, there was a decreasein plasma GSH-Px activity that had a significant positive correlation with Se content (R=0.36,P=0.01), an increasing level of plasma MDA, T-NOS and LPO that had negative correlationbetween MDA (R=-0.36,P=0.02),T-NOS (R=-0.30, P=0.05),and LPO (R=-0.31,P=0.04) with Secontent;4) Compared Se group with the healthy control group, plasma IL-1β, IgG,TNF-α andIL-6levels are significantly lower (P <0.05) in Se deficiency group, IL-6(R=0.35, P=0.03), IgG (R=0.39, P=0.02),IL-2（R=0.38*,P=0.03）,TNF-α (R=0.37, P=0.02) were positively correlatedwith Se content;5) Compared with the healthy control group, plasma levels of ALP and TPsignificantly increased, ALP (R=-0.32, P=0.03) and TP (R=-0.41, P=0.00) were negativelycorrelated with Se content;6) Compared with the healthy control group, plasma P4contentsignificantly lower, P4(R=0.79, P=0.00) was positively correlated with Se content;7) Plasmalevels of GSH-Px, MDA, IL-2, TNF-α, IL-6, TP, ALP were closely related to plasma Seconcentration. When plasma GSH-Px level was less than42.367U/mL, risk of Se deficiency inlactating dairy cows would significantly increase.Conclusions obtained that Se deficiency was a common problem in two intensive dairy farms,was over72%; Se deficiency not only affects the antioxidant and immune function, but alsoreduces lactating and reproductive performance of dairy cows; Risk prediction of Se deficiencywas developed by plasma GSH-Px for the lactating cow herds.