Effects Of Supplementation Of Nutrient Blockson Rumen Fermentation, Blood Physiological And Biochemical Parameters, Productionperformance And Meat Quality In Beef Cattle

This experiment was conducted to study the influence of supplementation of nutrient blocks on production performance of beef cattle. (Method) 90 Horqin cattle (b-ody weight = 427±24kg, age= 20-month-old) were randomly assigned to three gr-oups with 30 in each group in single-factor completely randomized block design. The treatments consisted of:1) group Ⅰ:feeding molasses blocks in pre-feeding time and alkaline-trace-elementsblocksduring the experimental period by supplementation; 2)group II:feeding alkaline trace-elementsblocks during the whole trial period by supplementation; 3)group Ⅲ:control group without supplementary blocks. The trial lasted for 194 d, including 14 d of preliminary period and 180 d of experimental period. Feed samples blood samples, rumen fluid samples and body weights were taken every 30d.The effects of nutrient blocks on performance, ruminal internal environmental parameters, blood physiological indicators, relevant hormone levels, slaughter performance, and meat quality of beef cattle were determined. The results were as follows:1. Supplementation of nutrient block has improve to growth performance of beef cattle.The average dry matter intake in group I was enhanced by 5% (P＜0.05) and that of group II was increased by 4% (P>0.05)compared with the control; the average daily weight gain of the beef cattle was increased by 11.2% (P>0,05) and 8% (P>0.05) in group I and group II relative to the control group, respectively, suggestin g that supplementation of nutrient blocks has improved feed utilization in beef cattle.2. The nutrient blocks can improve rumen internal environment in beef cattle.the rumen ph values were group Ⅰ>group Ⅱ>control group (P> 0.05).Acetic propionic acid was slightly higher than the control group (P> 0.05).In addition, concentrations of acetic acid, propionic acid, butyric acid, Mao acid, iso-mao acid,NH3-N and BCP were slightly higher in concentrations groups than the control group (P>0.05).It is evident that the use of nutrient blocks could better maintain the desired state of the cattle rumen environment.3. A nutrition blocks have varying degrees of impacts on blood physiological indicators in beef cattle. The results showed that:the number of white blood cells and other that nutrition blocks could improve to the metabolic activity of blood in beef cattle to a certain extent. Nutrition blocks have certain influence on blood biochemical parameters in beef cattle. At the 30th day of the tria,we oobserved that growth hormone (GH) levels in control group were significantly higher than that in molasses Group (p<0.05), Alkaline-trace-elements groups showed no difference with the other two groups (P>0.05). At the other sampling periods, the GH levels in the both test groups were higher than control group, and those in alkaline trace elements were the highest (P>0.05); in the test groups concentrations of LEP were higher than control group, and the concertrations in molasses groups were the highest (P>0.05); at the 60th day of the experiment Insulin-like growth factor (IGF) concentration in the treatment groups were significantly higher than control group, of which molasses group was the highest (P＜0.05); at the 120th day, the molasses group was significantly higher than the control group (P<0.05), alkaline trace elements groups showed no differences with the other groups (P>0.05); no significant differences were observed at the other sampling periods (P>0.05). The 60th day of the tria,the concentration in of insulin (INS) molasses group was significantly higher than the alkaline trace elements group (P＜0.05), there was no significant different control groups and treatment groups (P>0.05). Cortisol (Cor) concentrations at all sampling were not alterred by different treantment (P>0.05).Feeding nutrition blocks also have a certain impact on blood SOD levels in beef cattle. At the 30th and 60th days of the xperiment, the total SOD in cattle serum in the test groups were significantly higher than the control group (P＜0.05), that in molasses group was No sightly higher than group II (P>0.05); at 60d,120d and 180d of the xperiment blood GSH-PX concentrations were increased significantly by the treatment groups (P<0.05),at 60d and 120d, alkaline trace elements group has higher total SOD (P>0.05); at 180d alkaline trace elements groups was significantly higher than the control group (P＜0.01) and molasses Group (P＜0.05),at 30d and 90d, no significant difference were observed between groups (p<0.05);Ca concentrations in the test groups at 30d and 60d were significantly increased compared with the control group (P<0.01), and that was higher in molasses group than athor group (P>0.05), there was no significant difference at other sampling periods (P>0.05), at 180d, alkaline trace elements group p concentration was significantly higher than the control group (P<0.05), molasses group had no difference with the other two groups, there showed no significant difference at other sampling periods (P>0.05),; During the whole experiment, CP concentration was not changed by different groups (P>0.05); at 60d of the experiment, treatment groups had significantly higher LDH-L concentrations than the control group (P<0.01), No significant differences between the test group and molasses group the highest, at 180d LDH-L concentration in alkaline trace elements group was enhanced when compared with the control group (P…0.05), molasses group showed no difference with the other groups, the control group was minimum; Throughout the experimental period the ALP level showed no difference between groups (P>0.05).4. Feeding nutrient blocks does not adversely affect slaughter performance of beef cattle.5. Compared with the control group, the average profit of each cattle in group I was increased by ￥ 0.77/d, and group Ⅱ was increased by ￥ 0.23/d.