توصيفگر ها :
بلوس , نمره وضعيت بدني , گاو هلشتين , نوبت زايش , متابوليت هاي خون , وضعيت توليدمثلي
چكيده انگليسي :
The first experiment was carried out with the aim of investigating the effect of sustained release bolus and body condition score on metabolic status, uterine health, changes in body condition score and reproductive status of multiparous cows, and the second experiment was conducted with the aim of investigating the effect of sustained release bolus on metabolic status, uterine health, changes in body condition score and reproductive status of primiparous cows. For the first experiment, 140 multiparous Holstein cows (Parity = 3.9 ± 0.3, milk production in 305 days of the previous period = 14324 ± 338.56 and BCS greater than 2.75) were used for the first experiment. Based on the BCS at the beginning of the close-up period, the multiparous cows were divided into 2 groups: moderate body condition score (BCS ≥ 2.75) and high body condition score (BCS ≥ 3.5). so that the average BCS of multiparous cows was 3.37±0.5. Then, each group at the time of calving based on receiving or not receiving bolus (each bolus contains 63 mg of selenium, 750 mg of zinc, 2 g of copper, 1.2 g of manganese, 470,000 IU vitamin A with a release rate of 21 days) was divided into 2 subgroups. In this way, at the time of calving, we had 4 experimental treatments: 1- moderate body condition score, without receiving bolus (n=35) 2- moderate body condition score, with receiving bolus (n=35) 3- high body condition score, without receiving bolus (n=35) 4- High body condition score, with receiving bolus (n=35). To perform the second experiment, 60 primiparous cows (milk production of 305 days of the previous period of their mothers = 13994 ± 83.45 and average body condition score 3.35) were used. Heifers were divided into 2 groups at the time of calving based on receiving or not receiving bolus. In this way, we had 2 experimental treatments: 1- heifers without receiving bolus (n=30) 2- heifers' whit receiving bolus (n=30). The results of the first experiment showed that the serum concentrations of BHBA, bilirubin and albumin were affected by the consumption of bolus and BCS (P<0.05), while the serum concentrations of NEFA, total protein and the ratio of albumin to globulin were only influenced by bolus (P<0.05). The highest concentration of NEFA (P< 0.01) on the 28th day after calving and the entire period and the highest concentration of BHBA (P < 0.01) on the 14th and 28th day after calving related to cows with a high BCS and without receiving bolus. Cows with a high BCS and without receiving bolus, concentration of their blood bilirubin increased significantly (P<0.05) on the 14th day after calving and the whole period. Cows with a high BCS and without receiving bolus had the highest ALT concentration in the whole period (P<0.05).According to the results of the second experiment, in the group receiving bolus, concentration of albumin tended to increase significantly on day 28 after calving (P<0.05) and concentration of globulin tended to decrease significantly on day 42 after calving (P< 0.05). Consuming bolus in the time of calving reduced concentration of AST on the 14th day after calving and the entire period (P=0.06). Consumption of bolus with antioxidant properties increased the concentration of TAC on day 14 (P=0.05) and 42 (P<0.05) after calving and the entire experimental period (P<0.05). On the other hand, the highest levels of glutathione peroxidase and superoxide dismutase on the 42nd day after calving were related to heifers receiving bolus (P<0.05). Also, consumption of bolus with antioxidant properties significantly reduced the score of uterine secretions on the 28th day after calving (P<0.05). In general, this research showed that the use of bolus containing mineral-vitamin compounds during calving can reduce the negative effects of negative energy balance, increase the antioxidant capacity of the blood and improve the metabolic status in primiparous and multiparous cows. Finally, it improves the reproductive status and reduces open days.
