Use of modulators additives the ruminal fermentation in supplements high intake for finished bovines in pasture
Performance of young grazing cattle has been improved by energy supplementation. Additionally, several antibiotics (monensin, lasalocid) have resulted in a consistent grown response. On the other hand, data concerning the effect of virginiamycin in grazing cattle are scarce. Therefore, ninety six Nellore bull (480 ± 28 kg BW) were divided in five treatments with different level of supplement and additives blend (T1= 0.5% BW, T2=2% BW, T3=2% BW + virginiamycin (25 ppm), T4= 2% BW + virginiamycin (25 ppm) + monensin (20 ppm), T5= 2% BW + virginiamycin (25 ppm) + salinomycin (10 ppm). Continue grazing was practiced in Panicum maximum cv. Tanzania pasture during dry-season. We used a randomized block design. Twenty paddock (4/ treatment) were used divided two blocs (4 bull/ paddock). Average daily gain (ADG) was calculated using the initial and final individual live weight divided by the number of experimental days. Animals were slaughter in commercial slaughter room and hot carcass weights were obtained to calculate carcass dressing (CD). Statistic analyzer were determined according Proc Mixed SAS 9.0. Paddocks were used as experimental units. Treatments were considered fixed effect and, block aleatory effect. Treatments effects were tested using the following contrasts: 0.5% vs 2% BW. Animals supplemented with 2% BW shown higher ADG (P<0.01) and had highest CD when compared treatment 2%BW (1.313 vs 0.534 and 58.4 vs 53.9, respectively). The effect of virginiamycin and other treatments with 2% BW were tested using contrasts. There were difference (P<0.01) for liveweight gain between treatments 2% BW + virginiamycin (25 ppm) (1.225 kg/d) and 2% BW + virginiamycin (25 ppm) + monensin (20 ppm) (1.505 kg/d), However, 2% BW and 2% BW + virginiamycin (25 ppm) + salinomycin (10 ppm) were not statistically different, the ADG for this treatments were 1.229 kg/d and 1.296 kg/d, respectively. Animals supplemented with virginiamycin (P<0.01) had the highest carcass dressing (59.2) when compared with treatment 2% BW (57.8). Contrast with other treatments not shown statistic difference, achieved 58.7 and 58.0 for treatments 2% BW + virginiamycin (25 ppm) + monensin (20 ppm) and 2% BW + virginiamycin (25 ppm) + salinomycin (10 ppm), respectively. Therefore, increasing supplementation and use of additives may increase animal performance.
Acknowledgment: Phibro Animal Health Corporation.
Keywords: Monensin, pasture, virginiamycin.