Effects of humate on in vitro digestibility, and performance, carcass characteristics, and mineral status of wether lambs

Abstract

Two experiments were conducted to determine the effects of humate on in vitro digestibility, and performance, carcass characteristics, and mineral status of growing wether lambs. Experiment 1 consisted of three trials to determine the effect of humate on in vitro dry matter digestibility (IVDMD) of Coastal Bermuda grass hay (CBH). In Trial 1, six levels of humate (H): .0125,.025,.05,.I,.2, and.4%; were incubated with the substrate. The.0125 and.025% H increased (P <.05) IVDMD by 5.5 and 5.3% as compared to the control at 12 h. These treatments also increased IVDMD (P < .05) at 24 h by 10.6 and 7.2% as well as increasing the rate of IVDMD. Trial 2 H treatment levels were .0 1, . 1, and 1.0% H. After 12 h of incubation, the .0 I % H treatment increased IVDMD by 7.8% compared to the control. The addition of .01, . 1, and 1.0% H increased (P <.05) IVDMD at 24 h 13.2, 9.8, and 7.4% more than the control. Rate of IVDMD was greater than the control for all treatment groups at 12 and 24 h. Trial 3 treatment levels of H were humic acid (HA), fulvic acid (FA), a 50150 mixture of humic acid and fulvic acid (50150), and a raw humate powder (HP) at two dose levels (.5 ml and 1.0 ml). Low doses of 50/50 as well as low doses of HP increased (P <.05) IVDMD by 11.9 and 15.4% as compared to the control after 4 h of incubation. The low dose 50150 again increased IVDMD (P <.05) by 21.2% compared to the control at 24 h. Rate of digestion was greater in the low dose treatment of 50/50 at 4 h but not at any other time period. In Experiment 2, forty-eight wether lambs ( avg wt = 28.4 kg) were used to determine the effects of H on performance, carcass characteristics, and mineral status in the wether lamb. Lambs were blocked by initial weight and randomly assigned to one of four treatments (0, .5, 1.0, and 2.0% H in the diet) and fed a high concentrate diet for 63 d. Lambs were slaughtered after d 63 and carcass characteristics measured. Lambs fed 0 and .5% H consumed more feed (P <.05) than those fed 1.0 and 2.0% H (1.56 and 1.50 vs 1.36 and 1.25 kg/d, respectively). Lambs fed 0 and.5% H had a greater (P <.05) ADG than those fed 1.0 and 2.0% H (.26 and .25 vs .21 and .20 kg/d, respectively). Feed conversion (kg gain/kg feed) did not differ (P > 10) but favored lambs fed lower H levels with conversions of .17 and.17 for lambs fed 0 and.5% H treatments% .15 and .16for those fed 1.0 and 2.0% H. Hot carcass weight was lower (P < .05) in lambs fed 1.0 and 2.0% H (22.0 and 21.3 kg) compared to those fed 0 and.5% H (23.3 and 23.1 kg). Loin eye area was greatest (P < .05) in lambs fed 0% H (14.1 CM2) and lowest in lambs fed 2.0% H (12.9 CM2). No differences (P >.05) were noted in backfat thickness or yield grade due to dietary levels of humate. Liver Fe was higher (P <.05) in lambs fed 2.0% H (196 mg/kg DM) than in those fed O,.5, and 1.0% H (161, 164, and 163 mg/kg DM). No differences were observed in liver Cu or liver Zn. These data conclude that: 1) humate at .0125,.Ol,.025, and.1% can enhance the rate of digestion but not the overall extent and 2)humate fed at higher than .5% of the diet will decrease animal performance. Two experiments were conducted to determine the effects of humate on in vitro digestibility, and performance, carcass characteristics, and mineral status of growing wether lambs. Experiment I consisted of three trials to determine the effect of humate on in vitro dry matter digestibility (IVDMD) of Coastal Bermuda grass hay (CBH). In Trial 1, six levels of humate (H): .0125,.025,.05, I,.2, and.4%; were incubated with the substrate. The.0125 and.025% H increased (P <.05) IVDMD by 5.5 and 5.3% as compared to the control at 12 h. These treatments also increased IVDMD (P < .05) at 24 h by 10.6 and 7.2% as well as increasing the rate of IVDMD. Trial 2 H treatment levels were .0 1, . 1, and 1.0% H. After 12 h of incubation, the .0 I % H treatment increased IVDMD by 7.8% compared to the control. The addition of.Ol,.I, and 1.0% H increased (P < .05) IVDMD at 24 h 13.2, 9.8, and 7.4% more than the control-Rate of IVDMD was greater than the control for all treatment groups at 12 and 24 h. Trial 3 treatment levels of H were humic acid (HA), fulvic acid (FA), a 50150 mixture of humic acid and fulvic acid (50150), and a raw humate powder (HP) at two dose levels (.5 ml and 1.0 ml). Low doses of 50150 as well as low doses of HP increased (P <.05) IVDMD by 11.9 and 15.4% as compared to the control after 4 h of incubation. The low dose 50150 again increased IVDMD (P <.05) by 21.2% compared to the control at 24 h. Rate of digestion was greater in the low dose treatment of 50150 at 4 h but not at any other time period. In Experiment 2, forty-eight wether lambs ( avg wt = 28.4 kg) were used to determine the effects of H on performance, carcass characteristics, and mineral status in the wether lamb. Lambs were blocked by initial weight and randomly assigned to one of four treatments (0, .5, 1.0, and 2.0% H in the diet) and fed a high concentrate diet for 63 d. Lambs were slaughtered after d 63 and carcass characteristics measured. Lambs fed 0 and .5% H consumed more feed (P <.05) than those fed 1.0 and 2.0% H (1.56 and 1.50 vs 1.36 and 1.25 kg/d, respectively). Lambs fed 0 and.5% H had a greater (P <.05) ADG than those fed 1.0 and 2.0% H (.26 and .25 vs .21 and .20 kg/d, respectively). Feed conversion (kg gain/kg feed) did not differ (P > . I 0) but favored lambs fed lower H levels with conversions of .17and.17 for lambsfed 0 and .5% H treatments vs .15 and .16 for those fed 1.0 and 2.0% H. Hot carcass weight was lower (P < .05) in lambs fed 1.0 and 2.0% H (22.0 and 21.3 kg) compared to those fed 0 and.5% H (23.3 and 23.1 kg). Loin eye area was greatest (P < .05) in lambs fed 0% H (14.1 CM2) and lowest in lambs fed 2.0% H (I 2.9 CM2). No differences (P > .05) were noted in backfat thickness or yield grade due to dietary levels of humate. Liver Fe was higher (P < .05) in lambs fed 2.0% H (I 96 mg/kg DM) than in those fed 0, .5, and 1.0% H (I 61, 164, and 163 mg/kg DM). No differences were observed in liver Cu or liver Zn. These data conclude that: 1) humate at .0 1 25, .01, .025, and . I % can enhance the rate of digestion but not the overall extent and 2)humate fed at higher than .5 % of the diet will decrease animal performance.