PDF(Pubmed)
Abstract：
This study was designed to evaluate the effects of feeding increasing dietary concentrations of ergot alkaloids from cereal grains (EA; 0, 0.75, 1.5, 3.0 mg/kg of dietary DM) to feedlot cattle over backgrounding (BG) and finishing (FS) phases on health, welfare, and growth performance. Two hundred and forty commercial steers (280 ± 32 kg BW) were stratified by weight and randomly allocated to 16 pens (15 steers/pen), 4 of which were equipped with the GrowSafe system (1 pen/treatment) to measure individual feed intake. Each pen was randomly assigned to a treatment (n = 4/treatment). Treatments included 1) control (CTRL), no added EA; 2) CTRL + 0.75 mg/kg EA (EA075); 3) CTRL + 1.5 mg/kg EA (EA150); and 4) CTRL + 3.0 mg/kg EA (EA300). Steers were fed barley-based BG diets containing 40% concentrate: 60% silage (DM basis) for 84 d. Steers were then transitioned over 28 d to an FS diet (90% concentrate: 10% silage DM basis) and fed for 119 d before slaughter. The diet fed to EA300 steers was replaced with the CTRL diet after 190 d on feed (DOF), due to EA-induced hyperthermia starting at 165 DOF. In the BG phase, average meal length (P = 0.01) and size (P = 0.02), daily feeding duration (P = 0.03), final body weight (BW; P = 0.03), and total BW gain (P = 0.02) linearly decreased with increasing EA levels, while gain to feed (G:F) responded quadratically (P = 0.04), with EA150 having the poorest value. Increasing concentrations of EA in the diet linearly increased rectal temperature (P < 0.01) throughout the trial. Over the full FS phase, a quadratic response was observed for ADG (P = 0.05), final BW (P = 0.05), total BW gain (P = 0.02), and carcass weight (P = 0.05) with steers fed EA150 having the lowest performance, as EA300 steers were transferred to CTRL diet after 190 DOF. Dressing percentage (P = 0.02) also responded quadratically, with the lowest values observed for EA300. Thus, EA reduced ADG during BG and FS phases, although more prominently in FS, likely due to increased ambient temperatures and high-energy diet in FS triggering hyperthermia. When EA300 steers were transferred to the CTRL diet, compensatory gain promoted higher hot carcass weight (HCW) when compared with steers fed EA150. In conclusion, feeding feedlot steers diets with > 0.75 mg/kg EA caused reductions in performance and welfare concerns, although this breakpoint may be affected by duration of feeding, environmental temperatures, and EA profiles in the feed.
Ergot alkaloids (EA) are produced by a parasitic fungus (Claviceps purpurea) during the cereal grain growth cycle. Feeding cereal grain containing EA to beef cattle can cause constriction of blood vessels, hyperthermia, gangrene of extremities (ears, hoof, and tail), reduced feed intake and growth, and even death. Feed cleaning and processing technologies have been developed to remove EA from the human food chain, thus diverting contaminated feed for livestock use. We performed a beef cattle feedlot experiment to evaluate the impact of increasing levels of EA (0, 0.75, 1.50, 3.00 mg/kg of diet DM) on performance, health, and welfare. Steers fed 3.0 mg/kg of EA were transferred to the control diet (without EA) in the last half of finishing due to toxicity (hyperthermia). As EA levels increased, growth rate throughout the backgrounding and finishing phases decreased, while rectal temperatures increased and altered feeding behaviors occurred. Steers removed from 3 mg/kg EA diet exhibited compensatory gain, but their respiratory rate remained elevated 50 d after EA were last consumed.
Ergot alkaloids (EA) are produced by a parasitic fungus (Claviceps purpurea) during the cereal grain growth cycle. Feeding cereal grain containing EA to beef cattle can cause constriction of blood vessels, hyperthermia, gangrene of extremities (ears, hoof, and tail), reduced feed intake and growth, and even death. Feed cleaning and processing technologies have been developed to remove EA from the human food chain, thus diverting contaminated feed for livestock use. We performed a beef cattle feedlot experiment to evaluate the impact of increasing levels of EA (0, 0.75, 1.50, 3.00 mg/kg of diet DM) on performance, health, and welfare. Steers fed 3.0 mg/kg of EA were transferred to the control diet (without EA) in the last half of finishing due to toxicity (hyperthermia). As EA levels increased, growth rate throughout the backgrounding and finishing phases decreased, while rectal temperatures increased and altered feeding behaviors occurred. Steers removed from 3 mg/kg EA diet exhibited compensatory gain, but their respiratory rate remained elevated 50 d after EA were last consumed.
摘要：
这项研究旨在评估从谷物中增加麦角生物碱的饮食浓度（EA;0、0.75、1.5、3.0mg/kg饮食DM）对饲养场牛的影响，福利,和增长业绩。240辆商业转向(280±32千克体重)按重量分层，随机分配给16支钢笔(15辆转向/笔)，其中4个配备了GrowSafe系统（1笔/处理）以测量单个饲料摄入量。每个围栏被随机分配到治疗(n=4/治疗)。治疗包括1）对照（CTRL），不添加EA;2)CTRL+0.75mg/kgEA(EA075);3)CTRL+1.5mg/kgEA(EA150);和4)CTRL+3.0mg/kgEA(EA300)。饲喂以大麦为基础的BG饮食，其中含有40％的浓缩物：60％的青贮饲料（DM基础），持续84d。然后在28d内将Steers过渡到FS饮食（90％的浓缩物：10％的青贮饲料DM基础），并在屠宰前饲喂119d。饲喂EA300牛的饮食在饲喂190天后(DOF)用CTRL饮食代替，由于EA诱导的高温始于165自由度。在BG阶段,平均餐长(P=0.01)和大小(P=0.02)，每日喂养时间（P=0.03），最终体重（BW;P=0.03）和总BW增加（P=0.02）随EA水平的增加线性下降，而进给增益(G：F)二次响应(P=0.04)，EA150的价值最差。在整个试验过程中，饮食中EA浓度的增加线性增加了直肠温度（P<0.01）。在整个FS阶段，观察到ADG的二次响应(P=0.05)，最终BW（P=0.05），饲喂EA150的牛的总体重增加（P=0.02）和car体重量（P=0.05）性能最低，由于EA300牛在190自由度后被转移到CTRL饮食。穿衣百分比(P=0.02)也有二次反应，与EA300观察到的最低值。因此，EA在BG和FS阶段降低了ADG，尽管在FS中更为突出，可能是由于环境温度升高和FS中的高能量饮食引发热疗。当EA300牛被转移到CTRL饮食时，与饲喂EA150的牛相比，补偿性增重促进了更高的热car体重量（HCW）和敷料百分比。总之,饲喂饲喂饲喂>0.75mg/kgEA的饮食导致性能和福利问题的减少，虽然这个断点可能会受到喂食持续时间的影响，环境温度,和EA配置文件在饲料中。
