Carvalho Pedro H V, Latack Brooke C, Ferraz Junior Marcos V C, Flores Ruben, Sanchez-Cruz Gerson, Montaño Martin F, Zinn Richard A
Department of Animal Science, University of California, Davis, Davis, CA, United States.
Cooperative Extension, Division of Agriculture and Natural Resources, University of California, Holtville, Holtville, CA, United States.
Front Vet Sci. 2023 Feb 24;10:1039323. doi: 10.3389/fvets.2023.1039323. eCollection 2023.
Evaluation of the effects of feeding NutraGen supplement (NutraGen, NTG; Phibro Animal Health, Teaneck, NJ, USA) on growth performance, energetic efficiency, carcass characteristcs, and characteristics of digestion in calf-fed Holstein steers fed a conventional growing-finishing diet. Trial 1 evaluated growth performance, dietary energetics and carcass characteristics. Two hundred Holstein steer calves (134 ± 5 kg) were blocked by initial body weight (BW) and randomly assigned to 40 pens (5 steers/pen). Dietary treatments consisted of a steam-flaked corn-based growing-finishing diet supplemented with 0, 0.2, 0.4, or 0.6% NTG (DM basis). In trial 2, four Holstein steers (170 ±6 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate digestibility and ruminal characteristics using the treatments from trial 1. Compared to non-supplemented cattle, NTG increased BW (2.0%, = 0.02) and tended to increase ADG (3.6%, = 0.07) during the initial 56 d period. However, there were no treatment effects on overall growth performance and efficiency of dietary energy utilization after the first 56 days ( > 0.10). Supplementation of NTG increased (linear effect; ≤ 0.03) longissimus muscle area and kidney, pelvic, and heart fat. There was no effect ( ≥ 0.05) of NTG supplementation on other carcass characteristics, liver abscess incidence, or liver abscess scars. Supplementation decreased the molar proportion of ruminal propionate ( = 0.05) and tended to increase acetate:propionate molar ratio ( = 0.09). However, there was no effect of NTG supplementation on ruminal and total tract diet digestion. NTG increased performance of Holstein steers during the first 56 d on feed in the feedlot. In addition, the steers had an increase in KPH fat and LM area, indicating that the additive induced change in metabolism of the steers.
评估在以传统育成肥育日粮饲喂的荷斯坦阉牛中，添加NutraGen补充剂（NutraGen，NTG；美国新泽西州蒂内克市菲布罗动物保健公司）对生长性能、能量效率、胴体特性及消化特性的影响。试验1评估生长性能、日粮能量学及胴体特性。200头荷斯坦阉牛犊牛（134±5千克）按初始体重进行分组，并随机分配至40个围栏（每个围栏5头牛）。日粮处理包括以蒸汽压片玉米为基础的育成肥育日粮，分别添加0、0.2、0.4或0.6%的NTG（干物质基础）。在试验2中，选用4头装有瘤胃和十二指肠近端插管的荷斯坦阉牛（170±6千克），采用4×4拉丁方试验，使用试验1中的处理来评估消化率和瘤胃特性。与未添加的牛相比，在最初的56天期间，NTG使体重增加（2.0%，P = 0.02），且日增重有增加趋势（3.6%，P = 0.07）。然而，在最初的56天后，对于总体生长性能和日粮能量利用效率没有处理效应（P＞0.10）。添加NTG增加了（线性效应；P≤0.03）背最长肌面积以及肾、骨盆和心脏脂肪。添加NTG对其他胴体特性、肝脓肿发病率或肝脓肿瘢痕没有影响（P≥0.05）。添加使瘤胃丙酸的摩尔比例降低（P = 0.05），且乙酸:丙酸摩尔比有增加趋势（P = 0.09）。然而，添加NTG对瘤胃和全消化道日粮消化没有影响。在饲养场，NTG提高了荷斯坦阉牛在最初56天的采食性能。此外，阉牛的KPH脂肪和背最长肌面积增加，表明该添加剂引起了阉牛代谢的变化。
