University of Florida-IFAS, Range Cattle Research and Education Center, Ona 33865, USA.
J Anim Sci. 2010 Dec;88(12):4120-32. doi: 10.2527/jas.2009-2684. Epub 2010 Aug 20.
Two experiments were conducted to evaluate the effects of rumen-protected PUFA supplementation on performance and inflammation measures in beef calves after truck transportation and feedyard entry. In Exp. 1, 30 weaned Braford steers (BW = 218 ± 4.3 kg) were transported for 1,600 km over a 24-h period in a commercial trailer and delivered to a feedlot (d 0). Upon arrival (d 1), steers were stratified by BW and allocated to receive 1 of 3 treatments (10 steers/treatment), which consisted of grain-based concentrates without supplemental fat (NF), or with the inclusion of a rumen-protected SFA (SF; 2.1% as-fed basis) or PUFA source (PF; 2.5% as-fed basis). Shrunk BW was determined on d 1 and 30 for ADG calculation. Individual DMI was recorded from d 2 to 28. Blood samples were collected on d 0, 1, 4, 8, 15, 22, and 29 for determination of acute-phase protein concentrations. Steers fed PF had decreased (P = 0.04) mean DMI and tended to have reduced ADG (P = 0.07) compared with NF-fed steers (2.32 vs. 2.72% of BW, and 0.78 vs. 1.07 kg/d, respectively). No other treatment effects were detected. In Exp. 2, 48 weaned Brahman-crossbred heifers (BW = 276 ± 4.6 kg) were stratified by initial BW and randomly allocated to 6 pastures (8 heifers/pasture) before transportation (d -30 to 0). Pastures were randomly assigned (3 pastures/treatment) to receive (DM basis) 3.0 kg/heifer daily of NF, or 2.5 kg/heifer daily of a concentrate containing 5.7% (as-fed basis) of a rumen-protected PUFA source (PF). On d 0, heifers were transported as in Exp. 1. Upon arrival (d 1), 24 heifers were randomly selected (12 heifers/treatment), placed into individual feeding pens, and assigned the same pretransport treatment. Shrunk BW was recorded on d -30, 1, and 30 to determine ADG. Individual DMI was recorded daily from d 2 to 28. Blood samples were collected on d 0, 1, 4, 8, 15, 22, and 29 for determination of acute-phase protein concentrations. A treatment × day interaction was detected for haptoglobin (P < 0.01) because PF-fed heifers had decreased haptoglobin concentrations compared with NF-fed heifers on d 1, 4, and 8. No other treatment effects were detected. Data from this study indicate that PUFA reduces haptoglobin concentrations in beef calves after transport and feedlot entry when supplemented before and after transportation. Further, PUFA supplementation during the feedyard only appears to negatively affect cattle performance by decreasing ADG and DMI.
进行了两项实验，以评估瘤胃保护性 PUFA 补充剂对经过卡车运输和进入饲料场的肉牛犊在性能和炎症指标方面的影响。在实验 1 中，30 头断奶的布拉福德公牛（BW=218±4.3kg）在商业拖车中经过 24 小时的运输，行驶了 1600 公里，并被运送到一个饲料场（d0）。到达（d1）时，根据 BW 对牛进行分层，并分配接受 3 种处理之一（10 头牛/处理），包括不含补充脂肪的谷物型浓缩饲料（NF），或添加瘤胃保护性 SFA（SF；以干物质为基础，占 2.1%）或 PUFA 源（PF；以干物质为基础，占 2.5%）。为计算 ADG，在 d1 和 30 时确定收缩 BW。从 d2 到 28 时记录个体 DMI。在 d0、1、4、8、15、22 和 29 时采集血液样本，以确定急性期蛋白浓度。与 NF 喂养的牛相比（分别为 2.32%和 2.72%BW，0.78 和 1.07kg/d），PF 喂养的牛的平均 DMI 降低（P=0.04），并且 ADG 趋于降低（P=0.07）。未检测到其他处理效果。在实验 2 中，48 头断奶的婆罗门杂交小母牛（BW=276±4.6kg）在运输前（d-30 至 0）根据初始 BW 进行分层，并随机分配到 6 个围场（每围场 8 头）。围场（以 DM 为基础）随机分配（3 个围场/处理）每天接受 NF 的 3.0kg/头或每天含有 5.7%（以干物质为基础）瘤胃保护性 PUFA 源（PF）的浓缩物 2.5kg/头。在 d0 时，按照实验 1 的方式对小母牛进行运输。到达（d1）时，随机选择 24 头小母牛（12 头/处理），放入单独的饲养栏中，并分配相同的预运输处理。在 d-30、1 和 30 时记录收缩 BW，以确定 ADG。从 d2 到 28 时每天记录个体 DMI。在 d0、1、4、8、15、22 和 29 时采集血液样本，以确定急性期蛋白浓度。由于 PF 喂养的小母牛在 d1、4 和 8 时的 haptoglobin 浓度低于 NF 喂养的小母牛，因此检测到处理×天的交互作用（P<0.01）。未检测到其他处理效果。本研究的数据表明，PUFA 可降低运输和进入饲料场后的肉牛犊的 haptoglobin 浓度，在运输前后补充 PUFA。此外，在饲料场仅补充 PUFA 似乎会通过降低 ADG 和 DMI 来负面影响牛的性能。
