Department of Animal Science, University of Nebraska, Lincoln 68583.
Department of Animal Science, University of Nebraska, Lincoln 68583.
J Dairy Sci. 2021 Aug;104(8):8708-8720. doi: 10.3168/jds.2020-19657. Epub 2021 May 28.
Hydrolyzed feather meal (HFM) is a feed that is high in rumen undegradable protein; however, it is low in Lys compared with other high rumen undegradable protein sources. Additionally, processing methods differ by facility, which affects AA composition and protein digestibility. The objective of this study was to use lactating dairy cows to determine the effects of feeding 2 sources of HFM that differed by the amount of blood they contained and also to study the effects of supplementing rumen-protected (RP) Lys when these sources of HFM are fed. In this study, 12 multiparous Jersey cows were enrolled in a triplicated 4 × 4 Latin square with 4 periods 28 d in length. Cows were fed 2 total mixed rations that differed by source of HFM. The HFM was included at 4.5% of the diet dry matter, and one source was produced with the addition of poultry blood. Cows were randomly assigned to 1 of 4 treatment sequences. Treatments were as follows: HFM without added blood and no RP-Lys, HFM with added blood and no RP-Lys, HFM without blood and with RP-Lys (22 g of digestible Lys), and HFM with added blood and RP-Lys. The source of HFM containing blood tended to increase dry matter intake (18.3 vs. 17.3 ± 0.72 kg/d), and increased milk yield (20.5 vs. 18.4 ± 1.31 kg/d) and protein yield (0.788 vs. 0.694 ± 0.040 kg/d). The inclusion of RP-Lys did not affect milk or protein yield. In cows fed HFM containing blood, plasma concentration of Lys (82.1 vs. 70.8 ± 4.06 μM) and His (27.8 vs. 17.9 ± 3.15 μM) was higher. The addition of RP-Lys had no effect on the concentration of either plasma Lys or His. Gross energy intake tended to increase for HFM containing more blood (81.4 vs. 77.3 ± 3.29 Mcal/d); however, no difference was observed for intake of digestible energy (52.0 ± 2.20 Mcal/d) or metabolizable energy (46.4 ± 2.02 Mcal/d). Similar to dry matter intake, N intake increased with the inclusion of HFM containing blood, but crude protein digestibility decreased (61.6 vs. 66.0%). Results of this study highlight that source of HFM can be a factor that affects milk production and that this in part is due to differences in the profile of AA. Additionally, the observation that plasma His and milk protein increased with the consumption of HFM containing more blood suggests that His may have played a role in increasing milk and milk protein yield.
水解羽毛粉（HFM）是一种富含瘤胃未降解蛋白的饲料，但与其他富含瘤胃未降解蛋白的来源相比，其赖氨酸含量较低。此外，不同设施的加工方法不同，这会影响氨基酸组成和蛋白质消化率。本研究旨在利用泌乳奶牛确定 2 种来源的 HFM 的效果，这 2 种来源的 HFM 含有不同量的血液，并且还研究了当添加这些 HFM 来源时补充瘤胃保护（RP）赖氨酸的效果。在这项研究中，12 头荷斯坦奶牛参加了一个三重复 4×4 拉丁方试验，共 4 个为期 28 天的周期。奶牛被喂食 2 种总混合日粮，其来源不同。HFM 占日粮干物质的 4.5%，其中一种来源是在添加禽血的情况下生产的。奶牛随机分配到 4 种处理序列中的 1 种。处理如下：无添加血液且无 RP-赖氨酸、添加血液且无 RP-赖氨酸、无血液且添加 RP-赖氨酸（22 克可消化赖氨酸）和添加血液且添加 RP-赖氨酸。含血 HFM 的来源增加了干物质采食量（18.3 比 17.3±0.72kg/d），并增加了牛奶产量（20.5 比 18.4±1.31kg/d）和蛋白质产量（0.788 比 0.694±0.040kg/d）。添加 RP-赖氨酸并不影响牛奶或蛋白质产量。在喂食含血液 HFM 的奶牛中，血浆赖氨酸（82.1 比 70.8±4.06μM）和组氨酸（27.8 比 17.9±3.15μM）浓度更高。添加 RP-赖氨酸对血浆赖氨酸或组氨酸的浓度没有影响。含更多血液的 HFM 的总能摄入量有增加的趋势（81.4 比 77.3±3.29Mcal/d）；然而，可消化能（52.0±2.20Mcal/d）或代谢能（46.4±2.02Mcal/d）的摄入量没有差异。与干物质摄入量相似，随着含血液 HFM 的添加，氮摄入量增加，但粗蛋白消化率降低（61.6 比 66.0%）。本研究结果强调，HFM 的来源可能是影响牛奶产量的一个因素，部分原因是氨基酸组成的差异。此外，观察到随着血液含量较高的 HFM 的消耗，血浆组氨酸和牛奶蛋白增加，表明组氨酸可能在增加牛奶和牛奶蛋白产量方面发挥了作用。
