Spray-dried plasma protein (SDP) compared with blood meal (BM) may contain various functional and active components that may benefit animal health. The objective of this experiment was to investigate the effects of feeding SDP or BM on production and blood profile in dairy cows during the transition and early-lactation periods. Seventy-two Holstein cows at 14 d before calving were used in a randomized block design. During the prepartum period, cows were fed a typical late-gestation diet containing BM (100 g/cow per day; 100BM, n = 24) or SDP (100 g/cow per day; 100SDP; n = 48). After calving, cows that were fed BM prepartum were fed a typical lactation diet formulated to provide 100 g/d of BM (100BM). Half the cows that were fed 100SDP prepartum were fed a lactation diet formulated to provide 100 g/d of SDP (100SDP; n = 24), and half were fed a diet formulated to provide 400 g/d of SDP (400SDP; n = 24) on a dry matter basis where SDP replaced BM (100SDP) or BM and soybean products (400SDP). All diets were balanced for crude protein concentration and metabolizable protein supply assuming BM and SDP were equal in rumen-degradable protein and rumen-undegradable protein. All data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) as a randomized block design where contrasts were made for 100BM versus 100SDP for prepartum variables and 100BM versus 100SDP and 100SDP versus 400SDP for postpartum variables. Prepartum supplementation of SDP had no effect on plasma fatty acids and β-hydroxybutyrate (2 d before calving). Plasma fatty acids (255 ± 29 µEq/mL) and β-hydroxybutyrate (675 ± 70 µmol/L) at 8 and 14 d of lactation were not affected by SDP in the diet. Feeding SDP at 100 g/d compared with 100BM increased or tended to increase milk fat, protein, and lactose contents for 16 wk after parturition. Providing SDP at 400 g/d in the diet increased milk yield (42 vs. 39 kg/d), energy-corrected milk (44 vs. 41 kg/d), energy-corrected milk per kilogram of dry matter intake, and yields of milk fat (1.60 vs. 1.48 kg/d), protein (1.21 vs. 1.16 kg/d), and lactose compared with 100SDP. Body weight losses tended to be lower for 100SDP compared with 100BM without a difference between 100SDP and 400SDP. Plasma histidine concentration (d 14 of lactation) was lower for SDP compared with 100BM. In addition, plasma 1-methyl-l-histidine tended to be lower as inclusion rate of SDP increased. In conclusion, SDP at 400 g/d increased milk and milk component yields without an increase in feed intake. Studies evaluating effects of functional and active compounds in SDP on gut microbiome, gut health, and immune functions may be needed to determine mode of action.

与血粉（BM）相比，喷雾干燥的血浆蛋白（SDP）可能包含各种有益于动物健康的功能和活性成分。本实验的目的是研究在过渡期和哺乳期饲喂SDP或BM对奶牛生产和血液状况的影响。在产犊前14天，将72头荷斯坦奶牛用于随机区组设计。在产前期间，给奶牛饲喂典型的后期妊娠饲料，其中含有BM（每天100克/牛； 100BM，n = 24）或SDP（每天100克/牛； 100SDP； n = 48）。产犊后，给产前BM饲喂的奶牛饲喂典型的泌乳日粮，配制为提供100 g / d的BM（100BM）。喂养100SDP产前奶牛的一半饲喂配方为提供100 g / d SDP的泌乳日粮（100SDP； n = 24），半数的日粮以干物质为基础提供400 g / d的SDP（400SDP； n = 24），其中SDP替代了BM（100SDP）或BM和大豆产品（400SDP）。假设BM和SDP在瘤胃可降解蛋白和瘤胃不可降解蛋白中相等，则所有日粮的粗蛋白浓度和可代谢蛋白供应均保持平衡。使用SAS（SAS Institute Inc.，Cary，NC）的MIXED程序作为随机区组设计分析所有数据，其中对产前变量的100BM与100SDP进行对比，对产后变量对100BM对比100SDP和100SDP与400SDP进行对比。产前补充SDP对血浆脂肪酸和β-羟基丁酸酯（产犊前2 d）没有影响。饮食中的SDP不会影响哺乳期8和14 d的血浆脂肪酸（255±29 µEq / mL）和β-羟基丁酸酯（675±70 µmol / L）。分娩后16周，与100 BM相比，以100 g / d的剂量喂食SDP会增加或趋于增加乳脂，蛋白质和乳糖含量。在日粮中提供SDP 400 g / d可以增加牛奶产量（42 vs. 39 kg / d），能量校正的牛奶（44 vs. 41 kg / d），每千克干物质摄入量的能量校正的牛奶和单产与100SDP相比，牛奶脂肪（1.60 vs. 1.48 kg / d），蛋白质（1.21 vs. 1.16 kg / d）和乳糖。与100BM相比，100SDP的体重减轻趋于降低，而100SDP和400SDP之间没有差异。与100BM相比，SDP的血浆组氨酸浓度（哺乳期d 14）更低。此外，血浆1-甲基- 分娩后16周，与100 BM相比，以100 g / d的剂量喂食SDP会增加或趋于增加乳脂，蛋白质和乳糖含量。在日粮中提供400克/天的SDP可以增加牛奶产量（42比39公斤/天），能量校正的牛奶（44比41公斤/天），每公斤干物质摄入量的能量校正的牛奶和单产与100SDP相比，牛奶脂肪（1.60 vs. 1.48 kg / d），蛋白质（1.21 vs. 1.16 kg / d）和乳糖。与100BM相比，100SDP的体重减轻趋于降低，而100SDP和400SDP之间没有差异。与100BM相比，SDP的血浆组氨酸浓度（哺乳期d 14）更低。此外，血浆1-甲基- 分娩后16周，与100 BM相比，以100 g / d的剂量喂食SDP会增加或趋于增加乳脂，蛋白质和乳糖含量。在日粮中提供400克/天的SDP可以增加牛奶产量（42比39公斤/天），能量校正的牛奶（44比41公斤/天），每公斤干物质摄入量的能量校正的牛奶和单产与100SDP相比，牛奶脂肪（1.60 vs. 1.48 kg / d），蛋白质（1.21 vs. 1.16 kg / d）和乳糖。与100BM相比，100SDP的体重减轻趋于降低，而100SDP和400SDP之间没有差异。与100BM相比，SDP的血浆组氨酸浓度（哺乳期d 14）更低。此外，血浆1-甲基- 能量校正奶（44 vs. 41 kg / d），每千克干物质摄入量的能量校正奶，乳脂产量（1.60 vs. 1.48 kg / d），蛋白质（1.21 vs. 1.16 kg / d） ，以及乳糖与100SDP的比较。与100BM相比，100SDP的体重减轻趋于降低，而100SDP和400SDP之间没有差异。与100BM相比，SDP的血浆组氨酸浓度（哺乳期d 14）更低。此外，血浆1-甲基- 能量校正奶（44 vs. 41 kg / d），每千克干物质摄入量的能量校正奶，乳脂产量（1.60 vs. 1.48 kg / d），蛋白质（1.21 vs. 1.16 kg / d） ，以及乳糖与100SDP的比较。与100BM相比，100SDP的体重减轻趋于降低，而100SDP和400SDP之间没有差异。与100BM相比，SDP的血浆组氨酸浓度（哺乳期d 14）更低。此外，血浆1-甲基-随着SDP的包合率增加，1-组氨酸趋于降低。总之，以400 g / d的SDP可以增加牛奶和牛奶成分的产量，而不会增加采食量。可能需要开展研究来评估SDP中功能和活性化合物对肠道微生物组，肠道健康和免疫功能的影响，以确定作用方式。