Effects of dairy cow genotype with two planes of nutrition on energy partitioning between milk and body tissue.
Effects of dairy cow genotype with two planes of nutrition on energy partitioning between milk and body tissue.
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DOI：
10.3168/jds.s0022-0302(06)72170-1
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发表时间：
2006-03
影响因子：
3.5
通讯作者：
T. Yan;C. Mayne;T. Keady;R. E. Agnew
中科院分区：
文献类型：
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作者：
T. Yan;C. Mayne;T. Keady;R. E. Agnew
本研究中使用的数据来自一项2（基因型）× 2（营养平面）因子设计生产研究，使用荷尔斯坦-弗里西亚奶牛（n = 32）和挪威奶牛（n = 32），在泌乳1至44周期间提供草料青饲料。在泌乳第200天，高营养饲粮的精料夹杂物（g/kg干物质）分别为600、500和400，低营养饲粮的精料夹杂物（g/kg干物质）为300、200和100。分别于泌乳第80、160和240天在量热室中测定饲粮代谢能（ME）浓度，并将其应用于生产数据中计算代谢能摄入量。从泌乳第1周到第44周，无论营养水平如何，荷斯坦-弗里西奶牛的累积活重和体况评分均低于挪威奶牛，代谢能摄入量和乳能量输出均高于挪威奶牛。与挪威奶牛相比，荷斯泰因-弗里谢奶牛在泌乳早期和中期的产奶量与代谢能摄入的比例显著高于挪威奶牛，但在泌乳后期的增幅不显著。相比之下，荷斯泰因-弗里西亚奶牛在泌乳早期分配到身体组织的代谢能比例显著低于挪威奶牛，尽管在泌乳中期和后期差异不显著。当考虑代谢能摄入量和用于维持、乳汁和身体组织的能量时，在整个哺乳期间，提供高精日粮或低精日粮的2种基因型的泌乳代谢能利用效率相似。综上所述，荷斯泰因-弗里西亚奶牛比挪威奶牛能产生更多的乳能，这主要是由于代谢能摄入量更高，而且荷斯泰因-弗里西亚奶牛更有能力将更多的能量分配到牛奶中，而较少的能量分配到身体组织中。对能量分配的影响主要发生在泌乳早期和中期，在高精料日粮中尤为明显。
The data used in the present study were derived from a 2 (genotype) x 2 (plane of nutrition) factorial design production study using Holstein-Friesian (n = 32) and Norwegian (n = 32) first-lactation dairy cattle offered grass silage-based diets from 1 to 44 wk of lactation. The high nutrition diet had concentrate inclusions (g/kg of dry matter) of 600, 500, and 400 for lactation days of 200, respectively, and the low nutrition diet included concentrates at 300, 200, and 100 for the same periods. Dietary metabolizable energy (ME) concentrations were measured in calorimetric chambers at lactation d 80, 160, and 240 respectively, and then applied to production data to calculate ME intake. From wk 1 to 44 of lactation, Holstein-Friesian cows had a consistently lower accumulated live weight gain and body condition score, and a consistently higher ME intake and milk energy output than Norwegian cows, irrespective of the plane of nutrition. Compared with Norwegian cows using mean data derived from the 2 planes of nutrition, Holstein-Friesian cows produced a significantly higher proportion of milk energy output over ME intake in early and mid lactation, although this increase was not significant in late lactation. In contrast, Holstein-Friesian cows partitioned a significantly lower proportion of ME intake into body tissue than Norwegian cows in early lactation, although the differences were not significant in mid or late lactation. When ME intake and energy used for maintenance, milk, and body tissue were taken into account, the efficiency of ME use for lactation was similar between the 2 genotypes offered the high or low concentrate diet during the whole lactation. It is concluded that Holstein-Friesian cows can produce more milk energy than Norwegian cows, mainly as a result of higher ME intake and because of a greater ability to partition more energy into milk and less into body tissue. The effect on energy partitioning mainly occurs in early and midlactation and is particularly evident with high concentrate diets.