López M C, Estellés F, Moya V J, Fernández C
Institute for Animal Science and Technology, Polytechnic University of Valencia, 46022 Valencia, Spain.
J Dairy Sci. 2014 Dec;97(12):7821-32. doi: 10.3168/jds.2014-8424. Epub 2014 Oct 18.
The aim of this study was to assess the effect of substitution of dietary corn grain by dry citrus pulp or soybean hulls on energy and nitrogen partitioning, substrate oxidation, methane emission, and milk performance in dairy goats during midlactation. Twelve multiparous Murciano-Granadina goats of similar body weight (41.7 ± 2.8 kg) were split in 3 groups in an incomplete crossover design. One group of 4 goats was fed a mixed ration with 605 g/kg of dry matter of corn grain (CRG), another group replaced corn grain with dry citrus pulp (CTP), and the last with soybean hulls (SYH). The goats were allocated to individual metabolism cages. After 14 d of adaptation, feed intake, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded by a mobile open-circuit indirect calorimetry system using a head box. Dry matter intake was similar for all 3 groups (1.53 kg/d, on average). Total replacement of the concentrate with fibrous by-products increased fiber apparent digestibility. The metabolizable energy intake was significantly greater for diet CRG than SYH (1,193 vs. 1,079 kJ/kg of BW⁰·⁷⁵, respectively), CTP showed an intermediate value. The heat production was higher for the fiber diet than starchy diet (908 vs. 843 kJ/kg of BW⁰·⁷⁵ for SYH and CRG, respectively). The efficiency of use of metabolizable energy for milk production obtained by regression was 0.59. Goats fed CTP and SYH diets produced similar CH₄ emissions (34.8 g/d, on average), significantly higher compared with goats fed the CRG diet (24.7 g/d). Goats of the 3 treatments were in negative energy balance, so the oxidation of fat was greater than for carbohydrates. No significant differences were observed for milk production (1.72 kg/d), and milk fat was significantly greater for a more fibrous diet compared with a starchy diet (6.57 vs. 4.95% in SYH and CRG, respectively).
本研究的目的是评估用干柑橘渣或大豆皮替代日粮中的玉米对泌乳中期奶山羊能量和氮分配、底物氧化、甲烷排放及产奶性能的影响。采用不完全交叉设计，将12只体重相近（41.7±2.8千克）的经产穆尔西亚纳-格拉纳迪纳奶山羊分为3组。一组4只山羊饲喂含有605克/千克干物质玉米的混合日粮（CRG），另一组用干柑橘渣替代玉米（CTP），最后一组用大豆皮替代玉米（SYH）。将山羊分配到个体代谢笼中。适应14天后，在5天时间内每天记录采食量、粪便和尿液总排出量及产奶量。然后，使用头部面罩通过移动开路间接量热系统记录气体交换测量值。所有3组的干物质采食量相似（平均1.53千克/天）。用纤维副产品完全替代浓缩料提高了纤维表观消化率。日粮CRG的代谢能摄入量显著高于SYH（分别为1193和1079千焦/千克体重⁰·⁷⁵），CTP表现为中间值。纤维日粮的产热量高于淀粉日粮（SYH和CRG分别为908和843千焦/千克体重⁰·⁷⁵）。通过回归得到的用于产奶的代谢能利用效率为0.59。饲喂CTP和SYH日粮的山羊产生的甲烷排放量相似（平均34.8克/天），显著高于饲喂CRG日粮的山羊（24.7克/天）
