Faculty of Biosciences (BIOVIT), Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway.
UMR1213 Herbivores, Institut National de la Recherche Agronomique (INRA)-Clermont-Theix-Lyon, F-63122 Saint-Genès-Champanelle, France.
J Dairy Sci. 2017 Sep;100(9):7588-7601. doi: 10.3168/jds.2017-12768. Epub 2017 Jul 12.
The objective of this experiment was to examine how supplements of rapeseed oil or palm oil fatty acids would affect milk production and composition, body lipid stores, and energy balance in 30 multiparous goats of Norwegian dairy goat breed. The experiment lasted 230 d, with 1 to 120 d in milk (DIM) for indoor feeding (P1), 120 to 200 DIM for mountain grazing (P2), and 200 to 230 DIM for indoor feeding (P3). Grass silage was fed according to appetite during indoor feeding periods. After an adjustment period (1-60 DIM) when the control diet was given to the goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60-230 DIM) were (1) basal concentrate (control; no added fat); (2) control concentrate with 8% (added on air-dry basis) hydrogenated palm oil enriched with palmitic acid (POFA); and (3) control concentrate with 8% (added on air-dry basis) rapeseed oil (RSO). Individual energy balances based on energy intake and milk production were estimated on 10, 30, 60, 90, 120, 200, and 230 DIM. At the same times, body weight (BW), body condition score (BCS), body mass index, and body tissue stores using computed tomography were monitored. Silage intake was depressed by POFA throughout the experimental period. Reduced BW and body mass index were observed in the POFA and RSO groups, whereas no effect on BCS or body composition was observed throughout lactation. Generally, a minor decrease in BW was observed from 10 to 120 DIM (only 0.6 kg on average) and the total amount of body lipid was reduced by 4.4 kg. During the mountain grazing period, a further reduction in body lipid stores (2.7 kg) was observed, and BW was reduced by 3.9 kg in the same period. The goats mobilized, on average, 72% of their fat reserves during the first 200 DIM. In this period, dietary fat supplementation did not reduce the mobilization of adipose tissue but resulted in greater milk fat yield (2 kg more, on average, compared with the control group). Milk yield was not affected by POFA or RSO supplementation. Milk fat content was higher in the POFA group than in the control and RSO groups. Milk protein and lactose contents were not affected by lipid supplements. In late lactation, a rapid accumulation of fat deposits followed the intense mobilization during the grazing period. Dietary lipid supplements had no effect on milk fat yield at this stage. Milk production depends heavily on the ability to mobilize body lipid stores, and neither POFA nor RSO supplements at rates used in our study affected this mobilization.
本实验的目的是研究油菜籽或棕榈油脂肪酸补充剂如何影响 30 头挪威乳用山羊品种的多胎母羊的产奶量和组成、体脂储存和能量平衡。实验持续 230 天，室内饲养期为 1 至 120 天产奶（DIM）（P1），120 至 200 DIM 为山地放牧（P2），200 至 230 DIM 为室内饲养（P3）。在室内饲养期内，根据食欲给青贮饲料。在给山羊适应期（1-60 DIM）后，将动物分为 3 组，每组 10 只。处理（60-230 DIM）为（1）基础浓缩物（对照；未添加脂肪）；（2）对照浓缩物添加 8%（按风干基础计）氢化棕榈油，富含棕榈酸（POFA）；（3）对照浓缩物添加 8%（按风干基础计）油菜籽油（RSO）。根据能量摄入和产奶量，在 10、30、60、90、120、200 和 230 DIM 时估计个体能量平衡。同时，监测体重（BW）、体况评分（BCS）、身体质量指数和使用计算机断层扫描的身体组织储存。POFA 使青贮饲料的摄入量在整个实验期间受到抑制。POFA 和 RSO 组的 BW 和身体质量指数降低，而整个泌乳期的 BCS 或身体组成均未受影响。一般来说，从 10 到 120 DIM 时 BW 略有下降（平均仅下降 0.6 公斤），总体脂减少 4.4 公斤。在山地放牧期间，进一步观察到体脂储存减少（2.7 公斤），同期 BW 减少 3.9 公斤。山羊在最初的 200 DIM 内平均动员了 72%的脂肪储备。在此期间，脂肪补充饮食并没有减少脂肪组织的动员，但导致更多的乳脂产量（比对照组平均多 2 公斤）。POFA 或 RSO 补充剂对产奶量没有影响。POFA 组的牛奶脂肪含量高于对照组和 RSO 组。乳蛋白和乳糖含量不受脂质补充剂的影响。在泌乳后期，随着放牧期的剧烈动员，脂肪沉积迅速增加。在这个阶段，膳食脂质补充剂对乳脂产量没有影响。产奶量高度依赖于动员体脂储存的能力，而我们研究中使用的 POFA 或 RSO 补充剂均未影响这种动员。
