Moallem U, Katz M, Arieli A, Lehrer H
Department of Dairy Cattle, Institute of Animal Sciences, Volcani Center, P.O. Box 6, Bet-Dagan, 50250 Israel.
J Dairy Sci. 2007 Aug;90(8):3846-56. doi: 10.3168/jds.2007-0092.
Dry multiparous cows were used to investigate the effects on intake, production, and metabolism of either a supplement containing 55% dry propylene glycol (PGLY), a prilled fat supplement (PrFA) containing a low proportion of unsaturated fatty acids (FA), or calcium soaps of FA supplement (CaLFA) containing a high proportion of unsaturated FA. Fifty-three dry cows (256 d pregnant) were stratified into 4 groups and began one of the following dietary treatments: 1) control cows were fed a dry cow diet and at postpartum were fed a lactating cow diet; 2) diets of cows in the PGLY group were supplemented with 500 g/d per cow of dry PGLY until 21 d in milk (DIM); 3) diets of cows in the PrFA group were supplemented with 230 g/d per cow of PrFA until 100 DIM; 4) diets of cows in the CaLFA group were supplemented with 215 g/d per cow of CaLFA until 100 DIM. Prepartum DMI was lower in the PrFA and CaLFA groups than in the control and PGLY groups, whereas postpartum DMI in the PrFA group was higher than that in the control group. Milk production until 100 DIM in both fat-supplemented groups was 4.5% higher than that in the control group. Plasma glucose concentrations pre- and postpartum were higher in the PGLY group than in the PrFA and CaLFA groups, but were similar to those in the control group. Prepartum nonesterified FA (NEFA) concentrations in plasma were increased by 43 and 70% in the PrFA and CaLFA groups, respectively, as compared with the control and PGLY groups. Both fat supplements increased plasma beta-hydroxybutyrate concentrations over those of the PGLY and control groups pre- and postpartum. Peripartum plasma insulin concentrations in the control group were 1.7-fold higher than in the PrFA group and 2.1-fold higher than in the CaFA group. Differences between the PrFA and CaLFA groups were observed: DMI was higher pre- and postpartum in the PrFA group than in the CaLFA group, and prepartum plasma NEFA concentrations were 19% higher and insulin concentrations were 21% lower in the CaLFA group than in the PrFA group. No significant differences were observed in DMI, plasma glucose, NEFA, and beta-hydroxybutyrate concentrations between the control and PGLY groups. Feeding fat to cows during late pregnancy decreased the DMI and negatively affected the metabolic status of the cows, as reflected by plasma metabolites. Furthermore, protected fat with a high proportion of unsaturated FA (CaLFA) was more pronounced in increasing plasma NEFA concentrations and depressing plasma insulin concentrations than fat with a low proportion of unsaturated FA (PrFA).
选用经产干奶牛研究含55%干丙二醇（PGLY）的补充剂、含低比例不饱和脂肪酸（FA）的颗粒脂肪补充剂（PrFA）或含高比例不饱和FA的FA钙皂补充剂（CaLFA）对采食量、产奶量和代谢的影响。53头干奶牛（怀孕256天）被分为4组，开始以下饮食处理之一：1）对照组奶牛在干奶期饲喂干奶牛日粮，产后饲喂泌乳奶牛日粮；2）PGLY组奶牛的日粮中每头奶牛每天补充500克干PGLY，直至产奶21天（DIM）；3）PrFA组奶牛的日粮中每头奶牛每天补充230克PrFA，直至100 DIM；4）CaLFA组奶牛的日粮中每头奶牛每天补充215克CaLFA，直至100 DIM。PrFA组和CaLFA组的产前干物质采食量（DMI）低于对照组和PGLY组，而PrFA组的产后DMI高于对照组。两个补充脂肪组直至100 DIM的产奶量比对照组高4.5%。PGLY组产前和产后的血浆葡萄糖浓度高于PrFA组和CaLFA组，但与对照组相似。与对照组和PGLY组相比，PrFA组和CaLFA组产前血浆中非酯化脂肪酸（NEFA）浓度分别增加了43%和70%。两种脂肪补充剂在产前和产后均使血浆β-羟基丁酸酯浓度高于PGLY组和对照组。对照组围产期血浆胰岛素浓度比PrFA组高1.7倍，比CaFA组高2.1倍。观察到PrFA组和CaLFA组之间存在差异：PrFA组产前和产后的DMI高于CaLFA组，CaLFA组产前血浆NEFA浓度比PrFA组高19%，胰岛素浓度比PrFA组低21%。对照组和PGLY组在DMI、血浆葡萄糖、NEFA和β-羟基丁酸酯浓度方面未观察到显著差异。在妊娠后期给奶牛饲喂脂肪会降低DMI，并对奶牛的代谢状态产生负面影响，这从血浆代谢物中可以反映出来。此外，与含低比例不饱和FA的脂肪（PrFA）相比，含高比例不饱和FA的保护脂肪（CaLFA）在增加血浆NEFA浓度和降低血浆胰岛素浓度方面更为明显。
