文献类型： 外文期刊

作者： Girma, D. D. ¹ ; Ma, L. ¹ ; Wang, F. ¹ ; Jiang, Q. R. ¹ ; Callaway, T. R. ³ ; Drackley, J. K. ⁴ ; Bu, D. P. ¹ ;

作者机构： 1.Chinese Acad Agr Sci, Inst Anim Sci, State Key Lab Anim Nutr, Beijing 100193, Peoples R China

2.CAAS, World Agroforestry Ctr, Joint Lab Agroforestry & Sustainable Anim Husb, ICRAF,East & Cent Asia, Beijing 100193, Peoples R China

3.Univ Georgia, Dept Anim & Dairy Sci, Athens, GA 30602 USA

4.Univ Illinois, Dept Anim Sci, Urbana, IL 61801 USA

5.Hunan Coinnovat Ctr Safety Anim Prod, Changsha 410128, Hunan, Peoples R China

关键词： dietary energy; rumen-protected lysine; beta-hydroxybutyrate; transition cow

期刊名称：JOURNAL OF DAIRY SCIENCE （ 影响因子：4.034； 五年影响因子：4.354 ）

ISSN： 0022-0302

年卷期： 2019 年 102 卷 8 期

页码：

收录情况： SCI

摘要： The objective of this study was to investigate the effects of dietary energy levels and rumen-protected lysine supplementation on serum free fatty acid levels, beta-hydroxybutyrate levels, dry matter (DM) intake, and milk production and composition. Treatments were arranged in a 2 x 2 factorial design with 2 dietary energy levels [high net energy for lactation (NEL) = 1.53 Mcal/kg of DM vs. low NEL = 1.37 Mcal/kg of DM; HE vs. LE) fed either with rumen-protected lysine (bypass lysine; 40 g/cow per day) or without rumen-protected lysine (control). Sixty-eight third-lactation Holstein dairy cows entering their fourth lactation were randomly allocated to 4 treatments groups: HE with bypass lysine, HE without bypass lysine, LE with bypass lysine, and LE without bypass lysine. Groups were balanced based upon their expected calving date, previous milk yields, and body condition score. All cows were fed the same diet (NEL = 1.34 Mcal/kg of DM) during the dry period prior to the trial. Rumen-protected lysine was top-dressed on a total mixed ration to deliver 9.68 g/d of metabolizable lysine to pre- and postpartum cows. After calving, all cows received the same TMR (1.69 Mcal/kg of DM). Blood samples were collected at -21, -14, -7, 0, 3, 7, 14, and 21 d relative to calving, and free fatty acids and beta-hydroxybutyrate concentrations were measured. Amount of feed offered and orts were collected and measured for individual cows 4 d/wk. Milk samples were collected once per week following calving, and milk composition was analyzed. Feeding high NEL to close-up cows decreased the concentrations of free fatty acid and beta-hydroxybutyrate in prepartum cows but not in postpartum cows. Addition of rumen-protected lysine increased postpartum DM intake, and decreased serum free fatty acid and beta-hydroxybutyrate concentrations. Neither energy nor rumen-protected lysine supplementation nor their interaction affected milk yield or fat or lactose yields. However, cows in the group receiving HE with bypass lysine tended to produce more milk compared with other groups and had a lower blood beta-hydroxybutyrate concentration postpartum. These results indicate that feeding a high-energy diet together with rumen-protected lysine improved DM intake and lowered serum free fatty acid and beta-hydroxybutyrate concentrations in transition cows.