中文摘要：

本试验旨在研究围产期添加β-胡萝卜素对中国荷斯坦奶牛泌乳、繁殖性能的影响。选择胎次相同、产奶量、体重和体况评分值相近的中国荷斯坦奶牛36头，随机分为3组。3种处理日粮分别为：对照日粮、处理1日粮（对照日粮＋300mg β-胡萝卜素／（头·天））、处理Ⅱ日粮（对照日粮＋600mg β-胡萝卜素／（头·天））。预试期15d，试验期120d。结果表明，在奶牛额外添加VA 150000 IU／d的情况下，每头奶牛添加β-胡萝卜素300或600mg／d，对前3个泌SLB的牛奶成分以及乳中体细胞数没有显著的影响（P〉0.05）。但在产后3个月，对照组自然产奶量和标准乳逐月降低，而添加β-胡萝卜素组的自然产奶量和校正乳产量都有不同程度的提高。β-胡萝卜素的添加提高了血浆中β-胡萝卜素和VA的浓度（P〉0．05）；在产后8～12周，添加β-胡萝卜素300mg／d，显著提高了牛奶中β-胡萝卜素的含量（P〈0．01）。在产后1～3月期间，奶牛额外添加VA 150000IU／d同时添加β-胡萝卜素，降低了胎衣不下、子宫炎和乳房炎的发病率。在围产期β-胡萝卜素的添加提高了产奶量，提高了血浆中β-胡萝卜素和VA的浓度，提高了牛奶中β-胡萝卜素浓度，降低了胎衣不下、子宫炎和乳房炎的发病率。

英文摘要：

To study the effect of the addition of β-Carotene in experimental diets on lactating and reproduction performance. Thirty-six head of Holstein cows were selected according to the principle of same parity, similar milk production, body weight and body condition score. The cows were randomly divided into three groups., control group （basic diet ＋ 150 000 IU VA/ （head · day） ） ;treatment Ⅰ （control diet ＋ 300 mg β-carotene） ;reatment Ⅱ （control diet ＋ 600 mg β-carotene）. The trial last for 15 days for adaptation,and for 120 days for sampling. The results showed that there was no difference in milk composition and somatic cell counts of first 3-month postpartum between TRT Ⅰ ,TRT Ⅱ and CK when cows were fed with vitamin A at the level of 150 000 IU/d and supplemented with β-carotene at the level of 300 or 600 mg/d for each cow. After 3 months of postparturiency,the milk yield and fat-corrected milk yield were decreased in control group animals,but increased in the lactating cows for two β-carotene treatment groups. Supplementation of β-carotene resulted in an increased concentration of β-carotene and vitamin A in plasma when β-carotene was added to the diet at the level of 150,000 IU VA/（d ·cow） （P〉0. 05）. From 1 to 3 month of postparturiency, the incidence of retained placenta, hysteritis and mastitis was significantly decreased due to the addition of β-carotene to the diet of cows. Supplementation of β-carotene resulted in an increased milk production,increased concentration of β-carotene and vitamin A in plasma,increased concentration of β-carotene in milk,decreased incidence of retained placenta, hysteritis and mastitis.