【摘要】：本試驗(yàn)旨在研究相同日糧結(jié)構(gòu)下,不同物理有效中性洗滌纖維(peNDF)水平對(duì)泌乳牛咀嚼活動(dòng)、瘤胃發(fā)酵以及乳成分的影響。研究選取30頭、2胎次、體重約650 kg、產(chǎn)后120 d、日均產(chǎn)奶量33.2 kg、體況相近的健康荷斯坦奶牛為試驗(yàn)對(duì)象。采用單因素試驗(yàn)設(shè)計(jì),通過控制TMR的攪拌時(shí)間(10 min、18 min和60 min)得到不同peNDF水平的日糧,研究其對(duì)奶牛采食與反芻活動(dòng)、瘤胃發(fā)酵參數(shù)及乳成分等的影響。主要研究結(jié)果如下:1.延長(zhǎng)TMR的攪拌時(shí)間顯著降低日糧中peNDF8.0的含量(P0.01)。以賓州粗飼料顆粒分級(jí)篩進(jìn)行測(cè)定,10 min、18 min和60 min組對(duì)應(yīng)的peNDF8.0含量分別為11.25%、10.56%和9.02%。2.降低日糧peNDF8.0水平顯著增加奶牛的日采食次數(shù)(P0.05),降低剩料中NDF的含量(P0.01)、瘤胃pH(P0.01)、羧甲基纖維素酶(P0.001)、微晶纖維素酶(P=0.018)和β-葡聚糖酶活性(P=0.045),但不影響木聚糖酶的活性(P=0.751)。3.隨peNDF8.0水平的降低,瘤胃總揮發(fā)性脂肪酸無顯著變化;乙酸比例降低(59.92%、58.57%和56.08%,P=0.003);丙酸比例升高(24.91%、26.54%和29.12%,P=0.002);乙丙比降低(2.42、2.26、1.93,P=0.003)。4.降低日糧peNDF8.0水平對(duì)乳脂率、乳蛋白率、乳糖、非脂固形物和乳尿素氮等乳成分均無顯著影響(P0.05)。以上結(jié)果表明,在本試驗(yàn)條件下,保證奶牛健康和較佳瘤胃發(fā)酵的日糧peNDF水平為10.56%,對(duì)應(yīng)的攪拌時(shí)間為18 min。
[Abstract]:The purpose of this study was to study the effects of different physical and effective neutral detergent fiber (peNDF) levels on mastication, rumen fermentation and milk composition of lactating cattle under the same dietary structure. A total of 30 healthy Holstein cows with a body weight of about 650 kg, and a similar daily milk yield of 33.2 kg, were selected. By controlling the stirring time of TMR (10 min,18 min and 60 min), the diets with different peNDF levels were obtained by single factor design. The effects of different peNDF levels on feeding and ruminant activities, rumen fermentation parameters and milk composition of dairy cattle were studied. The main results are as follows: 1. Prolonging the stirring time of TMR significantly reduced the content of peNDF8.0 in diet (P0.01). The contents of peNDF8.0 in 10 min,18 min and 60 min groups were 11.25% and 9.02%, respectively. The decrease of dietary peNDF8.0 level significantly increased the daily intake times of dairy cows (P0.05), decreased the content of NDF, pH (P0.01), carboxymethyl cellulase (P0.001) in rumen, decreased the content of NDF (P0.01), and decreased the level of carboxymethyl cellulase (P0.001) in rumen. The activities of microcrystalline cellulase (P0. 018) and 尾-glucanase (P0. 045) did not affect the activity of Xylanase (P0. 751). 3. With the decrease of peNDF8.0 level, the total volatile fatty acids in rumen did not change significantly, but the ratio of acetic acid decreased (58.57% and 56.08% respectively). The ratio of propionic acid to propionic acid was increased (24.91%, 26.54% and 29.12%, P0. 002), and the ratio of ethylc to c was decreased (2. 42%, 2. 26% and 1. 93% P0. 003). The decrease of dietary peNDF8.0 level had no significant effect on milk composition, such as milk fat rate, milk protein rate, lactose, non-fat solids and milk urea nitrogen (P0.05). The results showed that the dietary peNDF level of healthy and better rumen fermentation of dairy cows was 10.56 and the stirring time was 18 min..
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S823.5

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 信;;牛乳成分、比重，

本文編號(hào)：2333873