Center for Nutrition and Pregnancy, Department of Animal Sciences, North Dakota State University, Fargo, ND 58108, USA.
J Anim Sci. 2011 May;89(5):1627-39. doi: 10.2527/jas.2010-3394.
The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed individually from d 40, and lambs were removed at parturition. Colostrum was milked from all ewes at 3 h postpartum, and one-half of the ewes (n = 42) were transitioned to a common diet meeting lactation requirements and mechanically milked for 20 d. Colostrum yield was greater (P = 0.02) for HSe ewes than ASe, whereas CON had greater (P < 0.05) colostrum yield than RES and HIH. Colostrum Se (%) was greater (P < 0.01) for HSe than ASe. Colostrum from ewes fed HSe had less (P = 0.03) butterfat (%), but greater (P ≤ 0.05) total butterfat, solids-not-fat, lactose, protein, milk urea N, and Se than ASe. Colostrum from HIH ewes had greater (P ≤ 0.02) solids-not-fat (%) than RES, whereas RES had greater (P ≤ 0.04) butterfat (%) than CON and HIH. Colostrum from ewes fed the CON diet had greater (P = 0.01) total butterfat than HIH. Total solids-not-fat, lactose, and protein were greater (P < 0.05) in colostrum from CON than RES and HIH. Ewes fed HSe had greater (P < 0.01) milk yield (g/d and mL/d) than ASe, and CON and HIH had greater (P < 0.01) yield than RES. Milk protein (%) was greater (P ≤ 0.01) in RES compared with CON or HIH. Ewes fed HSe had greater (P < 0.01) milk Se (µg/g and mg/d) than ASe on each sampling day. Milk from CON and HIH ewes had greater (P < 0.01) total solids-not-fat, lactose, protein, and milk urea N than RES. Total Se was greater (P = 0.02) in milk from ewes fed the CON diet compared with RES. Somatic cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.
本研究旨在探究妊娠期间营养水平和硒供应对初产母羊初乳和奶产量及营养成分的影响。选用 84 只 240 ± 17 d 龄、52.1 ± 6.2 kg 的罗姆尼羔羊，采用 2×3 因子设计，分为 6 个处理，分别为硒处理（适量硒（ASe，11.5 µg/kg BW）或高硒（HSe，77.0 µg/kg BW））和营养水平处理（60%（RES）、100%（CON）或 140%（HIH））。从妊娠第 40 天开始，母羊分别接受相应处理，羔羊于分娩时断奶。从妊娠第 40 天开始，母羊单独饲养，产羔后 3 h 挤奶，其中一半母羊（n = 42）转为满足泌乳需求的共同日粮，并进行机械挤奶 20 d。HSe 组母羊的初乳产量（P = 0.02）大于 ASe 组，而 CON 组的初乳产量（P < 0.05）大于 RES 和 HIH 组。HSe 组初乳的硒含量（%）高于 ASe 组（P < 0.01）。HSe 组初乳的乳脂（%）较低（P = 0.03），但总乳脂（%）、非脂固形物、乳糖、蛋白质、乳尿素氮和硒含量（P ≤ 0.05）较高。HIH 组的非脂固形物含量（%）高于 RES 组（P ≤ 0.02），而 RES 组的乳脂含量（%）高于 CON 和 HIH 组（P ≤ 0.04）。CON 组初乳的总乳脂含量（%）高于 HIH 组（P = 0.01）。CON 组的总非脂固形物、乳糖和蛋白质含量（%）均高于 RES 和 HIH 组（P < 0.05）。HSe 组的产奶量（g/d 和 mL/d）高于 ASe 组（P < 0.01），CON 和 HIH 组的产奶量（g/d 和 mL/d）均高于 RES 组（P < 0.01）。RES 组的乳蛋白（%）高于 CON 或 HIH 组（P ≤ 0.01）。HSe 组的初乳硒含量（µg/g 和 mg/d）在各个采样日均高于 ASe 组（P < 0.01）。CON 和 HIH 组的非脂固形物、乳糖、蛋白质和乳尿素氮含量（%）均高于 RES 组（P < 0.01）。CON 组的总硒含量（P = 0.02）高于 RES 组。CON 组的体细胞计数和总体细胞数（%）均高于 RES 组（P ≤ 0.05）。产奶量（g 和 mL）存在日的立方效应（P ≥ 0.01）。乳脂、非脂固形物、乳糖、乳尿素氮和硒浓度对日呈二次响应（P ≤ 0.01）。蛋白质（%）、总乳脂和总硒以及体细胞数（细胞/mL 和细胞/d）呈线性下降（P < 0.01）。这些结果表明，妊娠期间的营养水平会影响初产母羊的初乳和奶产量及营养成分，即使泌乳期的营养需求得到满足也是如此。
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