Department of Dairy and Animal Science, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Dairy Sci. 2011 Aug;94(8):4057-74. doi: 10.3168/jds.2011-4283.
The objective of this experiment was to investigate the effects of replacing conventional, solvent-extracted canola meal (control; CTRL) with high oil content; conventional, mechanically extracted canola meal (CMEC); high-oleic, low polyunsaturated fatty acid (FA) canola meal (HOLL); and high-erucic acid, low-glucosinolate rapeseed meal (RPS) on rumen function, digestibility, milk production, and milk FA composition in lactating dairy cows. The experimental design was a replicated 4×4 Latin square with 8 lactating dairy cows. Four of the cows were ruminally cannulated. All oilseed meals were included at approximately 12 to 13% of dietary dry matter (DM). Crude protein and fat concentrations (% of DM) of the meals were 43 and 3.1%, 32.8 and 16.1%, 45.2 and 13.7%, and 34.3 and 17.9% for CTRL, CMEC, HOLL, and RPS, respectively. All diets were formulated to supply net energy of lactation in excess of requirements. The CMEC and RPS diets were predicted to be about 1% deficient in metabolizable protein. Relative to the CTRL, inclusion of high-oil seed meals in the diet lowered ruminal acetate concentration and the molar acetate:propionate ratio and decreased DM intake. Milk yield generally followed DM intake and was lower for CMEC and RPS than the CTRL. Treatments had no effect on milk composition, other than an increase in milk urea nitrogen concentration for HOLL. Fat-corrected milk (3.5%) feed efficiency was increased by HOLL and RPS compared with CTRL. Urinary urea nitrogen losses were increased by HOLL, which, as a consequence, increased the ammonia-emitting potential of manure. The ratio of milk N-to-N intake was greater for CMEC and RPS. Replacing solvent-extracted canola meal with the high-oil meal decreased milk fat 12:0, 14:0, 16:0, and total saturated FA content and enhanced cis-9 18:1 and total monounsaturated FA concentrations. Relative to the CTRL, canola increased total trans FA in milk, whereas inclusion of HOLL in the diet increased trans-11 18:1 and cis-9, trans-11 CLA content. The RPS increased milk fat cis-13 22:1 content from 0.07 to 2.33 g/100g of FA. In conclusion, HOLL or RPS, which are likely to come from small-scale biodiesel plants where oil is cold pressed without hexane extraction, fed at levels at or above 12 to 13% of dietary DM may decrease feed intake and milk production, but can be used to alter milk FA composition in lactating dairy cows.
本实验的目的是研究用高油含量的传统溶剂浸提的油菜籽粕（对照；CTRL）代替常规、机械提取的油菜籽粕（CMEC）、高油酸、低多不饱和脂肪酸（FA）油菜籽粕（HOLL）和高芥酸、低硫代葡萄糖苷油菜籽粕（RPS）对泌乳奶牛瘤胃功能、消化率、产奶量和乳脂肪酸组成的影响。实验设计为 8 头泌乳奶牛的重复 4×4 拉丁方设计。其中 4 头奶牛进行了瘤胃套管。所有油籽粕的添加量约占日粮干物质（DM）的 12%至 13%。对照、CMEC、HOLL 和 RPS 的粗蛋白和脂肪浓度（DM%）分别为 43%和 3.1%、32.8%和 16.1%、45.2%和 13.7%和 34.3%和 17.9%。所有日粮均按提供超过泌乳净能需求的水平配制。CMEC 和 RPS 日粮预测代谢蛋白缺乏约 1%。与对照相比，日粮中添加高油籽粕降低了瘤胃乙酸浓度和乙酸：丙酸摩尔比，并降低了干物质采食量。产奶量通常与干物质采食量相关，CMEC 和 RPS 的产奶量低于对照。除 HOLL 组的乳尿素氮浓度升高外，处理对乳成分没有影响。与对照相比，HOLL 和 RPS 提高了脂肪校正奶（3.5%）的饲料效率。HOLL 增加了尿尿素氮的损失，从而增加了粪便的氨排放潜力。CMEC 和 RPS 的乳氮与氮摄入量之比更大。用高油油菜籽粕代替溶剂浸提的油菜籽粕降低了乳中 12:0、14:0、16:0 和总饱和脂肪酸含量，并增加了顺式-9 18:1 和总单不饱和脂肪酸浓度。与对照相比，油菜籽增加了乳中总反式脂肪酸，而日粮中添加 HOLL 增加了反式-11 18:1 和顺式-9、反式-11 CLA 的含量。RPS 将乳脂肪中顺式-13 22:1 的含量从 0.07 增加到 100g 脂肪酸中的 2.33g。总之，在日粮 DM 中添加水平在 12%至 13%或以上的 HOLL 或 RPS，可能会降低饲料采食量和产奶量，但可以用于改变泌乳奶牛乳脂肪酸组成，HOLL 或 RPS 可能来自于小规模生物柴油厂，这些工厂在没有己烷提取的情况下进行冷榨，获得油。
