Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada; Trouw Nutrition R&D, 3800 AG Amersfoort, the Netherlands.
Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada.
J Dairy Sci. 2022 May;105(5):4692-4710. doi: 10.3168/jds.2022-20880a.
The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.
初乳中特定的脂肪酸（FA）谱可能表明新生儿牛有生物学需求。本研究的目的是描述初乳、过渡乳和成熟乳中脂肪酸（FA）谱和产率在初产（PP）和经产（MP）奶牛中的特征。从 10 头饲喂相同产前和产后日粮的荷斯坦初产和经产奶牛中采集初乳。第 2 至 5 次和第 12 次挤奶分别称为过渡乳和成熟乳。总体而言，初乳中的短链 FA（C4:0 和 C6:0）比成熟乳分别低 61%和 50%。还存在产次和挤奶次数的互作，PP 奶牛在第 2 次挤奶时 C4:0 更高，而 MP 奶牛在第 12 次挤奶时 C4:0 更高。此外，PP 奶牛在第 2 至 4 次挤奶时 C6:0 浓度更高，而 MP 奶牛在第 12 次挤奶时 C6:0 浓度更高。棕榈酸（C16:0）和豆蔻酸（C14:0）在初乳中的含量分别比成熟乳高 38%和 19%。然而，总饱和脂肪酸相对稳定。支链脂肪酸（BCFA）在初乳中的含量比成熟乳低 13%，在整个挤奶期间 PP 奶牛的含量比 MP 奶牛高。在整个挤奶期间，PP 奶牛的反式单不饱和脂肪酸（MUFA）比例高 72%，而初乳中的 MUFA 比成熟乳低 13%。相比之下，顺式 MUFA 和总 MUFA不受挤奶次数和产次的影响。亚油酸（LA）在初乳中的含量比过渡乳和成熟乳高 25%，但α-亚麻酸（ALA）没有差异。因此，初乳中 LA 与 ALA 的比例比成熟乳高 29%，比 MP 奶牛高 33%。MP 奶牛中的亚油酸也高 15%，而 PP 奶牛中的 ALA 高 15%。共轭亚油酸（CLA，cis-9，trans-11）在 PP 奶牛中的含量高 2.7 倍，且初乳和成熟乳之间未检测到差异。总的来说，n-6 和 n-3 系列多不饱和脂肪酸（PUFA）在初乳中的含量比过渡乳和成熟乳高 40%以上。在 ARA、EPA、DPA、DHA 和总 n-3 PUFA 中，存在产次和挤奶次数的互作，表明 PP 奶牛在第 1 至 3 次挤奶时比例较高，而 MP 奶牛在整个挤奶期间比例相对稳定。尽管随后的挤奶次数中牛奶产量增加，但初乳中 EPA、ARA、DPA 和 DHA 的产量仍高于成熟乳。初乳中 n-3 和 n-6 FA 的比例和产量更高，可能对新生牛犊有特殊需求。PP 和 MP 奶牛之间也存在差异，这可能反映了不同的营养需求和分配。
