Wagner Lea A, Fritsche Dominik, Gross Josef J, Bruckmaier Rupert M, Wellnitz Olga
Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland.
Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland.
J Dairy Sci. 2023 Apr;106(4):2948-2962. doi: 10.3168/jds.2022-22641. Epub 2023 Feb 22.
Energy and nutrient deficiency in dairy cows in early lactation is considered to contribute to their increased susceptibility to mastitis. We have tested the hypothesis that feeding diets with high contents of either nitrogenic, glucogenic, or lipogenic components in early lactation affects both the endocrine and metabolic status, as well as the mammary immune competence. After calving, cows were fed increasing amounts of concentrate up to 10 kg/d rich in crude protein (nitrogenic, n = 10), glucogenic precursors (glucogenic, n = 11), or lipids (lipogenic, n = 11). In wk 3, one udder quarter was challenged with lipopolysaccharide (LPS) from Escherichia coli. Blood and milk were sampled on the day before LPS challenge (d -1), and on d 0, 1, 2, 3, and 9 after LPS challenge. On the day of LPS challenge additional samples were taken hourly for quarter milk and every 3 h for blood. Urea concentrations were higher in plasma and milk of cows fed the nitrogenic diet. However, plasma concentrations of glucose, cholesterol, triglycerides, β-hydroxybutyrate, nonesterified fatty acids, as well as insulin, glucagon, and insulin-like growth factor-1 were not affected by the different diets. The mammary immune challenge induced a substantial increase of somatic cell count (SCC) in the treated quarter, and a transient decrease of total milk yield and white blood cells similar in all diet groups for one day. The absolute phagocytosis of blood leukocytes was decreased; however, the phagocytosis per cell was increased in glucogenic-fed cows at 6 h after LPS challenge. During mammary inflammation an insulin resistance, shown by increased plasma glucose, insulin, and glucagon, developed similarly in all diet groups. β-hydroxybutyrate and nonesterified fatty acids were decreased at 1 d after LPS challenge in glucogenic-fed cows only. Cholesterol did not change, and triglycerides only decreased significantly in lipogenic-fed cows 6 h after challenge. On d 9 after LPS challenge, SCC and milk yield and metabolic factors were recovered in all groups. In conclusion, the endocrine and metabolic situation, and the immune response to intramammary LPS of dairy cows during early lactation was not substantially influenced by the elevated supply of nitrogenic, glucogenic, or lipogenic components due to the provided feed in this study.
泌乳早期奶牛的能量和营养缺乏被认为会导致其对乳腺炎的易感性增加。我们检验了这样一个假设：在泌乳早期饲喂富含含氮、生糖或生脂成分的日粮会影响内分泌和代谢状态以及乳腺免疫能力。产犊后，给奶牛饲喂逐渐增加量的精饲料，直至达到10千克/天，这些精饲料分别富含粗蛋白（含氮组，n = 10）、生糖前体（生糖组，n = 11）或脂质（生脂组，n = 11）。在第3周，用来自大肠杆菌的脂多糖（LPS）对一个乳房象限进行攻击。在LPS攻击前一天（第-1天）以及LPS攻击后的第0、1、2、3和9天采集血液和乳汁样本。在LPS攻击当天，每小时采集一次乳房象限乳汁样本，每3小时采集一次血液样本。饲喂含氮日粮的奶牛血浆和乳汁中的尿素浓度较高。然而，不同日粮对血浆中的葡萄糖、胆固醇、甘油三酯、β-羟丁酸、非酯化脂肪酸以及胰岛素、胰高血糖素和胰岛素样生长因子-1的浓度没有影响。乳腺免疫攻击导致处理象限的体细胞计数（SCC）大幅增加，并且所有日粮组的总产奶量和白细胞在一天内出现短暂下降。血液白细胞的绝对吞噬作用降低；然而，在LPS攻击后6小时，生糖组奶牛的单个细胞吞噬作用增强。在乳腺炎症期间，所有日粮组血浆葡萄糖、胰岛素和胰高血糖素升高所显示的胰岛素抵抗情况发展相似。仅在生糖组奶牛中，LPS攻击后1天β-羟丁酸和非酯化脂肪酸降低。胆固醇没有变化，仅在生脂组奶牛攻击后6小时甘油三酯显著降低。在LPS攻击后第9天，所有组的SCC、产奶量和代谢因子均恢复。总之，在本研究中，由于所提供的饲料，泌乳早期奶牛的内分泌和代谢状况以及对乳腺内LPS的免疫反应并未受到含氮、生糖或生脂成分供应增加的实质性影响。
