Młynek Krzysztof, Wnorowska Kalina, Danielewicz Agata, Natalello Antonio, Puppel Kamila
Institute of Animal Science and Fisheries, University of Siedlce, ul. B. Prusa 14, 08-110 Siedlce, Poland.
Department of Agriculture, Food and Environment, University of Catania, 95123 Catania, Italy.
Int J Mol Sci. 2025 May 1;26(9):4296. doi: 10.3390/ijms26094296.
In lactating dairy cows, negative energy balance (NEB) induces metabolic shifts, including enhanced lipolysis, leading to elevated concentrations of free fatty acids (FFAs) in circulation. Metabolic changes affect milk fat synthesis and the characteristics of milk fat globules (MFGs), particularly their size and distribution. Systemic FFA release inversely correlates with the restoration of the body condition score (BCS), suggesting that recovering the BCS may mitigate the negative effects of NEB on milk fat composition. This study aimed to investigate the relationship between BCS restoration, metabolic burden, and their effects on MFG characteristics in lactating cows. The study was conducted on two dairy farms (F1 and F2) with 80 Holstein-Friesian cows. Cows were grouped according to farm and diet, with average lactation yields of 9653 ± 259 kg (F1) and 9548 ± 341 kg (F2). Milk composition was analyzed, and blood and milk samples were collected at four lactation stages. The results showed a significant correlation between elevated circulating FFA concentrations, resulting from adipose tissue lipolysis during NEB, and alterations in MFG size and distribution. The restoration of BCS was inversely correlated with FFA release, suggesting that improvements in the BCS may mitigate the adverse effects of NEB on milk fat synthesis by regulating lipolysis. Additionally, higher β-hydroxybutyrate (BHBA) levels were associated with a reduction in MFG diameter, indicating disruptions in lipogenesis during metabolic stress. These findings highlight the complex relationship between metabolic stress, BCS restoration, and MFG characteristics, with implications for milk fat synthesis in lactating cows.
在泌乳奶牛中，负能量平衡（NEB）会引发代谢变化，包括增强脂肪分解，导致循环中游离脂肪酸（FFA）浓度升高。代谢变化会影响乳脂肪合成以及乳脂肪球（MFG）的特性，尤其是其大小和分布。全身FFA释放与体况评分（BCS）的恢复呈负相关，这表明恢复BCS可能会减轻NEB对乳脂肪组成的负面影响。本研究旨在探讨BCS恢复、代谢负担及其对泌乳奶牛MFG特性的影响之间的关系。该研究在两个奶牛场（F1和F2）进行，共有80头荷斯坦 - 弗里生奶牛。奶牛根据农场和日粮分组，平均泌乳量分别为9653±259千克（F1）和9548±341千克（F2）。分析了牛奶成分，并在四个泌乳阶段采集了血液和牛奶样本。结果表明，NEB期间脂肪组织脂肪分解导致循环中FFA浓度升高与MFG大小和分布的改变之间存在显著相关性。BCS的恢复与FFA释放呈负相关，这表明BCS的改善可能通过调节脂肪分解来减轻NEB对乳脂肪合成的不利影响。此外，较高的β - 羟基丁酸（BHBA）水平与MFG直径减小有关，表明代谢应激期间脂肪生成受到干扰。这些发现突出了代谢应激、BCS恢复和MFG特性之间的复杂关系，对泌乳奶牛的乳脂肪合成具有重要意义。
