Młynek Krzysztof, Danielewicz Agata, Strączek Ilona
Faculty of Agrobioengineering and Animal Sciences, University of Natural Sciences and Humanities in Siedlce, 08-110 Siedlce, Poland.
Animals (Basel). 2021 Jan 7;11(1):112. doi: 10.3390/ani11010112.
During early lactation in dairy cows, metabolic processes are adopted to provide energy and nutrients for the synthesis of milk compounds. High milk production potential includes sudden changes in energy metabolism (negative energy balance (NEB)) that can induce uncontrolled lipomobilization and high blood free fatty acid (FFA) levels. Destabilization of cows' energy may interfere with endocrine homeostasis, such as the secretion of leptin, a co-regulator of the appetite center. Therefore, it is important to analyze the physiological aspects of the maintenance of energy homeostasis in various dairy breeds. Usually it is crucial for the health of cows, influences the production cycle and lifetime yield, and determines the profitability of production and milk quality. The aim of this study was to analyze the energy metabolism of selected breed groups of cows and its variability in different stages of early lactation. The analysis was performed using data on the following parameters: body condition score (BCS), fatty acid (FA) fractions, basic milk constituents, and serum parameters (BHBA, glucose, and leptin). These results were analyzed in relation to parameters of energy metabolism during the stage up to the peak of lactation. An earlier peak of lactation was shown to be conducive to an increase in the content of non-esterified fatty acids (NEFAs) and of casein and κ-casein. During the study period, parameters characterizing the maintenance of energy homeostasis were usually lower in the Simmental and Black-and-White Lowland cows. Compared to the group with the highest production, their yield was from 2.8 to 4.7 kg lower, but the milk had a more beneficial fatty acid profile and nutrient content, determining suitability for cheese making. At the same time, they had lower levels of NEFAs and β-hydroxybutyrate in the blood, which indicates less spontaneous lipolysis of fat reserves. Concentrations of the appetite regulator leptin in the blood were correlated negatively ( ≤ 0.05) with the glucose concentration (-0.259) and positively with NEFA (0.416). The level of NEFAs was at the same time positively correlated with the content of saturated fatty acids in the milk (0.282-0.652; ≤ 0.05). These results contribute to our knowledge of the effect of production intensity on the maintenance of homeostasis up to the peak of lactation in dairy breeds with differing production potential. In practice, this may increase the possibilities of improving milk quality and the profitability of production.
在奶牛泌乳早期，机体通过代谢过程来提供能量和营养物质以合成乳汁成分。高产奶潜力包括能量代谢的突然变化（负能量平衡，NEB），这会引发不受控制的脂肪动员以及血液中游离脂肪酸（FFA）水平升高。奶牛能量的不稳定可能会干扰内分泌稳态，比如瘦素（食欲中枢的协同调节因子）的分泌。因此，分析不同奶牛品种能量稳态维持的生理方面很重要。这通常对奶牛健康至关重要，会影响生产周期和终生产奶量，并决定生产的盈利能力和牛奶质量。本研究的目的是分析选定奶牛品种组的能量代谢及其在泌乳早期不同阶段的变异性。分析使用了以下参数的数据：体况评分（BCS）、脂肪酸（FA）组分、基本乳汁成分以及血清参数（β - 羟基丁酸、葡萄糖和瘦素）。这些结果与泌乳高峰期之前阶段的能量代谢参数相关联进行分析。结果显示，较早的泌乳高峰期有利于非酯化脂肪酸（NEFA）以及酪蛋白和κ - 酪蛋白含量的增加。在研究期间，西门塔尔牛和黑白花低地奶牛中表征能量稳态维持的参数通常较低。与产量最高的组相比，它们的产奶量低2.8至4.7千克，但牛奶的脂肪酸谱和营养成分更有益，这决定了其适合制作奶酪。同时，它们血液中的NEFA和β - 羟基丁酸水平较低，这表明脂肪储备的自发脂解较少。血液中食欲调节因子瘦素的浓度与葡萄糖浓度呈负相关（≤0.05，-0.259），与NEFA呈正相关（0.416）。同时，NEFA水平与牛奶中饱和脂肪酸的含量呈正相关（0.282 - 0.652；≤0.05）。这些结果有助于我们了解生产强度对具有不同生产潜力的奶牛品种直至泌乳高峰期稳态维持的影响。在实际中，这可能会增加改善牛奶质量和生产盈利能力的可能性。
