Serva Lorenzo, Magrin Luisa, Marchesini Giorgio, Andrighetto Igino
Department of Animal Medicine, Production and Health, University of Padua, Viale dell'Università 16, 35030 Padua, Italy.
Animals (Basel). 2021 Dec 15;11(12):3566. doi: 10.3390/ani11123566.
The adoption of the mixer wagon and total mixed ration aimed to decrease dysmetabolic diseases and improve feed efficiency in dairy cows. Differences between theoretical and eaten diets are imputable to errors in diet preparation or cow feed sorting. We proposed a method to measure the chemical composition and particle size distribution of the ration and determined its peNDF content through a portable Near Infra-Red spectrophotometer that allowed the calculation of two indexes: the homogeneity and the sorting indexes. In a cohort of 19 Italian Holstein breeding farms, we studied the correlation of these indexes with the mixer wagon settings. Determination coefficients in the validation (R) for dry matter, crude protein, aNDF, and starch were 0.91, 0.54, 0.86, and 0.67, respectively. The ration fractions (%, / of wet weight) retained by the 3.8 and 1.8 mm sieves, and the bottom showed R of 0.46, 0.49, and 0.53, respectively. The homogeneity index regressed negatively with the mixer wagon load fullness (R = 0.374). The homogeneity-binary classification showed an odds ratio of 1.72 for dry matter and 0.39 for aNDF ( < 0.05). The sorting-binary classification showed an odds ratio of 2.54 for aNDF ( < 0.05). The studied farms showed low peNDF values (median = 17.9%).
采用搅拌车和全混合日粮旨在减少奶牛的代谢紊乱疾病并提高饲料效率。理论日粮与采食日粮之间的差异可归因于日粮配制误差或奶牛的饲料挑食。我们提出了一种测量日粮化学成分和粒度分布的方法，并通过便携式近红外分光光度计测定其有效中性洗涤纤维（peNDF）含量，该仪器可计算两个指标：均匀性指标和挑食指标。在19个意大利荷斯坦奶牛养殖场的队列中，我们研究了这些指标与搅拌车设置之间的相关性。干物质、粗蛋白、酸性洗涤纤维（aNDF）和淀粉在验证中的决定系数（R）分别为0.91、0.54、0.86和0.67。通过3.8毫米和1.8毫米筛网以及底部保留的日粮组分（湿重的%），其R值分别为0.46、0.49和0.53。均匀性指标与搅拌车装载饱满度呈负相关（R = 0.374）。均匀性二元分类显示，干物质的优势比为1.72，aNDF的优势比为0.39（P<0.05）。挑食二元分类显示，aNDF的优势比为2.54（P<0.05）。所研究的养殖场显示出较低的peNDF值（中位数 = 17.9%）。
