Sun Xuezhao, Chen Ao, Li Jianping
The Innovation Centre of Ruminant Precision Nutrition and Smart Farming, College of Animal Science and Technology, Jilin Agricultural Science and Technology University, Jilin 132109, China.
Jilin Inter-Regional Cooperation Centre for the Scientific and Technological Innovation of Ruminant Precision Nutrition and Smart and Ecological Farming, Jilin 132109, China.
Animals (Basel). 2023 Oct 10;13(20):3158. doi: 10.3390/ani13203158.
During winter and early spring, pasture supply is usually lower than the demand in New Zealand dairy farming systems and thus the 'autumn saved pastures' (stockpiling) are introduced to fill the gap. This study aimed to investigate the chemical, physical, and degradation characteristics of ryegrass pastures, the predominant forage in New Zealand, grown in autumn and winter. To serve as 'autumn saved pasture', nine ryegrass cultivars, comprising three types (three perennial, three hybrid, and three Italian), were grown in late autumn (Autumn) and early winter (Winter) and harvested after 7 and 9 weeks of regrowth, respectively. The experiment had two experimental factors: ryegrass type (or cultivar) and harvest season. These experimental factors were in a randomised block design with the forage plot as the experimental unit. The degradation characteristics were assessed in the rumen of fistulated cows using the in situ incubation technique. Perennial ryegrass had a greater neutral detergent fibre (NDF) concentration (468 g/kg dry matter (DM)) than the hybrid (435 g/kg DM) or Italian (414 g/kg DM) ryegrasses. Italian ryegrasses had the greatest soluble fraction of DM (64.2% vs. 46.7% and 40.7%) and the greatest degradation rate of an insoluble but degradable fraction of DM (0.221 vs. 0.189 and 0.145/h) than the hybrid and perennial ryegrasses. Compared with the Winter ryegrass, the Autumn ryegrass had a greater crude protein concentration (246 vs. 208 g/kg DM) and a greater NDF concentration (486 vs. 392 g/kg DM) but a lower calculated soluble carbohydrate concentration (152 vs. 263 g/kg DM). It is concluded that there are notable variations among the cultivars, highlighting distinctions in parameters, such as NDF concentration, soluble fractions, degradation rates, and nutrient content among the perennial, hybrid, and Italian ryegrasses, as well as the seasonal variations observed between autumn and winter growth. These findings will not only facilitate enhanced nutrition for dairy cows as they undergo the transition phase but also have practical implications for future research and dairy cow nutrition.
在冬季和早春，新西兰奶牛养殖系统中的牧场供应通常低于需求，因此引入了“秋季储备牧草”（青贮）来填补缺口。本研究旨在调查秋季和冬季生长的新西兰主要牧草黑麦草牧场的化学、物理和降解特性。为了作为“秋季储备牧草”，种植了9个黑麦草品种，包括3种类型（3种多年生、3种杂交和3种意大利型），分别在深秋（秋季）和初冬（冬季）种植，并在再生7周和9周后收获。该实验有两个实验因素：黑麦草类型（或品种）和收获季节。这些实验因素采用随机区组设计，以牧草地块作为实验单元。使用原位培养技术在瘘管牛的瘤胃中评估降解特性。多年生黑麦草的中性洗涤纤维（NDF）浓度（468克/千克干物质（DM））高于杂交黑麦草（435克/千克DM）或意大利黑麦草（414克/千克DM）。与杂交黑麦草和多年生黑麦草相比，意大利黑麦草的干物质可溶性部分最大（64.2%对46.7%和40.7%），干物质不可溶性但可降解部分的降解率最高（0.221对0.189和0.145/小时）。与冬季黑麦草相比，秋季黑麦草的粗蛋白浓度更高（246对208克/千克DM），NDF浓度更高（486对392克/千克DM），但计算出的可溶性碳水化合物浓度更低（152对263克/千克DM）。得出的结论是，不同品种之间存在显著差异，突出了多年生、杂交和意大利黑麦草在NDF浓度、可溶性部分、降解率和营养成分等参数上的区别，以及秋季和冬季生长之间观察到的季节性差异。这些发现不仅将有助于奶牛在过渡阶段获得更好的营养，而且对未来的研究和奶牛营养具有实际意义。
