Department of Animal Science, Agrotecnio Center, Universitat Lleida, Alcalde Rovira Roure 191, Lleida 25198, Catalonia, Spain.
Department of Animal Science, Agrotecnio Center, Universitat Lleida, Alcalde Rovira Roure 191, Lleida 25198, Catalonia, Spain.
J Dairy Sci. 2020 Nov;103(11):10882-10897. doi: 10.3168/jds.2019-17555. Epub 2020 Sep 18.
The aim of this study was to determine the effect of housing system (or manure management system) and season on manure N recovery and volatilization using an N mass balance. Dietary, milk, and manure N were monitored together with outside temperatures in 6 dairy barns. Three barns were designed as conventional freestalls (cubicle, CUB) with an automatic manure scraper system and concrete floor, in which the gutter in the middle was continuously scraped (every 2-4 h) and the slurry was conveyed toward an open-air concrete pool. The other 3 barns were designed as a loose housing system (HS) with a compost-bedded pack (CB) and conventional confinement housing provided with a feed alley that was cleaned mechanically (2-3 times per day). The farms under study were located near Lleida in the center of the Ebro valley, in northeastern Spain. Nitrogen recovery was measured twice under farm-like conditions either during spring-summer (3 mo of increasing temperatures) or fall-winter (3 mo of decreasing temperatures). The number of cows per barn ranged from 99 to 473, and average age, mean lactation, and parturition intervals were 4.1 yr, 2.43 lactations, and 426.6 d, respectively. In spring-summer, animals ate more [26.3 vs. 23.8 kg of dry matter (DM)/d] and produced more milk (34.6 vs. 31.3 kg/d ± 0.68). However, milk composition did not change. Stored manure from the CB system showed a higher DM concentration with respect to the CUB system (379.15 vs. 97.65 g/kg of fresh matter); however, N (31.45 vs. 40.2), NH-N (5.3 vs. 18.9) and its ratios with phosphorus (NH-N:P, 3.52 vs. 5.2) and potassium (NH-N:K, 0.615 vs. 2.69) showed the opposite trend. No differences were found in N intake (653 vs. 629.5 g/d) or milk N secretion (190 vs. 177.8 g/d for CUB and CB barns, respectively) although net N recovery of the excreted N (N - N) was significantly lower in manure in CB barns than in CUB systems (193.8 vs. 389.3 g/d). The proportion of N irreversible loss in relation to the N intake was higher in CB than in CUB barns (42.3 vs. 11.0%). There was no clear association between season and irreversible N losses; however, the housing system was pivotal in the association between N recovery in manure and irreversible losses by volatilization.
本研究旨在通过氮质量平衡来确定饲养系统（或粪便管理系统）和季节对粪便氮回收和挥发的影响。在 6 个奶牛场，监测了奶牛的日粮、牛奶和粪便氮以及外部温度。其中 3 个牛舍设计为传统的小隔间（牛栏，CUB），配有自动清粪刮板系统和混凝土地板，其中中间的排水沟被连续刮除（每 2-4 小时刮一次），粪浆被输送到露天混凝土池。另外 3 个牛舍设计为松散式饲养系统（HS），采用垫料床（CB）和传统的封闭式畜栏，畜栏配有饲料通道，每天机械清理（2-3 次）。研究农场位于西班牙东北部埃布罗河谷的莱里达附近。在类似农场的条件下，分两次在春季-夏季（温度升高 3 个月）或秋季-冬季（温度降低 3 个月）进行氮回收测量。每个牛舍的奶牛数量从 99 头到 473 头不等，平均年龄、平均泌乳期和产犊间隔分别为 4.1 年、2.43 次泌乳和 426.6 天。在春季-夏季，动物的采食量（26.3 公斤干物质（DM）/天比 23.8 公斤/天）和产奶量（34.6 公斤/天比 31.3 公斤/天±0.68）更高。然而，牛奶成分没有变化。CB 系统的储存粪便的 DM 浓度高于 CUB 系统（379.15 克/千克新鲜物质比 97.65 克/千克新鲜物质）；然而，氮（31.45 克/千克比 40.2 克/千克）、NH-N（5.3 毫克/千克比 18.9 毫克/千克）及其与磷（NH-N：P，3.52 比 5.2）和钾（NH-N：K，0.615 比 2.69）的比例呈相反趋势。CUB 和 CB 牛舍的氮摄入量（653 克/天和 629.5 克/天）或牛奶氮分泌量（190 克/天和 177.8 克/天）没有差异，但 CB 牛舍粪便中排泄氮（N-N）的净氮回收量明显低于 CUB 系统（193.8 克/天比 389.3 克/天）。与氮摄入量相比，CB 牛舍中氮不可逆转损失的比例高于 CUB 牛舍（42.3%比 11.0%）。季节和不可逆转氮损失之间没有明显的关联；然而，饲养系统是影响粪便氮回收和挥发不可逆转损失之间关系的关键因素。
