ABSTRACT

This study describes variation of nutritive value (NV), measured by proximal hyperspectral sensing (PHS), of herbage offered to cows on a pasture-based dairy farm. Metabolisable energy (ME), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and digestible organic matter digestibility (DOMD) were predicted from PHS of canopies during the 2016–17 and 2017–18 production seasons at Dairy 1, Massey University. Mixed linear models including production seasons and months within production seasons as fixed effects and paddocks as random effects were used to estimate least-squares means of herbage NV. Estimates of variance components were obtained with the same models but considering all factors as random effects. A simulation model, e-Cow, was used to explore the effects of herbage NV on dairy cow performance. The NV of herbage offered to cows dropped during summer compared to spring or autumn (P < 0.05). The contribution of the month within production season to NV variance (42.7%) was higher than production season (13.1%) or paddock (10.7%). Cow performance can be limited by ME and NDF, while CP is often found in excess of requirements. The use of canopy PHS for rapid herbage NV measurement can potentially be used to optimise grazing in pasture-based dairy farms.

摘要

本研究描述了通过近端高光谱传感 (PHS) 测量的在牧场奶牛场为奶牛提供的牧草的营养价值 (NV) 变化。根据 2016-17 和 2017-18 生产季节冠层的 PHS 预测可代谢能 (ME)、粗蛋白 (CP)、中性洗涤纤维 (NDF)、酸性洗涤纤维 (ADF) 和可消化有机物消化率 (DOMD)在梅西大学的 Dairy 1。混合线性模型包括生产季节和生产季节内的月份作为固定效应和围场作为随机效应，用于估计牧草 NV 的最小二乘均值。使用相同的模型获得方差分量的估计，但将所有因素视为随机效应。使用模拟模型 e-Cow 来探索牧草 NV 对奶牛生产性能的影响。P  < 0.05)。生产季节内月份对 NV 方差的贡献 (42.7%) 高于生产季节 (13.1%) 或围场 (10.7%)。奶牛的表现可能会受到 ME 和 NDF 的限制，而 CP 经常超出要求。使用冠层 PHS 进行快速牧草 NV 测量可用于优化牧场奶牛场的放牧。