Della Rosa Maria M, Bosher Troy J, Khan M Ajmal, Sandoval Edgar, Molano German, Dobson-Hill Brenna, Duranovich Federico N, Jonker Arjan
AgResearch Limited, Grasslands Research Centre, Palmerston North 4442, New Zealand.
School of Agriculture and Environment, College of Sciences, Massey University, Palmerston North 4410, New Zealand.
Anim Nutr. 2025 Apr 5;21:315-325. doi: 10.1016/j.aninu.2025.01.008. eCollection 2025 Jun.
The use of supplementary feeds, including concentrates, on New Zealand dairy farms has increased in recent decades and this could have mitigated methane (CH) emissions by decreasing the forage-to-concentrate ratio. The forage-to-concentrate ratio in the diet can be easily managed in cows that receive a total mixed ration, but under grazing conditions, the cows select their own diets by increasing or decreasing the herbage intake, likely depending on the amount of concentrates eaten. The feed selection will have a direct effect on the forage-to-concentrate ratio and the potential mitigation of CH emissions. The objective of the current study was to determine the effect of feeding increasing levels of concentrates in pasutre fed early lactation dairy cows on CH emissions. Thirty-two early lactation dairy cows fed fresh cut ryegrass-based herbage ad libitum were allocated to receive 0, 2, 4 and 6 kg dry matter of concentrates ( = 8 per treatment) per day in two equal meals during milking. The cows were on their respective full treatment diets for at least 14 days before CH measurements started. The CH emissions were measured in respiration chambers for 48 h. The CH yield (g/kg dry matter intake) and intensity (g/kg milk solids) decreased linearly by 0.76 and 5.3 units per kg of concentrate in the diet ( = 0.001 and = 0.009), respectively, with increasing the concentrate level. The variations in CH emissions after each feeding increased quadratically and linearly ( = 0.023 and = 0.038) after morning and afternoon feeding, respectively and the CH emissions reached the peak more rapidly after morning feeding (linear effect; = 0.029) when the concentrate level increased. For short-chain fatty acids, the proportion of acetate decreased by 0.72 units ( = 0.003) while the proportion of propionate increased by 0.16 units ( = 0.006) per kg of concentrate in the diet. Feeding concentrates is a simple feeding strategy to mitigate CH emissions from dairy cows. CH yield decreased linearly by increasing the concentrate inclusion level of the diet.
近几十年来，新西兰奶牛场补充饲料（包括精饲料）的使用有所增加，这可能通过降低草料与精饲料的比例来减少甲烷（CH）排放。在接受全混合日粮的奶牛中，日粮中的草料与精饲料比例很容易控制，但在放牧条件下，奶牛会通过增加或减少牧草摄入量来选择自己的日粮，这可能取决于所吃精饲料的量。饲料选择将直接影响草料与精饲料的比例以及CH排放的潜在减少量。本研究的目的是确定在放牧的早期泌乳奶牛中增加精饲料饲喂水平对CH排放的影响。32头早期泌乳奶牛自由采食新鲜切割的黑麦草为基础的牧草，在挤奶期间分两顿等量饲喂，每天分别给予0、2、4和6千克干物质的精饲料（每个处理8头）。在开始测量CH之前，奶牛在各自的全处理日粮上至少喂养14天。在呼吸室中测量CH排放48小时。随着精饲料水平的增加，CH产量（克/千克干物质摄入量）和强度（克/千克乳固体）分别以每千克日粮中精饲料线性下降0.76和5.3个单位（P = 0.001和P = 0.009）。每次喂食后CH排放的变化在早晨和下午喂食后分别呈二次方和线性增加（P = 0.023和P = 0.038），并且当精饲料水平增加时，早晨喂食后CH排放更快达到峰值（线性效应；P = 0.029）。对于短链脂肪酸，日粮中每千克精饲料，乙酸盐的比例下降0.72个单位（P = 0.003），而丙酸盐的比例增加0.16个单位（P = 0.006）。饲喂精饲料是减少奶牛CH排放的一种简单饲养策略。通过增加日粮中精饲料的添加水平，CH产量呈线性下降。
