Department of Animal Science, University of California, Davis 95616.
January Innovation, Lodi, CA 95240.
J Dairy Sci. 2021 Aug;104(8):8846-8856. doi: 10.3168/jds.2020-19109. Epub 2021 May 10.
California is the leading state for the production of almonds, with more than 400,000 bearing hectares of orchards that produced approximately 1 billion kilograms of shelled nuts in 2017. Almond hulls (AH) are a regional by-product feedstuff fed predominantly to dairy cattle in California. A 2012 study surveyed 40 dairy farms in California and found that 39 out of 104 total mixed rations contained AH, with a mean daily feeding rate of 1.45 kg/cow. In 2017, approximately 2 billion kilograms of AH was produced. At a feeding rate of 1.45 kg/cow daily, even if all 1.7 million lactating cows in California are consuming AH, there will be a surplus of AH on the market as the approximately 130,000 nonbearing hectares come into nut production. Therefore, the potential of feeding varying amounts of AH to lactating dairy cows was investigated using 12 Holstein cows with 4 primiparous and 8 multiparous cows. The dietary treatments were 4 total mixed rations containing 0, 7, 13, or 20% AH. The AH used contained 12.8% crude fiber (as-is basis), which was below the 15% legal limit set by state feed regulations. Diets were formulated so that as the inclusion rate of AH increased, the amount of steam-flaked corn and soyhull pellets decreased and soybean meal inclusion increased. Experimental design was a replicated 4 × 4 Latin square. Diet had a cubic effect on actual milk yield, energy-corrected milk yield, and dry matter intake, with the 7% AH diet having the highest values and the 13% AH diet having the lowest. The percent and yield of total solids and the yields of lactose and fat did not differ with diet, but percent and yield of protein declined linearly with increased AH inclusion, and fat percent increased linearly. Apparent total-tract digestibilities of dry matter and organic matter were higher with the inclusion of AH in the diet. Total percentage of the day spent ruminating increased linearly with higher amounts of AH. Overall, this work demonstrated that AH can be fed at varying amounts, up to 20% of the diet, to lactating dairy cows to support high levels of milk production and that increasing amounts of AH (up to 20%) in the diet could lead to improved digestibility and milk fat percentage but decreased milk protein production.
加利福尼亚州是杏仁的主要产地，拥有超过 40 万公顷的结果果园，2017 年生产了约 10 亿公斤去壳坚果。杏仁壳（AH）是加利福尼亚州主要供给奶牛的区域性副产品饲料。2012 年的一项研究调查了加利福尼亚州的 40 个奶牛场，发现 104 个总混合日粮中有 39 个含有 AH，奶牛的日平均喂养率为 1.45 公斤/头。2017 年，大约生产了 20 亿公斤的 AH。如果加利福尼亚州的 170 万头泌乳奶牛每天以 1.45 公斤/头的速度进食，即使所有泌乳奶牛都食用 AH，由于大约 13 万公顷的非结果果园开始产果，市场上仍会有多余的 AH。因此，研究人员使用 12 头荷斯坦奶牛（4 头初产奶牛和 8 头经产奶牛），研究了给泌乳奶牛喂食不同量的 AH 的可能性。日粮处理为 4 种总混合日粮，分别含有 0%、7%、13%和 20%的 AH。所用的 AH 含有 12.8%的粗蛋白（原样基础），低于州饲料法规规定的 15%的法定限制。日粮的配方是随着 AH 含量的增加，蒸汽压片玉米和大豆皮颗粒的用量减少，豆粕的用量增加。实验设计为重复 4×4 拉丁方设计。日粮对实际产奶量、校正奶产量和干物质采食量有立方效应，7%的 AH 日粮的产奶量最高，13%的 AH 日粮的产奶量最低。日粮对总固形物的百分率和产量、乳糖和脂肪的产量没有影响，但随着 AH 添加量的增加，蛋白质的百分率和产量呈线性下降，脂肪百分率呈线性上升。日粮中添加 AH 可提高干物质和有机物的全肠道消化率。随着日粮中 AH 含量的增加，反刍总时间的百分比呈线性增加。总的来说，这项研究表明，AH 可以以不同的量（高达日粮的 20%）添加到泌乳奶牛的日粮中，以支持高水平的产奶量，并且日粮中添加更多的 AH（高达 20%）可以提高消化率和乳脂率，但会降低乳蛋白产量。
