Context Palm-kernel cake (PKC) is a by-product widely evaluated as a feed additive in several species of ruminant animals. However, no information of its use in buffaloes is observed. Thus, considering the characteristics of PKC and that buffaloes are able to digest greater amounts of fibre than are other animals, it is thought that PKC can be used as a supplement for lactating buffaloes in pasture. Aims The aim of the present study was to evaluate the effects of concentrate supplementation and the inclusion of PKC instead of conventional concentrate ingredients on the production and composition of milk, intake and nutrient digestibility of lactating buffaloes in pasture during the dry season. Methods Five crossbred buffaloes with average bodyweight of 641.45 ± 45.87 kg were used and distributed in a 5 × 5 Latin square-design experiment. The treatments consisted in one treatment with mineral salt supplementation (cows fed just forage; MSS control group), and four other treatments in which the cows grazed and received 3 kg/day of concentrated supplementation. The four treatments with concentrated supplementation had different inclusion levels of PKC as a supplement, which were 0%, 30.24%, 66.38% and 90.62% of dry matter (DM) replacing corn and soybean meal. A contrast between the treatment with mineral salt supplementation (MSS control group) versus the four treatments supplemented with concentrate was analysed. In addition, to analyse the effect of inclusion of PKC in the concentrate supplement, the linear and quadratic effects were analysed by decomposing the sum of squares of each level of inclusion of PKC. Key results There was no difference (P > 0.05) in pasture DM intake among the supplemented animals and the control-group animals (MSS). The supplemented animals (regardless of the level of inclusion of PKC) had higher (P < 0.05) fat-corrected milk production and a higher percentage of fat and lactose in the milk than did the MSS control-group animals. The intake of the supplement, crude protein and total digestible nutrients showed a decreasing linear effect (P < 0.05) with the inclusion of PKC. The daily milk production showed a decreasing linear effect (P < 0.05) with the inclusion of PKC in the concentrate. Conclusions Concentrate supplementation for lactating buffaloes in pasture increases the amount of fat in the milk and the production of energy-corrected milk. The inclusion of PKC in concentrate supplement, replacing corn and soybean meal, decreases supplement intake and milk production. Implications The data suggested that PKC reduced milk solids when replacing conventional concentrate ingredients; however, PKC supplements stimulated milk yield when compared with mineral salt supplementation (MSS control group). Therefore, if the inclusion of PKC reduces feeding costs, it is an economic source of supplement to promote milk production.

中文翻译：

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哺乳水牛在加棕榈仁饼的牧场上的表现

背景 棕榈仁饼 (PKC) 是一种副产品，被广泛评估为几种反刍动物的饲料添加剂。然而，没有观察到它在水牛中的使用信息。因此，考虑到 PKC 的特性以及水牛比其他动物能够消化更多的纤维，人们认为 PKC 可以用作牧场中泌乳水牛的补充剂。目的 本研究的目的是评估在旱季期间补充精料和添加 PKC 代替常规精料成分对奶牛产奶量和成分、采食量和养分消化率的影响。方法 采用 5 × 5 拉丁方设计实验，使用平均体重为 641.45 ± 45.87 kg 的五头杂交水牛进行分配。处理包括一种添加矿物盐的处理（奶牛只饲喂草料；MSS 对照组），以及其他四种处理，其中奶牛放牧并接受 3 公斤/天的浓缩补充剂。4个浓缩添加处理的PKC作为添加物的添加水平不同，分别为0%、30.24%、66.38%和90.62%的干物质（DM）替代玉米和豆粕。分析了补充矿物盐的处理（MSS 对照组）与补充浓缩物的四种处理之间的对比。此外，为了分析在浓缩补充剂中包含 PKC 的影响，通过分解每个包含 PKC 水平的平方和来分析线性和二次效应。主要结果 无差异（P > 0。05) 补充动物和对照组动物 (MSS) 中牧场 DM 的摄入量。与 MSS 对照组动物相比，添加了补充剂的动物（无论 PKC 的加入水平如何）具有更高（P < 0.05）的脂肪校正牛奶产量以及牛奶中更高的脂肪和乳糖百分比。随着PKC的加入，补充剂、粗蛋白和总可消化营养素的摄入量显示出降低的线性效应（P < 0.05）。在浓缩物中加入 PKC 后，每日产奶量显示出线性下降（P < 0.05）。结论 为牧场中的泌乳水牛添加浓缩物可增加牛奶中的脂肪含量和能量校正牛奶的产量。在浓缩补充剂中加入 PKC，替代玉米和豆粕，减少补充剂摄入量和产奶量。影响 数据表明，PKC 在替代传统浓缩成分时减少了乳固体；然而，与矿物盐补充剂（MSS 对照组）相比，PKC 补充剂可刺激产奶量。因此，如果加入 PKC 可以降低饲养成本，它是促进产奶的经济补充剂。