Agroscope, Research Division Competitiveness and Systems Evaluation, Tänikon 1, 8356 Ettenhausen, Switzerland; Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland.
Agroscope, Research Division Competitiveness and Systems Evaluation, Tänikon 1, 8356 Ettenhausen, Switzerland.
J Dairy Sci. 2021 Apr;104(4):4775-4786. doi: 10.3168/jds.2020-19773. Epub 2021 Feb 19.
The optimal milking cluster should milk as gently as possible to minimize the mechanical effect on the teat tissue at an optimal milking performance and milk quality. The objective of this study was to investigate the influence of liner shape (round vs. triangular) and type of cluster ventilation (claw vs. mouthpiece chamber; MPC) on milking performance and vacuum at the teat end and in the MPC. Our hypothesis was that liner shape and cluster ventilation affect milking performance and MPC vacuum. Six Holstein Friesian cows were milked twice daily over 12 d with a bucket milker, using 4 different cluster types that combined liner shape and type of cluster ventilation at 3 different system vacuum settings (35, 42, and 50 kPa) in an incomplete randomized block design. Milk flow and vacuum in the MPC, at the teat end (measured in the short milk tube), and in the short pulse tube were continuously recorded during milking. Milk flow was higher, and hence main milking time was shorter, with the round than with the triangular liners. The MPC vacuum was lower in round than triangular liners, which was caused by higher air leakage between teat and liner barrel in the triangular liners. The MPC vacuum, as well as its cyclic fluctuations, increased at the end of milking (immediately before cluster detachment) in all cluster types, with the highest amplitude of fluctuation in the triangular liners with MPC ventilation. The MPC ventilation reduced the MPC vacuum in both liner types at the end of milking, and also in triangular liners during peak milk flow. Despite the observed differences of MPC vacuum, the ventilation type did not affect milking performance. However, milking with triangular MPC-ventilated liners caused an increased proportion of foamed milk, which could potentially have a negative effect on milk quality.
理想的挤奶杯应尽可能轻柔地挤奶，以最大限度地减少对乳头组织的机械影响，同时实现最佳的挤奶性能和牛奶质量。本研究的目的是探讨衬垫形状（圆形与三角形）和挤奶杯通风类型（杯架式与奶嘴室式；MPC）对挤奶性能和乳头末端及 MPC 中的真空的影响。我们的假设是衬垫形状和挤奶杯通风会影响挤奶性能和 MPC 真空。6 头荷斯坦弗里生奶牛在 12 天内每天用桶式挤奶机挤奶两次，使用 4 种不同的挤奶杯组合，这些组合在不完全随机分组设计中结合了衬垫形状和挤奶杯通风类型，在 3 种不同的系统真空设置（35、42 和 50 kPa）下进行。在挤奶过程中，连续记录 MPC 中的奶流和真空、乳头末端（在短奶管中测量）以及短脉冲管中的真空。圆形衬垫的奶流较高，因此主要挤奶时间较短。圆形衬垫的 MPC 真空较低，这是由于三角形衬垫中乳头与衬垫桶之间的空气泄漏较高所致。在所有挤奶杯类型中，MPC 真空在挤奶结束时（在挤奶杯脱落前）都会升高，其中三角形衬垫 MPC 通风的波动幅度最大。MPC 通风在挤奶结束时降低了两种衬垫类型的 MPC 真空，也降低了三角形衬垫的峰值奶流期间的 MPC 真空。尽管 MPC 真空存在差异，但通风类型并未影响挤奶性能。然而，使用三角形 MPC 通风衬垫会导致更多的泡沫奶，这可能对牛奶质量产生负面影响。
