农业工程学报2017，Vol.33Issue(9)：308-314,7.DOI:10.11975/j.issn.1002-6819.2017.09.041
挤奶机真空度对牛奶体细胞数和牛乳头末端壁厚的影响
Effect of vacuum degree of milking machine on milk somatic cell counts (SCC) and teat end wall thickness
摘要
Abstract
The same type of milking machine has the different system vacuum degree, and its set value is mainly from experience and lacks a specific scientific basis. However, during milk processing, farms keep the factory setting value of system vacuum degree for all dairy cows, which causes obvious health problems of dairy cows. Therefore, it is imperative to provide the scientific setting basis of system vacuum degree by quantifying the effect of milking machine system vacuum degree on milking characteristics and cows' health. The dry test and wet test were carried out at China Agricultural Machinery Testing Centre. Simulation milking device was applied to simulate peak milking process with the milk flow of 4.0 kg/min for the high yield dairy cow and 2.5 kg/min for the low yield dairy cow. The pulsation rate and pulsation ratio were set to 60 cycles/min and 60%, respectively, which remained unchanged throughout the experiment. System vacuum degree was set at 44, 46 and 48 kPa, respectively, by means of the vacuum regulator. VaDia vacuum tester was used for data acquisition when milking machine ran under no-load or simulated the milking process at each system vacuum degree. The milking time test was carried out at a dairy cattle field in the north of Jinan, Shandong Province. The setting program of pulsation rate and pulsation ratio was the same in dry test and wet test. Twelve high yielding Chinese Holstein cows were randomly selected. In continuous 3 months (from July to September), milking machine system vacuum degree was set at 44, 46 and 48 kPa respectively. Milking was performed at 5:00 and 17:00 every day, and milk yield, somatic cell count (SCC), milking time (only in morning milking) and teat end wall thickness before and after milking (only in morning milking) were measured. All parameters measured were compared with ANOVA (analysis of variance) using SPSS. The comparisons of multiple means were made using the Duncan's multiple range test, in order to classify the effect of the different treatments. The logarithm of SCC was used to normalize the distribution of SCC. The results showed that during peak milk flow period and over milking period, system vacuum degree was increased from 44 to 48 kPa, and the increasing rate of liner vacuum degree was 4.9% (P<0.001) and 10.8% (P<0.001), respectively. Meanwhile, the increasing rate of milking cup mouth vacuum degree was 373.8% (P<0.001) and 53.7%(P<0.001), respectively. There were no significant differences for milk yield, average milk flow rate and milking time except the logarithm of SCC (P<0.05) between 44 and 48 kPa system vacuum degree. Percentage change of the teat end wall thickness was lower at the lower system vacuum level (44 kPa) after milking, and increased (P<0.05) as the system vacuum level was raised to 48 kPa. The findings of this study indicated that with a lower vacuum level of 44 kPa, the cows were milked better than those with 46 or 48 kPa. The findings in current work provide a technical support for the optimization settings of working state parameters of milking machine in mechanization milking parlors in China.关键词
加工/农产品/农业机械/挤奶机/系统真空度/挤奶量/体细胞数/乳头末端壁厚Key words
processing/agricultural products/agricultural machinery/milking machine/system vacuum degree/machine milk yield/somatic cell counts/teat end wall thickness分类
农业科技引用本文复制引用
李小明,高振江,金红伟,肖红伟,王军,张维维..挤奶机真空度对牛奶体细胞数和牛乳头末端壁厚的影响[J].农业工程学报,2017,33(9):308-314,7.基金项目
农业部农产品质量安全监管(生鲜乳质量安全监管)项目(201484) （生鲜乳质量安全监管）
农业部农业技术试验示范专项经费(农机)项目-奶牛养殖全程机械化试验示范项目(201377) （农机）
农业部挤奶机关键部件试验平台研制项目(201206) （201206）
蒙牛乳业(集团)挤奶机系统检测评估项目(20150413) （集团）
