因势利导,扩大推广使用挤奶机——石家庄市挤奶机推广使用情况调查

石家庄市推广使用挤奶机颇见成效，最近我们除对这里的一般情况进行了解外，并走访了几家奶牛场和专业户，就使用机械挤奶发展的情况、经济效益、取得的经验和存在的问题进一步作了调查研究。总的认为，扩大推广使用挤奶机的时机已经成熟，迫切需要加大推广力度，为我国奶业的发展源源注入新的活力。一、从点到面，形势喜人第一台2×12新西兰制造的万宝纽帕尔斯鱼骨式挤奶机于1993年6月在石家庄河北省农科院畜牧场落户。第一批山东省淄博市博山农机厂生产的9JH—Ⅰ、Ⅱ型活塞式挤奶车于1994年秋为近郊奶牛专业户所采用。20头／次万宝纽帕尔…     

国内期刊文摘

我国第一台电动自控挤奶机北京市农机研究所、北京市自动化研究所与北郊农场牛场协作,最近研制成我国第一台电动自控挤奶机。它可用于坑道式及大型挤奶转台,为迅速发展我国大型乳牛场创造了条件。电动自控挤奶机由真空泵、挤奶杯、集乳器、电源箱、光电检测器、电器控制箱、牛奶     

介绍几种畜牧机械

1.9JZ—01自控挤奶机9JZ—01自控挤奶机是根据犊牛吸奶动作(按一定的真空度,挤奶脉动次数、挤奶节拍比)而设计的能自动挤奶、无奶自动停吸,乳杯自动脱落,自动回收,及自由调节位置的自控挤奶机。它适于转台式或大棚挤奶使用。     

奶用真空泵概述

影响机器挤奶的因素有两个:一是泌乳反射,二是机器结构。它们涉及到“人-机-畜”这个工程-生物学系统,只有在挤奶机工作能刺激泌乳反射条件下,才能保持牲畜的产奶量和保证挤出全部牛奶(奶流速度≤0.2公斤/分时被视为无奶)。如何使挤奶机达到这一要求,起决定作用的是挤奶装置系统的三大基本参数:真空     

挤奶机中脉动器的程序控制装置

目前挤奶机上普遍使用着两种类型的脉动器,一种是同步式脉动器,它使挤奶机的四个挤奶杯同时开闭;另一种是交替式脉动器,使前后两对挤奶杯的开闭有180°的相位角。此外尚有新近出现的连续(或叫顺序)式脉动器,在挤奶机四个挤奶杯各相邻的     

草原牌9J-2型挤奶机

草原牌9J-2型挤奶机是由中国农机院和通辽牧业机械厂联合设计组在总结我国几种挤奶机的基础上,吸收国外同种机型的优点设计而成的气动式交替两节拍挤奶     

欧洲挤奶机现状及发展趋势浅析

从最近几年欧洲挤奶机的发展情况来看,总体结构、工作效率没有太大的变化。作为未来型挤奶设备的科学研究,从70年代开始研究全自动挤奶机,即挤奶机器人,目前欧洲共有六具,其中德国两具分别由联邦农业研究中心和联邦牛奶研究中心主持研究。机器人为单体站台式,识别(挤奶时间间隔     

往复活塞式空压机常见故障及维修

一、往复活塞式空压机的工作原理 往复活塞式空压机一般由电动机经三角带带动轴旋转,再经连杆带动活塞产生往复运动,使气阀、活塞、汽缸所组成的活塞腔容积发生变化,达到压缩空气的目的.压缩空气经中冷器再进行压缩,最后进入储气罐.     

活塞式粘稠液体灌装机电机功率的计算

本文在对工作机构进行受力和能量消耗分析的基础上，介绍了一种活塞式粘稠液体灌装机电机功率计算及确定方法。     

活塞式粘稠液体灌同电机功率的计算

本文在对工作机构进行受力和能量消耗分析的基础上，介绍了一种活塞式粘稠液体灌装机电机功率计算及确定方法。     

Factors of variation influencing bulk tank somatic cell count in dairy sheep

Between January and December 2002, a total of 21,685 records for bulk tank milk somatic cell count (BTSCC) were obtained from 309 dairy ewe herds belonging to the Sheep Improvement Consortium in Castilla-Leon, Spain. Based on the first statistical model, ANOVA detected significant effects of herd, breed, month within herd, dry therapy, type of milking, contagious agalactia, and installations within machine milking on logBTSCC. A second statistical model was used on herds with machine milking to study the effect of the vacuum level and pulsation rate on BTSCC. Herd and month within herd were important variation factors as they explained 48.4 and 16.1% of the variance in BTSCC. Variability in logBTSCC among breeds ranged from 5.84 (Castellana) to 6.09 (Awassi and Spanish Assaf). Implementing dry-ewe therapy (5.91) significantly reduced logBTSCC compared with when it was not implemented (6.10). Hand milking elicited greater logBTSCC (6.07) than machine milking (5.94). Machine milking of ewes in milking parlors (logBTSCC: 5.88 to 5.94) was associated with better udder health than was the use of bucket-milking machines (6.04). Reduced vacuum levels and elevated pulsation rate during machine milking optimized BTSCC. In all cases, clinical outbreaks of contagious agalactia increased BTSCC. As a result, dry therapy was proposed as the main tool to reduce BTSCC. Optimization of milking-machine standards and parlor systems also improved udder health in dairy sheep.     

Short communication: Teat-end shape and udder-level milking characteristics and their associations with machine milking-induced changes in teat tissue condition

Machine milking-induced changes in teat tissue condition, such as congestion and edema, have been associated with teat canal openness, penetrability, and thus susceptibility to new intramammary infections and diminished animal well-being. The primary objective of this study was to investigate the association of teat-end shape and machine milking-induced short-term changes in teat tissue condition. Our secondary objective was to study the association of udder-level milking characteristics and short-term changes. Data from 125 Holstein cows were analyzed in a longitudinal prospective cohort study. Cows were housed in freestall pens with sand bedding, fed a total mixed ration, and milked 3 times per day. Teat-end shape was classified into 3 categories: pointed, flat, and round. Udder-level milking characteristics were obtained from electronic on-farm milk meters. Short-term changes in teat tissue condition after machine milking were assessed visually. Multivariable generalized mixed model analysis showed an association between teat-end shape and short-term changes. Compared with teats with round teat-end shape, the odds ratio (95% confidence interval) for short-term changes was 1.68 (0.53–5.31) and 0.03 (0.004–0.19) in teats with pointed and flat teat-end shape, respectively. There was an association between milking characteristics and short-term changes such that higher milk flow rate during the first 15 s of milking decreased the likelihood of short-term changes. The adjusted probability of short-term changes for a milking observation of a mid-lactation cow and an average first 15-s milk flow rate of 0.5 and 1.5 kg/min was 53.0% (42.8–63.8) and 32.9% (15.2–57.3), respectively. Our results suggest that teat-end shape may be one of the risk factors that contribute to machine milking-induced short-term changes. Milking characteristics (e.g., first 15-s milk flow rate) may have the potential as a measure to indirectly monitor teat tissue changes associated with machine milking on a daily basis, though further research is needed to validate this hypothesis and to establish thresholds that could serve as on-farm guidelines.     

Risk factors for clinical mastitis in herds with a low bulk milk somatic cell count. 2. Risk factors for Escherichia coli and Staphylococcus aureus

The incidence rate of clinical mastitis due to Escherichia coli and Staphylococcus aureus was studied in 125 herds with a low annual bulk milk somatic cell count (less than 150,000 cells/ml). Risk factors that were offered to a multivariate Poisson regression model included general management, housing, cleaning procedures, cow and cubicle cleanliness, feeds and feeding, dry cow management, milking procedures, machine milking, disease prevention, and milk production. Some differences in epidemiology between E. coli and S. aureus were observed. In the S. aureus model, more milking procedure and milking machine variables were present. The milk production, drinking water source, amount of bedding, and ventilation were other important factors in the S. aureus model. Teat disinfection was an important risk factor in the E. coli model but was much less important in the S. aureus model. Cleaning procedures were more important in the E. coli model. The main breed on the farm and percentage of cows leaking milk were other important factors in the E. coli model.     

Machine milking–induced changes in teat canal dimensions as assessed by ultrasonography

Changes in teat canal diameter as induced by machine milking are thought to be related to teat canal penetrability and susceptibility to new intramammary infections. The objective of this study was to describe the effects of machine milking on teat canal dimensions as assessed by ultrasonography and to evaluate postmilking changes of teat canal dimensions throughout an 8-h milking interval. Ultrasonographic images were taken of the left front and right hind teats of 80 Holstein cows milked 3 times per day. Imaging occurred before attachment of the milking unit after completion of premilking udder preparation (t?1), immediately after removal of the milking unit (t0), and then every hour after milking until 8 h had elapsed (t1 to t8). Teat canal length and teat canal diameter (at the proximal, middle, and distal regions) were measured. General linear mixed model analysis indicated differences in the relative change of teat canal length (compared with t?1) with least squares means (LSM) and 95% confidence interval (95% CI) of 11.1% (8.7–13.4%) after machine milking (t0). Teat canal length decreased throughout the 8-h milking interval but remained elevated relative to t?1. Teat canal diameter at the proximal and middle regions increased near the end of the milking interval, whereas that at the distal region did not change meaningfully during the 8 h of observation. Our findings suggest that the teat canal and its surrounding tissue is in a state of near-constant remodeling in cows milked 3 times daily. Future work is warranted to study the association between ultrasonographically assessed changes of teat canal dimensions after machine milking and teat canal penetrability to mastitis-causing pathogens.     

Modeling the interaction of milking frequency and nutrition on mammary gland growth and lactation

A mathematical model of biological mechanisms regulating lactation is constructed. In particular, the model allows prediction of the effect of milking frequency on milk yield and mammary regression, and the interaction of nutrition and milking frequency in determining yield. Possible interactions of nutrition with milking frequency on alveolar dynamics are highlighted. The model is based upon the association of prolonged engorgement (as a consequence of milk accumulation) of active secretory alveoli with changes in gene expression that result in impairment and, ultimately, cessation of milk secretion. The emptying of alveoli at milking, following alveolar contraction induced by oxytocin, prevents this process and also allows quiescent alveoli to reactivate. Prolonged engorgement results in apoptosis of the secretory cells and, hence, regression of the mammary gland. Milk yield is linked to alveolar populations, with secretion rates being modulated by nutrition and udder fill effects. The model was used to investigate different management scenarios, and is in agreement with experimental results. The model shows that while milking frequency drives alveolar population, and therefore potential milk production, actual production varies considerably with nutrition. A significant portion of the loss associated with once-daily milking was due to udder fill rather than loss of secretory tissue. The model showed qualitative agreement with experimental data, on the acute and chronic effects of temporary once-daily milking.     

饲养和挤奶方式对原料奶中细菌总数的影响

系统评价了昆明雪兰牛奶有限公司来自6个机械挤奶规模化奶牛场、6个机械挤奶奶牛合作社和6个手工挤奶奶站的原料奶的细菌总数。结果表明,机械挤奶规模化奶牛场、机械挤奶奶牛合作社原料奶和农户手工挤奶站原料奶细菌总数分别平均为346875mL-1,155206mL-1和2385167mL-1,农户手工挤奶站原料奶细菌总数显著高于机械挤奶规模化奶牛场和合作社(P<0.05),后两者之间无显著差异(P>0.05);     

Prospective cohort study of the relationship between milking machine liner slip,milking performance,and cow characteristics

We conducted a prospective cohort study to investigate the associations of machine milking liner slip with (1) milking performance and (2) cow characteristics. Parlor data including milk flow characteristics and data on the occurrence of milking machine liner slips from a 4,000-cow dairy with a thrice-daily milking schedule were obtained with electronic on-farm milk meters over a 2-mo period. We analyzed data from a total of 686,330 milking observations. A multivariable general linear mixed model revealed no association between liner slip and milking unit on time. Least squares means (95% confidence intervals, 95% CI) were 237 (235–238) s for milking observations with and without a liner slip. We observed statistically significant differences in average milk flow rate; however, these were biologically irrelevant. Least squares means were 3.40 (3.37–3.42) kg/min for a milking observation with and 3.42 (3.40–3.44) kg/min without a liner slip. A multivariable generalized linear mixed model showed an association between liner slip and cow characteristics. Compared with late-lactation cows, the odds ratios (OR, 95% CI) of occurrence of a liner slip were 2.03 (1.59–2.59) in early lactation cows and 1.26 (0.97–1.64) in cows from 101 to 200 days in milk. Presence of a nonlactating quarter increased the odds of liner slip occurrence [OR, 95% CI: 10.35 (8.02–13.35)]. Bimodal milking observations had higher odds of occurrence of a liner slip compared with milking observations with a unimodal milk flow curve [OR, 95% CI: 1.05 (1.005–1.09)]. A 1-kg increase in 2-min milk yield increased the odds of a liner slip [OR, 95% CI: 1.26 (1.25–1.28)]. We conclude that, in the study cohort presented herein, the negative effect of liner slips on milking performance can be diminished. The identified cow characteristics could offer unique opportunities to identify and manage cows at increased risk of liner slips.     

Increased teat wall thickness in response to machine milking

Transiently increased teat wall thickness in response to machine milking has been documented by various methods, including ultrasound. However, correlative ultrasonography and histology to detect the origin of this phenomenon is lacking. The first goal of the present study was to evaluate and compare milking-related changes of the teat tissue in 2 breeds of dairy cows (11 Simmental and 3 Holstein) using B-mode ultrasonography. Additionally, the observed changes were compared with ultrasonographic findings in a Holstein cow with periparturient udder edema. Finally, corresponding histological sections of the Simmental teats were analyzed and compared with those from a lactating nonmilked Angus cow. We hypothesized that the mechanical load of both stretching by the vacuum during phases of open teat cup liner and compression by the closed liner during machine milking results in a transient congestion of blood vessels in the teat wall. The barrel of 1 front teat of each cow was scanned immediately before and after machine milking (system vacuum: 42 kPa; pulsation rate: 60 cycles/min; pulsation ratio: 65:35). Shortly after milking (33 ± 6 min), the Simmentals were slaughtered, and their scanned teat was immediately removed and processed for investigation by light microscopy. Ultrasonography after milking revealed anechoic tubular structures mainly in the inner half of the teat wall. Histological examination revealed these structures to be thick-walled veins. The left front and hind teats of the nonmilked lactating cow, collected and prepared identically to those from the Simmental cows, showed the same histological features. Ultrasonographic measurements showed that the diameter of these veins significantly increased after milking compared with matching images before milking. This effect was most pronounced in the Holstein cows. Similarly, these veins were very prominent in the periparturient cow. However, neither the milked cows, including the periparturient cow, nor the lactating nonmilked cow provided any evidence of edematous extravasation on ultrasonography or histology. These findings corroborated our hypothesis that the increase in size of thick-walled veins in the teat tissue is the main reason for the thickening of the teat walls in response to machine milking.     

食品包装机的横封机构运动仿真分析

横封是食品包装过程的一个非常重要的工序,横封的结构决定了包装的速度和品质。对食品包装机几种常用的结构做了分析介绍,并对旋转式横封机构常用的转动导杆结构作了深入分析,建立数学模型,对其特性进行理论分析,运用ADAMS软件对转动导杆机构进行运动学分析。结果发现,随着导杆角度的变化,机构输出端的角速度与角加速度曲线变化,证明理论分析的正确性。此次研究为横封机构的研究及控制系统的设计提供理论依据,为食品包装机的设计提供技术支持。     

气动书籍包装机的设计与研究

为提高书籍包装的效率,设计一种结构新颖、性能稳定的气动书籍包装机,实现书籍自动装袋包装的功能。利用MATLAB和ADAMS建立运动力学数学模型并进行仿真,利用ANAYS进行关键部件的有限元分析,最后进行实际测试。该包装机关键零部件满足强度与硬度要求,减少了书籍包装的时间,包装成功率高。该气动书籍包装机性能稳定,可以连续高效地实现书籍包装功能,具有较高的经济效益。