Epidemiological Analyses of the Associations between bovine udder health and milking machine and milking management

This paper presents data from 158 dairy herds in northern Norway. The influence of the milking machine and milking management on the prevalence of subclinical mastitis and herd cell counts was calculated from a least squares model by a backward elimination procedure. It was shown that 16–45% of the herd udder health variation found at the start of the programme could be associated with milking machine and milking management variables. The following variables were found to be of significance: number of clusters in the herd, vaccum, function and vaccum regulator, undulation of pipeline, limping of pulsator, rate of pulsator, type of claw-piece, hygienic/-technical condition of liner, preparation time, air admission during application of teat cups, overmilking and machine-on time.     

Comparison of weigh-suckle-weigh and machine milking for measuring ewe milk production.

Thirteen crossbred ewes were used to compare weigh-suckle-weigh (WSW) and machine milking (MM) methods for determining milk production of ewes that were rearing single or twin lambs. At parturition, ewes were 13 mo of age and produced six single lambs and seven pairs of twin lambs. Milk production estimates were initiated on d 6 of lactation and a 3-d rotation of the two techniques was implemented. On d 6, milk production was measured using WSW; on d 7, MM was used. No measurement was made on d 8. The 3-d rotation was repeated 20 times throughout a 63-d lactation, resulting in 20 point estimates of milk production for each method of measurement for each ewe. The WSW procedure consisted of a 3-h period in which lambs were withheld from suckling their dams. This was followed by a suckling period, a second 3-h withholding period, and a second suckling period. Differences in pre- and postsuckling lamb weights of the second suckling period were defined as milk consumption and, indirectly, 3-h milk production. The MM procedure included an administration of 10 IU of oxytocin (i.v.), followed by evacuation of the udder with a machine using commercially available sheep milking equipment, and the milk was discarded. Lambs were withheld from suckling the ewes for a 3-h period, followed by a repetition of the oxytocin and machine milking procedures. Milk from the second milking was weighed. Milk production estimates determined using the WSW and MM techniques were similar (P = .42). Average 3-h milk production was 340 and 351 g for WSW and MM, respectively. Machine milking provides a reliable tool in evaluating the milk-producing ability of ewes that are rearing single or twin lambs.     

Technical note: machine milking of sows--lactational milk yield and litter weights.

This study was designed to 1) determine milk yield of sows that were machine milked; 2) assess the effects of pulsation rate, pulsation ratio, and pig removal on milk yield; and 3) assess litter weights. In Exp. 1, four sows were milked daily to 60 d postpartum. There were differences (P < .05) in milk yield among sows, the greatest being 1,898 mL/d. Daily milk yield peaked between 15 and 25 d postpartum. Litter weights were 18.0 +/- 1.0 kg at farrowing and 60.8 +/- 12.1 kg at d 60. In Exp. 2, four sows were milked daily for 28 d. Pulsation rate and ratio (150/min and 28:72, milk:rest, and 60/min and 50:50) were alternated on a daily basis and pigs were isolated for either 0 or 60 min before milking. The higher pulsation rate resulted in more milk per milking (202 +/- 13 vs 168 +/- 13 mL; P < .05). Pig removal resulted in 221 +/- 11 vs 148 +/- 14 mL milk (P < .01). Pig removal times and pulsation characteristics affect the amount of milk obtained, but milk removal from sows has a severe effect on litter weight. This system can be used to harvest sow's milk for pharmaceutical purposes, but supplementation of the pigs is necessary.     

Effect of an automatic milking system on milking traits

Recent studies in Japan of the effect of automatic milking systems (AMS) on the behavior of dairy cows have confirmed the labor-saving aspect of AMS, but have not solved some of the problems affecting milking traits. The influence of AMS on milking was examined in 39 Holstein cows at Iwate Agricultural Research Center from June 1998 to December 1999, by measuring and recording the yield per milking, milking finish time, milking frequency, and daily yield of milking. Four milking traits were analyzed separately as the objective variable in a linear model, with parity, days in milking, month after installation of the AMS as independent variables. Primiparous cows milked more frequently in the middle and late stage of lactation, yielded less per milking and less per day in the early stage of lactation than multiparous cows with the AMS. Lower frequencies were observed at noon and midnight for cleaning of the bulk tank. By contrast, higher milking frequency in the forenoon was shown. The yield per milking rose and declined, following a normal lactation curve. However, milking frequency rose slowly, and declined gradually in the late stage of lactation. After installing a one-way gate, the cows milked more frequently, with a lower yield per milking and a greater daily milk yield, than before installation.     

Influence of milking technique, milking hygiene and environmental hygiene parameters on the microbial contamination of milking machines

It was the aim of this study to investigate the effect of various factors of the milking technique, milking hygiene and environment on microbial contamination of the milking machine. In 31 dairy herds, the degree of bacterial contamination was examined by taking swabs at four locations (teat cup liner, claw, short and long milk tube) before the milking procedure was started using a standardized protocol (DIN ISO 6887-1:1999). Furthermore, the total germ count was determined in the first milk entering the bulk tank as well as in the bulk tank milk following milking. For each farm, the quality of the milking process and the condition of the milking machine as well as of various environmental factors were recorded. A subjective evaluation of the status of the milking cluster or other parts of the milking machine ("good" or "moderate-poor") gave more information about bacterial contamination than the determination of age and type of material used. A temperature of the rinsing water of < 42 degrees C increased the contamination with Pseudomonas spp. and coliform bacteria. Milking clusters kept out of the cluster pick-up between milking had a higher risk of microbial contamination. Various methods of teat cleaning before milking or of postmilking teat disinfection did not affect the contamination of the milking machine and the bulk tank milk with environmental bacteria. Furthermore, type of bedding material affected bacterial contamination of milking clusters and bulk tank milk. In conclusion, our results suggest that the microbial contamination of the milking machine is not only influenced by the sanitation pro-     

Analysis of factors affecting milking claw vacuum levels using a simulated milking device

Bovine mastitis is typically caused by microbial infection of the udder, but the factors responsible for this condition are varied. One potential cause is the milking system, and although previous studies have investigated various methods for inspecting these devices, most have not assessed methods for evaluating the milking units. With this in mind, we analyzed the factors that affect the vacuum inside the milking claw by using a simulated milking device and by measuring milking claw vacuum when adjusting the flow rate in five stages. The factors analyzed in each milking system were the vacuum pressure settings (high and low line system) , milk tube length (200‐328 cm), aperture diameter (14‐22.2 mm), constricted aperture diameter (12 mm), tubing configurations, lift formation (0‐80 cm), claw type (bottom and top flow) and use or non‐use of a milk sampler. The study findings demonstrated that all of these variables had a significant impact on claw vacuum and suggest that a diagnostic method using a simulated milking device should be considered when inspecting modern milking systems.     

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