CARE OF MILKING MACHINES

Southland Times, Issue 23948, 14 October 1939, Page 14

CARE OF MILKING MACHINES

EFFECT ON WELFARE OF COWS PAPER ISSUED ON RESEARCH WORK One of the most practical, valuable papers to come to my notice during long years of farming study is The Adjustment and Servicing of Milking Machines” by A. Leslie, F.R.C.V.S. (Veterinary Service, Federation ot Taranaki Co-op. Dairies, Eltham), and W. S. Whittleston, M.Sc., A.I.C. (Research Chemist, Laboratory N.Z. Co-op. Rennet Co., Ltd., Eltham) writes H. A. S. in The Dominion. The paper was presented at the annual general meeting of the New Zealand Veterinary Association and the National Dairy Conference, Wellington, in June and is intended to act as a guide to those whose job it is to keep the animals being milked by machines in good health. . The knowledge presented is the outcome of field observations in Taranaki by the veterinary staff of a co-opera-tive, self-financing, self-managed concern, the Veterinary Service op the Federation of Taranaki Co-op. Dairies, Eltham. This special investigation was enabled by finance from the Dairy Board and assistance from the New Zealand Co-op. Rennet Co., Ltd., Eltham. An account of the veterinary service organization was given 15 months ago. The authors of the paper declare that their field observations and recordings definitely established that there is a relation between the faulty action of milking machines and udder troubles. And lest some see here condemnation of machine-milking, let it be added that much harm has been found, too, resulting from faulty handwork, as in stripping. To illustrate the influence of machines out of order and the bad stripping effects, forcible examples are given. Here is one: A herd of heifers. All went well for four months. Then within a week 12 developed mastitis. The cause was found to be a sticking relief valve, which permitted the vacuum to mount to just over 17 inches (pressure). The valve was overhauled and adjusted to blow-off at 13 inches, with the result chat during the last 18 months no further trouble was experienced. In' another case of a herd of 65 cows, after the installation of a new, simple type of releaser machine, there were 29 cases of udder trouble. There had been little trouble with the old machine and the shed was splendidly _ kept, hygienically. On examination, it was found that the gauge was two inches out, having a 17-inch vacuum, when reading 15 inches. Further, the relief valve was unreliable, and at times allowed a 20-inch vacuum to mount, as the units were closed down Both faults were remedied and during last season only foui from 62 cows were culled for mastitis. UNRELIABLE GAUGES Vacuum gauges are. frequently unreliable. Even new ones have been found to be two to three inches out. This is one of the most important and sensitive parts of a machine. It should be regularly tested at least twice a season. One relies upon this instrument as the only indication of vacuum pressure. It is safe to say that a maximum permissible vacuum lies between 14 and 15 inches. A sound principle is to maintain the vacuum at the lowest point at which satisfactory milking can be obtained. The relief valve is u safety valve to prevent the vacuum rising to dangerous heights; hence it is imperative that it be in good working order. Certain types have proved unsatisfactory, the small spring-loaded ball valve specially SO. It is advised that the relief valve be taken to pieces and cleaned at the opening of each season and thereafter oiled once a week. In all cases, the adjustment should permit of blowing-off at the 14-151 b maximum. It is a serious mistake to believe that, because a given plant cannot maintain full vacuum when all cows are milking, the relief valve should be screwed down hard. If vacuum cannot be maintained then, it is because the pump is too small, or else there is a serious leakage of air into the plant. Screwing down is no cure. The best pulsator rate appears to be about 40 a minute. If it is toe slow, milking is retarded, and cups are inclined to fall off. However, too fast a rate can cause the very troubles associated with high vacuums, and, combined with these, can lead to much trouble. A point to be watched in pulsators is the wearing of the valves. These can, where necessary, be reground as are car valves. Oiling with separator oil is recommended. Mechani ■ cal pulsators are favoured, from experience, as opposed to those driven by the vacuum. The following interesting suggestion is made, when reviewing one make of pulsator, that can be adjusted while working:—“With this device it is possible to double the pulsator rate for short periods, and there is much evidence to show that if this be practised when the cow ceases to give down her milk, stripping may be reduced or eliminated altogether.” ' EQUALLY GOOD RESULTS The judgment given on cups, of soft inflations versus hard or moulded, is that equally good results have been found with each. But a warning is given about hard inflations, in that, though more rapid milkers than soft ones, their continuous vacuum on the teat end can lead to trouble. They should be operated at a lower level and not left on any longer than absolutely necessary. No definite emphasis is laid on metal or rubber top, this being regarded as a matter largely of what the cows are used to. Replacement of inflations is urged, for effective working. It must be borne in mind that it is the actual work done which determines its life. Where 60 cows are milked, change inflations every four to six weeks; but if 90 cows go through that same plant, change every three to four weeks Perished and slack inflations are the most common cause of cups falling off when the j vacuum is reasonably stable. Their renewal will often rejuvenate a plant. Perished inflations are condemned as a dangerous source of infection. With certain types of teats, even the most carefully adjusted cups require to be propped. If the practice is to be I harmless, the need is for complete adjustability. Props should set the cup I at a right level and allow slight flexi ibility for their natural movement. Cups pushed up hard against the udder cause injury there. With a simple orthodox machine in good order, the worst trouble arises when cups are on, but milk is not flowing—at the beginninig and end of the milking of any cow. It is therefore essential that the cows be “started” before the cups go on. Also it is highly desirable that they be removed the moment the milk stops flowing. The sightglass is strongly recommended. Feeling the milk-pipe has proved a very unreliable guide. I An interesting point is made of

change in tempo ot milking; to this is ascribed largely the value of stripping. And this is of speial importance. While much mastitis can be caused by milking machines, hand milking can also cause quite a lot of trouble. Rough stripping is undoubtedly a potent source of injury and there is little sense in setting the machine right if rough treatment during stripping causes injury to the teats The report concludes with suggestions for future development of milking plants. A big feature is made of low-level milk-pipes, wherewith machines could operate perfectly at a 9-10 in. vacuum. To meet this there has to be evolved a simple vacuum-operated non-surging milk-lift. This is most necessary. Of the plant generally, what is needed is a simple type, readily maintained, with a minimum of gadgets and so constructed that, even with carelessness, it will avoid causing serious injury to the cows. Much valuable work is in progress to these ends, on the part of milking machine makers and others. Meantime the farmer’s part is to make full and best use of that which he has. Well looked after, this serves really very well. But i T does require, speaking broadly, infinitely more care than has been bestowed in the past.