THE CREAM TEST.

Timaru Herald, Volume XCVIII, Issue 18084, 17 November 1924, Page 4

THE CREAM TEST.

WHY IT VARIES Because of tlie frequent variation of the test, many dairy tamers .sometimes think that they are not getting a “fan deal" irom their factories, 'these men ask why the test should vary when the conditions under which cream is Produced remain the same Irom day to clay. The same cows are, milked, the feed is the same, and the cream screw of the separator remains unaltered. Actually, il the test remains the same form week to week, it sliouiT] arouse suspicion as to the accuracy 01 the testing. Cream does vary in richness and lat, and because many dairy farmers do not quite uutlerstancl the causes of this variation misunderstandings arise l between suppliers and their factories. The variations do not indicate faulty testing, they are due to causes over which tno factory tester lias no control. There are several factors in the separation ut milk that cause variation ot the cream test, and dairy farmers should examine these* before doubting the authenticity of factory returns, in the first place, the separator should bo placed on a linn and solid foundation, and sot perfectly level. If this is not done, the working parts soon get thrown out ot j balance*, as the machine revolves during | the skunming process. Smooth running ' ensures 1 the* skim milk and creutu; flow- ■ ing freely to their respective outlets. it 'there is any vibration, the milk and cream get shaken together, and imperfect separation is the result. In the manipulation of the separator, it 1S important that the ofahk should be turned the correct number of times per minute. Instructions are given with every machine as to the speed at which the. handle should be turned to obtain the best results, and these instructions should be closely 'followed?' Atiy;M?hangoof speed alters the percentage, of butterfat m the? cream . On the other handj.'-V speed of the bowl throws cfukjfes*' skim milk; and A larger anion licr cream. Jf the speed of the bowl is much below the normal rate, the :c:reairr»; .\v ill be'^..iH>perteqU>g, !; i ! .ypy rated, from the milk serum, ;as some or the fat will pass into the skim milk, ’these are important ' factors in causing . a variation in the cream test. , ' The rate of ijqflow of milk into the bowl may also cause a varying test. Every machine is set to a certain capacity per hour, and it is assumed that the. milk flows at the same rate because of the boat regulating the inflow' into the bowl, but sometimes the tank is allowed to get-low, -or- tlw> faucet may not be opened to its' full capacity, with the result that the amount of milk flowing into the bowl is decreased, if the flow of milk into the bowl is decreased, a richer cream will be throw'll out. Variation in the richness of the milk of the herd also causes a variation of the cream test. At certain times of the year particularly in the autumn, the milk is richer and'if there be no alteration of the cream screw' of the separator the • test should be higher than at other times of the year. The milk test ot tlie herd is influenced by other factors, such as sexual disturbances, sudden changes in the weather, a complete change of feed, or exeitnienl of any kind.” The temperature of milk when separated also affects the cream test. Warm milk will flow more, readily and separate easier than cold milk, and, in consequence, milk should not ho sepaI rated when below a temperature of SO ! deg. Falir. The heat at which ,it is I drawn from the cow, i.c., 00 deg. I* a 11.., I is the most suitable temperature at I w'bicli to separate. Cold milk does not separate readily, os me co..i cieam. clogs the separator, arid, there,is a consequent loss of fai: in Ihe skim milk. Flushing the is a common cause of varying the "cron in tests because variation of il.c amount of water or skim milk may appreciably alter the yield or cream, it is easy enough to vary a pint or so in (lie amount used, and this limy vary I the icst from 2 try-a per cent., according to the ouautity of cream separated. The identical amount of flushintr venter should be used on each occasion to get evc.ii results Cionnlineo; .in every detail of the separator is also essential if even results are desired. Tim. richness of cream is rearldy • trovovned bv the cror.m screw, but, as i dairy farmers do not tinker frequently will', that, portion of the. machine, this factor ir.nv be regarded as a negligible cause in the curving test. The orwm screw should be operated to produce ilie icst of flic cream between -10 and 50 po,- cent. Skim milk left in fbc cream enuscs quick sourirw. It remains, then, for ad dairymen to carefullv consider , the reasons ref. out above. Thcv will find in most cases Hint flie trouble hen I in inaccurate or d..shorn”-!' tests at ! the freiorv, hut in conditions nvr 1 n-U.’cb the fact o'-v fester lias no control. I (“Journal of Agriculture,’ - ''. Victoria.