MILK TESTING.

Franklin Times, Volume 9, Issue 778, 24 October 1922, Page 2

MILK TESTING.

DAILY VARIATIONS. Some Data from Certificate of Record Work by W. M. Singleton, Assistant Director of the Dairy Division. Ever since the inception of the factory system of manufacturing' creese and butter the yeild from the milk supplied by -individual dairymen has received more or less attention. In the earlier days when payment was made on quantity alone, tests to disclose possible adulteration were in vogue, and this system prevailed generally until the introduction of the Babcock test The general use of this test lin New Zealand! has superseded the earlier tests for adulteration. It has been found that to add water does not increase the payment from the factory. ■’'No system seems to be inseparable from irritating factors. Although payment for milk on the butter-lfat basis is generally recognised to be the best yet devised, the human element must be introduced in making the tests. The work has therefore sometimes been cfuestioned by suppliers receiving a comparatively low test. While carelessness in the testing may justify some of these complaints, the larger proportion of the dissatisfaction is probably due to causes arising from the cows and' not to the factory testing. Equal Daily lYlilk Yield with Varying Tests. In the course of the certificate of record work carried out by the Dairy Division we have collected data from testing the samples of two consecutive days separately. These purebred cows are, as a class better cai’ed (for that the Individuals of an average dairy herd. Milking hours are more regular and care is taken in many cases to guard against such cows becoming' nervously upset. Despite such precautions the variations in percentages of fat from day to djay were sometimes found to be extraordinary. When the weight of milk does not vary from day to to day a cow might be expected to be in a uniform state of health. and her milk uniform in quality. ‘ This may be the mile,, but i,f so, the following exceptions have been authenticated by our officers:— Efiirst day, milk in pounds 24.0, 26$ 34.5 .18$, 39.8 Fat percentage/ 6.1, 7.3 5.8, 8.1, 4.2. Second day milk in pounds 24.0, 26.9, 34.5 18/7, 39 5. Fat percentage, 4.4, '6.1. 7.0. 6.3, 5.8. Difference' milk in pounds, 00, 0.0 0.0 0,2, 0.3. Fat percentage. IX 1.2, 1.2. 1.8, 1 6. Daily Milk Yield! not an Index of the Test. Dairymen and breeders frequently assume that if the weight of milk shows a decrease for the day the percentage of butter fat must sow an increase It is assumed on this reasoning that the cow secretes a practically mniform weight, of butter-fat each consecutive day, although this may increase or decrease over a period. If the, decrease in test be due to other than shortage of feed this reasoning, appears to be unsound. If cows are in good condition and feed is restricted! for a tyrne the expected result may occur. Ilf the cow' is in very low condition probably the test is also below normal. The examples following show that cows on, certificate of record test —not short or feed or J n low condition—may evidence a decrease in their daily milk wdi'ght and also a decrease in the percentage of fat as compared with the preceding or following day. Authenticated figures bearing ou this contention are : First day, milk in pounds 51.8, 20.6, 3.1 4, 31.8 32.8. Fat percentage ss, 7.6.' 7.3, 5.3. 4.3. \ Second day milk in pounds, 40$, 18.1 29 1, 27.8 2.4. Net percentage,' 2.6,' 6.1, 5.7. 4.8. 3.1. Difference, milk in pounds 40.9, 2.5 23, 4.0,' 5.4. Fat perecentage, 2.4' 1.5. 1.6. 0.5, 1.2. When a 'cow is producing her maximum milk yield for the day may be not not assume she is feeding particularly well If a cow is in the best of health it should not be unreasonable to expect an increase in perecentage of butter fat as well as in weight of milk. Judging from figures from certain « record data given below, if would appear that in such circumstances an increase in butter fat percentage is not unlikely. This recalls a statement of Dr Babcock’s to the effect that cows going from stable feed to pasture grass in the North American spring time are inclined to increase botoh in milk yield and percentages o>f hotter fat. The following are the figures' confirming the suggestion made as to such increases : First day, milk in pounds, 21.6. 28.2, 38.9 *36 0. Fat percentage’ 4.4, 4.7 3.3, '4 5. Second day, milk in pounds. 23.6 32.0, 43 0, 37.9. Fat percentage, 6.6 5.8 4,1/ 5.3.. Difference, milk in pounds, 2.0, 3.8, 4.1 19. Fat percentage 2.2, 1.1. 0,8,' 0.8. Menstruation Period. The effect on the daily yield of milk and perecentage of butter fat of the cow coming “in season’’ is difficult to forecast. Some cows appear to vary but little, if any ; others may evidence a decrease in milk .flield,* but the test may be unaffected ; while others, again may show a normal milk yield with a decrease in perecentage of butter fat. The variations may include both milk and test. When such is the case-the milk usually evidences a decrease more or less marked and the butter fat percentages are in many instances anc lined to evidence a decrease as well. The following figures represent variations at the period in question : Normal, milk in pounds, 28.5, 42.3 20 1, 31.3 41.4. Fat percentage 6.2 3.4, 5.8, 5.8, 3.5. In season milk in pounds 29.5. 375, 20$, 11.8, 336 Fat percent! age, 6.2. 3.4. 4.6 4.3, 2.6. Difference" milk in pounds, 1.0, 4.8. 0.1 19$ 7.8. Fat percentage, o.o* 0.0,' 1.2, 1.5, 09. Change of Milkers. It seems to be well known that

any influence wht'ch affects 'the cow in a manner which she dislikes will be reflected in her production. So long as the writer can remember it has been advocated that cows i-nauld. as far as possible, have the same milker at each milking. Some cows are affected very materially, while others are not so discriminating. When a variation is caused by a change of milker it is generally at the expense of the owner. £he new milker usually getting poorer results. An eminent authority has stated] that to get the best results from a cow; the milker must take the place of the calf in the cow’s affections. The evidence certainly points to the conclusion that the cow prefers old friends. Our cfata in this connection are, in part, as (follows : Regular milker, pounds in milk 29.6, 28.7. Fat percentage. 6.5. 6.3. Ne\V milker, mjik in pounds, 26.9. 26.3. Fat percentage. 4.1 4.9. Difference, milk in pounds. 2.7, 2.4. Fat perecentage, 2.4. 1.4. The work carried "out by the testing officers of the Dairy Division emphasises the fact that variations occur !im the butter fat percentage of a cow’s milk from day to day lo a degree many would not have thought possible. The comparative quantity of milk given (for the day cannot be taken as an index of the tent in every case, as our figures show that when the milk weight evidences an increase the test may show either an increase or a decrease, or remain normal. Although cows when in season are more likely .to yield a smaller quantity of milk than to give an increased flow many cows vary little in this resepct. The tost for the smaller yield of milk may remain normal, or vary from the normal m either direction. A change of milker seems to carry with it. as a rule, a penalty by way of a decrease in milk weight .and in many instances a reduction in the test as well. The foregoing information is put forward with a view to assuring dairymen and breeders that when vacations occur in tests for butter fat it should l not be immediately assumed that the variation is due to carelessness, lack of ability, or malice on the part’ of the person .conducting the teat.