MILK QUALITY

Manawatu Times, Volume LV, Issue 7322, 4 September 1930, Page 10

MILK QUALITY

Weather Influences The July issue of the Journal of the British Ministry of Agriculture contains an article by H. T. Craniield, advisory chemist of the Midland Agricultural College, on the effect of abnormal weather conditions on the quality of milk. In 1928-29 there was an unprecedented drought for England, which presented a serious problem for the dairy farmer. In the course of his article, tho writer says:— It is well-known that where a factor causes a drop in the yield of milk of a herd, the fat percentage rises in the majority of eases. There is no doubt that many farmers last summer were getting milk richer in fat than they realised, since this increased richness would be noticed only by thoso who periodically tested their milk or who made butter. The most remarkable effect, however, of the burnt-up pastures was the depression in the percentage of non-fatty solids. This fall in quality w-as very serious in some herds so serious, in fact, that the bulk milk frequently contained less than the piesumptive limit of 5.5 per cent. -Normal ly tho non-fatty solids content reaches its lowest level in July, rising again in August, but last year the maximum ot the depression occurred in September, i.c., in the driest month. A graph illustrates the variation in the monthly average percentages of nonfatty solids in a herd of 35 Shorthorn cows, the mixed milk of which had been sampled daily and analysed since Match of 1925. Although this herd received a supplementary ration during the di> period, the full in the percentage ot non-fatty solids was most marked, and only tho general high quality of the milk from this herd saved the percentage falling below 5.5 on all except three occasions. Another scries of figures from tnc. writer’s laboratory supplied corroborative evidence of this effect, fcin.ee the beginning of 1929 monthly samples ot : bulk milk from approximately 50 herds in Nottinghamshire had been received for analysis. The monthly variation ot the non-fatty solids content of the milk from these herds is given in the following table:—

It will be observed that nearly half of the September samples fell below the presumptive limit of 5.5 per cent, in non-fatty solids. This drought effect has been noted in past years by other observers. One iinds the following paragraph in the report on evidence submitted to the Boaid of Agriculture Committee appointed in 1900 to inquire and report as to what regulations (if any) might with advantage be made for determining what deficiency in the normal constituents of genuino milk or cream should raise a presumption, until the contrary was proved, that the milk or cream was not genuine:— ‘'Unusual mctcojological conditions, as, for instance, a prolonged drought or excessive rainfall, were referred to as unavoidably affecting thc_ condition _ ot cows and the quality of milk. A period of drought, however, tends apparently —-while do doubt diminishing tho yield —to raise the percentage of fat in milk, although it is stated that at the same time the solids not fat decrease. A period of excessive rainfall would probably have the effect of impoverishing milk, and two witnesses referred to the disastrous year 1579 as an instance o. this.” . . U. J. Lloyd, a former chemist to tin; British Dairy Farmers' Association, in an article published in Vol, XIX of the Journal of that association, states that in 1898 and 1599 (very dry years) milk fell below 8.5 per cent, in solids not tat during August and September, whilst the fat percentage was above the normal. Ho also mentions that the effect, was only temporary. A more recent reference to tho effect of dried-up pastures is found in the bulletin on “The Provision to I owns ot Milk of Proper Composition, tty ur. P. E. Nottbohm, of Hamburg, in reviewing the influence' of seasonal changes on tho solids-not-fat content of milk in Germany, Dr. Nottbohm reteis to a serious fall in this constituent dur-

ing July and August, so much so that the samples below 8. per cent, solids not fat arc numerous. He is of the opinion that lack of albuminoids, due to the constantly giazed pastures being dried up by the sun, is responsible for this fall. It appears that in Germany, where such conditions often prevail, farmers try to guard against this contingency by feeding concentrates. W hethcr this has or has not the desired effect. is not stated by Dr. Nottbohm. The writer suggests that dairy farmers should be cognisant of the effect of weather conditions on the composition of milk, and moreover include this remarkable drought factor in the list of unavoidable causes which from time to time may bring the quality of. their milk under suspicion of adulteration in the eyes of their customers and local authorities.

IO *9 n-< m-h « 5 o °r§ " m o a ?. . 60 5. 9 Y -S w p ° y do lZ* P.'W g ft 6 p V A w § £ s January .. . i • *i •» oLj 9.00 0 February .. 41 9.04 5 9.04 5 S.91 o May .. .. .. 50 8.93 0 June .. .. .. 47 8.94 4 July .. .. 8.84 16 August .. , .. * . .. 45 9.00 4 September i • • • .. 19 8.53 45 8.89 4 November .. 20 8.95 0 December .. 49 8.99 2