FEED FLAVOURS

Taranaki Daily News, 13 April 1935, Page 24 (Supplement)

FEED FLAVOURS

CORRELATION OF PASTURE investigations by expert. Suggestions, as the result of investigations, regarding the management of pastures to avoid feed-flavours are made by Mr. E. Bruce Levy, agrostologist to the Department of Agriculture, in a'comprehensive article in the March issue of the New Zealand Journal of Agriculture. He states, inter alia, that as part of the policy of endeavouring always to obtain the highest possible quality in dairy produce the matter of feed-flavour in butters has been the subject of a recent investigation. In this investigation, from the botanical point of view, 40 farms were visited and'the pastures examined as to their botanical composition. Dominance of species was noted in respect to grasses, clovers and weeds, and special attention was paid to stage and rate of growth and manurial practices followed. Prior to the investigation many'opinions were current as to the cause of feed-flavours in butters. It was contended, (1) that the type of pasture, particularly that induced by top-dressing, especially by superphosphate, vzas largely responsible; (2) that certain weeds and specific plants such as lotus major were largely contributory to the trouble; W) that it was largely a matter of dairy hygiene; (4) that it was not so much the class of food as the manner in which it was fed and the amount of scour it caused in the milking animal—the problem was again one of dairy hygiene coupled with digestion troubles in the animal itself (the question of scour was specifically stressed in the matter of peat swamp land); (5) that the flavour might arise from the decomposition of butterfat by the action of ferments or enzymes which are present in all plants (these enzymes are held to break down the butterfat into fatty acids and glycerine, and it is the fatty acids that are held to cause the taint and smell); (6) certain proprietary-manure interests have asserted definitely that superphosphate is to blame, and suggest that the remedy lies in the use of' a non-acid manure made, of rock-phosphate instead of superphosphate; (7) there is a very general agreement among Waikato suppliers that some modification of manuring methods, pasture, and herd management might succeed in lessening to some extent the strong feed-flavours, It is obvious from the above opinions that a specific investigation into the whole question of food-flavours in butter was warranted.

BOTANICAL INVESTIGATION.

The botanical investigation commenced early in September, and it soon became apparent that no specific weed in the pasture was responsible, the more weedy pastures in the early part of the season at least giving little or no feed-flavour, whereas the standard first-class pastures, dominantly rye-grass and white clover with little or no weed, gave the distinct characteristic feed-flavour in the cream, A scheme for the testing and grading of cream was inaugurated by the manager of the Morrinsville Co-operative Dairy Co., Ltd., Mr. A. M. Stirling, wherein the cream supplied night and morning from specially selected farms was subject to critical examination after its receipt at the factory and again the following day. Bacterial count, or acidity, does not appear to be a factor affecting the incidence or intensity of feediness, but occasionally may confuse the issues. All creams classed as “off” or doubtful in purity were, however, excluded in assessing intensity of feediness of flavour.

In the botanical surveys the following aspects were kept firmly in mind: (1) The chemical composition of the sward; (2) style of management and state and stage of growth when , grazed by the herd; (3) the manurial practices adopted. The contention among the farmers of the Waikato that pasture and herd management might succeed in lessening to some extent the strong feed-flavour seems to be substantially correct. That there is something in herd management is clearly indicated by an examination of morning cream compared with the night cream from the same herd and shed, and often from the same pastures.' It is consistently shown that the night cream is often .strongly feedy, and the morning cream is comparatively mild. The fact that morning. cream is less feedy than night cream does not support the opinion that enzymes or ferments are responsible for feed-flavour if it is correct that at night the plant tissues contain large amounts of these ferments and during the day the ferments are practically absent. This difference between night and morning milk is apparently largely influenced by the grazing habit of the cow at night as compared with day in relation to the amount consumed and the nearness or otherwise to milking-time that food is eaten. It is well known that if taint-producing feeds like turnips, cabbage, green lucerne, etc., are fed shortly prior to milking, bad feed-flav-ours develop; whereas if these are fed immediately after milking little or no taint is observed. If we regard young, luscious, quickly-growing pasture as being a taint-producing food, then the time of eating of this prior to milking will have a very decided influence in the feediness or otherwise of the milk or cream produced. It was ascertained that little or no grazing is done by a well-fed dairy herd between the hours of 1 a.m. and milking-time.

INCIDENTS OF GRAZING.

Observations go to show there is comparatively little grazing done between midnight and milking time in the morning, and this may have an important significance when coupled with the mild feed-flavour of the morning’s cream as compared with night cream. It brings up the question whether it is possible to manage the dairy herd in such a way that the luscious early spring growth is rationed so that the herd is off it and on non-luscious feed four to five hours prior to milking in the evening. The fact that the dairy herd automatically rations itself at night also points rather to the possibility of using the early luscious feed as night grazing rather than as day grazing as at present. A fairly standard practice at present is to put the cows in the day on to the young fresh luscious feed and then at night to put them on to harder feed, with or without hay or ensilage. Later on in the season the herd may at night have the run of day paddocks after these have been used as day paddocks for one or more days.

Another practice is to use special night paddocks regularly night after night. In all these practices the tendency is to graze fresh luscious feed by day and non-luscious or essentially grassy feeds by night. In view of the fact that the herd automatically rations itself by night it would appear sound as regards feedflavour control to reverse this practice, giving the herd access to the more luscious fqed after milking at night and the less luscious during the day, and pax-

ticularly from mid-day until milkingtime in the evening.

During the course of the investigation some attempts were made to ration the herd on several farms from mid-day onward, but the season was so erratic in respect to feedy flavour as to make these trials of little value. In addition, attempts to ration were made late in the season when hay and ensilage supplies were exhausted and when there were no special paddocks prepared for the purpose. Rationing under the above conditions was not wholly satisfactory, but none the less some slight improvement in the night cream was effected.

It would appear, if rationing is an essential to reduce feed-flavour in night creams, that an earnest endeavour should be made to get certain pastures on the farm more grassy, or to make more use during the day of the more grassy “night” paddocks than is made at present. If each farm had two or three grassy paddocks that are let get away somewhat long, and if these are. used from, say, 11 a.m. to milking-time in the evening, then there is a fair possibility of the feed-flavour problem in the night r'lk being considerably reduced. Newly laid down paddocks are essentially grassy, and if these are sown with certified rye-grass, cocksfoot, and paspalum, with a small amount of clover, they may be kept grassy for years by periodic dressings of sulphate of ammonia or ammoniated super. It is essential in following out such a practice to have the land well limed before using sulphate of ammonia either alone or in the form of ammoniated super. Nitrogenous manures are essentially grasspromoting, whilst phosphate, potash, and lime encourage clover rather than grass. Some farms are essentially grassy in virtue of the high per-acre stock-carry-ing capacity, as a result of which large quantities of quickly available nitrogen in the form of urine and dung are being applied regularly, and it is considered that when a farmer obtains a carrying capacity in the vicinity of one dairy cow per acre or a little better the farm definitely becomes grassy, and this offers the best final'’solution to the feed-flavour in the Waikato. It must be borne in mind that large areas of New Zealand are literally made by phosphate and stock, and in the making of these pastures the swards are essentially clovery —it may, in the early stages, be suckling clover or subterranean clover, or red clover in newly-sown pastures, and, later on, white clover associated with more or less grass according to the stocknitrogen excreted by the grazing animal In contradistinction to this phosphatemade country, naturally fertile country is essentially grassy rather than clovery, and in this the feed-flavour is not so acute. The Waikato soils are essentially light and pumiceous. They increase In warmth in the spring exceedingly rapidly, and when provided with adequate moisture give a remarkably early and luscious, growth, and it would appear that there is something in the newly-formed rapidly multiplying tissues of the plant that is decidedly prone to cause taint in milk, and in this stage grass as well as clover may be contributory. The grassy swards, however, tend J - mature hnd harden earlier than the clovers, and this hardening has a marked reducing effect on the taintproducing propensities of the herbage. The practice of keeping the sward short tends to encourage clover rather than grass and to produce greater quantities of young, vigorously growing leaf rich in protein, and these two factors appear to intensify feed-flavours. Allowing the pasture to develop more heightup to the 6in to Sin stage—operates in three ways: (1) Grasses are encouraged? (2) ciovens are suppressed; (3) the herbage is older and more hardened. The hardening of the pasture and consequent ageing of the leafage appears almost entirely to correct feed-flavours. This was noted particularly during the investigation as soon as a week or so of dry weather intervened between rains.

EFFECT OF TOP-DRESSING.

There is a widespread feeling that topdressing with phosphate is directly or indirectly the main catisft of feediness. It has been pointed out thAt feed-flavour in cream is apparently due largely to the clover when this is in a rapid stage of growth. It may be suckling clover, subterranean clover, red clover, Or white clover. In the case of certain farms where suckling clover is dominant little or no top-dressing has been applied during the last five years; therefore topdressing cannot be blamed for feedflavours in those instances, and yet the taint is identical with that secured on heavily top-dressed farms. Nevertheless it is obvious that top-dressing with phosphate, potash, and lime intensifies feediness in proportion to the growth of clover that such manures encourage, and it appears that the value of a phosphatic manure is relative to the clover growth it promotes.

If certain phosphatic manures do not increase feedy flavour in the early stages of pasture improvement in such soils as the Waikato, then they can be discarded. There has been an increase in the use of superphosphate, which is the main fertiliser used in the Waikato, and there has undoubtedly been a marked increase of feediness, a sure indication that superphosphate is doing its job of increasing production. Some farmers to-day, seeing this increase of feediness, are hesitant about applying more superphosphate and tend to look for other fertilisers or to reduce the use of superphosphate. This is bound merely to increase feediness and to result in loss of production, and it will prolong the time of transition from the clover-dominant to the grassdominant phase.

Certain specific weeds such as hogcress, popularly known as land cress in the Waikato, pennyroyal, watercress etc., are said to import characteristic feedflavours in the cream, but these can be detected apart altogether from the characteristic feed-flavour under investigation, the investigator says. In conclusion, the article states: The suggestions outlined in this report offer no explanation of the actual factor or factors responsible for feediness. The explanation is probably wrapped up in the complexities of chemical changes associated with very rapid growth—rapid formations of carbohydrate materials; transformation of these to soluble sugars by ferments; the rapid absorption of nitrogenous and mineral compounds and the chemical reactions in the formation of proteins of which young growth is rich.