Feeding the Dairy Herd FRESH PASTURE THE BEST DIET FOR COWS IN MILK

New Zealand Journal of Agriculture, Volume 74, Issue 3, 15 March 1947, Page 265

Feeding the Dairy Herd FRESH PASTURE THE BEST DIET FOR COWS IN MILK

By

M. M. COOPER,

Massey Agricultural College

AUTHOR’S ENGLISH APPOINTMENT

■ The author of this article, who holds the degrees of B.Agr.Sc., B.Litt. (Oxon), and Diploma of Rural Economy (Oxon), has been head of the Dairy Husbandry Department at Massey Agricultural College, Palmerston North, since he was discharged from the Second N.Z.E.F. with the rank of major early last year. He has now been appointed to the Chair of Agriculture recently established by the University of London, and tenable at Wye College (formerly the South-eastern Agricultural College), near Ashford. Mr. Cooper has had wide experience of farming in New Zealand and Great Britain. He was a New Zealand Rhodes Scholar, and is still in his early thirties.

FEEDING, and not breeding, is the factor limiting production on most New Zealand dairy farms. If the average, farmer could feed his herd as well as the most efficient, production would be not far below 3001 b. of butterfat a cow. Sixty guineas spent on a wellbred bull can be a poor investment if the standard of nutrition on the farm is not in keeping with the price paid for the herd sire. On many farms it would be more profitable to. spend half the money on the bull and put the balance into topdressing, pasture improvement, or the sowing of supplementary feed. f : -

IT is not possible, however, to dogmatise on the best methods of feeding. By observing the reaction of their stock and their bank balances successful farmers have evolved very different systems of feeding and feed conservation to suit the circumstances of their farms. The following examples from the Manawatu district may be quoted: One herd of about 50 cows averages nearly 4501 b. of butterfat a cow on pasture,- mangolds, and ample hay (about 1| tons a cow is saved annually). A 60-cow herd for town milk supply averages 4001 b. of butterfat a cow on grass and silage. This farmer rations autumn grass throughout the winter by means of an electric fence, and on about 90 acres produces 60,000 gallons of milk a year. He does no cropping and saves no hay. * A third farmer, on heavy swamp country, produces 2701 b. of butterfat ■to the . acre from grass and silage. Because of heavy bottom growth and damp soil he found it difficult to make good hay, and so he turned to silage, with first-class results. ? A fourth Manawatu herd, •of 120 cows, averages 3501 b. of butterfat on a more or less conventional diet of grass, silage, hay, and supplementary crops. This herd is also fed autumn grass in the late winter and early spring in breaks limited by an electric fence. Seasonal production is characterised by an early peak, indicating the great value of this grass at a critical period of feed supply. Good pasture management is common'to all these farms. Each farmer realises that fresh, leafy pasture is the best and cheapest food for milking stock under New Zealand conditions, and that no crop or conserved pasture can approach good grass in efficiency. The main effort in each instance is ' to provide a supply of such grass

for as long as possible during the dairying season.

Stages of Pasture Growth

But grass has deficiencies as well as virtues. About three-quarters of its growth is made in six months of the year, it is greatly affected by climate, and its quality varies- widely .with the stage of growth. Shakespeare, for dramatic purposes, recognised seven stages of man: For nutritional purposes it is important to recognise four stages of pasture. The first is the young and immature stage' best described as “sappy.” That is the dangerous stage associated with scouring, facial eczema, grass staggers, and similar dietetic troubles. The second is the leafy stage when fibre has risen sufficiently to give the pasture some substance.. It is often described as the 4 to sin. stage, but in mid-spring the grass can grow to a foot and still retain its desirable nutritive qualities. At that stagejust

before the main species break into seed heads can be cut and handled conveniently to provide material for first-class silage.; Such silage, properly made, will have a high feed value and will be very suitable for feeding to stock when they are in heavy productionfor example, in a dry summer ■period or just after calving. In fact, the best of the silage should always be reserved for such periods and the inferior qualities for periods when the stock are dry. • Grass-drying in Britain is carried out relatively early in this second stage. The product compares very favourably in feeding value with that favourite of concentrates, linseed cake. It is rich in protein, highly digestible, and capable of sustaining milk production at a high level. Grass-drying adds nothing to the food value of its product; all the value is present in grass at its best grazing stage.

The third stage in pasture ‘ growth is the flowering —the latest at which it should be cut for hay or silage. Compared with the preceding stage, the percentage of protein is lower, the percentage of fibre is higher} and there is a fall in digestibility. The pasture has passed from a “watery concentrate” to a roughage. No longer is it a. food for high-producing stock; it has descended to the category of good maintenance food, with a little over for production.

In , the last stage the seeds are mature, fibre has reached a maximum, and protein content and digestibility have fallen to the lowest levels. The pasture has then become second-rate roughage, with very limited value for dry stock. Too often grass is approaching this stage when it is cut for hay. Certainly hay is easily made with such a mature crop, but the product can never be classed as useful for the milking herd. Furthermore, the recovery of this late-cut pasture is not good. Cutting usually coincides with the driest spell of the year and the plant has been , allowed to complete its full cycle of growth. Grazing or. early cutting has a pruning effect and keeps the pasture in a juvenile, leafy state. /

Mixed Pastures

Generally, New Zealand’s best pastures consist dominantly of ryegrass and white clover. These- two species are the mainstays, but a leavening of other species is valuable. In the warmer northern districts paspalum is particularly useful in the summer, for it grows actively at a time when ryegrass tends to slump; the Dominion’s well-managed ryegrasswhite clover-paspalum pastures are probably among the highest producing in the world. Where climate does not favour paspalum, cocksfoot may conveniently replace it to achieve a similar balancing of growth.

A difficulty in the management of these mixed pastures is that one species may achieve such a dominance as to suppress the others and so depress annual production. That is true of paspalum, and it is characteristic of paspalum-dominant pastures that they give poor growth in the spring, when ryegrass is normally most active. To avoid such harmful dominance, paspalum ’ pastures should be kept in check in the late summer. It is generally true that to suppress any species it should be hard grazed when it is making most active growth compared with other constituents of the pasture.

There is probably a place for special pastures on many dairy farms. Italian ryegrass gives good out-of-season growth and provides a valuable bite of grass at a critical time of pasture shortage. It has the disadvantage of being an annual, but a recentlydeveloped hybrid type of ryegrass known as Hl promises well. It has the winter growth of Italian and much of the persistency of perennial. Field trials extending over five years indicate that this grass has a real future in lengthening the period of the year during which good grass will be available.

Extending Growing Season

The growing season of pasture can be extended by other means. Autumn topdressing with superphosphate, for instance, encourages winter growth and increases the proportion of out-of-season grass. Drainage of heavy country operates in two ways: Not only does it encourage the betterquality grasses with a long growing season, but it makes the soil warmer, permitting earlier active growth. Winter spelling of pastures also promotes earlier spring growth, as well as avoiding severe mechanical damage to pastures, with a consequent entry of docks and flat weed.

However, the most effective method of' providing grass for the late winter is the "cool storage” of autumn grass. A proportion of the autumn flush is scrupulously saved for July- August, so that the newly-calved cows will have available a sufficiency of the “watery concentrate” necessary to high production. It has been estimated that this method of feeding, in which milking cows get a third to half of their total food requirements from this grass and the balance from hay and silage, means a gain in production of up' to 201 b. of butterfat a cow.

The time of closing these paddocks will vary from district to district; in the Manawatu mid-April is usually suitable. It is very important that the pasture should be eaten out well and

chain harrowed before being shut up, or the rough clumps will turn yellow and deteriorate badly at the base. That is the only waste, for in a normal season the clean, fresh growth will stand well through ' the winter, and in the hardest month of the year, August,, the -farmer can view with satisfaction a paddock of what is, for practical purposes, first-class spring pasture. x

Feed Off in Breaks

In the utilisation of this grass feeding off by breaks is all-import-ant, or the cows will waste more than they eat by dunging and trampling. The portable electric fence is very useful, and in a matter of a few minutes can be shifted to provide a fresh ration of grass daily. Supplements can be fed out on the area grazed the previous day.

- The immediate food value of this saved pasture is not the only dividend the system pays. The growth response of these pastures after they have been eaten off is amazing. The grass benefits from going through most of the winter with plenty of cover to the crown, and from the return of stock fertility. The result is that such paddocks are as much as a fortnight ahead of paddocks grazed hard throughout the winter. One of the biggest obstacles to early spring growth is sqvere defoliation in the winter , and the consequent pugging resulting from such heavy grazing.

The driest and best-drained portions of the farm should be closed up; with heavy land there is too much damage to the sward in wet weather. z

Rotational Grazing

It is generally agreed that the maximum of nutrients is obtained from pasture by a system of rotational grazing. That does not mean that the farm should be closely subdivided by expensive full-scaie fencing.. On a dairy farm the job can be done just as well by three wires and a post to the chain, or by a properly-main-tained electric fence. The important point is to have flexibility in grazing, so that every .two' or , three days at least the herd is moved to a fresh paddock, and the paddock they leave is cleaned up by dry . stock, chain harrowed, and the pasture allowed to grow to the desirable stage for grazing.

As the spring flush gets ahead of grazing demands, paddocks can be taken out of the grazing rotation and saved for hay or silage. If there are insufficient subdivisions, this surplus feed is invariably left as rough clumps of very low feed value which will be neglected by the milking herd until

feed becomes so short that they have to be eaten. If a farmer regards these clumps as weeds in his pasture, he will have the right attitude toward them.

The first surplus of feed usually comes before the normal time of closing pastures for hay, and in that respect silage is useful. If this surplus feed is used for silage, it can be cut in late October-early November, when haymaking is not feasible because of the weather. But the weather is ideal for recovery, and within a month the silage paddocks can be back in the grazing rotation, at a time when grass normally becomes a little short.

Bias Against Silage

There is much bias against silage, but why that should be is difficult to understand. Well-made silage is a good food for milking stock. It provides a means of conserving grass when it still has a good food value. It is not so liable to weather damage as hay, and though the losses in food value in ensiling are considerable, they are not heavier than in haymaking, particularly if the hay is affected by weather or left to become • over-mature. Harvesting is spread— acre of silage cut in November is an acre less of hay to be made in December. There is greater flexibility in paddocks being taken out of or returned to the grazing rotation, and the aftermath from early-cut silage is much better than from late-cut hay.

The main objection to silage is the heavy lifting involved, but silage is handled only once to the stack or pit. Though hay is lighter, it may have to be handled three or four times, according to the system of haymaking and the weather. There is also the anxiety about getting the hay in in reasonable condition. From the aspects of both farm and pasture management, silage has much to recommend it in districts of abundant pasture growth.

Because of the variation in

pasture growth with the weather from season to season, too. much stress cannot be laid on the necessity for adequate food reserves. The farmer must cater not only for the average season but for the abnormal season. If he comes out of a winter with 10 tons of hay. and 50 tons of silage as a surplus, he should not feel that it provides an excuse for saving less in the following year; he should regard it as a reserve with which to cope with the bad season which inevitably turns up every few years.

Pasture is the economic strength of New Zealand farming, but it can also be a weakness if provision is not made for the difficult days.