Feeding Cows to Avoid Milk Fever and its Complications

New Zealand Journal of Agriculture, Volume 76, Issue 6, 15 June 1948, Page 582

Feeding Cows to Avoid Milk Fever and its Complications

A MARKED seasonal variation occurs in the incidence of milk fever and its complications grass staggers and acidosis. This article by J. C. Gerring, Veterinarian, Department 1 of Agriculture, Hamilton, shows that these diseases are closely associated with the feed conditions at and. for some weeks after calving. Serious losses occur in certain seasons, and it is maintained that they can be largely avoided by providing ample feed for this critical time of the year.

ONE morning last spring a Waikato farmer found nine of his cows down, all within 48 hours of calving. Fortunately, with suitable treatment •they all recovered. These were typical uncomplicated cases of milk fever. In 1945 this farmer was not so fortunate. Cows went down a week to six weeks after calving and most of them resisted treatment, some of them dying in a fit. These were complicated cases of grass staggers and acidosis. How can this seasonal difference be accounted for? A mild winter in 1947 was followed by a good growth in the early spring, good supplies of hay were still on hand, and production in the first few months was well above average. In 1945, on the other hand, a long, cold winter was followed by a late, spring, hay and silage supplies were exhausted, cows continued to lose condition after calving, and production figures dropped below average. ■ - This striking fluctuation in the availability of spring feed is characteristic of grassland farming, which depends on the vagaries of the climate. Farmers must adopt measures that will tide them over such contingencies

to avoid losses cause by complicated cases of grass staggers and acidosis. Fluctuation of Pasture Growth Obviously, considerable yearly variation exists in the growth of pasture, but in general grass begins to grow vigorously in the spring, growth rising to a peak in October-November. It then falls away sharply in Decem-ber-January with the onset of dry summer weather, and rises again with the autumn rains. A low level is maintained in the winter months; growth seldom being entirely dormant. How this fits in with the food requirements of the dairy cow is illustrated in the accompanying graph. The food available is that of an average season. Even under those conditions, when grass alone is depended on, the feed available is inadequate for the cow’s requirements during July and August. When pasture growth is later than normal, as occurred in 1945, this discrepancy is accentuated, the shortage continuing into September. The extent to which provision is made for such an- adverse season is a measure of the efficiency of a grassland farmer. ' Hay and Silage The graph also shows a surplus over feed requirements in late spring and again in autumn. The late spring supplies of grass must be utilised by making hay and silage to provide for the periods of deficiency. Farmers stocking to capacity should shut up 30 to 40 per cent, of their farms for this purpose. In practice the average farmer uses only half this area, but experience has shown that farmers who save adequate hay and feed it liberally during the early part of the milking season have least trouble from milk fever and its complications. Growth surplus to requirements in the autumn should be kept in “cold storage” by closing paddocks during March or April, the saved grass being rationed to the milking cows in late

winter and early spring, in conjunction with hay and silage. This is another guarantee against a period of short supply.

On less-improved farms there is much to be said for a small area of roots to feed to cows after calving, though the daily supply may be no more than 20 to 301 b. a head.

With ample feed available, cows should be brought through the winter on a gradually-rising plane of nutrition. A week before calving they should be placed in a relatively-bare but well-sheltered paddock and fed all the hay they will eat. It is wise to keep the best-quality hay for-this time of the year. Cows should be maintained under these conditions for three or four days after calving to give them time to settle down. This practice will reduce to a minimum cases of uncomplicated milk fever.

Supplementary feeding with hay should continue until the spring growth comes away and maturesthat is, when it is 4 to sin. high. Lush, immature grass alone is insufficient to maintain cows in good bodily condition as well as providing for 1 high production. By balancing up this pasture, hay will do much to prevent complicated cases of milk fever.

Value of Molasses

Most farmers are aware of the value of molasses in preventing these diseases. That is the result of the feed value in molasses rather than of any special medicinal virtue. As a feed, molasses is costly compared with hay, and on those grounds should not be considered as a substitute. However, if supplies of hay are short, feeding jib. of molasses a cow daily will help to increase the feed intake and so reduce losses caused by grass staggers and acidosis.

Farmers must appreciate how constant are the yearly food requirements of their dairy cows and how variable is the feed

position from season to season. Making provision for the adverse season is the best assurance against losses from these diseases.