REARING OF CALVES

Bay of Plenty Beacon, Volume 16, Issue 7, 13 October 1950, Page 3

REARING OF CALVES

BAY FARMERS CO-OPERATE IN ENDING WASTE

(Contributed by W. H. Mandeno, Consulting Officer, N.Z. Dairy Board)

For the last few years Bay of Plenty farmers have been co-oper-ating in a survey to determine the wastage in calves reared. Of the 29,308 calvings recorded in 45/46 season 4,800 were from the area covered by the Bay of Plenty and East Coast Herd Improvement Association. Through the three yeail? about 100,000 calves were recorded. Under such a large scale a survey conducted in herds of varying production levels can give valuable “field” confirmation or otherwise of more intensive work done at research centres like Ruakura and Massey.

Extensive tabulation of results makes it easy for readers to see the important features in the analyses of data from those farmers who cooperate. Whilst the proportion of “Bay” farmers who have calves vaccinated against abortion is about the average for the country it is surprising that worm drenches are used only to about half the extent in other districts. Concentrate feeding and cropping for the herd do not appear to differ greatly from the average over the country, but the high percentage of farmers using stock licks may be accounted for by the fairly common Cobalt deficiency of the higher ground. This percentage will have fallen since the Department of Agriculture has shown that money spent on lick is largely wasted unless a deficiency really exists —and in the case of cobalt the generally accepted correction is made through topdressing.

It is important to know the facts about calf wastage throughout the country. For every three cows calving one calf is reared so that in the national herd of 7.75 million cows the calves will number about 500,000. Up to 20 months of age when they approach calving troubles about 35,000 will have died. Such a loss surely justifies considerable expenditure on research into methods which will reduce such an annual drain on the industry. Many factors regarding wastage are discussed in the Dairy Board Annual Reports, but the two most striking facts relate to the major cause of loss and period which apparently requires most care in the life of the calf. It is shown that over one-third of deaths are due to scours. This may seem obvious to those who have high losses, but whereas the veterinary . profession has at its hand many helpful drugs and even vaccines it is the farmer himself who is most able. to control the onset of trouble. Generally scouring is due to bacterial infection of the digestive organs. There have to be then, active or “virulent” bacteria placed so that they can attack the weakened intestinal linings. It would be fairly safe to say that bacteria occur wherever calves are reared. They are not active however unless warmth, moisture and food are present in which condition they can quickly increase and at such times they are particularly dangerous. The calf itself has protection against the onslaught of bacteria, but such safety mechanisms are broken down under a variety of circumstances such as overfeeding and exposure to excessive cold and rain. Can Be Overcome It would seem that these factors can be overcome especially as the most dangerous period is in the first month—in fact losses fall off quickly during the first four months. If more strict attention to detail is required it is comforting to know that it is most likely to pay for a short period Although it is well known that colostrum gives the newly-born calf its supply of natural resistance to infection a surprising number of farmers do not feed “beastings” for more than one day. With suitable supplements American workers have successfully reared calves without colostrum, but it appears to pay in reduced losses to make use of this natural product which should not go into the -vat. In fact Australian workers are developing techniques whereby colostrum from all the herd can be preserved for calf feeding so that no new milk suitable for separating need be used. Although many people feeding whole milk for less than four weeks have no losses it is shown that less calves die if whole milk is the diet for over six weeks. Ii may, however, be more economical to sell the butterfat and risk an increased loss in calves. The way the calves are fed may have an important bearing on the incidence of digestive upsets and the present increase in tubefeeding will give useful data on the technique which is

similar to one used successfully in Australia.

Feeding conditions as regards cleanliness have an important bearing on the rate of loss, but this requires both conditions for multiplication of bacteria and also poor care of the calves otherwise it is hard to explain how some survive. A really capable man will often confound observers by his success whilst breaking most of the rules, but this in no way invalidates the same rules which can help to check on avoidable waste. A point of some interest is the tendency for more calves to be bought into lower than average producing herds than into good herds. In the lower level herds there is also more wastage, but eight per cent of calves raised on such farms are destined for sale as dairy stock. Few people would buy from a low producing herd; but it may emphasise the problems associated with dependance on purchased stock. Although the cost of rearing heifers may be considerable it would seem unwise to risk a policy of purchase unless the breeding background of stock is known.