The need of a control of costs and production begins to make itself more strongly in modem developing farm units in dairy husbandry. It has been checked what costs are most important in dairy farming. The cost of roughages and concentrates for the herd amounts to approximately 70% of the net cost price per kg of milk. This percentage is practically independent of the number of cattle per hectare. If the feeding-costs per kind of fodder (roughages and concentrates) and the yield of the herd can be controlled, the farmer controls two major parameters in his farm management. The costs per SE (Starch Equivalent) per kind of roughage have been calculated on the basis of various costfactors both based on work done by the farmer himself and on contractor's tariffs (table 12).
Three dairy-farms were controlled for two years in order to examine the results of a method of control. The yield of milk was estimated per month on the basis of the expected standard-cow-production and the expected number of standard-cows per 10 days. It appeared that these estimations were rather accurate. For selection in the herd estimations were made of the lactationproductions (305 days) based on 60, 100, 160 and 200 days of lactation after calving. It appeared that these estimations based on the standard values of the cows were very accurate. The correlation-coefficients between the estimations and the real yields were very high. As a result of these high correlations it should be considered to restrict the milk-sampling (periods of 3 weeks) in milk-recording to 3 or 5 samples in the beginning of the lactation. This would save costs considerably. Besides the milk-yield, estimations were also made of the need of SE per month for each farm, and the supply of SE from roughages and the necessary SE from concentrated fodder.
For the grazing-period a method was applied to calculate the need of concentrates by means of the standard-values of individual cows and the standard-cow-production of the herd. This method was necessary, because in the grazing period the low productive and dry cows get more SE from grass than they need for maintenance and production. It appeared that the estimation of the need of SE was comparable with other methods of estimation. Every month the calculated quantity of concentrates was compared with the quantity really needed. It happened that there were months with great deviations, mainly caused by an adaptation to changing circumstances (the weather, the quantity of grass available, the quality of roughages) and giving too much and sometimes too little concentrated fodder. With the prices calculated (level 1975) for roughages, the prices of concentrates and the estimated prices of milk a calculation was made of the feeding-income per month (milk-money minus feedingcosts). It appeared that the costs per kg of milk, based on the costs calculated showed great differences between the summer and the winter period. The estimation of the net margin based on the prices of table 12 proved to be wrong.
The real costs per SE were higher than estimated. On the basis of the real costs calculations were made of the costs per SE and per cost-factor for several roughages. Rises in wages and the way of using grassland (percentage of cutting) proved to be important causes of increasing costs.
For the system applied the farmer needs the following information:
- the composition of his dairy herd
- the feeding-strategy applied
- the expected standard-cow production
One can calculate the milk-production from the quick method for the calculation of the number of standard-cows and the expected standard-cow production. Then it is easy to calculate the need of SE for maintenance and production. The total need of SE can be met by the supply of roughages and the concentrates to be given. In this way a budget can be made that should later be compared with the real situation.