Resumen de GM 01. Study of some fertility indices of dairy herds monitored by computerized information systems
Magda María Gilhermino, M. A. R. de Freitas, A. R. Zambianchi, S. F. Grossi, L. M. Vanni
The objective of this work is to verify the tendency of some fertility indices of monitored dairy herds from 1992 to 1995. In developed countries the use of computerized information systems has contributed significantly to the increase milk production. Data from a program of monitoring dairy farms developed by the “Estação Experimental de Zootecnia de Ribeirão Preto, IZ/SAA, SP, Brasil” were studied from 1992 to 1995. The fertility indices used to assess the performance are described: a) calving interval to conception (days); b) days open; c) percentage of cows that re-calved; d) number of services per conception. There was a tendency for the calving interval to conception to decrease over the years. This indice is a good parameter to assess herd efficiency. It reflects improvements of the herds in cow fertility, heat detection efficiency and artificial insemination. The days open take into account all cows that did not yet conceive within 12 month period, hence it shows the poorest cows in the herd. Surprisely, the percentage of cows that re-calved tended to decrease over the years. This work showed that it is difficult to state if the herd performance has improved or not based only in the studied indices. The results suggested that many factors are involved when assessing dairy herd fertility indices, specially in developing countries where milk policy does not always motivate the dairy farmer to have a tight policy with his cows. It is also important to understand that over the years farmers have learnt ‘what’ and ‘how’ to record, as a consequence, some fertility indices seemed to be worse but they were more realistic than previous figures. Educational programmes for dairy farmers on the information needs and use for farm management should be supported and implemented.
