Statistical Methods to Produce "Good" Bovine Frozen Semen

A "good" bovine frozen semen must have: high fertility, low costs, good genetic values. The genetic value is associated to the sire and the Artificial Insemination (AI) centre can only optimize the management of the progeny test program. The high fertility and the low costs are strictly linked to the qualitative level of the technical management of the AI centre. The optimization of the management of an AI centre can be done by the choice of the best systems of semen handling and analysis, using the methods of the Statistical Quality Control (SQC). To support the production in an AI centre, it becomes important to set up some statistical instruments aiming to performing a Statistical Quality Control. These instruments (such as Control Charts) should allow the monitoring of the production because the various lots, produced by the same centre, should have a basically constant number of motile spermatozoa after thawing (the quality parameter with the better correlation with the fertility). Moreover, this number should range within the tolerance limits established by the centre. Only in this way the production activity of an AI centre may become of industrial type. The system that aims to maximize the production level, in an AI centre, as a function of the number of motile spermatozoa after thawing, consists of predicting forward motility and concentration, after thawing, of a batch of semen and using these values to compute the correct number of straws to produce for the batch (for each bull). The ARIMA models can be used to forecast the percentage of motile sperms after thawing for bulls with continue production, while to forecast the concentration it is necessary to verify the loss of spermatozoa during the semen handling.