The present study aimed to determine the contribution of the genetic effect of bulls used via artificial insemination on the dairy production of Brown Swiss cows from the El Mantaro Agricultural Experiment Station of the National University of Central Peru, in terms of daily milk production (PLD) and by lactation (PLC). In total, 112 lactations were used, from a total of 49 cows, daughters of 7 Brown Swiss bulls, standardized to 305 days (PLE) and two milking by non-linear projection. The statistical analysis was carried out by using a mixed linear model, considering as fixed factors the number of lactations, year, season and age at calving of the cow, and as a random factor the genetic effect of the bull. Corrected phenotypic means were obtained for PLD and PLC with the correction factors obtained from the model, and predictions of the predicted transmission ability (PTA) of the evaluat...

The aim of this study was to validate the use of mathematical equations to predict the weight and yield of the carcass of guinea pigs based on their morphometric measurements. The following measurements were determined in 60 male and female guinea pigs aging 11 to 12 weeks: head width (AC), head length (LC), thoracic depth (PT, thoracic width (AT), body length (LM) and left leg thickness (EP), in addition to live weight (BW). Carcass weight (PC) and yield (RC) were estimated based on carcasses of animals slaughtered after 12 hours of fasting. A multiple regression model and the Stepwise Regression procedure of the SAS statistical software were used to select and assess the contribution of the biometric attributes in determining the prediction equation with optimal goodness-of-fit characteristics for the variables to be predicted. It was found that PV, AC and AT are the best predictors of...