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Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 03/07 Podcast
Factors associated with grower herd performance in three New Zealand pig farms

Factors associated with grower herd performance in three New Zealand pig farms

Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 03/07 vor 19 Jahren

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The aim of this observational study was to identify performance
parameters, which can be used to predict market weight of a batch
of pigs on commercial farms. For that purpose, we obtained weekly
retro- and prospective production records from three New Zealand
pig farms. The observation periods on farms A, B, and C were 140,
127 and 90 weeks, respectively. As we expected the data to be
autocorrelated, we used two modelling approaches for multivariable
analysis: An autoregressive (AR) model and an ordinary least
squares (OLS) regression model (‘naive approach’). Analyses were
performed separately for each farm. Using an AR-model, we
identified four production parameters (weaning age, two sample
weights and days to market) across the three farms that were
effective in predicting market weight with accuracies greater than
70%. All AR-models yielded stationary and normally distributed
residuals. In contrast, residuals of the OLS-models showed
remaining autocorrelation on farms B and C indicating biased model
estimates. Using an AR-model also has the advantage that immediate
future observations can be forecasted. This is particularly useful
as all predictor variables (apart from ‘Days to market’) could be
obtained a month prior to marketing on all farms.