Comparison of Different Mathematical Models for Describing the Complete Lactation of Akkaraman Ewes in Turkey

- Journal title : Asian-Australasian Journal of Animal Sciences
- Volume 19, Issue 11, 2006, pp.1551-1555
- Publisher : Asian Australasian Association of Animal Production Societies
- DOI : 10.5713/ajas.2006.1551

Title & Authors

Comparison of Different Mathematical Models for Describing the Complete Lactation of Akkaraman Ewes in Turkey

Keskin, Ismail; Dag, Birol;

Keskin, Ismail; Dag, Birol;

Abstract

This study was carried out to investigate the use of three different mathematical models (Wood, Quadratic and Cubic) for describing the lactation curve of Akkaraman ewes. Data were collected from 42 ewes that were three years of age and from the same flock raised in The State Farm of in Konya Province. All ewes lambed in March. They were hand milked twice daily and the first milk test was performed with in the first month after lambing (mean = 27.8 day, SD = 4.26) in an attempt to describe the peak yield. The differences between estimated total milk yields by the models were not significant. The models were adequate for describing total milk yield. The differences between peak yields were not significant. The Wood model estimated the time of peak yield earlier than the other models and observed values (p<0.01). Especially the Cubic model's peak time was very close to really peak time (34.30 vs. 35.33 days). values of the models ranged from 85.85% to 96.20%. The Cubic model gave the best value (p<0.01). Correlation coefficients between descriptive values of the models changed from 0.32 to 1.00. Total milk yields of the models were highly correlated (above 0.99) with the total milk yield calculated by the Fleischmann method (p<0.01). As a result the Cubic model showed the best fit to the data collected from Akkaraman ewes and allowed a suitable description of the shape of the lactation curve.

Keywords

Akkaraman;Ewes;Lactation Curve;Milk Yield;Mathematical Model;

Language

English

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