Application of different models to the lactation curves of unimproved Awassi ewes in Turkey
Yükleniyor...
Dosyalar
Tarih
2005
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
SOUTH AFRICAN JOURNAL OF ANIMAL SCIENCES
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
The objective of this study was to investigate the use of four different mathematical functions (Wood, Inverse Polynomial, Quadratic and Cubic models) for describing the lactation curve of unimproved Awassi ewes. Data were collected from 136 ewes from the same flock raised on the State Farm of Gozlu the Konya Province of Turkey. The differences in estimated total milk yields between the models were not statistically significant. All models were adequate in describing total milk yield, though total milk yield estimated using the Cubic model was very close to total milk yield calculated by the Fleischmann method. Age effects on model parameters were not significant. The Inverse Polynomial model overestimated the peak yield significantly. Estimated peak yields of the Wood and Cubic model were similar while that obtained from the Quadratic model was significantly lower than that or the other models. Day of peak yield estimated by the models varied between 10.2 and 56.4 days. The differences between days of peak yield estimated using the different models were significant. R-2 values of the models ranged from 0.724 to 0.977. The Cubic model gave the best R-2 value. The lowest mean square prediction error was found using the Cubic model. Correlation coefficients between total milk yield calculated by the Fleischmann method and estimated total milk yield from the other models ranged from 0.933 to 0.998. The highest correlation coefficient was found for the Cubic model. As a result, the Cubic model showed the best fit to the data collected from unimproved Awassi ewes and allowed a suitable description of the shape of the lactation curve.
Açıklama
Anahtar Kelimeler
unimproved Awassi, sheep, ewes, lactation curve, milk yield, mathematical model
Kaynak
SOUTH AFRICAN JOURNAL OF ANIMAL SCIENCE
WoS Q Değeri
Q4
Scopus Q Değeri
Q3
Cilt
35
Sayı
4
