Growth curve in Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs

KOCABAŞ Z., Kesici T., Elicin A.

TURKISH JOURNAL OF VETERINARY & ANIMAL SCIENCES, cilt.21, sa.3, ss.267-275, 1997 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 21 Sayı: 3
  • Basım Tarihi: 1997
  • Dergi Adı: TURKISH JOURNAL OF VETERINARY & ANIMAL SCIENCES
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.267-275
  • Anahtar Kelimeler: linear model, common regression, homogeneity of regression, pure error, lack of fit, lambs, GERMINATION
  • Ankara Üniversitesi Adresli: Evet

Özet

Weekly body weights from approximately 10 weeks of age to 19-29 weeks of age were used to study growth curve in Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs. A linear model was fitted to means of body weights using age as independent variable. The linear model provided a good fit with R-2 values of 99%, 99.3% and 98.9% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman, respectively. After that, a common regression coefficient was calculated as within lambs regression coefficient, which gave R-2 values of 95.9%, 97% and 95.8% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs, respectively. However, test of homogeneity of regression coefficient verified that there was an evidence of a statistically significant diversity of regression coefficients fitted to each lamb, which means that the growth pattern of ail lambs cannot be represented by a common regression equation. Moreover, the data were analysed considering several measurement on body-weight at each time point. in this way, residual sum of squares was divided into two parts: pure error from repeated measurements and lack of Wt sum of squares. This method led to a decline in R-2 values, which were 79.1%, 91.7% and 88.4% for Akkaraman, Ivesi x Akkaraman and Malya x Akkaraman lambs, respectively.