فهرست مقالات fat tailed sheep

• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  1 - Inbreeding Effects on Average Daily Gains and Kleiber Ratios in Iranian Moghani Sheep
  N. Ghavi Hossein-Zadeh
  The objective of the present study was to evaluate the effects of inbreeding on average daily gains and Kleiber ratios in Moghani sheep. Traits included average daily gain from birth to 3 months (ADG1), average daily gain from birth to 6 months (ADG2), average daily gai چکیده کامل

  The objective of the present study was to evaluate the effects of inbreeding on average daily gains and Kleiber ratios in Moghani sheep. Traits included average daily gain from birth to 3 months (ADG1), average daily gain from birth to 6 months (ADG2), average daily gain from 3 months to 6 months (ADG3), average daily gain from 3 months to 9 months (ADG4), average daily gain from 3 months to yearling (ADG5) and corresponding Kleiber ratios (KR1, KR2, KR3, KR4 and KR5, respectively). Data and pedigree information used in this study were collected at the Breeding Station of Moghani sheep during 1987-2005. All the animals were grouped into three classes according to the inbreeding coefficients obtained by their pedigree: the first class included non-inbred animals (F=0%); and the second and third classes included inbred animals (00.10, respectively). There were significant regression coefficients of ADG5 and KR5 on inbreeding of all lambs for changing 1% inbreeding (P<0.01). Indeed, there were significant regression coefficients of ADG3 (P<0.01) and KR3 (P<0.05) on inbreeding of twin-born lambs for a change of 1% in inbreeding. In addition, there were significant regression coefficients of ADG1 (P<0.05) and ADG5 (P<0.05) on inbreeding of male lambs and significant regression coefficient of ADG2 (P<0.05) on inbreeding of female lambs for a change of 1% in inbreeding. Effects of inbreeding on average daily gains and Kleiber ratios in Moghani sheep was not very pronounced in the flock. Planned matings are, however, suggested to avoid accumulation of inbreeding and appearance of its deleterious effects. پرونده مقاله
• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  2 - Study of Factors Affecting Longevity and Survival of Iranian Guilan Sheep Using Linear and Non-Linear Models
  م. نداف فهمیده ن. قوی حسین زاده م. گلشنی
  The objective of this study was to evaluate non-genetic factors affecting longevity and survival of Guilan sheep from birth to yearling. Longevity and survival records of 41037 lambs born from 496 rams and 10256 ewes of Guilan sheep were analyzed using linear and Weibul چکیده کامل

  The objective of this study was to evaluate non-genetic factors affecting longevity and survival of Guilan sheep from birth to yearling. Longevity and survival records of 41037 lambs born from 496 rams and 10256 ewes of Guilan sheep were analyzed using linear and Weibull models. Results indicated that the overall mean of longevity was 1260.84 days. The fixed effects of flock, dam age, sex, year and month of birth and interaction between dam age-sex had significant effects on longevity (P<0.05). But birth type, birth weight and interactions of sex-birth type and dam age-birth type had no significant effect on longevity (P>0.05). Male lambs had lower survival and greater hazard ratio compared with female lambs. Lambs which born in recent years and last months of year had greater hazard ratios and lower survival in the period from birth to 2-months and birth to yearling. Lambs which born in early months of year had greater survival and lower hazard ratio than those birth to 3, 6 and 9 months of age. Although twin lambs had lower survival and greater hazard from birth to 2 and 3 months of age periods, difference of single and twin lambs was not significant in other time periods. In conclusion, linear and non-linear models can be used to study the survival of lambs and it’s possible to improve this important item through modifying non-genetic factors. پرونده مقاله