The effects of some environmental factors affecting on the weaning weight of sistani beef calves

Abstract

This experiment analyses the growth of calves of the conservation nucleus for Sistani cattle. Data in this study were obtained from the Sistani cattle Research Station of Sistan and Baluchistan province in Iran. Weaning weights data was available on 372 Sistani beef calves (198 male and 174 female), born between 2003 and 2007. The effects of sire, age of dam, year/season of birth, sex of calf andbirth weight was used as a covariate on the 205 days weaning weight which was computed by analysis ofvariance (GLM). Overall mean of the 205 days weaning weight of all calves was 127.25 kg. According tothe age of the dam, the weaning weight increased up to 7 years (with the exception of 6 years) and after the maximum (137.6 kg) decreased. The minimum values were found in the group of 8 years old (97.7kg) cows. With respect to birth year, the highest weannig weight (141.1 kg) was observed in 2007 and the lowest (101.66 kg) ni 2003. The year effect varied but the trend observed is that of an increase in weaning weight with time. For birth season, Spring, Summer, Autumn and Winter, the 205 days weannig weight was 112.2, 115.3, 123.2 and 131 kg, respectively. Male calves reached 121.6 kg and female calves 119.2 kg mean value of the adjusted weaning weight. © Medwell Joumals, 2011.