Pakistan Veterinary Journal (Mar 2002)
REPEATABILITY ESTIMATES OF SOME PRODUCTIVE AND REPRODUCTIVE TRAITS IN RED SINDHI CATTLE
Abstract
The breeding records of 179 Red Sindhi cattle maintained at the Livestock Experiment Station Hab Choki, Balochistan, during the years 1982-97 were used in the present study. An effort was made to estimate the repeatability for some productive and reproductive traits by using the Mixed model least squares and maximum likelihood procedures. The repeatability estimates for milk yield, lactation length, dry period, service period, gestation period and calving interval were 0.361 ± 0.05, 0.03 ± 0.05, 0.029 ± 0.06, 0.17± 0.06, 0.94 ± 0.55 and 0.167 ± 0.06, respectively in model 1, whereas in model 2 estimates for milk yield, lactation length, dry period, Service period, gestation period and calving interval were 0.354 ± 0.05. 0.041 ± 0.05, 0.040 ± 0.06, 0.173 ± 0.06, 0.98 ± 0.056 and 0.165 ± 0.06, respectively. The repeatability estimates are used in determining the amount of culling that can be safely done on the basis of records. A high estimate of repeatability provides enough evidence for selection or rejection of the individual based on single record. Whereas a low estimate of repeatability justifies accumulation of further records. A moderate estimate of repeatability (0.361) for lactation milk yield obtained in the present study indicates that the cows can be selected for milk yield on the basis of relatively lesser records in the present herd.
