DefinePK

Abstract

Mating between closely related (than the average of population) individuals is termed as inbreeding and is unavoidable in commercial breeding programmes in dairy cattle. Consequences of inbreeding include genetic drift, loss of hetrozygosity, and decrease in genetic variance. In breeding coefficients were estimated through using a total of 7345 pedigree records of Sahiwal cattle maintained at 6 institutional herds viz. LES, Jahangirabad (Khanewal), Khizerabad (Sargodha), Bahadurnagar (Okara), Kalurkot (Bhakar), Fazilpur (Rajanpur) and Shergarh (Okara) of Punjab province of Pakistan from year of birth 1973 to 2007. The overall inbreeding coefficient of all animals was 0.56%. Total 766 (10sires and 756 cows) animals (10.43%) were found inbred. The average inbreeding coefficient amongst inbred animals was 5.33%. Maximum average inbreeding coefficient (25%) was observed in the herds maintained at Kalurkot, Fazilpur and Shergarh having relative small population size. It was followed by Jahangirabad and Khizerabad, while the lowest value of IBC was at Bahadurnagar with the highest number of animals inbred. Minimum (2.48%)IBC was found in the cows born during 1996 with 34 number of cows. The maximum 68 inbred cows were observed in the birth year, 2001.