Relationship of Lactoferrin Gene with a Number of Growth Traits in Holstein Calves

This study was conducted at the Dairy Cattle Farm pertaining to the Department of Animal Production, College of Agriculture in Abu-Ghraib (20 km West of Baghdad) and Al-Jaderiah, as well as at the Biotechnology Physiology Laboratory at the College of Agriculture, University of Baghdad, Al-Jaderiah, in collaboration with the Laboratory specific for molecular genetic analysis during the period from 27/11/2015 to 1/ 04/2016. The objective of this study was to identify the polymorphism of lactoferrin gene and their relationship with some growth and productive traits for 28 Holstein cows and their births. The distribution percentage of lactoferrin gene polymorphism in cow's sample were 17.86 and 82.14 % for AA and AB respectively. The variation between these percentages were highly significant (P?0.01). The allele frequency for A and B were 0.59 and 0.41 respectively, according to the lactoferrin gene analysis carried out currently. The effect of lactoferrin gene polymorphism. The body weight and dimensions of calves at birth did not affected by lactoferrin gene polymorphism. At weaning, the variation in heart girth was significant (P?0.05), whereas, the weight and dimensions have not significantly influenced by lactoferrin gene polymorphism. The calf's body weight at 12 months old was 328.78 ? 5.99 kg for those born from AB cows, being greater (P?0.05) than those born from AA cows (3.16.75 ? 10.19 kg). Moreover, AA genotype exhibited better (P?0.05) service per conception, non-return rate and calving interval, along with interval between calving and subsequent successful mating (P?0.01) than AB one. The calves mortality rate at weaning was significantly (P?0.01) affected by lactoferrin gene polymorphism. It can be concluded from the study of gene expression for lactoferrin gene, the possibility of adopted them in cattle breeding strategy by increasing the economic gain of the breeding schemes, by selecting and crossing the high growth calves genotypes or phenotypes.