In the Search of Genetic Polymorphism of Lactoferrin with PCR- RFLP in Imported Holsteins in a Large Tunisian Herd

The rate of subclinical mastitis inferred from somatic cell scores is high in Tunisian dairy cattle. Other than management, susceptibility of cows to infections may be of great impact on the mammary health. Lactoferrin seems to influence resistance of dairy cows to mastitis infections. The objective of this study was to search for genes coding for lactoferrin in imported Holstein cows managed in a large herd in the North of Tunisia. A total of 52 blood samples were collected. Genomic DNA was extracted and all individuals were genotyped for polymorphism of lactoferrin gene by PCR-RFLP analysis. Amplification of the lactoferrin gene fragment revealed an 1143 bp long product by electrophoresis following PCR. After restriction enzyme digestion with HinfI, two alleles were characterized by only one restriction fragment. All screened individuals were homozygous showing the same band pattern in all samples by the PCR-RFLP, implying the existence of only one genotype for the lactoferrin locus. This study may be generalized to cover the Tunisian Holstein population for possible identification of resistant animals to mastitis infection and that have polymorphic lactoferrin genes