Document Type : Research Paper
Authors
1 Corresponding Author, Department of Animal Science, Golpayegan Branch, Islamic Azad University, Golpayegan, Iran. E-mail: smirhabibi@iau.ac.ir
2 Department of Biotechnology Research, Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. E-mail: h.emrani@areeo.ac.ir
3 Department of Animal Science, Faculty of Agriculture, Isfahan University of Technology, Isfahan, Iran. E-mail: h.asadollahi@ag.iut.ac.ir
4 Department of Animal Science, Golpayegan Branch, Islamic Azad University, Golpayegan, Iran. E-mail: mhaghighat@iau.ac.ir
Abstract
Objective: The first foreign breed of cattle imported to the United States to cross with the native cattle was the Brown Swiss breed, which has a high tolerance to climate change and little change in milk yield with environmental conditions. This breed is known for having higher quality milk than the Holstein breed. So far, little research has been conducted on the production and reproductive characteristics of the Brown Swiss breed and its genetic loci. The results of recent studies show that in addition to phenotypic and pedigree information, molecular marker information can be used as an auxiliary tool in the selection of domestic animals. Milk caseins are one of the most important proteins in milk, whose natural role is to interfere in the formation of micelles and curdling of cheese. Kappa casein is one of the most important caseins, which is very important in the quality of the produced cheese and the efficiency of turning milk into cheese. Several reports have shown the polymorphism of the kappa casein gene locus with milk production traits. The kappa casein gene is the most important major gene that influence the milk production related traits. The aim of this study was investigate the association of this gene with production related traits breeding value in Brown Swiss cattle in Iran.
Method: The present investigation was undertaken on the data of Brown Swiss cattle of Golpayegan dairy farm. Genomic DNA was extracted from 150 blood sample by modified salting out method. The PCR-RFLP method was carried out to amplify and digests the interested sequence. The HinfI restriction enzyme was used to digest of 350 bp of kappa casein gene. To estimate allelic and genotypic frequencies in this population and also calculate Hardy-Weinberg equilibrium, the chi-square test (XT2) and the likelihood ratio test (Gr 2) were used.
Results: The results of enzymatic digestion of the 350 bp fragment of kappa casein gene showed that the frequencies of genotypes AA, AB and BB for this gene are 0.20, 0.61 and 0.19 respectively and the allele frequencies are 0.505 and 0.495 for allele A and B respectively. Genotypes were not distributed according to the Hardy-Weinberg equilibrium. The average milk production, length of lactation days, birth weight and age at first calving were 7302±2438 kg, 346±76.89 days, 41.89±4.7 kg and 832±74 days, respectively. Genetic parameters were estimated by REML method and WOMBAT software. Heritability and repeatability for milk yield were estimated 0.154 and 0.309 respectively.
Conclusion: The association of the breeding value of milk yield traits, with detected genotype of each animal, was used in statistical analysis based on the General Linar Models and no significant effect was observed for this gene.
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