Runs of homocigosity and its association with productive traits in Mexican Holstein cattle

Abstract

The objective of this study was to describe the runs of homozygosity (ROH) detected in the Mexican Holstein population and to associate them with milk, fat and protein yields, and conformation final score. After imputation and genomic quality control, 4,227 genotyped animals with 100,806 SNPs markers each were used. ROH with a minimum length of 1 Mb and a minimum of 10 SNPs were included in the analysis. One heterozygous SNP marker and five missing genotypes per ROH were allowed. A total of 425,098 ROH were found in the studied population (71.83 ± 10.73 ROH per animal), with an average length and coverage of 4.80 ± 0.77 Mb, and 276.89 Mb, respectively. The average chromosome length covered by ROH was 10.40 ± 3.70 Mb. ROH between 1 and 2 Mb were the most frequent in the population (51.33%) while those between 14 and 16 Mb were the least frequent (1.20%). Long chromosomes showed a larger number of ROH. Chromosomes 10 and 20, had a greater percentage of their length covered by ROH because they presented a largest number of long ROH (>8 Mb). From the total ROH, 17 were detected in 1,847 animals and distributed among different chromosomes, and were associated with milk, fat and protein yield and percentage, and conformation final score. Of the ROH with effects on production traits, the majority were found with a length between 1 and 4 Mb. These results show evidence of genomic regions preserved by genetic selection and associated with the improvement of the productivity and functionality of dairy cattle.

Growth Performance and Feed Intake Assessment of Italian Holstein Calves Fed a Hay-Based Total Mixed Ration: Preliminary Steps towards a Prediction Model

“…Using the data obtained in the present study, farmers could produce heavier (and consequently better-conformed) calves [63], resulting in heavier and higher-value primal carcass cuts if they are male or in heifers with better body conformation. These possibilities could be particularly interesting for heifer rearing, since studies [64][65][66] report a strong relationship between conformation traits and lifetime production efficiency.…”

Genome-wide assessment of runs of homozygosity in Sahiwal cattle of Pakistan

“…There was also evidence of overlap between the ROH islands in the cattle breeds originally chosen for beef and dairy production, indicating that the pressure of selection may act on traits unrelated to these two categories. An ROH in BTA6 was shown to be related to fat, protein, and milk production in Mexican Holstein cattle [53]. This ROH was 5.21 Mb in length.…”