Among the four major dairy breeds in Canada, the average inbreeding level for heifers born in 2025 is highest for Holstein at 10.32%, followed by Jersey (7.74%), Brown Swiss (7.23%) and Ayrshire (7.12%). In terms of controlling the rate of increase in inbreeding for females born since 2010, the Jersey, Ayrshire and Brown Swiss breeds are doing the best among these four breeds, averaging +.11%. +.12% and +.12% per year, respectively, compared to rate of increase of +.25% per year for Holstein. 

Among the breeds with the smallest populations in Canada, Canadienne continues to have the highest average inbreeding, now at 10.94% for females born in 2025, but the average rate of increase since 2010 has been relatively low at +.09% per year. Guernsey heifers born in 2025 average 6.25% inbreeding and the average change since 2010 has also been at +.09% per year. For Milking Shorthorn, heifers born in 2025 average 3.28% inbreeding based on available pedigree data for the breed and the rate of increase has been low at +.06% per year for heifers born since 2010.

Below is a graph showing the inbreeding trend for the four largest dairy breeds based on registered females born in Canada since 1970 as well as a specific graph for the Holstein population alone.  For further information, please feel free to contact Lactanet Canada staff.