Pedigree analysis and inbreeding effects over morphological traits in Campolina horse population.

The research article discusses a study conducted to observe the population structure and effects of inbreeding among the Campolina horse population from Brazil. The study determined that unchecked inbreeding can potentially diminish genetic diversity and negatively affect the population’s morphological traits.

Methodology

• The researchers analyzed phenotype information from 43,465 individual Campolina horses, which was provided by the Campolina Breeders Association.
• In connection to this, a pedigree file consisting of data from 107,951 horses was utilized to link the phenotyped individuals.
• For calculation purposes, software was used to compute the genealogical parameters and the inbreeding coefficient was assessed via the diagonal of the relationship matrix.
• The effective population size was calculated using the inbreeding rate and census information. Additionally, the stratification, i.e., the variation in the population was evaluated through the average relationship coefficient between horses born in different regions of Brazil.
• To assess the influence of inbreeding on morphological traits, the inbreeding coefficient was employed as a covariate in the random regression model.

Findings

• The study discovered that the inbreeding coefficient has been increasing since 1990, indicating a rise in inbred mating. This increase has influenced the effective population size by decreasing genetic variability.
• The paternal inbreeding was observed to be higher than maternal inbreeding, hinting at a possible preference for inbred horses during reproduction.
• Additionally, the average genetic relationship coefficient was lower for animals born in different states compared to those born within the same state, shedding light on regional breeding practices.
• Crucially, the increase in the inbreeding coefficient has had negative associations with all studied traits, emphasizing the need to prevent long-term genetic losses.

Conclusions

• Even though the study doesn’t demostrate an extreme shrinking of the population up until the current date, there are signs of increasing average relationship coefficients. This could potentially lead to a drastic decrease in genetic variability if inbred mating isn’t effectively managed within the Campolina horse population.