Atresia coli inherited in Holstein cattle

Area of Science:

• Veterinary Genetics
• Animal Reproduction
• Congenital Malformations

Background:

• Atresia coli is a congenital intestinal defect in calves.
• Understanding the genetic basis of atresia coli is crucial for breeding programs.
• Previous hypotheses suggested a single-locus autosomal recessive inheritance pattern.

Purpose of the Study:

• To test the hypothesis that atresia coli is inherited as an autosomal recessive trait at a single locus.
• To investigate the role of carrier parents and inbreeding in the occurrence of atresia coli.
• To evaluate the effectiveness of early pregnancy diagnosis in identifying at-risk pregnancies.

Main Methods:

• Designed mating experiments involving putative carrier sires and dams.
• Analyzed offspring from planned and contemporary matings for atresia coli incidence.
• Assessed inbreeding coefficients and dominance relationships in affected calves.
• Retrospectively analyzed early pregnancy diagnoses in dams.

Main Results:

• Planned matings produced 59 normal and 8 atresia coli calves, closely matching the expected 8.1 affected calves based on autosomal recessive inheritance.
• Affected calves from both planned and contemporary matings exhibited inbreeding.
• One case of atresia coli was observed in 628 contemporary births, suggesting a low incidence in the general herd.
• Early pregnancy diagnosis in dams was inconclusive for predicting atresia coli in genetically predisposed calves.

Conclusions:

• The findings support the hypothesis that atresia coli in Holstein calves is inherited as an autosomal recessive trait.
• Carrier parents and inbreeding are significant factors associated with atresia coli.
• Further research is needed to refine diagnostic methods for early identification of affected or carrier animals.