Genetic divergence in various Sahiwal x Holstein crossbred grades

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Livestock Breeding

Background:

• Understanding genetic divergence is crucial for improving cattle breeds.
• Crossbreeding programs aim to combine desirable traits from different breeds.
• The Sahiwal and Friesian breeds represent diverse genetic origins and production potentials.

Purpose of the Study:

• To assess genetic divergence and clustering patterns between Sahiwal and Friesian grades.
• To evaluate the production increase in crossbred cattle relative to the proportion of superior parent genes.
• To propose a breeding plan for stabilizing breed type in crossbred populations.

Main Methods:

• Mahalanobis's D(2) statistic was used to measure genetic divergence.
• Canonical Variate Analysis (CVA) was employed for clustering patterns.
• Data were adjusted for significant effects of farms, periods, and seasons.

Main Results:

• Forty cattle grades were successfully grouped into 11 distinct clusters.
• Production levels did not show a linear increase beyond 50% of the superior parent (Friesian) genes.
• Grading up to complete gene replacement did not necessarily lead to higher production in cattle.

Conclusions:

• Crossbreeding strategies require careful planning as simple gene replacement does not guarantee superior production.
• A proposed breeding plan is essential for stabilizing breed type in crossbred cattle populations.
• Further research into optimal crossbreeding proportions and breed stabilization is warranted.