Open Nucleus Breeding System (ONBS) | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Overview of the ONBS Breeding Programme

Introduction to the ONBS Programme: 

• The ONBS (Optimum Nucleus Breeding Scheme) is a crucial breeding program aimed at enhancing genetic traits in cattle. 
• This program is particularly valuable in regions where traditional field-based progeny testing may not be feasible due to various limitations.

Implementation in Sahiwal Crossbred Cattle: 

• The ONBS initiative is being executed in Sahiwal crossbred cattle under the supervision of NDDB (National Dairy Development Board). 
• The program is structured into two distinct phases to optimize genetic selection and breeding outcomes.

Phase I of the Programme: 

• Initially, a genetically superior nucleus herd of Sahiwal cows is established. 
• The top 24 cows from this nucleus herd are selected based on desirable genetic traits. 
• Selected cows undergo super ovulation multiple times, resulting in the production of viable embryos. 
• These embryos are then transferred into recipient animals for further development. 
• Ultimately, 3 male and 3 female calves are produced per donor, and their performance is meticulously recorded.

Selection Process and Genetic Improvement: 

• Male calves are evaluated based on the performance records of their siblings. 
• The top 4 crossbred males are retained for further breeding, while the others are sold to enhance genetic diversity in crossbred cows.
•  Female crossbreds undergo a similar evaluation process, and top performers are selected as donors for subsequent breeding cycles.

Transition to Phase II: 

• In the second phase, crossbred cows from Phase I replace Sahiwal cows as donors. 
• The top four male offspring from the first phase are utilized for breeding. 
• The breeding process, involving Multiple Ovulation and Embryo Transfer (MOET), is repeated annually to produce successive generations of male and female calves.

Continuous Genetic Improvement: 

• The breeding strategy involves inter se mating of F1 generation animals. 
• Top males from F2 generation and an I sire are used for breeding selected crossbred cows. This cycle of selection and breeding is perpetuated annually to sustain genetic progress.

Advantages and Disadvantages of ONBS 

Advantages: 

• Offers precise control over genetic changes. 
• Ensures reliable data collection on various performance metrics. 
• Facilitates the integration of advanced technologies like embryo sexing and gene transfer. 

Disadvantages: 

• Technically intricate and operationally costly. 
• Vulnerable to disease outbreaks due to centralized operations. 
• Possibility of increased inbreeding and genetic drift in small populations, necessitating careful management strategies.