Simulation Report: Herd 19 (PTA)

For this simulation, I inherited a dairy farm from my parents and oversaw all mating decisions. I planned to use breeding values with strong correlations for production while regulating inbreeding. The main goal was “to breed a better cow that will maximize herd profitability.” Herd 19 was designated and used for net merit predicted transmitting ability. Herd 20 was selected for fat and protein percentages in my second session (Chittenden). In Simulation session one, I selected for milk PTA for herd 19 and selected for fat percentage for herd 20. For herd 19, I had a steady increase for milk PTA except between years two and three ending with 170 PTA. This decline was caused by a significant decrease in the number of cows I had. I had a loss of about 25 cows which altered my data set negatively. For herd 20, my fat percentage PTA peaked between years three and four at 0.05% and slowly declined after ending up at 0.02%. This decline occurred
This was not the best decision as it had negative outcome, but I thought it would increase my progress. For genetic variation we couldn’t really change the breeding value to alter the heritability due to the program. In relation to accuracy, we had nine records that we given to us through the simulation. It would’ve be interesting if we had type and health traits to see how those alter the rate of change. I used the maximum amount of bulls possible like I did in the first session which again, hindered my progress by having elite and average bulls mating. For the generation interval I mated the younger bulls first followed by the older bulls. I also kept older cows in my herd, the oldest being twelve, as long as they had high component values. If I was to do this simulation again I would cull them because that is not necessarily a real-life situation. Cows typically leave the herd between ages four and