New Tool Helps Dairy Farmers
Dairy farmers across the country can thank scientists in the Department of Dairy Science for providing them with more complete information for selecting bulls for increased herd life of daughters and hopefully increasing productivity on their farms.
Chandraratne Dematawewa, visiting scholar, and Ron Pearson, professor of dairy science, have created an extended lactation curve to improve the productive life measurements used for all dairy cows. Their research has already made an immediate and direct impact on the dairy industry.
Productive life measurements are used by producers to help them select superior bulls that will sire cows that stay in their herd longer, produce milk for a longer period of time, and ultimately create more profit for their operations.
Productive life measures how long a dairy cow stays in the herd over her lifetime when compared to her herdmates. This trait was formerly measured for 305 days (a standard lactation length) for their first five years of life. Although it would be ideal that all cows milk at the industry standards, some cows are not bred at the right time or milk for longer lactations.
Dematawewa and Pearson knew the values were not as accurate as they could be for cows that milked or lived longer than the values accounted for. Thanks to their research, a new curve has been created and each day a cow is producing milk throughout her whole lifetime is used in her productive life value.
“After 305 days, the degree of genetic control determining milk production is reduced,” says Pearson. “Management and other factors are keeping cows in the milking herd. We were looking for a way to allow extra days in the productive life values so that credit was given for the cow’s extended days of production but were not counted as much as earlier days in the lactation.”
Creating the new lactation curve was a bit of a challenge. Since lactation curves had only been kept for the first 305 days of all animals’ first five years of life, they did not have as many values for longer lactations. Only data from the past 10 years was used. Using the lactation records provided by the USDA from almost a million cows, the research team worked to create a new lactation curve that is 999 days long. In the new curve, each day that a cow is lactating is counted in the productive life measurement so that the cow is given a more accurate value for her complete lifetime.
“Now, a cow is allowed as many days as she has,” adds Pearson. “Each day is weighted individually.”
The new changes have already had direct influence on the industry. Since the new curve is already being used on the farm, the new genetic evaluation for productive life is helping producers make an educated decision about which bulls to select for their herd. The records are now more accurate than those that were in place before.
“Productive life is now more representative of the real values,” says Pearson.
And for the researchers, this project has been a great success. The new lactation curve and weighted days are making direct impacts on the farm by provide more accurate information about the dairy bulls that producers are using.
“What I’m happiest with is that we started this project a year-and-a-half ago and it is already implanted and having an impact on the dairy industry,” Pearson says. “It is already affecting the national productive life values for all breeds and it’s neat to be a part of that.”