Evaluating brown mid-rib (BMR) dwarf pearl millet as a forage for lactating dairy cows

Evaluating brown mid-rib (BMR) dwarf pearl millet as a forage for lactating dairy cows

Summary

     Brown Midrib (BMR) dwarf pearl millet may provide northeastern dairy farmers with an alternative forage source for lactating dairy cows to increase annual forage yield, add crop diversity and enhance nutrient utilization. Pearl millet is a summer annual with a shorter growing season than corn and therefore increases the growing season for winter annuals in a double cropping system. Pearl millet grows well in heat and performs well with inconsistent moisture. It offers more summer opportunities to spread manure at a more appropriate time when growing crops can rapidly utilize nutrients before they are lost to the environment. Pearl millet has to be shown to adequately support milk production in order to replace a portion of the corn silage acres on northeast dairy farms. Our hypothesis is that the BMR dwarf variety of pearl millet proposed in this project would support milk production in high-producing dairy cows due to its higher fiber digestibility and higher leaf to stem ratio than regular pearl millet. To test this hypothesis, we proposed a crossover feeding trial with 16 lactating cows. The effect of partial replacement of corn silage in the diet with BMR dwarf pearl millet on feed intake, milk production, digestibility, nitrogen utilization, rumination, enteric methane emissions and farm profitability is being evaluated.   

Objectives/Performance Targets

1. To evaluate the effect of including BMR dwarf pearl millet silage in a high producing dairy cow ration on dry matter intake and milk production . 
2. To investigate the effect of diet inclusion of BMR dwarf pearl millet silage on milk components and fatty acid profile. 
3. To evaluate the total tract nutrient digestibility and nitrogen utilization of a dairy cow diet containing BMR dwarf pearl millet silage.  
4. To examine the effect of BMR dwarf pearl millet silage inclusion in the diet of high producing dairy cows on enteric methane emissions, resting time, rumination time, and activity. 
5. To elucidate the economic impacts on farm profitability of growing BMR dwarf pearl millet silage in partial substitution of corn silage. 

We are on tract to accomplish these objectives and will begin to look at our results in light of these objectives at the completion of the second and final period of our experiment at the end of January 2017.  

Accomplishments/Milestones

     We successfully coordinated the harvest and ensiling of 10 acres of pearl millet in August 2016. Our IACUC #47341 was approved on September 29th, 2016. We picked 16 cows plus 1 spare cow for our experiment and they were moved to the Penn State tie stall research barn on November 17th, 2016 to monitor pretrial intake and accustom the cows to the tie stall. The first day of the trial was on November 26th, 2016. Feed intake, body weight, rumination, and milk yield are being monitored. We are finish the sampling of urine, feces, milk, and gas emissions this week before Christmas to complete the first period. So far, our plans are running smoothly and I hope that they continue as planned.

Impacts and Contributions/Outcomes

     The second period is planned to start on December 31st to be completed by the end of January. Data and sample analysis will begin immediately following the end of the experiment. Our goal is to submit an abstract for an oral presentation at the 2017 meeting of the American Dairy Science Association in Pittsburg, PA. A manuscript will be prepared and submitted for publication in the Journal of Dairy Science during 2017. If invited to speak, results will be shared at the Penn State Dairy Cattle Nutrition conference in Grantville, PA in the fall of 2017. 

Collaborators: