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394
Greenhouse gas emission related traits differ in RFI divergent lactating dairy cows

Wednesday, July 20, 2016: 3:00 PM
Grand Ballroom I (Salt Palace Convention Center)
Dagnachew Hailemariam , Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
Ghader Manafiazar , Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
John Basarab , Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
Filippo Miglior , Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
Graham Plastow , Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
Zhiquan Wang , Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
Audio File Recorded Presentation (mp4)
Abstract Text:

In dairy cattle, the magnitude of dry matter intake (DMI), methane (CH4) and carbon dioxide (CO2) reduction in feed efficient (-RFI) lactating cows is not well documented. The objective of this study was to quantify the comparative advantage of -RFI lactating dairy cows managed in an intensive tie-stall system with regard to DMI, CH4 and CO2 emission. RFI was predicted for 43 lactating dairy cows with components of metabolic body weight (MBW), empty body weight change (EBWC), and milk production energy requirements (MPER) over 255 days in milk (DIM) using a random regression technique, and correspondingly, DMI, CH4, CO2 and other traits were measured. CH4 and CO2 emissions were measured from lactating dairy cows using a GreenFeed system (C-Lock Inc., Rapid City, SD). The measurement was performed in three batches (15 cows in each) twice a day (09:00 - 12:00; 18:00 - 20:30 h) for 14 consecutive test days. Prior to each test period cows were allowed to visit the unit twice a day (4-7 days) for adaptation purpose. The RFI prediction revealed 19 cows with –RFI (efficient) and 24 cows with +RFI (inefficient). The mean dry matter intake (DMI), CH4 production (g/day), CH4 yield (g/kg of DMI), CH4 g/kg of milk, milk yield (kg/d) and CO2 g/d were calculated for both -RFI (N = 19) and +RFI (N = 24) groups. Data was analyzed using t-test for each trait and the result indicated that -RFI cows have significantly (P<0.05) decreased DMI (20±3 vs. 23±3), CH4, g/d (334±71 vs. 392±70), and CO2 g/d (12,070±1,348 vs. 12,895±1,704) and CH4 g/kg of milk (9±2 vs. 10±2) compared to their +RFI counterparts. As expected, body weight, milk yield and CH4 (g/kg DMI), were not statistically significant (P > 0.05), between -RFI and +RFI groups. Taken together, feed efficient lactating dairy cows compared to the inefficient cows consumed less feed, emitted less daily CH4 (g/d), CH4 (g/kg of milk) and CO2 (g/d) by 13.0, 14.8, 10 and 6.4 % respectively, without differing in milk production.  

Keywords:

RFI, methane, carbon dioxide

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