Location: Dairy Forage ResearchTitle: High partial feed conversion efficiency appears to be a persistent trait associated with reduction in selected measures of methane emissions in dairy cattle) Author
|Powell, J mark|
Submitted to: International Conference on Greenhouse Gasses and Animal Agriculture
Publication Type: Proceedings
Publication Acceptance Date: 3/4/2013
Publication Date: 6/23/2013
Citation: Arndt, C., Wattiaux, M.A., Powell, J.M., Aguerre, M.J. 2013. High partial feed conversion efficiency appears to be a persistent trait associated with reduction in selected measures of methane emissions in dairy cattle. International Conference on Greenhouse Gasses and Animal Agriculture. 7(2):516. Interpretive Summary:
Technical Abstract: In the United States enteric methane (CH4) contributes approximately 21% of all anthropogenic CH4 emissions. Alongside dietary manipulations, exploiting among-animal variation in feed conversion efficiency (FCE) may offer possible CH4 mitigation strategies. This experiment was designed to evaluate the medium-term persistency of FCE and related measures, and to determine the relationship between CH4 emission and selected measures of digestive and metabolic functions among cows with high and low partial FCE for milk [pFCEmk, kg milk/kg dry matter intake (DMI)]. The study was conducted at the U.S. Dairy Forage Research Center, Prairie du Sac, Wisconsin, USA. First, only cows with more than 100 days in milk were pre-selected (n=140). Then, pFCEmk was used as a criterion to select 16 cows, grouped into eight pairs (high and low pFCEmk). All cows were fed the same standard diet: 28.2% corn silage, 26.7% alfalfa silage, 23.2% high moisture corn, 7.1% distillers’ dried grains, 3.6% soybean meal, 8.8% roasted soybeans, and 2.4% vitamins and minerals on a dry matter (DM) basis. During a four-day CH4 emission measurement period (collected on two pair at a time, as cows were placed individually in one of four air-flow-controlled chambers), total mixed ration, feed refusals, and milk samples were collected daily, with total fecal collection conducted for the first three days, to measure digested organic matter intake and digested neutral detergent fiber intake (DNDFI). The relative difference between the low and high pFCEmk cow groups persisted over the duration of the study. The high pFCEmk cows had higher energy expenditures but were more efficient for total energy expenditure in milk, body weight gain, and maintenance per unit of feed DM and digestible organic matter consumed. Contrary to preliminary results, pFCEmk had no effect on daily CH4 emission in this trial. However, similar CH4/DNDFI warrants further investigation to evaluate if DNDFI could be used as a reliable predictor of CH4 emissions across a range of diets. Further research should focus also on the relationship between pFCEmk and CH4 emission, and the possibility of genetic selection of cows for greater energy efficiency and lower CH4 emissions.