Methane production, ruminal fermentation characteristics, nutrient digestibility, nitrogen excretion, and milk production of dairy cows fed conventional or brown midrib corn silage.
The objective of this study was to examine the effect of replacing conventional corn silage (CCS) with brown midrib corn silage (BMCS) in dairy cow diets on enteric CH4emission, nutrient intake, digestibility, ruminal fermentation characteristics, milk production, and N excretion. Sixteen rumen-cannulated lactating cows used in a crossover design (35-d periods) were fed (ad libitum) a total mixed ration (forage:concentrate ratio = 65:35, dry matter basis) based (59% dry matter) on either CCS or BMCS. Dry matter intake and milk yield increased when cows were fed BMCS instead of CCS. Of the milk components, only milk fat content slightly decreased when cows were fed the BMCS-based diet compared with when fed the CCS-based diet (3.81 vs. 3.92%). Compared with CCS, feeding BMCS to cows increased yields of milk protein and milk fat. Ruminal pH, protozoa numbers, total VFA concentration, and molar proportions of acetate and propionate were similar between cows fed BMCS and those fed CCS. Daily enteric CH4emission (g/d) was unaffected by dietary treatments, but CH4production expressed as a proportion of gross energy intake or on milk yield basis was lower for cows fed the BMCS-based diet than for cows fed the CCS-based diet. A decline in manure N excretion and a shift in N excretion from urine to feces were observed when BMCS replaced CCS in the diet, suggesting reduced potential of manure N volatilization. Results from this study show that improving fiber quality of corn silage in dairy cow diets through using brown midrib trait cultivar can reduce enteric CH4emissions as well as potential emissions of NH3and N2O from manure. However, CH4emissions during manure storage may increase due to excretion of degradable OM when BMCS diet is fed, which merits further investigation.
Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College Street, Sherbrooke, QC, Canada J1M 0C8.
F
F
Hassanat
Département des Sciences Animales, Université Laval, 2425, rue de l'Agriculture, Quebec, QC, Canada G1V 0A6.
R
R
Gervais
Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College Street, Sherbrooke, QC, Canada J1M 0C8. Electronic address: chaouki.benchaar@agr.gc.ca.
C
C
Benchaar
D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000187:drug effects; D005260:Female; D005285:Fermentation; D007774:Lactation / Q000187:drug effects; D008697:Methane / Q000096:biosynthesis; D008892:Milk / Q000737:chemistry; D009584:Nitrogen / Q000378:metabolism; D012417:Rumen / Q000378:metabolism; D012820:Silage; D003313:Zea mays / Q000378:metabolism*
D009584:Nitrogen; D008697:Methane
N excretion; brown midrib corn silage; conventional corn silage; methane