Title: Hot Topic: Brown marmorated stink bug odor compounds do not transfer into milk by feeding bug-contaminated corn silage to lactating dairy cattle Authors
|Fultz, S.W. -|
|Harris, Christina -|
|Van Hekken, Diane|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2014
Publication Date: April 1, 2014
Citation: Baldwin, R.L., Zhang, A., Fultz, S., Abubeker, S.U., Harris, C., Connor, E.E., Van Hekken, D.L. 2014. Hot Topic: Brown marmorated stink bug odor compounds do not transfer into milk by feeding bug-contaminated corn silage to lactating dairy cattle. Journal of Dairy Science. 97:1877-1884. Interpretive Summary: Interpretive Summary: The brown marmorated stink bug (Halyomorpha halys) is an invasive Asian species of stink bug responsible for damage to agricultural crops, including feed crops, in the northeastern United States. We sought to evaluate if corn crops with high infestation by brown marmorated stink bug odor compounds pose a risk to milk quality and quantity, feed intake by cows, and silage quality from crops with infestations. This work is the first to demonstrate that the odor compounds (E-2-decenal) does not transfer to milk when delivered directly to the rumen of lactating cows. Moreover, this odor-causing compound cannot be detected in feedstuffs following ensiling, a standard dairy practice. Thus, we find that concern over contamination of milk by this agricultural pest is not warranted.
Technical Abstract: Brown marmorated stink bug (BMSB), Halyomorpha halys, is an emerging invasive species of grave concern to agriculture as a polyphagous plant pest with potential negative impact on the dairy industry. We sought to determine the risk of including BMSB contaminated silage in lactating dairy cow rations. First, six dairies, either highly infested (n = 3; 30 to 100 bugs per stalk) or not infested (n = 3) were sampled to assess prevalence of bug secretion compounds tridecane and E-2-decenal (odor component) in silage and milk. Second, using wild BMSB, a mini-silo dose response experiment (adding 100, 50, 25, 10, and 1 fresh crushed bugs/0.5 Kg chopped corn) was conducted to assess the impact of ensiling on BMSB odor compounds. Finally, synthetic BMSB secretion compounds (10 g tridecane and 5 g E-2-decenal) were ruminally infused 2 times daily over 3 d and samples of milk, urine, and rumen fluid were collected to evaluate disposition. Samples were analyzed by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Milk production and feed composition were unaffected (P > 0.05) when BMSB contaminated silage was fed. Moreover, no E-2-decenal was detected in silage nor milk (detection threshold = 0.00125 ppm). Dose response of tridecane in mini-silo samples exhibited a linear relationship (R2 = 0.78) with BMSB added; however, E-2-decenal was completely decomposed and undetectable in spiked mini-silos after ensiling. Both synthetic secretion compounds infused into rumen were undetectable in all milk and urine samples. Content of E-2-decenal was also not detectable in rumen fluid; however, tridecane was detected at 15 min post-infusion but not present thereafter. Feed intake was unaffected by infusion treatment and BMSB secretion compounds were not observed in milk. Compounds from the metathoracic gland of BMSB are not able to contaminate milk due to either the ensiling process or metabolism within the rumen. Concern over BMSB stink odor compounds contaminating the fluid milk supply even on highly infested farms is not warranted.