Evaluation of the CowVac for controlling flies on Minnesota organic dairy farms

Abstract Text: The objective of this study was to evaluate the efficacy of the CowVac (Spalding Laboratories, Reno, NV) in on-farm organic dairy production systems to control horn flies, stable flies, and face flies.  The CowVac utilizes a chute apparatus and powerful vacuums to suction flies off the cows as they walk through the system.  The study utilized eight organic dairy farms during the summer of 2015 in Minnesota, and herds ranged from 30 to 350 cows.  The farms were divided into pairs by location and during the first period of the summer (June to July) the CowVac was set up on one farm and during the second period of the summer (August to September) the CowVac was sent to its paired farm. Farms were visited once per week to collect flies (or collect and count flies) from the CowVac, as well as count and record flies on cows. Bulk tank milk, fat, and protein production and SCC were collected on farms during the entire study period.  Data were analyzed using the GLM procedure of SAS. Independent variables for analyses were the fixed effects of farm, CowVac presence, housing scenario, and period.  Horn fly numbers on cows were reduced (P < 0.05) by 44% on farm in the presence of a CowVac (11.4 vs. 20.5 flies/side) compared to the absence of a CowVac.  Stable fly (5.4 vs. 7.1 fly/leg) and face fly (1.0 vs. 1.0 fly/cow) numbers were similar (P > 0.05) on farm whether the CowVac was present or absent on farms, respectively.  Milk production was similar (P > 0.05) for farms with the CowVac (15.5 kg/d) compared to without (15.3 kg/d) the CowVac.  The presence of a CowVac on farm reduced (P < 0.05) horn fly population growth rates (-0.008 vs. 0.002 flies/d) compared to the absence of a CowVac.  Cows on farms with no housing (100% pasture) tended (P = 0.07) to have reduced horn fly numbers (11.7 vs. 28.3 flies/side) in the presence of a CowVac compared to the absence of a CowVac on farm.  Cows on farms with housing had similar (P > 0.60) horn fly numbers (11.2 vs. 14.8 flies/side) in the presence of a CowVac compared to the absence of a CowVac on farm.   In summary, these results indicate the CowVac was effective in reducing horn fly numbers on cows and reduced horn fly growth rates during the pasture season in organic dairy production systems.

Keywords: Organic, CowVac, Fly Control