Calf and Fly Management Options for Organic Dairies
2016-04
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Calf and Fly Management Options for Organic Dairies
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2016-04
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Heifer calves (n = 102) were used to evaluate the effect of once or twice daily feeding on growth and behavior of calves in an organic group management system. Calves were assigned to replicate feeding groups of 10 in super hutches by birth order, during two seasons from September to December 2013 and March to May 2014 at the University of Minnesota West Central Research and Outreach Center, Morris. Calves in groups were the experimental unit. Breed groups of calves were: Holsteins (HO; n = 26), crossbreds (n = 45) including combinations HO, Montbéliarde, and Viking Red selected for high production, and crossbreds (n = 31) including combinations of HO, Jersey, Normande, and Viking Red selected for robustness. Treatment groups were 1) once daily feeding (1X) or 2) twice daily feeding (2X). Calf groups were fed 6 L per calf/daily (2X, 3 L/feeding) of 13% total solids organic milk then weaned at 60 d when the group consumption averaged 0.91 kg starter/calf daily. Body weight and hip height were recorded at birth, once/wk, at weaning, and at 90 d of age. Hobo Pendant G loggers were applied to the right rear leg of calves to measure total lying and standing time. Data were analyzed using PROC MIXED of SAS. Independent variables for analyses were the fixed effects of birth weight (co-variable), season of birth, treatment group, along with replicate as a random effect. Weaning group performance was gain per day, 1X (0.79 kg) and 2X (0.81 kg); weaning weight, 1X (92.7 kg) and 2X (93.3 kg); and weaning hip height, 1X (95.2 cm), and 2X (95.3 cm). Daily gain to 90d were 0.85 vs. 0.85 kg, and daily gain to 120 d were 0.85 vs. 0.83 kg for 1X and 2X calves, respectively. For lying time, 1X (988 min/d) and 2X (995 min/d) were not different from each other. During the evening hours, the 2X calves had lower lying times (34 min/hr for 1X; 28 min/hr for 2X) per hr because they were fed at 6pm every evening. In summary, group-fed calves fed once per day in an organic production had similar average daily gains and body dimensions compared to calves fed twice per day. Key words: group housing, organic dairy, profitability The objective of this study was to evaluate the efficacy of a commercial vacuum fly trap (TRAP; CowVac, Spalding Laboratories, Reno, NV) in on-farm organic dairy production systems to control horn flies, stable flies, and face flies. The TRAP 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 in size. The farms were divided into pairs by location and during the first period of the summer (June to July) the TRAP was set up on one farm and during the second period of the summer (August to September) the TRAP was sent to its paired farm. Farms were visited once per week to collect flies (or collect and count flies) from the TRAP, 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, TRAP presence, housing scenario, and period. Horn fly numbers on cows were reduced by 44% on farm in the presence of a TRAP (11.4 vs. 20.5 flies/side) compared to the absence of a TRAP. Stable fly (5.4 vs. 7.1 fly/leg) and face fly (1.0 vs. 1.0 fly/cow) numbers were similar on farm whether the TRAP was present or absent on farms, respectively. Milk production was similar for farms with the TRAP (15.5 kg/d) compared to without (15.3 kg/d) the TRAP. Both bulk tank milk and milk components were statistically similar in the presence and absence of the TRAP, so benefits of the TRAP were too small to measure. The presence of a TRAP on farm reduced horn fly population growth rates (-1.01 vs. 1.00 flies/d) compared to the absence of a TRAP. Cows on farms with no housing (100% pasture) tended to have reduced horn fly numbers (11.7 vs. 28.3 flies/side) in the presence of a TRAP compared to the absence of a TRAP on farm. Cows on farms with housing had similar horn fly numbers (11.2 vs. 14.8 flies/side) in the presence of a TRAP compared to the absence of a TRAP on farm. In summary, these results indicate the TRAP was effective in reducing horn fly numbers on cows and reduced horn fly growth rates during the pasture season in organic dairy production systems but benefits in improved milk production were not evident. Key words: organic dairy, horn fly, stable fly
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University of Minnesota M.S. thesis. April 2016. Major: Animal Sciences. Advisor: Bradley Heins. 1 computer file (PDF); xii, 70 pages.
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Kienitz, Myrrh-Anna. (2016). Calf and Fly Management Options for Organic Dairies. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/181798.
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