Preference Pastures in Missouri Pastures

Transcription

1 Experiments to Investigate the Impact of Experiments to Investigate the Impact of Weed Infestations Weed on Removal Cattle Grazing on Preference Cattle Grazing Missouri Preference Pastures in Missouri Pastures Dr. Kevin Bradley, University of Missouri

2 Cattle prefer to eat a grass-based diet. However, as grass becomes scarce they will consume other plants that are not as preferred such as weeds (Olsen 1999, Marten 1978). Previous research shows that many weeds can be just as nutritious as the desired forage, especially in the early vegetative stages of growth (Marten and Andersen 1975; Payne et al. 2010; Rosenbaum et al. 2011). Research has also shown that cattle do not graze randomly, but rather preferentially and often based on memory and a previous grazing experience (Lyons and Machen 2001).

3 Objectives: In mixed tall fescue and legume pastures, to determine the effects of herbicide application and subsequent weed and legume removal on: 1. Weed Density 2. Forage Grass & Legume Groundcover 3. Total Forage Yields 4. Beef Cattle Grazing Distribution

4 Materials and Methods: Use of GPS Tracking Collars At each location, Lotek 3300 GPS tracking collars were fitted to 3 crossbred beef cows ranging from 800 to 1,100 lbs in weight. Collars were set to fix and record GPS satellite positions at 1-hr intervals throughout the experiment. Cattle were fitted with collars 1 month prior to the herbicide applications at each location in order to provide a baseline level of the grazing preference and distribution within each pasture.

5 Research Locations Albany, Missouri (2009): 90 acre continuously grazed pasture Initial density of 24 weeds/m 2 Shelbina, Missouri (2010): 31 acre continuously grazed pasture Initial density of 18 weeds/m 2 Galena, Missouri (2009): 35 acre continuously grazed pasture Initial density of 9 weeds/m 2

6 Results: Forage Response

7 Weed Density (#/m 2 ) Influence of Pasture Herbicide Treatment on Weed Density over Time (Albany, MO 2009) Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

8 Weed Density (#/m 2 ) Influence of Pasture Herbicide Treatment on Weed Density over Time (Galena, MO 2009) Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

9 Weed Density (# / m 2 ) Influence of Pasture Herbicide Treatment on Weed Density over Time (Shelbina, MO 2010) 25 Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

10 Albany, Missouri 2009 Treated Untreated

11 Shelbina, MO 2010 Treated Untreated

12 Galena, Missouri 2009 Treated Untreated

13 Groundcover (%) Influence of Pasture Herbicide Treatment on Clover Groundcover over Time (Albany, MO 2009) Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

14 Groundcover (%) Influence of Pasture Herbicide Treatment on Clover Groundcover over Time (Galena, MO 2009) Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

15 Groundcover (%) Influence of Pasture Herbicide Treatment on Clover Groundcover over Time (Shelbina, MO 2010) Treated Untreated Months After Treatment Indicates a significant difference between herbicide-treated and untreated weed density, LSD=0.05.

16 Lbs/A Comparisons of Forage Yield Components Between Herbicide-treated and Untreated Portions of a Pasture for 3 Months Following Application (Albany, MO 2009) A Weeds 795 A Grass+Clover 863 a 99 B 210 B 527 A 149 B 569 a 431 b 481 a 484 a 311 a Trt Unt Trt Unt Trt Unt Months After Application Indicates a significant difference between herbicide-treated and untreated total forage yields, LSD=0.05.

17 Lbs/A Comparisons of Forage Yield Components Between Herbicide-treated and Untreated Portions of a Pasture for 3 Months Following Application (Galena, MO 2009) A 459 A 2189 a 1803 a 37 B Weeds 294 A 72 B Grass+Clover 212 A 1392 a 1437 a 1146 a 918 b Trt Unt Trt Unt Trt Unt Months After Application Indicates a significant difference between herbicide-treated and untreated total forage yields, LSD=0.05.

18 Lbs/A Comparisons of Forage Yield Components Between Herbicide-treated and Untreated Portions of a Pasture for 4 Months Following Application (Shelbina, MO 2010) Weeds Grass+Clover 56 A 161 A 77 A 72 A A 33 A 91 A 87 A 1450 a 1472 a 1238 a 1386 a 2900 a 2451 a 2416 a 2385 a Trt Unt Trt Unt Trt Unt Trt Unt Months After Application There were no differences between herbicide-treated and untreated total forage yields, LSD=0.05.

19 Results: Cattle Grazing Response

20 Ratio of Animal Visits to Treated Versus Untreated Pastures Change in Cattle Distribution on Herbicide-treated and Untreated Portions of a Pasture for 4 Months Following Application (Albany, Missouri 2009) 6 a 4 ab bc 2 cd d Months After Application Means followed by the same letter are not different, LSD=0.05.

21 Ratio of Animal Visits to Treated Versus Untreated Pastures Change in Cattle Distribution on Herbicide-treated and Untreated Portions of a Pasture for 3 Months Following Application (Galena, Missouri 2009) ab b a a Months After Application Means followed by the same letter are not different, LSD=0.05.

22 Ratio of Animal Visits to Treated Versus Untreated Pastures Change in Cattle Distribution on Herbicide-treated and Untreated Portions of a Pasture for 4 Months Following Application (Shelbina, MO 2010) ab a 1 abc bc 0.5 c Months After Application Means followed by the same letter are not different, LSD=0.05.

23 Albany Fix Points Prior to Application (7/8-7/29) Treated 53% (250 fixes) Untreated 47% (225 fixes) Dr. Kevin Bradley, University of Missouri

24 Albany Fix Points 1 Month After Application (7/30-8/25) Treated 51% (295 fixes) Untreated 49% (283 fixes) Dr. Kevin Bradley, University of Missouri

25 Albany Fix Points 2 Months After Application (8/26-9/29) Treated 77% (511 fixes) Untreated 23% (156 fixes) Dr. Kevin Bradley, University of Missouri

26 Albany Fix Points 3 Months After Application (9/30-10/27) Treated 84% (1043 fixes) Untreated 16% (202 fixes) Dr. Kevin Bradley, University of Missouri

27 Albany Fix Points 4 Months After Application (10/28-11/24) Treated 77% (869 fixes) Untreated 23% (328 fixes) Dr. Kevin Bradley, University of Missouri

28 Albany Fix Points for All 4 Months After Application Treated -72% (2,718 fixes) Untreated -28% 969 fixes) Dr. Kevin Bradley, University of Missouri

29 Conclusions: Forage Response At all locations, broadleaf weeds were substantially reduced and legumes were almost completely eliminated in herbicide-treated compared to untreated portions of the pastures. By 3 months after treatment, the weed content of the total forage yields was lower in herbicidetreated compared to untreated portions of the pastures at Albany and Galena but not Shelbina. By 3 months after treatment, the forage grass and legume component of the total forage yields was higher in herbicide-treated compared to untreated portions of the pastures at Galena but not Albany or Shelbina.

30 Conclusions: Cattle Distribution By 3 to 4 months after treatment, the distribution of cattle in herbicide-treated compared to untreated portions of the pastures increased by 1.5 to 5x across 3 research locations. The degree of distribution increase correlated to initial and final weed density: Albany = 24 weeds/m 2, 5x distribution increase Shelbina = 18 weeds/m 2, 1.6x distribution increase Galena = 9 weeds/m 2, 1.5x distribution increase Results also suggest that cattle preferentially graze weed-free pastures, even when legumes are removed through herbicide treatment.