Goat Friendly Pastures
The objective of this SARE grant project, “Goat Friendly Pastures”, is to evaluate methods of parasite avoidance through grazing management. This evaluation considered the effect of cattle grazing behind goats. Antidotal observations indicate that the cattle consume parasites (L-3 larvae) on pastures, thus sparing the grazing goats. In this case there was no treatment effect related to cows grazing in front of goats on tall fescue pastures. Nevertheless, significant observations were made during the study. Abnormally favorable weather conditions prevailed throughout the 120 day grazing period resulting in abundant pasture growth. Due to an average residual dry matter levels of 1400 lbs DM/acre (9 inch pasture height) following each grazing sequence indicates that modest pasture heights may provide significant protection for goats grazing tall fescue pastures. Few goats contracted enough parasite infections for major concern. The impact of this work is not that the grazing cows had no effect of parasite infections; however the work implies an important element within the total goat grazing management system. This trial suggests that forage height need not be extreme for parasite avoidance on tall fescue pasture.
The objective of this SARE grant project, “Goat Friendly Pastures”, is to evaluate methods of parasite avoidance through grazing management. This evaluation considered the effect of cattle grazing behind goats. Antidotal observations indicate that the cattle consume parasites (L-3 larvae) on pastures, thus sparing the grazing goats. In this case there were no treatment effects.
Twenty four dry open does were randomly allocated to 6 grazing paddocks. Each paddock was determined to be 0.22 acres resulting in a stock density of 18-goats/acre. The goats were grazed for 21 days and rotated forward in to a second, third and fourth set of 0.22 acre paddocks. Grazing duration was June 1 through September 28. Goats were grazed together with three-1500 lb Holstein cows grazing 21 days behind the grazing goats. Cows were grazed behind paddocks 1, 3 and 5 while paddocks 2, 4 and 6 were mowed to cow grazing height. All goats were de-wormed August 28 and returned to their assigned paddock sequence to graze following the cow grazed paddocks (paddocks 1, 3, 5) and mowed pastures (paddocks 2, 4, 6). Goats were allowed to graze for 28 days in September. Each goat was evaluated for gastro-intestinal parasite eggs by fecal egg counts (FEC) and assigned an anemia rating by FAMACHA methodology (color assessment of the lower eye membrane). Animals were selected for de-worming when FAMACHA membrane colors 4 and 5 were observed (ratings 1-5, 1=not anemic, 5=extremely anemic). There was no treatment effect related to type of management following the forward grazing of goats. Goats grazing following the cows were comparable with goats grazing following the mower and were observed to have essentially the same BCS 2.1 and 1.9, FAMACHA readings 3.1 and 3.1 and fecal egg counts of 3.3 and 3.7 eggs/gram all respectively. Goats from both treatments contracted low levels of parasite infections and less than 1/3 of the goat herd was de-wormed during the study. However, a review of the weather conditions at this time period June-September, may explain why there were no effects. The year, 2004 was a year for above normal temperatures and precipitation. Above normally high incidences of precipitation occurred in June, 0.06 inches; July, 0.99 inches; August, 0.71 inches; and September, 0.76 inches (UKAWC-2005). These conditions were favorable for parasite development and infection. At the same time, these conditions were also favorable for abundant pasture growth even during the normal tall fescue dormant season. Even though goats grazed in paddocks for 21-days with a stocking density of 18 goats/acre few infections occurred.
Impacts and Contributions/Outcomes
The impact of this work is not that the grazing cows had no effect of parasite infections; however the work implies an important element within the total goat grazing management system. This trial suggests that forage height need not be extreme for parasite avoidance on tall fescue pasture. A rising plate pasture meter was used to determine dry matter (DM) residuals following 21 day grazing sessions. Plate height x DM calibrations were conducted at the start of the grazing sessions and midway through the grazing sessions (R2=.95). The average available DM residual for paddocks was 1400 lbs DM/acre. Using a common assumption, 150 lbs-DM/acre inch (Southern Forages, Forage Pocket Guide 2000), residual pastures height was 9 inches. These results may indicate that there is some unknown grazing height between 9 inches and the parasite infection zone (assumed to be 2-3 inches of height) in which goats can safely graze pasture plants. Therefore, goats grazing in pasture rotation, allowing adequate pasture re-growth between gratings, may be an effective method of parasite avoidance. Pasture heights need not be extreme for avoidance protection.
Secondly, this study indicates that dry non-pregnant does can be maintained in a medium body condition on high allowance of tall fescue without grain supplementation. The July- September BCS indicates a recovery from lactation and a maintenance of body condition at 2.0 (scale 1-5). However, weight gains were observed to be low to moderate.