Co-grazing of sheep and goats: Benefits and constraints

Co-grazing of sheep and goats has been practiced throughout history and is commonplace around the world. However, its benefits may not be fully appreciated and means to maximize them have not been extensively studied. Advantages of co-grazing of sheep and goats are derived primarily from differences in preferences for particular plant species and parts, abilities or willingness to consume forages that are not highly preferred and would have greater adverse effects on the other species, and physical capabilities to gain access to specific types of vegetation. Hence, the degree to which total stocking rate or carrying capacity is greater for co- versus mono-species grazing increases with increasing vegetation diversity and, concomitantly, decreasing dietary overlap. Perhaps the most important management decision pertaining to co-grazing is appropriate stocking rates. A simple ‘baseline’ or ‘starting point’ method of estimating co-grazing stocking rates is: (number with mono-species grazing×(100−% overlap)/100) + (number with mono-species grazing×(% overlap×0.5/100)). The equation is applied to both sheep and goats, with values added to determine the total stocking rate. Botanical composition and available forage mass are important determinants of numbers of both sheep and goats with mono-species grazing, and factors affecting nutrient requirements such as body weight and production state, preference for or willingness to consume forages present, and desired length of grazing will have impact as well. Previous experience with the particular grazing and animal conditions will aid in projecting mono-species stocking rates. Estimates of dietary overlap when co-grazing should be based on the most accurate method available, which in many instances may be prior experience or visual observation at different times of the day and in various seasons. However, the equation noted above has limitations. It assumes that intake of forages potentially consumed by each animal species is equal, which obviously is not always true. Furthermore, interactions between stocking rates when the two species graze together versus alone are not considered. Nonetheless, because of its simplicity, the method may have value in field settings, and illustrates the importance of browse plant species in many grazing systems and why management practices are frequently employed to maintain or increase their prevalence and vegetation diversity. © 2008 Elsevier B.V. All rights reserved.