Age and body condition score and diets of grazing goats

Abstract

Diet selection by juvenile and adult non -pregnant, non-lactating goats and the diets of adult non -productive goats with low (<1.5; grading scale 0-5) and moderate ( >_ 2.5) body condition score (BCS) are described by microhistological analysis of fecal samples for a Chihuahuan desert vegetation in northern Mexico. In the rainy season, adult goats utilized more (P < 0.10) shrubs than juvenile goats (70.4 vs 58.6 %), but, in the dry season, the diet of both groups contained equal amounts of shrubs. The proportion of forbs and grasses in the goats' diet also tended to vary (P < 0.10) between age groups in the rainy season. Juvenile goats generally had lower consumption of plants with spines than adult goats. Goats with low BCS selected more (P < 0.10) shrubs than goats with moderate BCS in the rainy season. Forbs were eaten in larger amounts by does with moderate BCS (38% of the diet) during the rainy season compared to goats with low BCS (30.9 %). Regardless of age and body reserves, grasses formed less than 5% of goat diets in both seasons. Mean similarity index for juvenile and adult goats was 75, while mean similarity index for goats with low and moderate BCS was 78. For all classes of goats, Larrea tridentata (DC.) Cov., the dominating species in the plant community, was the only plant selected at proportions below those found in ground cover in the rainy season. These data indicate that, during the rainy season, juvenile goats mixed their diets to achieve more even use of forages than adult goats. These results also indicate that high utilization of shrubs, including resinous and fibrous forages, appeared to be an adaptive foraging strategy of goats with low fat reserves, when forage was readily available.

Diets of Prairie Dogs, Goats, and Sheep on a Desert Rangeland

“…Grass was the least prevalent of the 3 forage classes in the goat diets, and although graminoids constituted an important part of goat diets, goats continued to follow a browsing strategy. Grass use by goats in our study was several times larger than that reported in shrub-dominated plant communities in arid zones (Sidahmed et al 1981;Mellado et al 1991Mellado et al , 2003Mellado et al , 2004, which reaffirms that goats are very flexible in the vegetation classes they consume. By looking at the selectivity indices, it was clear that grasses were not preferred items for goats.…”

“…Two forbs of singular importance for the 3 animal species throughout the year were S. elaeagnifolium and S. angustifolia, which made up 9, 12 and 10% of the prairie dog, goat and sheep diets, respectively (average across 4 seasons). The importance of these forage species for prairie dogs (Fagerstone et al 1977;Summers and Linder 1978;Uresk 1984) and goats (Mellado et al 2003(Mellado et al , 2004 has been previously reported. The trends for forbs in diets of the 3 kinds of animals and standing crop suggest that competition was intense throughout the study period.…”

The food habits of goats on rangelands with different amounts of fourwing saltbush (Atriplex canescens) cover

“…This finding agrees with the results of previous studies in this habitat (Mellado et al, 2003(Mellado et al, , 2004b. Solanum elaeagnifolium, a highly unpalatable forb (Mellado et al, 2008b), was preferred during the dry season (spring) by the goats in the control pasture.…”

“…Forbs usually become important components of goat diets if the availability of high-quality forbs is increased, normally during the rainy season (Mellado et al, 2003(Mellado et al, , 2004b. In the present study, the goats selected a higher (p < 0.01) proportion of forbs during the fall (the end of the rainy season) than during other seasons.…”

Diet selection and n-3 polyunsaturated fatty acid deposition in lambs as affected by restricted time at pasture

“…C. squarrosa is the main plant species in the experimental region, and was highly available to lambs; therefore it was a preferred diet component of lambs for both longer and shorter grazing times. Lambs/kids prefer to browse on fresh, young and palatable forages at pasture 14 , 15 . The high palatable and nutritional content of A. ramosum most likely accounted for it being strongly selected by lambs in July.…”