Nutrient Value of Anagyris foetida L. at different growing stages (Case of Kesekaran, Gilan Gharb, Kermanshah rangelands)

Background: The stability of arid and semi-arid rangeland ecosystems is mostly affected its vegetation. Therefore, assessment of plant communities is necessary for protect these ecosystems. On the other hand, it is necessary to be aware of the variations in the nutritional value of plant species at different times of growth in estimating the production of available animal fodder throughout each habitat. By considering the appropriate time of forage harvesting of various plant species, while achieving the highest efficiency in the secondary production of livestock. It is possible to reduce the degradation caused by uncontrolled grazing in the rangelands as well. Therefore, the current study aimed to examine the nutritional value of Stinking wood (Anagyris foetida L.) at different stages of growth in its natural habitat. Materials and methods: For the study, we visited the species habitat in winter and spring. To analyze the vegetative content at different stages namely, vegetative growth, flowering and seeding were harvested. Dates were early January 2017for leaves harvesting, January 2017 for flowers and in mid-June 2018 at seed maturation. Thirty shrubs were used for the harvesting in the same year. Then, the samples were dried in the full shade and then placed in marked separate containers. It was sent to the laboratory at the right time to analyze the nutritional value of the forage. In the contemporary study, the chemical compounds of samples analysis with AOAC (1990) standard were used. The basic method for measuring the percentage of crude protein is the Kjeldahl method. This method is based on calculating the percentage of nitrogen in each nutriment and estimating the desired coefficient. The measurement of insoluble fibers in acid detergent (ADF) was performed by a raw fiber measuring device (fiberglass) of the Takator model. Moreover, an oven (incubator model) was applied to measure dry matter. The amount of metabolic energy per kilogram of dry matter was also determined from the equation provided by SCA (Standing Committee on Agriculture). Forage nutritional value data were analyzed in a completely randomized design. Results: The mean canopy cover of Stinking wood (A. foetida) includes 1531 m2/ha with a mean number of 322 individuals (and 32% of the presence over the habitat). In denser extents, mainly areas with lower altitudes on the northern slope, where these areas had relatively deeper and more fertile soil, the amount of canopy cover of Stinking wood sometimes reaches 6100 m2/ha. The results of variance analysis of chemical compounds showed the dry matter digestibility and energy estimation in different vegetative stages of Stinking wood in its natural habitat. The dry matter digestibility, crude protein, nitrogen, metabolic energy, and the number of insoluble fibers in acidic detergent factors are significant (p = 0.01). In addition, the study results of the different vegetative stage's effects on the D.M.D, C.P, N, and M.E percentage showed that their values decreased with the development of vegetative stages (p = 0.01). While the study results of the diverse vegetative stage's effect on the A.D.F percentage revealed that, their values increased with the development of vegetative stages (p = 0.01). Conclusion: The results showed that the nutritional value of Stinking wood (A. foetida) forage is higher in the vegetative growth stage than in the final stages of growth and seed stage. Therefore, the ideal time to use the Stinking wood (A. foetida) forage is in vegetative growth stage, which should be known as grazing time. Moreover, this species has the ability to be used to improve natural areas under change and on the verge of extinction. In addition to its unique characteristics, in times when the natural area is without vegetation, grazing on a habitat can prevent energy and weight loss, as well as financial burden to feed the cattle fodder.