تعيين واحد دامي و نياز علوفه روزانه گوسفند نژاد زل استفاده كننده از مراتع مازندران (مطالعه موردي : غرب مازندران )

Determination of Unit Animal Daily Forage Requirement for Sheep (Zel Race) Grazing in Mazandaran Rangelands (Case Study: West Mazandaran Rangelands)

To achieve an acceptable level of animal performance, a matching of animal feed requirement with the needed quantity of forage, with due attention to forage quality, is essential. In this study, feed requirement of Zel race sheep, grazing on mazandaran rangelands was estimated. For calculation of the ratio of ram to ram + lamb a number of 10 rams, ten 3-month old and ten 6-month old lambs were weighted, the respective weights being recorded and then used. Overall average sheep weight was found as 30.48 kgs. The average weight for the ten rams, ten 3, and ten 6-month old rams were 47.67, 19.75, and 23.53 kgs respectively. The ratio of ram to sheep weight was found to be 1.56 and the ratio of 3 and 6-month old lambs to sheep (Zel race) were 0.67, and 0.7 respectively. For a determination of animal feed requirement, based on forage quality, samples of plant species in different phonological stages were taken for in-vitro analysis. Analysis and assessment of crude protein, digestibility and metabolizable energy were carried out. In vegetative phonological stage, the highest protein percentage was recorded for Medicago saliva whilst the highest metabolizable energy for Medicago coronata. Taking into account the distances between sheep yards and rangeland, topographic conditions, vegetation density, as well as distances between animal watering stations and additional 50% was added to the pre-calculated animal feed requirement, using the formula ME =1.8+0.1 W where W stands for live weight. Based upon forage quality in any of the phonological stages as well as plant nutritional composition, the daily forage requirement of unit animal was determined to be 0.8, 0.91, and 0.97 kgs/day in the plant phonological stages of vegetative, flowering and maturity, respectively.