بررسی وضعیت تغذیه‌ای گاوهای شیری در مناطق روستایی دو شهرستان اصفهان و برخوار - میمه

Eight hundred and fifty two multiparous Holstein cows in mid-lactation were used in a completely randomized and nested design with two treatments and three replications. Treatments were: 1) Isfahan and 2) Borkhar-Meymeh. Replications were: 1) class of one to five cows 2) class of six to ten cows and 3) class of eleven to twenty cows. Paired t-test was used for the comparison of nutrient consumption and requirement. The obtained results of one-year-old experiment indicated that township and different classes had no effect on consumption of dry matter intake (DMI), net energy lactating (NEL), metabolizable protein (MP), calcium (Ca), phosphorus (P), potassium (K), magnesium (Mg), sodium (Na), chlorine (Cl), sulphur (S), selenium (Se), zinc (Zn), copper (Cu), iodine (I), vitamin A, vitamin D, vitamin E, rumen degradable protein (RDP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and non-fiber carbohydrate (NFC). Township had a significant effect on consumption of rumen undegradable protein (RUP) (P<0/05). Township and different classes had no effect on nutrient requirements of dairy cattle. The difference between consumption and requirement for kg DMI, Mcal/d NEL, g Mp, (g absorbable) Ca, P, K, Mg, Na, Cl, S, mg per kg Se, Zn, Cu, I, Iu/d vitamin A, vitamin D, vitamin E, g/d RDP, RUP, percentage of dry matter NDF, ADF and NFC were -1/6, -2/5, -630/2, -21/8, -5, 40/6, 0, -3/3, 44/2, -7/4, -3/11, -38/7, -3/26, -4/45, -14834, -234, -342/5, -542/5, -886, 28/5, 17/5 and -10/4, respectively. The difference between consumption and requirement was not significant for P, Mg and Na. This difference had a significant effect on the rest of nutrients (P<0/05). The results of this study indicated that we can feed dairy cattle by using diets containing protein supplements and mineral-vitamin premix and improve milk yield and percentage of milk protein's rural areas of Holstein cows.