تاثیر سطوح مختلف مکمل آلی کبالت و نیاسین در جیره بر عملکرد گاوهای شیری

A study was performed to evaluate effects of dietary levels of organic cobalt and niacin supplementation (as glucoheptonate and nicotinic acid) on milk production and compositions of 12 multiparturient dairy cows in postpartum stage of early lactation period. Animals were assigned to a 44ا single Latin square cross over design randomly. Treatments and periods were 4 and the length of each period was 21 days which records were collected at the end of week 3 of each period. Duration of experiment was 84 days totally. Treatments were including: 10 Control group (without any supplement), 2. 30mg/day cobalt supplement, 3. 14g/day niacin supplement and 4. 30mg/day cobalt +14g/day niacin supplement. Milk samples were sending to lab every 21 days regularly. Also blood samples gathered from every cow via coccygeal vein and were sending to veterinary lab at the end of each period for analyzing of blood parameters such as glucose, BHB, NEFA, and vitamin B12. Results showed that cobalt and niacin supplementations had a significant effect on milk production (both noncorrected and corrected for 3,5 and 4 fat) (p<0,05). Also cobalt and niacin supplementations had a significant effect on milk compositions including protein, total solids, solid not fat percentage and total production of daily protein (p<0,05), but not on fat and lactose percentages and total production of daily fat. Blood parameters were changed using cobalt, niacin or cobalt + niacin supplementations positively and significantly (p<0,05). The cobalt + niacin supplementation had a reasonable effect on more performance traits and blood parameters.

کلیدواژه ها:

گاوهای شیری ، جیره های غذایی ، مکمل ها (غذایی) ، کبالت ، نیکوتین آمید