| Abstract | Vitamin A ima ključnu ulogu u imunitetu mlade teladi. Cilj ovog rada je utvrditi sadržaj retinola u plazmi sisajuće angus teladi i plazmi krava od poroda do 4. mjeseca starosti držanih u sustavu krava tele. Pokus je proveden na ekološkoj farmi goveda. Nasumično je izabrano 10 krava i njihova telad u čijoj je plazmi određivana koncentracija retinola. Krave su provele prvih 60 dana zatvorene u staji gdje su hranjene sa sijenom, sjenažom i soli u kamenu s vitaminom A. Od 60. do 90. dana krave su puštene na ispašu zajedno s teladi. Koncentracije retinola u plazmi teladi 1., 4., 31., 59. i 90. dana iznosile su 19,9, 23,1, 16,4, 19,5 i 34,1 μg/dL. Koncentracije retinola u plazmi krava 1., 4., 31., 59. i 90. dana iznosile su 24,3, 23,5, 24,4, 25,9, 39,3 μg/dL. Sijeno, sjenaža i vitaminsko mineralna sol sadržavale su dovoljno vitamina A da adekvatno opskrbe krave i telad. Nakon promjene hranidbe krava sa sijena i sjenaže na pašu primjećen je značajan porast retinola u plazmi krava i teladi. |
| Abstract (english) | Vitamin A has a vital role in the immunity of young calves. The aim of this study is to determine the retinol content in the plasma of angus calves and cows from birth until the age of 4 months in a cow-calf operation. The experiment took place on an organic cow farm. Ten cows and their calves were randomly selected and used to determine the retinol plasma concentrations. The cows spent the first 60 postnatal days in a stable where they were fed hay, haylage and rock salt containing vitamin A. After 60 days the cows were let out with their calves onto pastures for the next 30 days. The retinol concentrations in calf plasma on the 1st, 4th, 30th, 59th and 90th days were 19,9, 23,1, 16,4, 19,5 i 34,1 μg/dL. The retinol concentrations in cow plasma on the 1st, 4th, 30th, 59th and 90th days were 24,3, 23,5, 24,4, 25,9, 39,3 μg/dL. Hay, haylage and rock salt with vitamins contained enough vitamin A to adequately supply the cows and the calves. A significant rise of retinol concentrations in the cow and calf plasmas was noticed after feed changes were applied from hay and haylage to pasturage. |
