فهرست مطالب aboulfazl zali

Selenium, as an essential dietary trace element, has an important biological role in the health and growth performance of cows and dairy cows. The purpose of this study was to investigate the effects of replacing mineral selenium supplement with nano selenium particles in the feeding of suckling calves and its impacts on the growth performance and skeletal structure of suckling calves. The number of 32 newborn Holstein calves with an average body weight of 37.85 ± 4.35 kg in the form of a completely randomized design with 4 treatments (eight calves in each treatment) for 83 days according to the supplemental consumption of milk or drinking water with sources different selenium were placed. Treatments include: 1) inorganic selenium: providing 0.3 mg of selenium per kilogram of dry matter with sodium selenite, 2) low level of nano selenium: providing 0.15 mg of selenium per kilogram of dry matter with nanoparticles prepared from selenium, 3) Medium level of nano-selenium: providing 0.3 mg of selenium per kilogram of dry matter with nanoparticles prepared from selenium, 4) High level of nano-selenium: providing 0.45 mg of selenium per kilogram of dry matter with nanoparticles prepared from selenium. . The results showed that supplementing milk with selenium nanoparticles did not affect the performance of calves during the pre-weaning period, but significantly improved it after weaning compared to calves fed sodium selenite. So the daily gain and feed efficiency in the second period increased secondarily (p < 0.01) and the medium level was the highest

In this study، 32 multiparous non lactating Holstein cows were used to investigate the effects of chromium-l-methionine (Cr-Met) supplementation and dietary energy source on production and nutrient digestibility during the periparturient period. Cows were fed a total mixed ration from 28 days before anticipated calving through 28 days after calving. The study was designed as a randomized complete block design with 2 (energy sources) × 2 (Cr-Met levels) factorial arrangement. Energy sources in the prepartum were fish oil and grain، and were fish oil and palm fat powder in the postpartum. The Cr-Met was supplemented at dosages of 0 or 0. 08 mg of Cr/kg of metabolic body weight. Fish oil Supplementation had no significant effect on prepartum dry matter intake (DMI) but tended to decrease postpartum DMI (P< 0. 1). Supplemental Cr-Met increased prepartum and postpartum DMI significantly (P<0. 05). The effect of treatments on milk production was not significant. No differences were detected in milk composition except for fat percentage in which cows were fed the fish oil had lower percentage of fat compare to others. Supplemental Cr-Met had no significant effect on nutrient digestibility in the prepartum and postpartum. Use of fish oil had no effect on nutrient digestibility in the prepartum، but decreased digestibility of dry matter، organic matter، and crude protein in the postpartum (P<0. 05). Results of this study indicate no significant interaction between chromium supplementation and energy source.