The effect of pre-breeding vitamin E and selenium injection on reproductive performance, antioxidant status, and progesterone concentration in estrus-synchronized Mehraban ewes.

The present study was conducted to assess the effects of pre-breeding vitamin E and selenium (ESe) injections on the reproductive performance, antioxidant status, and serum progesterone (P4) concentration in estrus-synchronized Mehraban ewes. During the breeding season, 38 ewes (3-4 years) were divided into two groups (n = 18), and the synchronization of estrus was achieved by intravaginal insertion of 0.3 g progesterone CIDR device for 13 days followed by 350 IU eCG at CIDR withdrawal. Ewes were kept under pasture conditions and exposed to Mehraban rams 48 h following CIDR withdrawal. The experimental treatments were control and ESe injection. The ESe group was received three intramuscular (5 mL) injections of Ese (0.5 mg/mL of selenium as sodium selenite and 50 IU vitamin E as DL-α- tocopheryl) once every 2 weeks. Specifically, Ese was administered at 2 weeks before CIDR insertion, at the times of CIDR insertion and CIDR withdrawal. Fertility, prolificacy, lambing rate, and birth weight were recorded after parturition. Blood samples were collected at CIDR insertion, CIDR withdrawal, 5, 10, and 15 days after ram exposure. Fertility, prolificacy, lambing rate, and birth weight did not improve by Ese treatment, but viability of lambs was higher in ESe than control (P < 0.05). Serum total antioxidant capacity at day 5 and P4 at day 10 after ram exposure was higher in ESe than control (P < 0.05). In conclusion, sheep breeders can use ESe at CIDR insertion and withdrawal times to potentiate antioxidant status and progesterone profile of estrus-synchronized Mehraban ewes.

Effects of different sources of nitrogen on performance, relative population of rumen microorganisms, ruminal fermentation and blood parameters in male feedlotting lambs.

Slow-release urea (SRU) can substitute dietary protein sources in the diet of feedlotting ruminant species . However, different SRU structures show varying results of productive performance. This study was conducted to investigate the effect of different sources of nitrogen on performance, blood parameter, ruminal fermentation and relative population of rumen microorganisms in male Mehraban lambs. Thirty-five male lambs with an average initial BW of 34.7 ± 1.8 kg were assigned randomly to five treatments. Diets consisted of concentrate mixture and mineral and vitamin supplements plus (1) alfalfa and soybean meal, (2) wheat straw and soybean meal, (3) wheat straw and urea, (4) wheat straw and Optigen® (a commercial SRU supplement) and (5) wheat straw and SRU produced in the laboratory. No statistical difference was observed in animal performance and DM intake among treatments. The mean value of ruminal pH and ammonia was higher (P < 0.05) for the SRU diet compared with WU diet. The difference in pH is likely to be due to the higher ammonia level as VFAs concentrations were unchanged. The level of blood urea nitrogen (BUN) was different among treatments (P = 0.065). The highest concentration of BUN was recorded in Optigen diet (183.1 mg/l), whereas the lowest value was recorded in wheat straw-soybean meal diet (147 mg/l). The amount of albumin and total protein was not affected by the treatments. The relative population of total protozoa, Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminococcus albus in the SRU treatment was higher (P < 0.01) than that in urea treatment at 3 h post-feeding. During the period of lack of high-quality forage and in order to reduce dietary costs, low-quality forage with urea sources can be used in the diet. Results of microbial populations revealed that SRU can be used as a nitrogen source which can sustainably provide nitrogen for rumen microorganism without negative effects on the performance of feedlotting lambs.